Last data update: Dec 09, 2024. (Total: 48320 publications since 2009)
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Primaquine for uncomplicated Plasmodium vivax malaria in children younger than 15 years: a systematic review and individual patient data meta-analysis
Commons RJ , Rajasekhar M , Allen EN , Yilma D , Chotsiri P , Abreha T , Adam I , Awab GR , Barber BE , Brasil LW , Chu CS , Cui L , Edler P , Gomes Mdsm , Gonzalez-Ceron L , Grigg MJ , Hamid MMA , Hwang J , Karunajeewa H , Lacerda MVG , Ladeia-Andrade S , Leslie T , Longley RJ , Monteiro WM , Pasaribu AP , Poespoprodjo JR , Richmond CL , Rijal KR , Taylor WRJ , Thanh PV , Thriemer K , Vieira JLF , White NJ , Zuluaga-Idarraga LM , Workman LJ , Tarning J , Stepniewska K , Guerin PJ , Simpson JA , Barnes KI , Price RN . Lancet Child Adolesc Health 2024 BACKGROUND: Primaquine, the only widely available treatment to prevent relapsing Plasmodium vivax malaria, is produced as 15 mg tablets, and new paediatric formulations are being developed. To inform the optimal primaquine dosing regimen for children, we aimed to determine the efficacy and safety of different primaquine dose strategies in children younger than 15 years. METHODS: We undertook a systematic review (Jan 1, 2000-July 26, 2024) for P vivax efficacy studies with at least one treatment group that was administered primaquine over multiple days, that enrolled children younger than 15 years, that followed up patients for at least 28 days, and that had data available for inclusion by June 30, 2022. Patients were excluded if they were aged 15 years or older, presented with severe malaria, received adjunctive antimalarials within 14 days of diagnosis, commenced primaquine more than 7 days after starting schizontocidal treatment, had a protocol violation in the original study, or were missing data on age, sex, or primaquine dose. Available individual patient data were collated and standardised. To evaluate efficacy, the risk of recurrent P vivax parasitaemia between days 7 and 180 was assessed by time-to-event analysis for different total mg/kg primaquine doses (low total dose of ∼3·5 mg/kg and high total dose of ∼7 mg/kg). To evaluate tolerability and safety, the following were assessed by daily mg/kg primaquine dose (low daily dose of ∼0·25 mg/kg, intermediate daily dose of ∼0·5 mg/kg, and high daily dose of ∼1 mg/kg): gastrointestinal symptoms (vomiting, anorexia, or diarrhoea) on days 5-7, haemoglobin decrease of at least 25% to less than 7g/dL (severe haemolysis), absolute change in haemoglobin from day 0 to days 2-3 or days 5-7, and any serious adverse events within 28 days. This study is registered with PROSPERO, CRD42021278085. FINDINGS: In total, 3514 children from 27 studies and 15 countries were included. The cumulative incidence of recurrence by day 180 was 51·4% (95% CI 47·0-55·9) following treatment without primaquine, 16·0% (12·4-20·3) following a low total dose of primaquine, and 10·2% (8·4-12·3) following a high total dose of primaquine. The hazard of recurrent P vivax parasitaemia in children younger than 15 years was reduced following primaquine at low total doses (adjusted hazard ratio [HR] 0·17, 95% CI 0·11-0·25) and high total doses (0·09, 0·07-0·12), compared with no primaquine. In 525 children younger than 5 years, the relative rates of recurrence were also reduced, with an adjusted HR of 0·33 (95% CI 0·18-0·59) for a low total dose and 0·13 (0·08-0·21) for a high total dose of primaquine compared with no primaquine. The rate of recurrence following a high total dose was reduced compared with a low dose in children younger than 15 years (adjusted HR 0·54, 95% CI 0·35-0·85) and children younger than 5 years (0·41, 0·21-0·78). Compared with no primaquine, children treated with any dose of primaquine had a greater risk of gastrointestinal symptoms on days 5-7 after adjustment for confounders, with adjusted risks of 3·9% (95% CI 0-8·6) in children not treated with primaquine, 9·2% (0-18·7) with a low daily dose of primaquine, 6·8% (1·7-12·0) with an intermediate daily dose of primaquine, and 9·6% (4·8-14·3) with a high daily dose of primaquine. In children with 30% or higher glucose-6-phosphate dehydrogenase (G6PD) activity, there were few episodes of severe haemolysis following no primaquine (0·4%, 95% CI 0·1-1·5), a low daily dose (0·0%, 0·0-1·6), an intermediate daily dose (0·5%, 0·1-1·4), or a high daily dose (0·7%, 0·2-1·9). Of 15 possibly drug-related serious adverse events in children, two occurred following a low, four following an intermediate, and nine following a high daily dose of primaquine. INTERPRETATION: A high total dose of primaquine was highly efficacious in reducing recurrent P vivax parasitaemia in children compared with a low dose, particularly in children younger than 5 years. In children treated with high and intermediate daily primaquine doses compared with low daily doses, there was no increase in gastrointestinal symptoms or haemolysis (in children with 30% or higher G6PD activity), but there were more serious adverse events. FUNDING: Medicines for Malaria Venture, Bill & Melinda Gates Foundation, and Australian National Health and Medical Research Council. |
Association between chlorine-treated drinking water, the gut microbiome, and enteric pathogen burden in young children in Haiti: an observational study
Chac D , Slater DM , Guillaume Y , Dunmire CN , Ternier R , Vissières K , Juin S , Lucien MAB , Boncy J , Sanchez VM , Dumayas MG , Augustin GC , Bhuiyan TR , Qadri F , Chowdhury F , Khan AI , Weil AA , Ivers LC , Harris JB . Int J Infect Dis 2024 107165 OBJECTIVE: The effects of sanitation and hygiene interventions on the gut microbiome and enteric pathogen burden are not well understood. We measured the association between free chlorine residue (FCR) levels in drinking water, microbiome composition, and stool enteric pathogens in infants and young children in Haiti. METHODS: FCR levels were measured in household drinking water and enteric pathogen burden was evaluated using multiplex RT-PCR of stool among 131 children from one month to five years of age living in Mirebalais, Haiti. Microbiome profiling was performed using metagenomic sequencing. RESULTS: Most individuals lived in households with undetectable FCR measured in the drinking water (112/131, 86%). Detection of enteric pathogen DNA in stool was common and did not correlate with household water FCR. The infant microbiome in households with detectable FCR demonstrated reduced richness (fewer total number of species, P=0.04 Kruskall-Wallis test) and less diversity by Inverse Simpson measures (P=0.05) than households with undetectable FCR. Infants in households with a detectable FCR were more likely to have abundant Bifidobacterium. Using in vitro susceptibility testing, we found that some Bifidobacterium species were resistant to chlorine. CONCLUSIONS: FCR in household drinking water did not correlate with enteric pathogen burden in our study. |
Innate immune activation restricts priming and protective efficacy of the radiation-attenuated PfSPZ malaria vaccine
Senkpeil L , Bhardwaj J , Little MR , Holla P , Upadhye A , Fusco EM , Swanson Ii PA , Wiegand RE , Macklin MD , Bi K , Flynn BJ , Yamamoto A , Gaskin EL , Sather DN , Oblak AL , Simpson E , Gao H , Haining WN , Yates KB , Liu X , Murshedkar T , Richie TL , Sim BKL , Otieno K , Kariuki S , Xuei X , Liu Y , Polidoro RB , Hoffman SL , Oneko M , Steinhardt LC , Schmidt NW , Seder RA , Tran TM . JCI Insight 2024 A systems analysis was conducted to determine the potential molecular mechanisms underlying differential immunogenicity and protective efficacy results of a clinical trial of the radiation-attenuated whole sporozoite PfSPZ Vaccine in African infants. Innate immune activation and myeloid signatures at pre-vaccination baseline correlated with protection from Pf parasitemia in placebo controls. These same signatures were associated with susceptibility to parasitemia among infants who received the highest and most protective PfSPZ Vaccine dose. Machine learning identified spliceosome, proteosome, and resting dendritic cell signatures as pre-vaccination features predictive of protection after highest-dose PfSPZ vaccination, whereas baseline CSP-specific IgG predicted non-protection. Pre-vaccination innate inflammatory and myeloid signatures were associated with higher sporozoite-specific IgG Ab response but undetectable PfSPZ-specific CD8+ T-cell responses post-vaccination. Consistent with these human data, innate stimulation in vivo conferred protection against infection by sporozoite injection in malaria-naïve mice while diminishing the CD8+ T-cell response to radiation-attenuated sporozoites. These data suggest a dichotomous role of innate stimulation for malaria protection and induction of protective immunity of whole-sporozoite malaria vaccines. The uncoupling of vaccine-induced protective immunity achieved by Abs from more protective CD8+ T cell responses suggest that PfSPZ Vaccine efficacy in malaria-endemic settings may be constrained by opposing antigen presentation pathways. |
Rapid outbreak sequencing of Ebola virus in Sierra Leone identifies transmission chains linked to sporadic cases.
Arias A , Watson SJ , Asogun D , Tobin EA , Lu J , Phan MVT , Jah U , Wadoum REG , Meredith L , Thorne L , Caddy S , Tarawalie A , Langat P , Dudas G , Faria NR , Dellicour S , Kamara A , Kargbo B , Kamara BO , Gevao S , Cooper D , Newport M , Horby P , Dunning J , Sahr F , Brooks T , Simpson AJH , Groppelli E , Liu G , Mulakken N , Rhodes K , Akpablie J , Yoti Z , Lamunu M , Vitto E , Otim P , Owilli C , Boateng I , Okoror L , Omomoh E , Oyakhilome J , Omiunu R , Yemisis I , Adomeh D , Ehikhiametalor S , Akhilomen P , Aire C , Kurth A , Cook N , Baumann J , Gabriel M , Wölfel R , Di Caro A , Carroll MW , Günther S , Redd J , Naidoo D , Pybus OG , Rambaut A , Kellam P , Goodfellow I , Cotten M . Virus Evol 2016 2 (1) vew016 To end the largest known outbreak of Ebola virus disease (EVD) in West Africa and to prevent new transmissions, rapid epidemiological tracing of cases and contacts was required. The ability to quickly identify unknown sources and chains of transmission is key to ending the EVD epidemic and of even greater importance in the context of recent reports of Ebola virus (EBOV) persistence in survivors. Phylogenetic analysis of complete EBOV genomes can provide important information on the source of any new infection. A local deep sequencing facility was established at the Mateneh Ebola Treatment Centre in central Sierra Leone. The facility included all wetlab and computational resources to rapidly process EBOV diagnostic samples into full genome sequences. We produced 554 EBOV genomes from EVD cases across Sierra Leone. These genomes provided a detailed description of EBOV evolution and facilitated phylogenetic tracking of new EVD cases. Importantly, we show that linked genomic and epidemiological data can not only support contact tracing but also identify unconventional transmission chains involving body fluids, including semen. Rapid EBOV genome sequencing, when linked to epidemiological information and a comprehensive database of virus sequences across the outbreak, provided a powerful tool for public health epidemic control efforts. |
Effect of primaquine dose on the risk of recurrence in patients with uncomplicated Plasmodium vivax: a systematic review and individual patient data meta-analysis
Commons RJ , Rajasekhar M , Edler P , Abreha T , Awab GR , Baird JK , Barber BE , Chu CS , Cui L , Daher A , Gonzalez-Ceron L , Grigg MJ , Hwang J , Karunajeewa H , Lacerda MVG , Ladeia-Andrade S , Lidia K , Llanos-Cuentas A , Longley RJ , Pereira DB , Pasaribu AP , Pukrittayakamee S , Rijal KR , Sutanto I , Taylor WRJ , Thanh PV , Thriemer K , Vieira JLF , Watson JA , Zuluaga-Idarraga LM , White NJ , Guerin PJ , Simpson JA , Price RN . Lancet Infect Dis 2023 BACKGROUND: Primaquine is used to eliminate Plasmodium vivax hypnozoites, but its optimal dosing regimen remains unclear. We undertook a systematic review and individual patient data meta-analysis to investigate the efficacy and tolerability of different primaquine dosing regimens to prevent P vivax recurrence. METHODS: For this systematic review and individual patient data meta-analysis, we searched MEDLINE, Web of Science, Embase, and Cochrane Central for prospective clinical studies of uncomplicated P vivax from endemic countries published between Jan 1, 2000, and June 8, 2023. We included studies if they had active follow-up of at least 28 days, and if they included a treatment group with daily primaquine given over multiple days, where primaquine was commenced within 7 days of schizontocidal treatment and was given alone or coadministered with chloroquine or one of four artemisinin-based combination therapies (ie, artemether-lumefantrine, artesunate-mefloquine, artesunate-amodiaquine, or dihydroartemisinin-piperaquine). We excluded studies if they were on prevention, prophylaxis, or patients with severe malaria, or if data were extracted retrospectively from medical records outside of a planned trial. For the meta-analysis, we contacted the investigators of eligible trials to request individual patient data and we then pooled data that were made available by Aug 23, 2021. We assessed the effects of total dose and duration of primaquine regimens on the rate of first P vivax recurrence between day 7 and day 180 by Cox's proportional hazards regression (efficacy analysis). The effect of primaquine daily dose on gastrointestinal symptoms on days 5-7 was assessed by modified Poisson regression (tolerability analysis). The study was registered with PROSPERO, CRD42019154470. FINDINGS: Of 226 identified studies, 23 studies with patient-level data from 6879 patients from 16 countries were included in the efficacy analysis. At day 180, the risk of recurrence was 51·0% (95% CI 48·2-53·9) in 1470 patients treated without primaquine, 19·3% (16·9-21·9) in 2569 patients treated with a low total dose of primaquine (approximately 3·5 mg/kg), and 8·1% (7·0-9·4) in 2811 patients treated with a high total dose of primaquine (approximately 7 mg/kg), regardless of primaquine treatment duration. Compared with treatment without primaquine, the rate of P vivax recurrence was lower after treatment with low-dose primaquine (adjusted hazard ratio 0·21, 95% CI 0·17-0·27; p<0·0001) and high-dose primaquine (0·10, 0·08-0·12; p<0·0001). High-dose primaquine had greater efficacy than low-dose primaquine in regions with high and low relapse periodicity (ie, the time from initial infection to vivax relapse). 16 studies with patient-level data from 5609 patients from ten countries were included in the tolerability analysis. Gastrointestinal symptoms on days 5-7 were reported by 4·0% (95% CI 0·0-8·7) of 893 patients treated without primaquine, 6·2% (0·5-12·0) of 737 patients treated with a low daily dose of primaquine (approximately 0·25 mg/kg per day), 5·9% (1·8-10·1) of 1123 patients treated with an intermediate daily dose (approximately 0·5 mg/kg per day) and 10·9% (5·7-16·1) of 1178 patients treated with a high daily dose (approximately 1 mg/kg per day). 20 of 23 studies included in the efficacy analysis and 15 of 16 in the tolerability analysis had a low or unclear risk of bias. INTERPRETATION: Increasing the total dose of primaquine from 3·5 mg/kg to 7 mg/kg can reduce P vivax recurrences by more than 50% in most endemic regions, with a small associated increase in gastrointestinal symptoms. FUNDING: Australian National Health and Medical Research Council, Bill & Melinda Gates Foundation, and Medicines for Malaria Venture. |
Effect of adherence to primaquine on the risk of Plasmodium vivax recurrence: a WorldWide Antimalarial Resistance Network systematic review and individual patient data meta-analysis
Mehdipour P , Rajasekhar M , Dini S , Zaloumis S , Abreha T , Adam I , Awab GR , Baird JK , Brasil LW , Chu CS , Cui L , Daher A , do Socorro MGomes M , Gonzalez-Ceron L , Hwang J , Karunajeewa H , Lacerda MVG , Ladeia-Andrade S , Leslie T , Ley B , Lidia K , Llanos-Cuentas A , Longley RJ , Monteiro WM , Pereira DB , Rijal KR , Saravu K , Sutanto I , Taylor WRJ , Thanh PV , Thriemer K , Vieira JLF , White NJ , Zuluaga-Idarraga LM , Guerin PJ , Price RN , Simpson JA , Commons RJ . Malar J 2023 22 (1) 306 BACKGROUND: Imperfect adherence is a major barrier to effective primaquine radical cure of Plasmodium vivax. This study investigated the effect of reduced adherence on the risk of P. vivax recurrence. METHODS: Efficacy studies of patients with uncomplicated P. vivax malaria, including a treatment arm with daily primaquine, published between January 1999 and March 2020 were identified. Individual patient data from eligible studies were pooled using standardized methodology. Adherence to primaquine was inferred from i) the percentage of supervised doses and ii) the total mg/kg dose received compared to the target total mg/kg dose per protocol. The effect of adherence to primaquine on the incidence of P. vivax recurrence between days 7 and 90 was investigated by Cox regression analysis. RESULTS: Of 82 eligible studies, 32 were available including 6917 patients from 18 countries. For adherence assessed by percentage of supervised primaquine, 2790 patients (40.3%) had poor adherence (≤ 50%) and 4127 (59.7%) had complete adherence. The risk of recurrence by day 90 was 14.0% [95% confidence interval: 12.1-16.1] in patients with poor adherence compared to 5.8% [5.0-6.7] following full adherence; p = 0.014. After controlling for age, sex, baseline parasitaemia, and total primaquine dose per protocol, the rate of the first recurrence was higher following poor adherence compared to patients with full adherence (adjusted hazard ratio (AHR) = 2.3 [1.8-2.9]). When adherence was quantified by total mg/kg dose received among 3706 patients, 347 (9.4%) had poor adherence, 88 (2.4%) had moderate adherence, and 3271 (88.2%) had complete adherence to treatment. The risks of recurrence by day 90 were 8.2% [4.3-15.2] in patients with poor adherence and 4.9% [4.1-5.8] in patients with full adherence; p < 0.001. CONCLUSION: Reduced adherence, including less supervision, increases the risk of vivax recurrence. |
Primaquine dose and the risk of haemolysis in patients with uncomplicated Plasmodium vivax malaria: a systematic review and individual patient data meta-analysis
Rajasekhar M , Simpson JA , Ley B , Edler P , Chu CS , Abreha T , Awab GR , Baird JK , Bancone G , Barber BE , Grigg MJ , Hwang J , Karunajeewa H , Lacerda MVG , Ladeia-Andrade S , Llanos-Cuentas A , Pukrittayakamee S , Rijal KR , Saravu K , Sutanto I , Taylor WRJ , Thriemer K , Watson JA , Guerin PJ , White NJ , Price RN , Commons RJ . Lancet Infect Dis 2023 BACKGROUND: Primaquine radical cure is used to treat dormant liver-stage parasites and prevent relapsing Plasmodium vivax malaria but is limited by concerns of haemolysis. We undertook a systematic review and individual patient data meta-analysis to investigate the haematological safety of different primaquine regimens for P vivax radical cure. METHODS: For this systematic review and individual patient data meta-analysis, we searched MEDLINE, Web of Science, Embase, and Cochrane Central for prospective clinical studies of uncomplicated P vivax from endemic countries published between Jan 1, 2000, and June 8, 2023. We included studies if they had active follow-up of at least 28 days, if they included a treatment group with daily primaquine given over multiple days where primaquine was commenced within 3 days of schizontocidal treatment and was given alone or coadministered with chloroquine or one of four artemisinin-based combination therapies (ie, artemether-lumefantrine, artesunate-mefloquine, artesunate-amodiaquine, or dihydroartemisinin-piperaquine), and if they recorded haemoglobin or haematocrit concentrations on day 0. We excluded studies if they were on prevention, prophylaxis, or patients with severe malaria, or if data were extracted retrospectively from medical records outside of a planned trial. For the meta-analysis, we contacted the investigators of eligible trials to request individual patient data and we then pooled data that were made available by Aug 23, 2021. The main outcome was haemoglobin reduction of more than 25% to a concentration of less than 7 g/dL by day 14. Haemoglobin concentration changes between day 0 and days 2-3 and between day 0 and days 5-7 were assessed by mixed-effects linear regression for patients with glucose-6-phosphate dehydrogenase (G6PD) activity of (1) 30% or higher and (2) between 30% and less than 70%. The study was registered with PROSPERO, CRD42019154470 and CRD42022303680. FINDINGS: Of 226 identified studies, 18 studies with patient-level data from 5462 patients from 15 countries were included in the analysis. A haemoglobin reduction of more than 25% to a concentration of less than 7 g/dL occurred in one (0·1%) of 1208 patients treated without primaquine, none of 893 patients treated with a low daily dose of primaquine (<0·375 mg/kg per day), five (0·3%) of 1464 patients treated with an intermediate daily dose (0·375 mg/kg per day to <0·75 mg/kg per day), and six (0·5%) of 1269 patients treated with a high daily dose (≥0·75 mg/kg per day). The covariate-adjusted mean estimated haemoglobin changes at days 2-3 were -0·6 g/dL (95% CI -0·7 to -0·5), -0·7 g/dL (-0·8 to -0·5), -0·6 g/dL (-0·7 to -0·4), and -0·5 g/dL (-0·7 to -0·4), respectively. In 51 patients with G6PD activity between 30% and less than 70%, the adjusted mean haemoglobin concentration on days 2-3 decreased as G6PD activity decreased; two patients in this group who were treated with a high daily dose of primaquine had a reduction of more than 25% to a concentration of less than 7 g/dL. 17 of 18 included studies had a low or unclear risk of bias. INTERPRETATION: Treatment of patients with G6PD activity of 30% or higher with 0·25-0·5 mg/kg per day primaquine regimens and patients with G6PD activity of 70% or higher with 0·25-1 mg/kg per day regimens were associated with similar risks of haemolysis to those in patients treated without primaquine, supporting the safe use of primaquine radical cure at these doses. FUNDING: Australian National Health and Medical Research Council, Bill & Melinda Gates Foundation, and Medicines for Malaria Venture. |
Genital tract microbiome dynamics are associated with time of Chlamydia infection (preprint)
Zhao L , Lundy SR , Eko FO , Igietseme JU , Omosun YO . bioRxiv 2022 19 Background: We have previously shown that the time of Chlamydia infection was crucial in determining the chlamydial infectivity and pathogenesis. This study aims to determine whether the time of Chlamydia infection affects the genital tract microbiome. This study analyzed mice vaginal, uterine, and ovary/oviduct microbiome with and without Chlamydia infection. The mice were infected with Chlamydia at either 10:00 am (ZT3) or 10:00 pm (ZT15). Result(s): The results showed that mice infected at ZT3 had higher Chlamydia infectivity than those infected at ZT15. There was more variation in the compositional complexity of the vaginal microbiome (alpha diversity) of mice infected at ZT3 than those mice infected at ZT15 throughout the infection within each treatment group, with both Shannon and Simpson diversity index values decreased over time. The analysis of samples collected four weeks post-infection showed that there were significant taxonomical differences (beta diversity) between different parts of the genital tract-vagina, uterus, and ovary/oviduct-and this difference was associated with the time of infection. Firmicutes and Proteobacteria were the most abundant phyla within the microbiome in all three genital tract regions for all the samples collected during this experiment. Additionally, Firmicutes was the dominant phylum in the uterine microbiome of ZT3 Chlamydia infected mice. Conclusion(s): The results show that the time of infection is associated with the microbial dynamics in the genital tract. And this association is more robust in the upper genital tract than in the vagina. This result implies that more emphasis should be placed on understanding the changes in the microbial dynamics of the upper genital tract over the course of infection. Copyright The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license. |
Genital tract microbiome dynamics are associated with time of Chlamydia infection in mice
Zhao L , Lundy SR , Eko FO , Igietseme JU , Omosun YO . Sci Rep 2023 13 (1) 9006 We have previously shown that the time of Chlamydia infection was crucial in determining the chlamydial infectivity and pathogenesis. This study aims to determine whether the time of Chlamydia infection affects the genital tract microbiome. This study analyzed mice vaginal, uterine, and ovary/oviduct microbiome with and without Chlamydia infection. The mice were infected with Chlamydia at either 10:00 am (ZT3) or 10:00 pm (ZT15). The results showed that mice infected at ZT3 had higher Chlamydia infectivity than those infected at ZT15. There was more variation in the compositional complexity of the vaginal microbiome (alpha diversity) of mice infected at ZT3 than those mice infected at ZT15 throughout the infection within each treatment group, with both Shannon and Simpson diversity index values decreased over time. The analysis of samples collected four weeks post-infection showed that there were significant taxonomical differences (beta diversity) between different parts of the genital tract-vagina, uterus, and ovary/oviduct-and this difference was associated with the time of infection. Firmicutes and Proteobacteria were the most abundant phyla within the microbiome in all three genital tract regions for all the samples collected during this experiment. Additionally, Firmicutes was the dominant phylum in the uterine microbiome of ZT3 Chlamydia infected mice. The results show that the time of infection is associated with the microbial dynamics in the genital tract. And this association is more robust in the upper genital tract than in the vagina. This result implies that more emphasis should be placed on understanding the changes in the microbial dynamics of the upper genital tract over the course of infection. |
In silico toxicology protocols.
Myatt GJ , Ahlberg E , Akahori Y , Allen D , Amberg A , Anger LT , Aptula A , Auerbach S , Beilke L , Bellion P , Benigni R , Bercu J , Booth ED , Bower D , Brigo A , Burden N , Cammerer Z , Cronin MTD , Cross KP , Custer L , Dettwiler M , Dobo K , Ford KA , Fortin MC , Gad-McDonald SE , Gellatly N , Gervais V , Glover KP , Glowienke S , Van Gompel J , Gutsell S , Hardy B , Harvey JS , Hillegass J , Honma M , Hsieh JH , Hsu CW , Hughes K , Johnson C , Jolly R , Jones D , Kemper R , Kenyon MO , Kim MT , Kruhlak NL , Kulkarni SA , Kümmerer K , Leavitt P , Majer B , Masten S , Miller S , Moser J , Mumtaz M , Muster W , Neilson L , Oprea TI , Patlewicz G , Paulino A , Lo Piparo E , Powley M , Quigley DP , Reddy MV , Richarz AN , Ruiz P , Schilter B , Serafimova R , Simpson W , Stavitskaya L , Stidl R , Suarez-Rodriguez D , Szabo DT , Teasdale A , Trejo-Martin A , Valentin JP , Vuorinen A , Wall BA , Watts P , White AT , Wichard J , Witt KL , Woolley A , Woolley D , Zwickl C , Hasselgren C . Regul Toxicol Pharmacol 2018 96 1-17 The present publication surveys several applications of in silico (i.e., computational) toxicology approaches across different industries and institutions. It highlights the need to develop standardized protocols when conducting toxicity-related predictions. This contribution articulates the information needed for protocols to support in silico predictions for major toxicological endpoints of concern (e.g., genetic toxicity, carcinogenicity, acute toxicity, reproductive toxicity, developmental toxicity) across several industries and regulatory bodies. Such novel in silico toxicology (IST) protocols, when fully developed and implemented, will ensure in silico toxicological assessments are performed and evaluated in a consistent, reproducible, and well-documented manner across industries and regulatory bodies to support wider uptake and acceptance of the approaches. The development of IST protocols is an initiative developed through a collaboration among an international consortium to reflect the state-of-the-art in in silico toxicology for hazard identification and characterization. A general outline for describing the development of such protocols is included and it is based on in silico predictions and/or available experimental data for a defined series of relevant toxicological effects or mechanisms. The publication presents a novel approach for determining the reliability of in silico predictions alongside experimental data. In addition, we discuss how to determine the level of confidence in the assessment based on the relevance and reliability of the information. |
Factors Associated With Severe Illness in Patients Aged <21 Years Hospitalized for COVID-19.
Choudhary R , Webber BJ , Womack LS , Dupont HK , Chiu SK , Wanga V , Gerdes ME , Hsu S , Shi DS , Dulski TM , Idubor OI , Wendel AM , Agathis NT , Anderson K , Boyles T , Click ES , Silva JD , Evans ME , Gold JAW , Haston JC , Logan P , Maloney SA , Martinez M , Natarajan P , Spicer KB , Swancutt M , Stevens VA , Rogers-Brown J , Chandra G , Light M , Barr FE , Snowden J , Kociolek LK , McHugh M , Wessel DL , Simpson JN , Gorman KC , Breslin KA , DeBiasi RL , Thompson A , Kline MW , Boom JA , Singh IR , Dowlin M , Wietecha M , Schweitzer B , Morris SB , Koumans EH , Ko JY , Siegel DA , Kimball AA . Hosp Pediatr 2022 12 (9) 760-783 OBJECTIVES: To describe COVID-19-related pediatric hospitalizations during a period of B.1.617.2 (Delta) variant predominance and to determine age-specific factors associated with severe illness. PATIENTS AND METHODS: We abstracted data from medical charts to conduct a cross-sectional study of patients aged <21 years hospitalized at 6 US children's hospitals during July-August 2021 for COVID-19 or with an incidental positive SARS-CoV-2 test. Among patients with COVID-19, we assessed factors associated with severe illness by calculating age-stratified prevalence ratios (PR). We defined severe illness as receiving high-flow nasal cannula, positive airway pressure, or invasive mechanical ventilation. RESULTS: Of 947 hospitalized patients, 759 (80.1%) had COVID-19, of whom 287 (37.8%) had severe illness. Factors associated with severe illness included coinfection with RSV (PR 3.64) and bacteria (PR 1.88) in infants; RSV coinfection in patients aged 1-4 years (PR 1.96); and obesity in patients aged 5-11 (PR 2.20) and 12-17 years (PR 2.48). Having ≥2 underlying medical conditions was associated with severe illness in patients aged <1 (PR 1.82), 5-11 (PR 3.72), and 12-17 years (PR 3.19). CONCLUSIONS: Among patients hospitalized for COVID-19, factors associated with severe illness included RSV coinfection in those aged <5 years, obesity in those aged 5-17 years, and other underlying conditions for all age groups <18 years. These findings can inform pediatric practice, risk communication, and prevention strategies, including vaccination against COVID-19. |
Preservation of lymphocyte functional fitness in perinatally-infected and treated HIV+ pediatric patients displaying sub-optimal viral control
Khanolkar A , Muller WJ , Simpson BM , Cerullo J , Williams R , Sowers SB , Matthews K , Mercader S , Hickman CJ , D'Aquila RT , Liu G . Commun Med (Lond) 2022 2 BACKGROUND: Host-pathogen dynamics associated with HIV infection are quite distinct in children versus adults. We interrogated the functional fitness of the lymphocyte responses in two cohorts of perinatally infected HIV+ pediatric subjects with early anti-retroviral therapy (ART) initiation but divergent patterns of virologic control. We hypothesized that sub-optimal viral control would compromise immune functional fitness. METHODS: The immune responses in the two HIV+ cohorts (n = 6 in each cohort) were benchmarked against the responses measured in age-range matched, uninfected healthy control subjects (n = 11) by utilizing tests for normality, and comparison [the Kruskal-Wallis test, and the two-tailed Mann-Whitney U test (where appropriate)]. Lymphocyte responses were examined by intra-cellular cytokine secretion, degranulation assays as well as phosflow. A subset of these data were further queried by an automated clustering algorithm. Finally, we evaluated the humoral immune responses to four childhood vaccines in all three cohorts. RESULTS: We demonstrate that contrary to expectations pediatric HIV+ patients with sub-optimal viral control display no significant deficits in immune functional fitness. In fact, the patients that display better virologic control lack functional Gag-specific T cell responses and compared to healthy controls they display signaling deficits and an enrichment of mitogen-stimulated CD3 negative and positive lymphocyte clusters with suppressed cytokine production. CONCLUSIONS: These results highlight the immune resilience in HIV+ children on ART with sub-optimal viral control. With respect to HIV+ children on ART with better viral control, our data suggest that this cohort might potentially benefit from targeted interventions that might mitigate cell-mediated immune functional quiescence. |
Studying the post-COVID-19 condition: research challenges, strategies, and importance of Core Outcome Set development.
Munblit D , Nicholson TR , Needham DM , Seylanova N , Parr C , Chen J , Kokorina A , Sigfrid L , Buonsenso D , Bhatnagar S , Thiruvengadam R , Parker AM , Preller J , Avdeev S , Klok FA , Tong A , Diaz JV , Groote W , Schiess N , Akrami A , Simpson F , Olliaro P , Apfelbacher C , Rosa RG , Chevinsky JR , Saydah S , Schmitt J , Guekht A , Gorst SL , Genuneit J , Reyes LF , Asmanov A , O'Hara ME , Scott JT , Michelen M , Stavropoulou C , Warner JO , Herridge M , Williamson PR . BMC Med 2022 20 (1) 50 BACKGROUND: A substantial portion of people with COVID-19 subsequently experience lasting symptoms including fatigue, shortness of breath, and neurological complaints such as cognitive dysfunction many months after acute infection. Emerging evidence suggests that this condition, commonly referred to as long COVID but also known as post-acute sequelae of SARS-CoV-2 infection (PASC) or post-COVID-19 condition, could become a significant global health burden. MAIN TEXT: While the number of studies investigating the post-COVID-19 condition is increasing, there is no agreement on how this new disease should be defined and diagnosed in clinical practice and what relevant outcomes to measure. There is an urgent need to optimise and standardise outcome measures for this important patient group both for clinical services and for research and to allow comparing and pooling of data. CONCLUSIONS: A Core Outcome Set for post-COVID-19 condition should be developed in the shortest time frame possible, for improvement in data quality, harmonisation, and comparability between different geographical locations. We call for a global initiative, involving all relevant partners, including, but not limited to, healthcare professionals, researchers, methodologists, patients, and caregivers. We urge coordinated actions aiming to develop a Core Outcome Set (COS) for post-COVID-19 condition in both the adult and paediatric populations. |
Characteristics and Clinical Outcomes of Children and Adolescents Aged <18 Years Hospitalized with COVID-19 - Six Hospitals, United States, July-August 2021.
Wanga V , Gerdes ME , Shi DS , Choudhary R , Dulski TM , Hsu S , Idubor OI , Webber BJ , Wendel AM , Agathis NT , Anderson K , Boyles T , Chiu SK , Click ES , Da Silva J , Dupont H , Evans M , Gold JAW , Haston J , Logan P , Maloney SA , Martinez M , Natarajan P , Spicer KB , Swancutt M , Stevens VA , Brown J , Chandra G , Light M , Barr FE , Snowden J , Kociolek LK , McHugh M , Wessel D , Simpson JN , Gorman KC , Breslin KA , DeBiasi RL , Thompson A , Kline MW , Bloom JA , Singh IR , Dowlin M , Wietecha M , Schweitzer B , Morris SB , Koumans EH , Ko JY , Kimball AA , Siegel DA . MMWR Morb Mortal Wkly Rep 2021 70 (5152) 1766-1772 During June 2021, the highly transmissible(†) B.1.617.2 (Delta) variant of SARS-CoV-2, the virus that causes COVID-19, became the predominant circulating strain in the United States. U.S. pediatric COVID-19-related hospitalizations increased during July-August 2021 following emergence of the Delta variant and peaked in September 2021.(§) As of May 12, 2021, CDC recommended COVID-19 vaccinations for persons aged ≥12 years,(¶) and on November 2, 2021, COVID-19 vaccinations were recommended for persons aged 5-11 years.** To date, clinical signs and symptoms, illness course, and factors contributing to hospitalizations during the period of Delta predominance have not been well described in pediatric patients. CDC partnered with six children's hospitals to review medical record data for patients aged <18 years with COVID-19-related hospitalizations during July-August 2021.(††) Among 915 patients identified, 713 (77.9%) were hospitalized for COVID-19 (acute COVID-19 as the primary or contributing reason for hospitalization), 177 (19.3%) had incidental positive SARS-CoV-2 test results (asymptomatic or mild infection unrelated to the reason for hospitalization), and 25 (2.7%) had multisystem inflammatory syndrome in children (MIS-C), a rare but serious inflammatory condition associated with COVID-19.(§§) Among the 713 patients hospitalized for COVID-19, 24.7% were aged <1 year, 17.1% were aged 1-4 years, 20.1% were aged 5-11 years, and 38.1% were aged 12-17 years. Approximately two thirds of patients (67.5%) had one or more underlying medical conditions, with obesity being the most common (32.4%); among patients aged 12-17 years, 61.4% had obesity. Among patients hospitalized for COVID-19, 15.8% had a viral coinfection(¶¶) (66.4% of whom had respiratory syncytial virus [RSV] infection). Approximately one third (33.9%) of patients aged <5 years hospitalized for COVID-19 had a viral coinfection. Among 272 vaccine-eligible (aged 12-17 years) patients hospitalized for COVID-19, one (0.4%) was fully vaccinated.*** Approximately one half (54.0%) of patients hospitalized for COVID-19 received oxygen support, 29.5% were admitted to the intensive care unit (ICU), and 1.5% died; of those requiring respiratory support, 14.5% required invasive mechanical ventilation (IMV). Among pediatric patients with COVID-19-related hospitalizations, many had severe illness and viral coinfections, and few vaccine-eligible patients hospitalized for COVID-19 were vaccinated, highlighting the importance of vaccination for those aged ≥5 years and other prevention strategies to protect children and adolescents from COVID-19, particularly those with underlying medical conditions. |
Application of MALDI-TOF mass spectrometry, and DNA sequencing-based SLST and MLST analysis for the identification of Cronobacter spp. isolated from environmental surveillance samples.
Sulaiman IM , Tang K , Segars K , Miranda N , Sulaiman N , Simpson S . Arch Microbiol 2021 203 (8) 4813-4820 Cronobacter spp. are emerging infectious foodborne bacteria that can cause acute meningitis and necrotizing enterocolitis in neonates and immunocompromised individuals. Although, little is known about its reservoirs or transmission routes, it has been linked to powdered infant formula worldwide. Three Cronobacter spp. (C. sakazakii, C. malonaticus, and C. turicensis) have been described as more virulent, and isolated frequently from infant meningitis cases. The estimated mortality rates are as high as 80% in infants. Thus, surveillance and typing of Cronobacter spp. isolated from food and environmental samples is essential to prevent contamination and spread of this pathogen. In this study, we have characterized 83 Cronobacter isolates recovered from various environmental samples by conventional microbiologic protocols. Species identification was accomplished by VITEK 2 system and real-time PCR analysis. Subsequently, these isolates were analyzed using VITEK MS system. Single locus sequence typing (SLST) was achieved by characterizing the regions of 16S rRNA and rpoB genes. Multilocus sequence typing (MLST) was performed by sequence characterization of seven housekeeping genes (atpD, fusA, glnS, gltB, gyrB, infB, and pps) using ABI 3500XL Genetic Analyzer. VITEK MS system identified, the majority of isolates as Cronobacter sakazakii with a high confidence value (99.9%). MLST analysis ascertained 12 distinct clonal complexes (CC1, CC4, CC8, CC13, CC17, CC21, CC31, CC40, CC52, CC64, CC73, and CC83) for the recovered C. sakazakii isolates. The results suggest that the MALDI-TOF MS is a reliable diagnostic tool for rapid species identification whereas 7-loci MLST is a powerful technique to discriminate and differentiate Cronobacter spp. isolates. |
Aspergillus versicolor Inhalation Triggers Neuroimmune, Glial, and Neuropeptide Transcriptional Changes.
Ladd TB , Johnson JAJr , Mumaw CL , Greve HJ , Xuei X , Simpson E , Barnes MA , Green BJ , Croston TL , Ahmed C , Lemons A , Beezhold DH , Block ML . ASN Neuro 2021 13 17590914211019886 Increasing evidence associates indoor fungal exposure with deleterious central nervous system (CNS) health, such as cognitive and emotional deficits in children and adults, but the specific mechanisms by which it might impact the brain are poorly understood. Mice were exposed to filtered air, heat-inactivated Aspergillus versicolor (3 × 10(5) spores), or viable A. versicolor (3 × 10(5) spores) via nose-only inhalation exposure 2 times per week for 1, 2, or 4 weeks. Analysis of cortex, midbrain, olfactory bulb, and cerebellum tissue from mice exposed to viable A. versicolor spores for 1, 2, and 4 weeks revealed significantly elevated pro-inflammatory (Tnf and Il1b) and glial activity (Gdnf and Cxc3r1) gene expression in several brain regions when compared to filtered air control, with the most consistent and pronounced neuroimmune response 48H following the 4-week exposure in the midbrain and frontal lobe. Bulk RNA-seq analysis of the midbrain tissue confirmed that 4 weeks of A. versicolor exposure resulted in significant transcriptional enrichment of several biological pathways compared to the filtered air control, including neuroinflammation, glial cell activation, and regulation of postsynaptic organization. Upregulation of Drd1, Penk, and Pdyn mRNA expression was confirmed in the 4-week A. versicolor exposed midbrain tissue, highlighting that gene expression important for neurotransmission was affected by repeated A. versicolor inhalation exposure. Taken together, these findings indicate that the brain can detect and respond to A. versicolor inhalation exposure with changes in neuroimmune and neurotransmission gene expression, providing much needed insight into how inhaled fungal exposures can affect CNS responses and regulate neuroimmune homeostasis. |
Aztreonam-Avibactam Susceptibility Testing Program for Metallo-Beta-Lactamase-Producing Enterobacterales in the Antibiotic Resistance Laboratory Network, March 2019 to December 2020.
Bhatnagar A , Boyd S , Sabour S , Bodnar J , Nazarian E , Peinovich N , Wagner C , Craft B , Vagnone PS , Simpson J , Stone VN , Therrien M , Bateman A , Lower D , Huang JY , Gumbis S , Lonsway D , Lutgring JD , Karlsson M , Brown AC . Antimicrob Agents Chemother 2021 65 (8) Aac0048621 Aztreonam-avibactam is a drug combination pending phase 3 clinical trials and is suggested for treatment of severe infections caused by metallo-beta-lactamase (MBL)-producing Enterobacterales by combining ceftazidime-avibactam and aztreonam. Beginning in 2019, four Antibiotic Resistance Laboratory Network regional laboratories offered aztreonam-avibactam susceptibility testing by broth microdilution. For 64 clinical isolates tested, the MIC(50) and MIC(90) of aztreonam-avibactam were 0.5/4 μg/mL and 8/4 μg/mL, respectively. Aztreonam-avibactam displayed potent in vitro activity against the MBL-producing Enterobacterales tested. |
Continued HPV vaccination in the face of unexpected challenges: A commentary on the rationale for an extended interval two-dose schedule.
Whitworth HS , Schiller J , Markowitz LE , Jit M , Brisson M , Simpson E , Watson-Jones D . Vaccine 2021 39 (6) 871-875 Existing human papillomavirus (HPV) vaccines are highly effective for prevention of HPV infection, the leading cause of cervical cancer and a significant cause of many other oral and anogenital cancers [1]. World Health Organization (WHO) has recommended including HPV vaccination of girls in national immunization programs since 2009 [2] and, in 2018, WHO’s Strategic Advisory Group of Experts (SAGE) on Immunization agreed that vaccination is the most critical intervention for cervical cancer elimination [3]. As of May 2020, 41% of low-and-middle income countries and 81% of high-income countries had introduced HPV vaccination [4]. Whilst a number of barriers exist to HPV vaccination programs, the worldwide HPV vaccine shortage is a current obstacle due to increasing demand. Expanding production capacity will take several years [5]. |
The risk of Plasmodium vivax parasitaemia after P. falciparum malaria: An individual patient data meta-analysis from the WorldWide Antimalarial Resistance Network
Hossain MS , Commons RJ , Douglas NM , Thriemer K , Alemayehu BH , Amaratunga C , Anvikar AR , Ashley EA , Asih PBS , Carrara VI , Lon C , D'Alessandro U , Davis TME , Dondorp AM , Edstein MD , Fairhurst RM , Ferreira MU , Hwang J , Janssens B , Karunajeewa H , Kiechel JR , Ladeia-Andrade S , Laman M , Mayxay M , McGready R , Moore BR , Mueller I , Newton PN , Thuy-Nhien NT , Noedl H , Nosten F , Phyo AP , Poespoprodjo JR , Saunders DL , Smithuis F , Spring MD , Stepniewska K , Suon S , Suputtamongkol Y , Syafruddin D , Tran HT , Valecha N , Van Herp M , Van Vugt M , White NJ , Guerin PJ , Simpson JA , Price RN . PLoS Med 2020 17 (11) e1003393 BACKGROUND: There is a high risk of Plasmodium vivax parasitaemia following treatment of falciparum malaria. Our study aimed to quantify this risk and the associated determinants using an individual patient data meta-analysis in order to identify populations in which a policy of universal radical cure, combining artemisinin-based combination therapy (ACT) with a hypnozoitocidal antimalarial drug, would be beneficial. METHODS AND FINDINGS: A systematic review of Medline, Embase, Web of Science, and the Cochrane Database of Systematic Reviews identified efficacy studies of uncomplicated falciparum malaria treated with ACT that were undertaken in regions coendemic for P. vivax between 1 January 1960 and 5 January 2018. Data from eligible studies were pooled using standardised methodology. The risk of P. vivax parasitaemia at days 42 and 63 and associated risk factors were investigated by multivariable Cox regression analyses. Study quality was assessed using a tool developed by the Joanna Briggs Institute. The study was registered in the International Prospective Register of Systematic Reviews (PROSPERO: CRD42018097400). In total, 42 studies enrolling 15,341 patients were included in the analysis, including 30 randomised controlled trials and 12 cohort studies. Overall, 14,146 (92.2%) patients had P. falciparum monoinfection and 1,195 (7.8%) mixed infection with P. falciparum and P. vivax. The median age was 17.0 years (interquartile range [IQR] = 9.0-29.0 years; range = 0-80 years), with 1,584 (10.3%) patients younger than 5 years. 2,711 (17.7%) patients were treated with artemether-lumefantrine (AL, 13 studies), 651 (4.2%) with artesunate-amodiaquine (AA, 6 studies), 7,340 (47.8%) with artesunate-mefloquine (AM, 25 studies), and 4,639 (30.2%) with dihydroartemisinin-piperaquine (DP, 16 studies). 14,537 patients (94.8%) were enrolled from the Asia-Pacific region, 684 (4.5%) from the Americas, and 120 (0.8%) from Africa. At day 42, the cumulative risk of vivax parasitaemia following treatment of P. falciparum was 31.1% (95% CI 28.9-33.4) after AL, 14.1% (95% CI 10.8-18.3) after AA, 7.4% (95% CI 6.7-8.1) after AM, and 4.5% (95% CI 3.9-5.3) after DP. By day 63, the risks had risen to 39.9% (95% CI 36.6-43.3), 42.4% (95% CI 34.7-51.2), 22.8% (95% CI 21.2-24.4), and 12.8% (95% CI 11.4-14.5), respectively. In multivariable analyses, the highest rate of P. vivax parasitaemia over 42 days of follow-up was in patients residing in areas of short relapse periodicity (adjusted hazard ratio [AHR] = 6.2, 95% CI 2.0-19.5; p = 0.002); patients treated with AL (AHR = 6.2, 95% CI 4.6-8.5; p < 0.001), AA (AHR = 2.3, 95% CI 1.4-3.7; p = 0.001), or AM (AHR = 1.4, 95% CI 1.0-1.9; p = 0.028) compared with DP; and patients who did not clear their initial parasitaemia within 2 days (AHR = 1.8, 95% CI 1.4-2.3; p < 0.001). The analysis was limited by heterogeneity between study populations and lack of data from very low transmission settings. Study quality was high. CONCLUSIONS: In this meta-analysis, we found a high risk of P. vivax parasitaemia after treatment of P. falciparum malaria that varied significantly between studies. These P. vivax infections are likely attributable to relapses that could be prevented with radical cure including a hypnozoitocidal agent; however, the benefits of such a novel strategy will vary considerably between geographical areas. |
Rotavirus Genotypes in Hospitalized Children with Acute Gastroenteritis Before and After Rotavirus Vaccine Introduction in Blantyre, Malawi, 1997 - 2019.
Mhango C , Mandolo JJ , Chinyama E , Wachepa R , Kanjerwa O , Malamba-Banda C , Matambo PB , Barnes KG , Chaguza C , Shawa IT , Nyaga MM , Hungerford D , Parashar UD , Pitzer VE , Kamng'ona AW , Iturriza-Gomara M , Cunliffe NA , Jere KC . J Infect Dis 2020 225 (12) 2127-2136 INTRODUCTION: Rotavirus vaccine (Rotarix®, RV1) has reduced diarrhea-associated hospitalizations and deaths in Malawi. We examined the trends in circulating rotavirus genotypes in Malawi over a 22-year period to assess the impact of RV1 introduction on strain distribution. METHODS: Data on rotavirus-positive stool specimens among children age <5 years hospitalized with diarrhea in Blantyre, Malawi before (July 1997 - October 2012, n=1765) and after (November 2012 - October 2019, n=934) RV1 introduction were analyzed. Rotavirus G and P genotypes were assigned using reverse transcription polymerase chain reaction. RESULTS: A rich rotavirus strain diversity circulated throughout the 22-year period; Shannon (H) and Simpson diversity (D) indices did not differ between the pre- and post-vaccine periods (H' p < 0.149: D' p < 0.287). Overall, G1 (n=268/924; 28.7%), G2 (n=308/924; 33.0%), G3 (n=72/924; 7.7%) and G12 (n=109/924; 11.8%) were the most prevalent genotypes identified following RV1 introduction. The prevalence of G1P[8] and G2P[4] genotypes declined each successive year following RV1 introduction, and were not detected after 2018. Genotype G3 re-emerged and became the predominant genotype from 2017. No evidence of genotype selection was observed seven years post-RV1 introduction. CONCLUSION: Rotavirus strain diversity and genotype variation in Malawi is likely driven by natural mechanisms rather than vaccine pressure. |
Antibiotic stewardship in the intensive care unit. An Official American Thoracic Society Workshop Report in Collaboration with the AACN, CHEST, CDC, and SCCM
Wunderink RG , Srinivasan A , Barie PS , Chastre J , Dela Cruz CS , Douglas IS , Ecklund M , Evans SE , Evans SR , Gerlach AT , Hicks LA , Howell M , Hutchinson ML , Hyzy RC , Kane-Gill SL , Lease ED , Metersky ML , Munro N , Niederman MS , Restrepo MI , Sessler CN , Simpson SQ , Swoboda SM , Guillamet CV , Waterer GW , Weiss CH . Ann Am Thorac Soc 2020 17 (5) 531-540 Intensive care units (ICUs) are an appropriate focus of antibiotic stewardship program efforts because a large proportion of any hospital's use of parenteral antibiotics, especially broad-spectrum, occurs in the ICU. Given the importance of antibiotic stewardship for critically ill patients and the importance of critical care practitioners as the front line for antibiotic stewardship, a workshop was convened to specifically address barriers to antibiotic stewardship in the ICU and discuss tactics to overcome these. The working definition of antibiotic stewardship is "the right drug at the right time and the right dose for the right bug for the right duration." A major emphasis was that antibiotic stewardship should be a core competency of critical care clinicians. Fear of pathogens that are not covered by empirical antibiotics is a major driver of excessively broad-spectrum therapy in critically ill patients. Better diagnostics and outcome data can address this fear and expand efforts to narrow or shorten therapy. Greater awareness of the substantial adverse effects of antibiotics should be emphasized and is an important counterargument to broad-spectrum therapy in individual low-risk patients. Optimal antibiotic stewardship should not focus solely on reducing antibiotic use or ensuring compliance with guidelines. Instead, it should enhance care both for individual patients (by improving and individualizing their choice of antibiotic) and for the ICU population as a whole. Opportunities for antibiotic stewardship in common ICU infections, including community- and hospital-acquired pneumonia and sepsis, are discussed. Intensivists can partner with antibiotic stewardship programs to address barriers and improve patient care. |
Human monkeypox - After 40 years, an unintended consequence of smallpox eradication.
Simpson K , Heymann D , Brown CS , Edmunds WJ , Elsgaard J , Fine P , Hochrein H , Hoff NA , Green A , Ihekweazu C , Jones TC , Lule S , Maclennan J , McCollum A , Muhlemann B , Nightingale E , Ogoina D , Ogunleye A , Petersen B , Powell J , Quantick O , Rimoin AW , Ulaeato D , Wapling A . Vaccine 2020 38 (33) 5077-5081 Smallpox eradication, coordinated by the WHO and certified 40 years ago, led to the cessation of routine smallpox vaccination in most countries. It is estimated that over 70% of the world's population is no longer protected against smallpox, and through cross-immunity, to closely related orthopox viruses such as monkeypox. Monkeypox is now a re-emerging disease. Monkeypox is endemic in as yet unconfirmed animal reservoirs in sub-Saharan Africa, while its human epidemiology appears to be changing. Monkeypox in small animals imported from Ghana as exotic pets was at the origin of an outbreak of human monkeypox in the USA in 2003. Travellers infected in Nigeria were at the origin of monkeypox cases in the UK in 2018 and 2019, Israel in 2018 and Singapore in2019. Together with sporadic reports of human infections with other orthopox viruses, these facts invite speculation that emergent or re-emergent human monkeypox might fill the epidemiological niche vacated by smallpox. An ad-hoc and unofficial group of interested experts met to consider these issues at Chatham House, London in June 2019, in order to review available data and identify monkeypox-related research gaps. Gaps identified by the experts included:The experts further agreed on the need for a better understanding of the genomic evolution and changing epidemiology of orthopox viruses, the usefulness of in-field genomic diagnostics, and the best disease control strategies, including the possibility of vaccination with new generation non-replicating smallpox vaccines and treatment with recently developed antivirals. |
The efficacy of dihydroartemisinin-piperaquine and artemether-lumefantrine with and without primaquine on Plasmodium vivax recurrence: A systematic review and individual patient data meta-analysis.
Commons RJ , Simpson JA , Thriemer K , Abreha T , Adam I , Anstey NM , Assefa A , Awab GR , Baird JK , Barber BE , Chu CS , Dahal P , Daher A , Davis TME , Dondorp AM , Grigg MJ , Humphreys GS , Hwang J , Karunajeewa H , Laman M , Lidia K , Moore BR , Mueller I , Nosten F , Pasaribu AP , Pereira DB , Phyo AP , Poespoprodjo JR , Sibley CH , Stepniewska K , Sutanto I , Thwaites G , Hien TT , White NJ , William T , Woodrow CJ , Guerin PJ , Price RN . PLoS Med 2019 16 (10) e1002928 BACKGROUND: Artemisinin-based combination therapy (ACT) is recommended for uncomplicated Plasmodium vivax malaria in areas of emerging chloroquine resistance. We undertook a systematic review and individual patient data meta-analysis to compare the efficacies of dihydroartemisinin-piperaquine (DP) and artemether-lumefantrine (AL) with or without primaquine (PQ) on the risk of recurrent P. vivax. METHODS AND FINDINGS: Clinical efficacy studies of uncomplicated P. vivax treated with DP or AL and published between January 1, 2000, and January 31, 2018, were identified by conducting a systematic review registered with the International Prospective Register of Systematic Reviews (PROSPERO): CRD42016053310. Investigators of eligible studies were invited to contribute individual patient data that were pooled using standardised methodology. The effect of mg/kg dose of piperaquine/lumefantrine, ACT administered, and PQ on the rate of P. vivax recurrence between days 7 and 42 after starting treatment were investigated by Cox regression analyses according to an a priori analysis plan. Secondary outcomes were the risk of recurrence assessed on days 28 and 63. Nineteen studies enrolling 2,017 patients were included in the analysis. The risk of recurrent P. vivax at day 42 was significantly higher in the 384 patients treated with AL alone (44.0%, 95% confidence interval [CI] 38.7-49.8) compared with the 812 patients treated with DP alone (9.3%, 95% CI 7.1-12.2): adjusted hazard ratio (AHR) 12.63 (95% CI 6.40-24.92), p < 0.001. The rates of recurrence assessed at days 42 and 63 were associated inversely with the dose of piperaquine: AHRs (95% CI) for every 5-mg/kg increase 0.63 (0.48-0.84), p = 0.0013 and 0.83 (0.73-0.94), p = 0.0033, respectively. The dose of lumefantrine was not significantly associated with the rate of recurrence (1.07 for every 5-mg/kg increase, 95% CI 0.99-1.16, p = 0.0869). In a post hoc analysis, in patients with symptomatic recurrence after AL, the mean haemoglobin increased 0.13 g/dL (95% CI 0.01-0.26) for every 5 days that recurrence was delayed, p = 0.0407. Coadministration of PQ reduced substantially the rate of recurrence assessed at day 42 after AL (AHR = 0.20, 95% CI 0.10-0.41, p < 0.001) and at day 63 after DP (AHR = 0.08, 95% CI 0.01-0.70, p = 0.0233). Results were limited by follow-up of patients to 63 days or less and nonrandomised treatment groups. CONCLUSIONS: In this study, we observed the risk of P. vivax recurrence at day 42 to be significantly lower following treatment with DP compared with AL, reflecting the longer period of post-treatment prophylaxis; this risk was reduced substantially by coadministration with PQ. We found that delaying P. vivax recurrence was associated with a small but significant improvement in haemoglobin. These results highlight the benefits of PQ radical cure and also the provision of blood-stage antimalarial agents with prolonged post-treatment prophylaxis. |
The haematological consequences of Plasmodium vivax malaria after chloroquine treatment with and without primaquine: a WorldWide Antimalarial Resistance Network systematic review and individual patient data meta-analysis.
Commons RJ , Simpson JA , Thriemer K , Chu CS , Douglas NM , Abreha T , Alemu SG , Anez A , Anstey NM , Aseffa A , Assefa A , Awab GR , Baird JK , Barber BE , Borghini-Fuhrer I , D'Alessandro U , Dahal P , Daher A , de Vries PJ , Erhart A , Gomes MSM , Grigg MJ , Hwang J , Kager PA , Ketema T , Khan WA , Lacerda MVG , Leslie T , Ley B , Lidia K , Monteiro WM , Pereira DB , Phan GT , Phyo AP , Rowland M , Saravu K , Sibley CH , Siqueira AM , Stepniewska K , Taylor WRJ , Thwaites G , Tran BQ , Hien TT , Vieira JLF , Wangchuk S , Watson J , William T , Woodrow CJ , Nosten F , Guerin PJ , White NJ , Price RN . BMC Med 2019 17 (1) 151 BACKGROUND: Malaria causes a reduction in haemoglobin that is compounded by primaquine, particularly in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. The aim of this study was to determine the relative contributions to red cell loss of malaria and primaquine in patients with uncomplicated Plasmodium vivax. METHODS: A systematic review identified P. vivax efficacy studies of chloroquine with or without primaquine published between January 2000 and March 2017. Individual patient data were pooled using standardised methodology, and the haematological response versus time was quantified using a multivariable linear mixed effects model with non-linear terms for time. Mean differences in haemoglobin between treatment groups at day of nadir and day 42 were estimated from this model. RESULTS: In total, 3421 patients from 29 studies were included: 1692 (49.5%) with normal G6PD status, 1701 (49.7%) with unknown status and 28 (0.8%) deficient or borderline individuals. Of 1975 patients treated with chloroquine alone, the mean haemoglobin fell from 12.22 g/dL [95% CI 11.93, 12.50] on day 0 to a nadir of 11.64 g/dL [11.36, 11.93] on day 2, before rising to 12.88 g/dL [12.60, 13.17] on day 42. In comparison to chloroquine alone, the mean haemoglobin in 1446 patients treated with chloroquine plus primaquine was - 0.13 g/dL [- 0.27, 0.01] lower at day of nadir (p = 0.072), but 0.49 g/dL [0.28, 0.69] higher by day 42 (p < 0.001). On day 42, patients with recurrent parasitaemia had a mean haemoglobin concentration - 0.72 g/dL [- 0.90, - 0.54] lower than patients without recurrence (p < 0.001). Seven days after starting primaquine, G6PD normal patients had a 0.3% (1/389) risk of clinically significant haemolysis (fall in haemoglobin > 25% to < 7 g/dL) and a 1% (4/389) risk of a fall in haemoglobin > 5 g/dL. CONCLUSIONS: Primaquine has the potential to reduce malaria-related anaemia at day 42 and beyond by preventing recurrent parasitaemia. Its widespread implementation will require accurate diagnosis of G6PD deficiency to reduce the risk of drug-induced haemolysis in vulnerable individuals. TRIAL REGISTRATION: This trial was registered with PROSPERO: CRD42016053312. The date of the first registration was 23 December 2016. |
Cervical determinants of anal HPV infection and high-grade anal lesions in women: a collaborative pooled analysis
Lin C , Slama J , Gonzalez P , Goodman MT , Xia N , Kreimer AR , Wu T , Hessol NA , Shvetsov Y , Ortiz AP , Grinsztejn B , Moscicki AB , Heard I , Del Refugio Gonzalez Losa M , Kojic EM , Schim van der Loeff MF , Wei F , Longatto-Filho A , Mbulawa ZA , Palefsky JM , Sohn AH , Hernandez BY , Robison K , Simpson SJr , Conley LJ , de Pokomandy A , van der Sande MAB , Dube Mandishora RS , Volpini LPB , Pierangeli A , Romero B , Wilkin T , Franceschi S , Hidalgo-Tenorio C , Ramautarsing RA , Park IU , Tso FK , Godbole S , D'Hauwers KWM , Sehnal B , Menezes LJ , Heraclio SA , Clifford GM . Lancet Infect Dis 2019 19 (8) 880-891 BACKGROUND: Cervical cancer screening might contribute to the prevention of anal cancer in women. We aimed to investigate if routine cervical cancer screening results-namely high-risk human papillomavirus (HPV) infection and cytohistopathology-predict anal HPV16 infection, anal high-grade squamous intraepithelial lesions (HSIL) and, hence, anal cancer. METHODS: We did a systematic review of MEDLINE, Embase, and the Cochrane library for studies of cervical determinants of anal HPV and HSIL published up to Aug 31, 2018. We centrally reanalysed individual-level data from 13 427 women with paired cervical and anal samples from 36 studies. We compared anal high-risk HPV prevalence by HIV status, cervical high-risk HPV, cervical cytohistopathology, age, and their combinations, using prevalence ratios (PR) and 95% CIs. Among 3255 women with anal cytohistopathology results, PRs were similarly calculated for all anal HSIL and HPV16-positive anal HSIL. FINDINGS: Cervical and anal HPV infections were highly correlated. In HIV-negative women, anal HPV16 prevalence was 41% (447/1097) in cervical HPV16-positive versus 2% (214/8663) in cervical HPV16-negative women (PR 16.5, 95% CI 14.2-19.2, p<0.0001); these values were 46% (125/273) versus 11% (272/2588) in HIV-positive women (4.4, 3.7-5.3, p<0.0001). Anal HPV16 was also associated with cervical cytohistopathology, with a prevalence of 44% [101/228] for cervical cancer in HIV-negative women (PR vs normal cytology 14.1, 11.1-17.9, p<0.0001). Anal HSIL was associated with cervical high-risk HPV, both in HIV-negative women (from 2% [11/527] in cervical high-risk HPV-negative women up to 24% [33/138] in cervical HPV16-positive women; PR 12.9, 95% CI 6.7-24.8, p<0.0001) and HIV-positive women (from 8% [84/1094] to 17% [31/186]; 2.3, 1.6-3.4, p<0.0001). Anal HSIL was also associated with cervical cytohistopathology, both in HIV-negative women (from 1% [5/498] in normal cytology up to 22% [59/273] in cervical HSIL; PR 23.1, 9.4-57.0, p<0.0001) and HIV-positive women (from 7% [105/1421] to 25% [25/101]; 3.6, 2.5-5.3, p<0.0001). Prevalence of HPV16-positive anal HSIL was 23-25% in cervical HPV16-positive women older than 45 years (5/20 in HIV-negative women, 12/52 in HIV-positive women). INTERPRETATION: HPV-based cervical cancer screening programmes might help to stratify anal cancer risk, irrespective of HIV status. For targeted secondary anal cancer prevention in high-risk groups, HIV-negative women with cervical HPV16, especially those older than 45 years, have a similar anal cancer risk profile to that of HIV-positive women. FUNDING: International Agency for Research on Cancer. |
Alternative water transport and storage containers: Assessing sustained use of the PackH2O in rural Haiti
Martinsen A , Hulland E , Phillips R , Darius JA , Felker-Kantor E , Simpson D , Stephens M , Thomas E , Quick R , Handzel T . Am J Trop Med Hyg 2019 100 (4) 981-987 The PackH2O water backpack carrier was developed to provide safe storage and relieve stress of head-loading during water transport with traditional containers such as buckets and jerry cans. We conducted an evaluation to assess both self-reported and observed use over a 6-month period between November 2014 and May 2015. A total of 866 packs were distributed to 618 households in six communities in rural Haiti, and 431 and 441 households were surveyed at midline and end line, respectively. We performed linear regression to assess change of self-reported use over time. Although 79.3% of respondents reported continued use of the 20-L pack after 6 months, other measures of self-reported use were low, with only 16.8% reporting to have used the pack the last time they collected water and 10.3% preferring the pack over other water collection containers. In addition, only 10.2% of all people collecting water at community sources were observed using packs and 12.0% of all households surveyed had water in the pack at the time of visit. Pack use varied by community and demographics. Although women were targeted during distribution, men preferred the pack and were more commonly observed using it at the community water sources. In conclusion, the use of the PackH2O was not widely adopted in rural Haiti; however, further research is needed to assess the pack acceptance in areas where back-loading is more common and in emergency settings. |
Decolonization to reduce postdischarge infection risk among MRSA carriers
Huang SS , Singh R , McKinnell JA , Park S , Gombosev A , Eells SJ , Gillen DL , Kim D , Rashid S , Macias-Gil R , Bolaris MA , Tjoa T , Cao C , Hong SS , Lequieu J , Cui E , Chang J , He J , Evans K , Peterson E , Simpson G , Robinson P , Choi C , Bailey CCJr , Leo JD , Amin A , Goldmann D , Jernigan JA , Platt R , Septimus E , Weinstein RA , Hayden MK , Miller LG . N Engl J Med 2019 380 (7) 638-650 BACKGROUND: Hospitalized patients who are colonized with methicillin-resistant Staphylococcus aureus (MRSA) are at high risk for infection after discharge. METHODS: We conducted a multicenter, randomized, controlled trial of postdischarge hygiene education, as compared with education plus decolonization, in patients colonized with MRSA (carriers). Decolonization involved chlorhexidine mouthwash, baths or showers with chlorhexidine, and nasal mupirocin for 5 days twice per month for 6 months. Participants were followed for 1 year. The primary outcome was MRSA infection as defined according to Centers for Disease Control and Prevention (CDC) criteria. Secondary outcomes included MRSA infection determined on the basis of clinical judgment, infection from any cause, and infection-related hospitalization. All analyses were performed with the use of proportional-hazards models in the per-protocol population (all participants who underwent randomization, met the inclusion criteria, and survived beyond the recruitment hospitalization) and as-treated population (participants stratified according to adherence). RESULTS: In the per-protocol population, MRSA infection occurred in 98 of 1063 participants (9.2%) in the education group and in 67 of 1058 (6.3%) in the decolonization group; 84.8% of the MRSA infections led to hospitalization. Infection from any cause occurred in 23.7% of the participants in the education group and 19.6% of those in the decolonization group; 85.8% of the infections led to hospitalization. The hazard of MRSA infection was significantly lower in the decolonization group than in the education group (hazard ratio, 0.70; 95% confidence interval [CI], 0.52 to 0.96; P=0.03; number needed to treat to prevent one infection, 30; 95% CI, 18 to 230); this lower hazard led to a lower risk of hospitalization due to MRSA infection (hazard ratio, 0.71; 95% CI, 0.51 to 0.99). The decolonization group had lower likelihoods of clinically judged infection from any cause (hazard ratio, 0.83; 95% CI, 0.70 to 0.99) and infection-related hospitalization (hazard ratio, 0.76; 95% CI, 0.62 to 0.93); treatment effects for secondary outcomes should be interpreted with caution owing to a lack of prespecified adjustment for multiple comparisons. In as-treated analyses, participants in the decolonization group who adhered fully to the regimen had 44% fewer MRSA infections than the education group (hazard ratio, 0.56; 95% CI, 0.36 to 0.86) and had 40% fewer infections from any cause (hazard ratio, 0.60; 95% CI, 0.46 to 0.78). Side effects (all mild) occurred in 4.2% of the participants. CONCLUSIONS: Postdischarge MRSA decolonization with chlorhexidine and mupirocin led to a 30% lower risk of MRSA infection than education alone. (Funded by the AHRQ Healthcare-Associated Infections Program and others; ClinicalTrials.gov number, NCT01209234 .). |
Modeling the impact of obesity on the lifetime risk of chronic kidney disease in the United States using updated estimates of GFR progression from the CRIC study
Yarnoff BO , Hoerger TJ , Shrestha SS , Simpson SK , Burrows NR , Anderson AH , Xie D , Chen HY , Pavkov ME . PLoS One 2018 13 (10) e0205530 RATIONALE & OBJECTIVE: As the prevalence of obesity continues to rise in the United States, it is important to understand its impact on the lifetime risk of chronic kidney disease (CKD). STUDY DESIGN: The CKD Health Policy Model was used to simulate the lifetime risk of CKD for those with and without obesity at baseline. Model structure was updated for glomerular filtration rate (GFR) decline to incorporate new longitudinal data from the Chronic Renal Insufficiency Cohort (CRIC) study. SETTING AND POPULATION: The updated model was populated with a nationally representative cohort from National Health and Nutrition Examination Survey (NHANES). OUTCOMES: Lifetime risk of CKD, highest stage and any stage. MODEL, PERSPECTIVE, & TIMEFRAME: Simulation model following up individuals from current age through death or age 90 years. RESULTS: Lifetime risk of any CKD stage was 32.5% (95% CI 28.6%-36.3%) for persons with normal weight, 37.6% (95% CI 33.5%-41.7%) for persons who were overweight, and 41.0% (95% CI 36.7%-45.3%) for persons with obesity at baseline. The difference between persons with normal weight and persons with obesity at baseline was statistically significant (p<0.01). Lifetime risk of CKD stages 4 and 5 was higher for persons with obesity at baseline (Stage 4: 2.1%, 95% CI 0.9%-3.3%; stage 5: 0.6%, 95% CI 0.0%-1.1%), but the differences were not statistically significant (stage 4: p = 0.08; stage 5: p = 0.23). LIMITATIONS: Due to limited data, our simulation model estimates are based on assumptions about the causal pathways from obesity to CKD, diabetes, and hypertension. CONCLUSIONS: The results of this study indicate that obesity may have a large impact on the lifetime risk of CKD. This is important information for policymakers seeking to set priorities and targets for CKD prevention and treatment. |
Point-Counterpoint: The Hope-Simpson hypothesis and its implications regarding an effect of routine varicella vaccination on herpes zoster incidence
Harpaz R , van Hoek AJ . J Infect Dis 2018 218 S57-s62 Some 50 years ago, Edgar Hope-Simpson published his hypothesis regarding the interactions between varicella and herpes zoster. As part of this hypothesis, Hope-Simpson postulated that reactivation of varicella zoster virus (VZV) was under immunological control, and that this immunological control could be boosted "endogenously" due to reactivation of latent VZV, and "exogenously" due to exposure to varicella. This hypothesis has important policy implications and remains a source of debate today; namely, does reducing VZV circulation through effective pediatric varicella vaccination programs lead to unintended increases in herpes zoster (HZ) incidence? This article provides 2 very different perspectives on this issue. The first perspective (Rafael Harpaz: Evidence Against an Effect) highlights the empiric experience of the United States, with its population of >300 million, a highly effective national varicella vaccination program lasting >20 years, and with several credible sources of data regarding HZ incidence. The US data have shown an increase in HZ incidence that preceded the availability of varicella vaccination by decades; indeed, HZ rates appear to have plateaued among older adults since varicella vaccination was introduced. Furthermore, HZ rates are not different in states having higher vs lower preschool varicella vaccination rates. The second perspective (Albert J. van Hoek: Evidence for an Effect) cites data that persons with close exposure to children appear to be at lower risk of HZ before universal VZV vaccination, but not so thereafter. Due to historic demographic changes, exogenous boosting could play a role in explaining the observed increase in HZ before varicella vaccination. Thus, it might be difficult to separate declines in exogenous boosting due to demographic changes from those caused by the varicella vaccination program. Additional data will be needed to conclusively rule out an impact of varicella vaccination on HZ. |
Molecular strain typing of the yaws pathogen, Treponema pallidum subspecies pertenue.
Katz SS , Chi KH , Nachamkin E , Danavall D , Taleo F , Kool JL , Addo KK , Ampofo W , Simpson SV , Ye T , Asiedu KB , Ballard RC , Chen CY , Pillay A . PLoS One 2018 13 (9) e0203632 Yaws is a neglected tropical disease caused by the bacterium Treponema pallidum subspecies pertenue. The disease primarily affects children under 15 years of age living in low socioeconomic conditions in tropical areas. As a result of a renewed focus on the disease owing to a recent eradication effort initiated by the World Health Organization, we have evaluated a typing method, adapted from and based on the enhanced Centers for Disease Control and Prevention typing method for T. pallidum subsp. pallidum, for possible use in epidemiological studies. Thirty DNA samples from yaws cases in Vanuatu and Ghana, 11 DNA samples extracted from laboratory strains, and 3 published genomic sequences were fully typed by PCR/RFLP analysis of the tpr E, G, and J genes and by determining the number of 60-bp repeats within the arp gene. Subtyping was performed by sequencing a homonucleotide "G" tandem repeat immediately upstream of the rpsA gene and an 84-bp region of tp0548. A total of 22 complete strain types were identified; two strain types in clinical samples from Vanuatu (5q11/ak and 5q12/ak), nine strain types in clinical samples from Ghana (3q12/ah, 4r12/ah, 4q10/j, 4q11/ah, 4q12/ah, 4q12/v, 4q13/ah, 6q10/aj, and 9q10/ai), and twelve strain types in laboratory strains and published genomes (2q11/ae, 3r12/ad, 4q11/ad, 4q12/ad, 4q12/ag, 4q12/v, 5r12/ad, 6r12/x, 6q11/af, 10q9/r, 10q12/r, and 12r12/w). The tpr RFLP patterns and arp repeat sizes were subsequently verified by sequencing analysis of the respective PCR amplicons. This study demonstrates that the typing method for subsp. pallidum can be applied to subsp. pertenue strains and should prove useful for molecular epidemiological studies on yaws. |
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