Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-30 (of 149 Records) |
Query Trace: Kersh G[original query] |
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At-home diagnostics solutions for chlamydia and gonorrhea
Kersh EN , Mena LA . Jama 2024 This Viewpoint discusses the US Food and Drug Administration’s authorization of marketing an at-home testing system for chlamydia and gonorrhea as a good first step in boosting access to screening and treatment and in reducing infection rates. | eng |
A mutation associated with resistance to synthetic pyrethroids is widespread in US populations of the tropical lineage of Rhipicephalus sanguineus s.l
Stone NE , Ballard R , Bourgeois RM , Pemberton GL , McDonough RF , Ruby MC , Backus LH , López-Pérez AM , Lemmer D , Koch Z , Brophy M , Paddock CD , Kersh GJ , Nicholson WL , Sahl JW , Busch JD , Salzer JS , Foley JE , Wagner DM . Ticks Tick Borne Dis 2024 15 (4) 102344 The brown dog tick, Rhipicephalus sanguineus sensu lato (s.l.), is an important vector for Rickettsia rickettsii, causative agent of Rocky Mountain spotted fever. Current public health prevention and control efforts to protect people involve preventing tick infestations on domestic animals and in and around houses. Primary prevention tools rely on acaricides, often synthetic pyrethroids (SPs); resistance to this chemical class is widespread in ticks and other arthropods. Rhipicephalus sanguineus s.l. is a complex that likely contains multiple unique species and although the distribution of this complex is global, there are differences in morphology, ecology, and perhaps vector competence among these major lineages. Two major lineages within Rh. sanguineus s.l., commonly referred to as temperate and tropical, have been documented from multiple locations in North America, but are thought to occupy different ecological niches. To evaluate potential acaricide resistance and better define the distributions of the tropical and temperate lineages throughout the US and in northern Mexico, we employed a highly multiplexed amplicon sequencing approach to characterize sequence diversity at: 1) three loci within the voltage-gated sodium channel (VGSC) gene, which contains numerous genetic mutations associated with resistance to SPs; 2) a region of the gamma-aminobutyric acid-gated chloride channel gene (GABA-Cl) containing several mutations associated with dieldrin/fipronil resistance in other species; and 3) three mitochondrial genes (COI, 12S, and 16S). We utilized a geographically diverse set of Rh sanguineus s.l. collected from domestic pets in the US in 2013 and a smaller set of ticks collected from canines in Baja California, Mexico in 2021. We determined that a single nucleotide polymorphism (T2134C) in domain III segment 6 of the VGSC, which has previously been associated with SP resistance in Rh. sanguineus s.l., was widespread and abundant in tropical lineage ticks (>50 %) but absent from the temperate lineage, suggesting that resistance to SPs may be common in the tropical lineage. We found evidence of multiple copies of GABA-Cl in ticks from both lineages, with some copies containing mutations associated with fipronil resistance in other species, but the effects of these patterns on fipronil resistance in Rh. sanguineus s.l. are currently unknown. The tropical lineage was abundant and geographically widespread, accounting for 79 % of analyzed ticks and present at 13/14 collection sites. The temperate and tropical lineages co-occurred in four US states, and as far north as New York. None of the ticks we examined were positive for Rickettsia rickettsii or Rickettsia massiliae. |
Prevalence and risk factors for Q fever, spotted fever group rickettsioses, and typhus group rickettsioses in a pastoralist community of northern Tanzania, 2016-2017
Moorthy GS , Rubach MP , Maze MJ , Refuerzo RP , Shirima GM , Lukambagire AS , Bodenham RF , Cash-Goldwasser S , Thomas KM , Sakasaka P , Mkenda N , Bowhay TR , Perniciaro JL , Nicholson WL , Kersh GJ , Kazwala RR , Mmbaga BT , Buza JJ , Maro VP , Haydon DT , Crump JA , Halliday JEB . Trop Med Int Health 2024 BACKGROUND: In northern Tanzania, Q fever, spotted fever group (SFG) rickettsioses, and typhus group (TG) rickettsioses are common causes of febrile illness. We sought to describe the prevalence and risk factors for these zoonoses in a pastoralist community. METHODS: Febrile patients ≥2 years old presenting to Endulen Hospital in the Ngorongoro Conservation Area were enrolled from August 2016 through October 2017. Acute and convalescent blood samples were collected, and a questionnaire was administered. Sera were tested by immunofluorescent antibody (IFA) IgG assays using Coxiella burnetii (Phase II), Rickettsia africae, and Rickettsia typhi antigens. Serologic evidence of exposure was defined by an IFA titre ≥1:64; probable cases by an acute IFA titre ≥1:128; and confirmed cases by a ≥4-fold rise in titre between samples. Risk factors for exposure and acute case status were evaluated. RESULTS: Of 228 participants, 99 (43.4%) were male and the median (interquartile range) age was 27 (16-41) years. Among these, 117 (51.3%) had C. burnetii exposure, 74 (32.5%) had probable Q fever, 176 (77.2%) had SFG Rickettsia exposure, 134 (58.8%) had probable SFG rickettsioses, 11 (4.8%) had TG Rickettsia exposure, and 4 (1.8%) had probable TG rickettsioses. Of 146 participants with paired sera, 1 (0.5%) had confirmed Q fever, 8 (5.5%) had confirmed SFG rickettsioses, and none had confirmed TG rickettsioses. Livestock slaughter was associated with acute Q fever (adjusted odds ratio [OR] 2.54, 95% confidence interval [CI] 1.38-4.76) and sheep slaughter with SFG rickettsioses case (OR 4.63, 95% CI 1.08-23.50). DISCUSSION: Acute Q fever and SFG rickettsioses were detected in participants with febrile illness. Exposures to C. burnetii and to SFG Rickettsia were highly prevalent, and interactions with livestock were associated with increased odds of illness with both pathogens. Further characterisation of the burden and risks for these diseases is warranted. |
Intrinsic risk factors for alpha-gal syndrome in a case-control study, 2019-2020
Taylor ML , Kersh GJ , Salzer JS , Jones ES , Binder AM , Armstrong PA , Choudhary SK , Commins GK , Amelio CL , Biggerstaff BJ , Beard CB , Petersen LR , Commins SP . Ann Allergy Asthma Immunol 2024 BACKGROUND: Alpha-gal syndrome (AGS) is an allergy to galactose-α-1,3-galactose (alpha-gal), a carbohydrate found in most mammals. Evidence indicates that AGS develops following a tick bite, and in the United States, AGS is most associated with bites from Amblyomma americanum (lone star tick); however, not all persons bitten by ticks develop clinical AGS. OBJECTIVE: This study investigated intrinsic risk factors associated with the development of AGS. METHODS: We performed a case-control study among adults presenting for diagnosis or management of AGS at an allergy clinic in North Carolina during 2019-2020 and compared them to controls enrolled from two nearby internal medicine clinics. A questionnaire gathered epidemiologic and tick exposure data and blood was obtained for alpha-gal specific IgE (sIgE) and other testing. RESULTS: The 82 enrolled case patients and 191 controls did not differ significantly by age or sex. Case patients were more likely than controls to have A or O blood types (non-B-antigen), have experienced childhood allergies, and have a family history of AGS and other food allergies. Case patients were also more likely to report experiencing long healing times for insect bites or stings and a family history of allergy to stinging or biting insects. CONCLUSION: This study suggests that intrinsic factors contribute to risk of developing AGS. Some traits are genetic, but common behaviors among households and family units likely also contribute. Identification of these risk factors can inform personal risk, aid healthcare providers in understanding susceptible populations, and contribute to ongoing understanding of AGS epidemiology. |
Novel strain of multidrug non-susceptible Neisseria gonorrhoeae in the USA
Reimche JL , Pham CD , Joseph SJ , Hutton S , Cartee JC , Ruan Y , Breaux M , Ivanof C , Joshi A , DeMartino M , Kirby JE , Barbee LA , Kersh EN , Roosevelt KA , Hsu KK . Lancet Infect Dis 2024 Unsuccessful treatment of gonorrhoea has not yet occurred in the USA, and cases of gonorrhoea that are non-susceptible to cephalosporins have been rare. In 2019, non-susceptibility to ceftriaxone conferred by the mosaic penA 60.001 allele was found in a Neisseria gonorrhoeae multilocus sequence type (MLST) 1901 isolate from Nevada.1 In this Correspondence, we present two additional US cases of the penA 60.001 allele identified in MLST 8123, an emerging international multidrug non-susceptible N gonorrhoeae lineage. Although these cases responded to ceftriaxone treatment, N gonorrhoeae isolates from the first known patient (case 1) demonstrated in-vitro non-susceptibility to ceftriaxone as well as non-susceptibility or resistance to drugs previously recommended for front-line treatment. | | In August, 2022, N gonorrhoeae grown from urine culture from a patient with urethritis in primary care in Massachusetts displayed non-susceptibility to cephalosporins (the minimum inhibitory concentrations were 1·0 μg/mL for ceftriaxone and >1·0 μg/mL for cefixime by agar dilution; the minimum inhibitory concentration for cefixime was 1·5 μg/mL by gradient strip) and azithromycin and resistance to ciprofloxacin, penicillin, and tetracycline (appendix pp 6–7). Antimicrobial susceptibility testing was done with gradient strips at the state public health laboratory Massachusetts and then confirmed via agar dilution at the US Centers for Disease Control and Prevention (CDC). The patient (case 1) had already been successfully diagnosed on nucleic acid amplification test (NAAT) with gonorrhoea and was given 500 mg ceftriaxone intramuscularly and asked to return to primary care where, 9 days after treatment, he was asymptomatic, had normal results during examination, and tested negative by urine culture and pharyngeal and rectal NAAT recommended by the Massachusetts sexually transmitted diseases programme to document N gonorrhoeae clearance from any site of infection. The patient reported that he had not travelled outside USA in the 60 days before onset of symptoms. He disclosed female sex worker contacts, but insufficient information was provided to trace the contacts. |
Advantages and limitations of current diagnostic laboratory approaches in syphilis and congenital syphilis
Cao W , Thorpe PG , O'Callaghan K , Kersh EN . Expert Rev Anti Infect Ther 2023 21 (12) 1339-1354 INTRODUCTION: The reemergence of syphilis, especially congenital syphilis, presents a significant public health threat. Accurate diagnosis of syphilis depends on recognition of a constellation of symptoms, review of medical and sexual history, and multiple laboratory tests. While reliable, current tests for syphilis can be difficult to interpret, which can lead to delays in treatment. AREA COVERED: This review summarizes the major advantages and limitations of available diagnostic laboratory methods for syphilis, provides an update on recent advances in laboratory tools, and highlights the urgent need for coordinated efforts to create new tools to halt the resurgence of syphilis. EXPERT OPINION: In syphilis, the wide variety of short-lived signs and symptoms followed by periods of latency create diagnostics challenges. Currently available laboratory tests, when positive, require additional information to interpret (prior testing, treatment, and sexual history). Point-of-care tests that can rapidly and accurately detect both treponemal and non-treponemal antibodies would be a huge step toward reducing test turnaround time and time to treatment. Incorporating biological insights and technology innovations to advance the development of direct detection assays is urgently needed. A comprehensive coordinated effort is critical to stem the tide of rising syphilis in the United States and globally. |
Health care provider knowledge regarding alpha-gal syndrome - United States, March-May 2022
Carpenter A , Drexler NA , McCormick DW , Thompson JM , Kersh G , Commins SP , Salzer JS . MMWR Morb Mortal Wkly Rep 2023 72 (30) 809-814 Alpha-gal syndrome (AGS) is an emerging, tick bite-associated immunoglobulin E-mediated allergic condition characterized by a reaction to the oligosaccharide galactose-alpha-1,3-galactose (alpha-gal), which is found in mammalian meat and products derived from mammals, including milk, other dairy products, and some pharmaceutical products. Symptoms range from mild (e.g., a rash or gastrointestinal upset) to severe (anaphylaxis); onset typically occurs ≥2 hours after exposure to alpha-gal. No treatment or cure is currently available. Despite the potential life-threating reactions associated with AGS, most patients perceive that health care providers (HCPs) have little or no knowledge of AGS. A U.S. web-based survey of 1,500 HCPs revealed limited knowledge of AGS, identified areas for continuing medical education, and described self-reported diagnostic and management practices. Overall, 42% of surveyed HCPs had never heard of AGS, and among those who had, fewer than one third knew how to diagnose the condition. Two thirds of respondents indicated that guidelines for the diagnosis and management of AGS would be useful clinical resources. Limited awareness and knowledge of AGS among HCPs likely contributes to underdiagnosis of this condition and inadequate patient management, and underestimates of the number of AGS patients in the United States, which currently relies on laboratory testing data alone. |
Geographic distribution of suspected alpha-gal syndrome cases - United States, January 2017-December 2022
Thompson JM , Carpenter A , Kersh GJ , Wachs T , Commins SP , Salzer JS . MMWR Morb Mortal Wkly Rep 2023 72 (30) 815-820 Alpha-gal syndrome (AGS) is an emerging, tick bite-associated allergic condition characterized by a potentially life-threatening immunoglobulin E (IgE)-mediated hypersensitivity to galactose-alpha-1,3-galactose (alpha-gal), an oligosaccharide found in most nonprimate mammalian meat and products derived from these mammals. Specific symptoms and severity of AGS vary among persons, and no treatment or cure is currently available. During 2010-2018, more than 34,000 suspected cases of AGS were identified in the United States, but current knowledge of where cases occur is limited. This study examined alpha-gal-specific IgE (sIgE) antibody testing results submitted to the commercial laboratory responsible for nearly all testing in the United States before 2022 to assess the geographic distribution and magnitude of this emerging condition. During January 1, 2017-December 31, 2022, a total of 357,119 tests were submitted from residences in the United States, corresponding to 295,400 persons. Overall, 90,018 (30.5%) persons received a positive test result in the study period, and the number of persons with positive test results increased from 13,371 in 2017 to 18,885 in 2021. Among 233,521 persons for whom geographic data were available, suspected cases predominantly occurred in counties within the southern, midwestern, and mid-Atlantic U.S. Census Bureau regions. These data highlight the evolving emergence of AGS and can be used to help state and local health agencies initiate surveillance and target public health outreach and health care provider education to high-risk localities. |
Global emergence and dissemination of Neisseria gonorrhoeae ST-9363 isolates with reduced susceptibility to azithromycin (preprint)
Joseph SJ , Thomas Iv JC , Schmerer MW , Cartee J , St Cyr S , Schlanger K , Kersh EN , Raphael BH , Gernert KM . bioRxiv 2021 2021.08.05.455198 Neisseria gonorrhoeae multi-locus sequence type (ST) 9363 genogroup isolates have been associated with reduced azithromycin susceptibility (AZMrs) and show evidence of clonal expansion in the U.S. Here we analyze a global collection of ST-9363 genogroup genomes to shed light on the emergence and dissemination of this strain. The global population structure of ST-9363 genogroup falls into three lineages: Basal, European, and North American; with 32 clades within all lineages. Although, ST-9363 genogroup is inferred to have originated from Asia in the mid-19th century; we estimate the three modern lineages emerged from Europe in the late 1970s to early 1980s. The European lineage appears to have emerged and expanded from around 1986 to 1998, spreading into North America and Oceania in the mid-2000s with multiple introductions, along with multiple secondary reintroductions into Europe. Our results suggest two separate acquisition events of mosaic mtrR and mtrR promoter alleles: first during 2009-2011 and again during the 2012-2013 time, facilitating the clonal expansion of this genogroup with AZMrs in the U.S. By tracking phylodynamic evolutionary trajectories of clades that share distinct demography as well as population-based genomic statistics, we demonstrate how recombination and selective pressures in the mtrCDE efflux operon granted a fitness advantage to establish ST-9363 as a successful gonococcal lineage in the U.S. and elsewhere. Although it is difficult to pinpoint the exact timing and emergence of this young genogroup, it remains critically important to continue monitoring it, as it could acquire additional resistance markers.Competing Interest StatementThe authors have declared no competing interest. |
Mechanistic basis for decreased antimicrobial susceptibility in a clinical isolate of Neisseria gonorrhoeae possessing a mosaic-like mtr efflux pump locus (preprint)
Rouquette-Loughlin CE , Reimche JL , Balthazar JT , Dhulipala V , Gernert KM , Kersh EN , Pham CD , Pettus K , Abrams AJ , Trees DL , St Cyr S , Shafer WM . bioRxiv 2018 448712 Recent reports suggest that mosaic-like sequences within the mtr (multiple transferable resistance) efflux pump locus of Neisseria gonorrhoeae likely originating from commensal Neisseria sp. by transformation can increase the ability of gonococci to resist structurally diverse antimicrobials. Thus, acquisition of numerous nucleotide changes within the mtrR gene encoding the transcriptional repressor (MtrR) of the mtrCDE efflux pump-encoding operon or overlapping promoter region for both along with those that cause amino acid changes in the MtrD transporter protein were recently reported to decrease gonococcal susceptibility to numerous antimicrobials, including azithromycin (Azi) (Wadsworth et al. 2018. MBio. doi.org/10.1128/mBio.01419-18). We performed detailed genetic and molecular studies to define the mechanistic basis for why such strains can exhibit decreased susceptibility to MtrCDE antimicrobial substrates including Azi. We report that a strong cis-acting transcriptional impact of a single nucleotide change within the -35 hexamer of the mtrCDE promoter as well gain-of-function amino acid changes at the C-terminal region of MtrD can mechanistically account for the decreased antimicrobial susceptibility of gonococci with a mosaic-like mtr locus.IMPORTANCE Historically, after introduction of an antibiotic for treatment of gonorrhea, strains of N. gonorrhoeae emerge that display clinical resistance due to spontaneous mutation or acquisition of resistance genes. Genetic exchange between members of the Neisseria genus occurring by transformation can cause significant changes in gonococci that impact the structure of an antibiotic target or expression of genes involved in resistance. The results presented herein provide a framework for understanding how mosaic-like DNA sequences from commensal Neisseria that recombine within the gonococcal mtr efflux pump locus function to decrease bacterial susceptibility to antimicrobials including antibiotics used in therapy of gonorrhea. |
Selective whole genome amplification as a tool to enrich specimens with low Treponema pallidum genomic DNA copies for whole genome sequencing (preprint)
Thurlow CM , Joseph SJ , Ganova-Raeva L , Katz SS , Pereira L , Chen C , Debra A , Vilfort K , Workowski K , Cohen SE , Reno H , Sun Y , Burroughs M , Sheth M , Chi KH , Danavall D , Philip SS , Cao W , Kersh EN , Pillay A . bioRxiv 2021 10 Downstream next generation sequencing (NGS) of the syphilis spirochete Treponema pallidum subspecies pallidum (T. pallidum) is hindered by low bacterial loads and the overwhelming presence of background metagenomic DNA in clinical specimens. In this study, we investigated selective whole genome amplification (SWGA) utilizing multiple displacement amplification (MDA) in conjunction with custom oligonucleotides with an increased specificity for the T. pallidum genome, and the capture and removal of CpG-methylated host DNA using the NEBNext Microbiome DNA Enrichment Kit followed by MDA with the REPLI-g Single Cell Kit as enrichment methods to improve the yields of T. pallidum DNA in isolates and lesion specimens from syphilis patients. Sequencing was performed using the Illumina MiSeq v2 500 cycle or NovaSeq 6000 SP platform. These two enrichment methods led to 93-98% genome coverage at 5 reads/site in 5 clinical specimens from the United States and rabbit propagated isolates, containing >14 T. pallidum genomic copies/ul of sample for SWGA and >129 genomic copies/ul for CpG methylation capture with MDA. Variant analysis using sequencing data derived from SWGA-enriched specimens, showed that all 5 clinical strains had the A2058G mutation associated with azithromycin resistance. SWGA is a robust method that allows direct whole genome sequencing (WGS) of specimens containing very low numbers of T. pallidum, which have been challenging until now. Copyright The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available for use under a CC0 license. |
Considerations for endpoint titer determination in syphilis testing using newly marketed, automated rapid plasma reagin instruments
Shukla M , Pereira L , Sun Y , Fakile YF , Kersh EN , Cao W . Public Health Rep 2023 333549231176007 Syphilis is a sexually transmitted disease (STD) caused by the bacterium Treponema pallidum, subspecies pallidum (T. pallidum).1 The resurgence of syphilis in the last 2 decades is a major public health concern in the United States. In 2020, a total of 133 945 cases of all stages of syphilis were reported in the United States, an increase of more than 70% since 2015. The national rate of congenital syphilis has increased 254% since 2016. In 2020, a total of 2148 cases of congenital syphilis were reported, including 149 congenital syphilis–related stillbirths and infant deaths.2 However, syphilis diagnosis is still challenging, partially because of overlapping and ambiguous clinical presentation, particularly during early infection.3 For laboratory testing, darkfield microscopy examinations and direct molecular detection of T. pallidum from clinical specimens are definitive methods for diagnosing early syphilis, but both methods are currently not widely performed at local, reference, or public health laboratories and have challenges in identifying asymptomatic or early-stage infection without the presence of visible lesions for suitable specimen collection.4 Darkfield microscopy requires special equipment and experienced operators for reliable results.5 US Food and Drug Administration (FDA)–cleared molecular tests for syphilis are still not available, and laboratory-developed molecular tests are limited in availability. Therefore, serological tests that detect treponemal and nontreponemal antibodies remain the mainstay for routine laboratory diagnosis of active syphilis infection.6 |
Evaluation of three automated nontreponemal rapid plasma reagin (RPR) tests for the laboratory diagnosis of syphilis
Shukla MR , Pereira L , Gaynor AM , Sun Y , Edwards D , Simmons T , Andrews CW , Park IU , Hong J , Cao W , Kersh EN , Fakile Y . J Clin Microbiol 2023 61 (6) e0016823 Automated nontreponemal rapid plasma reagin (RPR) tests were recently introduced in the United States for syphilis testing and limited performance data are available. In collaboration with the Association of Public Health Laboratories, three public health laboratories (PHL) were chosen through a competitive selection process to evaluate the performance of three FDA-cleared automated RPR test systems: BioPlex 2200 Syphilis Total & RPR assay (Bio-Rad Laboratories), AIX 1000 (Gold Standard Diagnostics), and ASI Evolution (Arlington Scientific). Panels prepared at the CDC included: a qualitative panel comprised of 734 syphilis reactive/nonreactive sera; a quantitative panel of 50 syphilis reactive sera (RPR titer 1:64 to 1:1,024); and a reproducibility panel of 15 nonreactive and reactive sera (RPR titer 1:1 to 1:64). Panels were shipped frozen to the PHL and tested on the automated RPR systems following manufacturers' instructions. Prior test results were blinded to all laboratories. When compared to manual RPR (Arlington Scientific) performed at the CDC as a reference test, the qualitative panel results demonstrated an overall concordance of 95.9% for AIX 1000, 94.6% for ASI Evolution, and 92.6% for Bioplex RPR; quantitative panel showed within range titer of 2-fold for 94% of specimens for AIX 1000, 68% for ASI Evolution, and 64% for BioPlex RPR, and the reproducibility testing panel demonstrated point estimates ranging from 69 to 95%. Automated RPR instruments could reduce turnaround time and minimize interpretation errors. However, additional evaluations with more specimens could assist laboratories with implementing automated RPR tests and understanding their limitations. |
Genomic analysis of 1710 surveillance-based Neisseria gonorrhoeae isolates from the USA in 2019 identifies predominant strain types and chromosomal antimicrobial-resistance determinants
Reimche JL , Clemons AA , Chivukula VL , Joseph SJ , Schmerer MW , Pham CD , Schlanger K , St Cyr SB , Kersh EN , Gernert KM . Microb Genom 2023 9 (5) This study characterized high-quality whole-genome sequences of a sentinel, surveillance-based collection of 1710 Neisseria gonorrhoeae (GC) isolates from 2019 collected in the USA as part of the Gonococcal Isolate Surveillance Project (GISP). It aims to provide a detailed report of strain diversity, phylogenetic relationships and resistance determinant profiles associated with reduced susceptibilities to antibiotics of concern. The 1710 isolates represented 164 multilocus sequence types and 21 predominant phylogenetic clades. Common genomic determinants defined most strains' phenotypic, reduced susceptibility to current and historic antibiotics (e.g. bla (TEM) plasmid for penicillin, tetM plasmid for tetracycline, gyrA for ciprofloxacin, 23S rRNA and/or mosaic mtr operon for azithromycin, and mosaic penA for cefixime and ceftriaxone). The most predominant phylogenetic clade accounted for 21 % of the isolates, included a majority of the isolates with low-level elevated MICs to azithromycin (2.0 µg ml(-1)), carried a mosaic mtr operon and variants in PorB, and showed expansion with respect to data previously reported from 2018. The second largest clade predominantly carried the GyrA S91F variant, was largely ciprofloxacin resistant (MIC ≥1.0 µg ml(-1)), and showed significant expansion with respect to 2018. Overall, a low proportion of isolates had medium- to high-level elevated MIC to azithromycin ((≥4.0 µg ml(-1)), based on C2611T or A2059G 23S rRNA variants). One isolate carried the penA 60.001 allele resulting in elevated MICs to cefixime and ceftriaxone of 1.0 µg ml(-1). This high-resolution snapshot of genetic profiles of 1710 GC sequences, through a comparison with 2018 data (1479 GC sequences) within the sentinel system, highlights change in proportions and expansion of select GC strains and the associated genetic mechanisms of resistance. The knowledge gained through molecular surveillance may support rapid identification of outbreaks of concern. Continued monitoring may inform public health responses to limit the development and spread of antibiotic-resistant gonorrhoea. |
Tick bite as a risk factor for alpha-gal specific IgE antibodies and development of alpha-gal syndrome
Kersh GJ , Salzer J , Jones ES , Binder AM , Armstrong PA , Choudhary SK , Commins GK , Amelio CL , Kato CY , Singleton J , Biggerstaff BJ , Beard CB , Petersen LR , Commins SP . Ann Allergy Asthma Immunol 2023 130 (4) 472-478 BACKGROUND: The disaccharide galactose-α-1,3-galactose (alpha-gal) is expressed in mammals other than humans, apes, and old-world monkeys. In humans, elevated immunoglobulin E (IgE) antibodies specific for alpha-gal can result in allergic hypersensitivity known as alpha-gal syndrome (AGS). Case reports and series suggest that tick bites can induce alpha-gal-specific IgE (sIgE) antibodies. OBJECTIVE: To evaluate tick exposure as a risk factor for AGS and elevated alpha-gal sIgE level. METHODS: We conducted a case-control study comparing patients with AGS from a North Carolina allergy clinic with controls who were patients at a nearby internal medicine clinic. Cases and controls were administered a questionnaire to obtain information about demographics, home environment, outdoor activities, and recollection of tick bite. Serum samples taken at the time of enrollment were tested for total IgE, alpha-gal sIgE, and antibodies to other tick-borne pathogens. RESULTS: The patients with AGS were more likely to recall finding a tick on themselves (odds ratio [OR], 11.20; 95% confidence interval [CI], 4.97-25.15), live near wooded forest (OR, 2.27; 95% CI, 0.92-5.55), and spend 17 or more hours per week outdoors in wooded areas (OR, 5.58; 95% CI, 2.56-12.19). The patients with AGS were also more likely to report 4 or more tick bites (OR, 33.05; 95% CI, 9.92-155.12) and reactions at the site of tick bites (OR, 7.93; 95% CI, 3.74-16.80). Furthermore, elevated alpha-gal sIgE level was observed in 33% of the controls and was associated with tick exposure in the controls (OR, 4.25; 95% CI, 2.21-8.18). CONCLUSION: The results define tick bite as a risk factor for AGS and elevated alpha-gal sIgE level. |
Tropical Q Fever
Kersh GJ . Am J Trop Med Hyg 2022 107 (2) 219-220 Infection with the Gram-negative bacterium Coxiella burnetii can result in a variety of clinical presentations that are collectively referred to as Q fever. These can range from a mild, self-limiting febrile illness to more insidious chronic infections such as Q fever endocarditis. C. burnetii infections have been found in most of the world, with Europe, Australia, and North America seeming to have the majority of cases. In areas where surveillance is conducted for Q fever, it is a disease that most would consider rare. The United States has conducted national surveillance for Q fever since 2000 and reports an annual average incidence of 0.036 cases per 100,000 persons for 2008 through 2017.1 The European Centre for Disease Prevention and Control reported 0.2 Q fever notifications per 100,000 persons for the European Union/European Economic Area in 2019.2 Despite the low numbers of reported cases, many areas report fairly high levels of seroprevalence, suggesting that asymptomatic exposures are common. | | The baseline circumstance of widespread asymptomatic infections with a minority of infections resulting in detected disease makes the occurrence of exceptional outbreaks notable. Perhaps the most notable of such outbreaks occurred in the Netherlands between 2007 and 2010, where more than 4,000 acute Q fever cases were recorded in a limited geographic area.3 During this outbreak, most cases presented with pneumonia. Other, more limited outbreaks have been reported in a variety of locations, including England, Germany, and Bosnia.4–6 |
Advances in Sexually Transmitted Infection Testing at Home and in Nonclinical Settings Close to the Home.
Kersh EN . Sex Transm Dis 2022 49 S12-s14 A commentary on recent successes and challenges for home STI specimen collection, for point-of-care test usage close to the home, and implications of COVID-19 self-tests for future STI self-test development. |
Clinical and laboratory features of patients diagnosed with Alpha-gal Syndrome - 2010-2019
Binder AM , Cherry-Brown D , Biggerstaff BJ , Jones ES , Amelio CL , Beard CB , Petersen LR , Kersh GJ , Commins SP , Armstrong PA . Allergy 2022 78 (2) 477-487 BACKGROUND: Alpha-gal syndrome (AGS) is an IgE-mediated allergy to galactose-alpha-1,3-galactose. Clinical presentation ranges from hives to anaphylaxis; episodes typically occur 2-6 hours after exposure to alpha-gal-containing products. In the United States, lone star tick bites are associated with development of AGS. To characterize features of AGS, we evaluated a cohort of patients presenting for care at the University of North Carolina, focusing on symptoms, severity, and identifying features unique to specific alpha-gal-containing product exposures. METHODS: We performed a chart review and descriptive analysis of 100 randomly selected patients with AGS during 2010-2019. RESULTS: Median age at onset was 53years, 56% were female, 95% reported White race, 86% reported a history of tick bite, and 75% met criteria for anaphylaxis based on involvement of 2 organ systems. Those reporting dairy reactions were significantly less likely to report isolated mucocutaneous symptoms (3% vs 24%; ratio [95% CI]: 0.1 [0.1, 0.3]) than those who tolerated dairy, and were more likely to report gastrointestinal symptoms (79% vs 59%; ratio [95% CI]: 1.3 [0.7, 2.6]), although this difference was not statistically significant. Dairy-tolerant patients demonstrated higher alpha-gal sIgE titers (as a percentage of total IgE) than dairy-reactive patients (GM 4.1[95% CI: 2.7, 6.1] vs. GM 2.5 [95% CI: 1.3, 4.8], respectively; ratio - 1.6 [95% CI: -1.0, 3.9]). CONCLUSION: While tick exposure is common in the southern United States, nearly all AGS patients reported a tick bite. Gastrointestinal symptoms were prominent among those reporting reactions to dairy. Anaphylaxis was common, underscoring the severity and need to raise awareness of AGS among patients and providers. |
Selective Whole-Genome Amplification as a Tool to Enrich Specimens with Low Treponema pallidum Genomic DNA Copies for Whole-Genome Sequencing.
Thurlow CM , Joseph SJ , Ganova-Raeva L , Katz SS , Pereira L , Chen C , Debra A , Vilfort K , Workowski K , Cohen SE , Reno H , Sun Y , Burroughs M , Sheth M , Chi KH , Danavall D , Philip SS , Cao W , Kersh EN , Pillay A . mSphere 2022 7 (3) e0000922 Downstream next-generation sequencing (NGS) of the syphilis spirochete Treponema pallidum subspecies pallidum (T. pallidum) is hindered by low bacterial loads and the overwhelming presence of background metagenomic DNA in clinical specimens. In this study, we investigated selective whole-genome amplification (SWGA) utilizing multiple displacement amplification (MDA) in conjunction with custom oligonucleotides with an increased specificity for the T. pallidum genome and the capture and removal of 5'-C-phosphate-G-3' (CpG) methylated host DNA using the NEBNext Microbiome DNA enrichment kit followed by MDA with the REPLI-g single cell kit as enrichment methods to improve the yields of T. pallidum DNA in isolates and lesion specimens from syphilis patients. Sequencing was performed using the Illumina MiSeq v2 500 cycle or NovaSeq 6000 SP platform. These two enrichment methods led to 93 to 98% genome coverage at 5 reads/site in 5 clinical specimens from the United States and rabbit-propagated isolates, containing >14 T. pallidum genomic copies/μL of sample for SWGA and >129 genomic copies/μL for CpG methylation capture with MDA. Variant analysis using sequencing data derived from SWGA-enriched specimens showed that all 5 clinical strains had the A2058G mutation associated with azithromycin resistance. SWGA is a robust method that allows direct whole-genome sequencing (WGS) of specimens containing very low numbers of T. pallidum, which has been challenging until now. IMPORTANCE Syphilis is a sexually transmitted, disseminated acute and chronic infection caused by the bacterial pathogen Treponema pallidum subspecies pallidum. Primary syphilis typically presents as single or multiple mucocutaneous lesions and, if left untreated, can progress through multiple stages with various clinical manifestations. Molecular studies often rely on direct amplification of DNA sequences from clinical specimens; however, this can be impacted by inadequate samples due to disease progression or timing of patients seeking clinical care. While genotyping has provided important data on circulating strains over the past 2 decades, WGS data are needed to better understand strain diversity, perform evolutionary tracing, and monitor antimicrobial resistance markers. The significance of our research is the development of an SWGA DNA enrichment method that expands the range of clinical specimens that can be directly sequenced to include samples with low numbers of T. pallidum. |
Characterization of a Neisseria gonorrhoeae Ciprofloxacin panel for an antimicrobial resistant Isolate Bank.
Liu H , Tang K , Pham CD , Schmerer M , Kersh EN , Raphael BH . PLoS One 2022 17 (3) e0264149 OBJECTIVES: Neisseria gonorrhoeae (gonococcus) infection is one of the most commonly reported nationally notifiable conditions in the United States. Gonococcus has developed antimicrobial resistance to each previously used antibiotic for gonorrhea therapy. However, some isolates may be still susceptible to no longer recommended, yet still effective antibiotics. This in turn suggests that targeted therapy could slow resistance development to currently recommended empirical treatments. We curated a gonococcal Ciprofloxacin Antibiotic Resistance Isolate Bank panel (Cipro-panel) as a tool for validating or developing new tests to determine ciprofloxacin susceptibility. METHOD: The Cipro-panel was selected using whole genome sequencing, bioinformatic tools, and antimicrobial susceptibility testing (AST) data. Isolates were further selected based on nucleotide variations in gyrA and parC genes. RESULTS: We selected 14 unique N. gonorrhoeae isolates from the 2006-2012 Gonococcal Isolate Surveillance Project (GISP) collection. They represented a wide range of antimicrobial susceptibility to ciprofloxacin and commonly observed nucleotide variations of gyrA and parC genes. This Cipro-panel consists of 5 isolates with resistant phenotypes (MIC > = 1 g/mL), 8 isolates with susceptible phenotypes (MIC < = 0.06 g/mL), and 1 isolate falling in the Clinical and Laboratory Standards Institute defined intermediate range. Among the gyrA variations we observed a total of 18 SNPs. Four positions had nonsynonymous changes (nucleotide positions 272, 284, 1093, and 1783). The first two positions (272 and 284) have been linked previously with resistance to ciprofloxacin (i.e. amino acid positions 91 and 95). For the parC gene, we observed a total of 21 possible SNPs. Eight of those SNPs resulted in non-synonymous amino acid changes. One location (amino acid 87) has been previously reported to be associated with ciprofloxacin resistance. CONCLUSIONS: This Cipro-Panel is useful for researchers interested in developing clinical tests related to ciprofloxacin. It could also provide additional choices for validation, quality assurance purposes and improve antibiotic usage. |
HISTOLOGIC LESIONS IN PLACENTAS OF NORTHERN FUR SEALS (CALLORHINUS URSINUS) FROM A POPULATION WITH HIGH PLACENTAL PREVALENCE OF COXIELLA BURNETII.
Conway R , Duncan C , Foster RA , Kersh GJ , Raverty S , Gelatt T , Frank C . J Wildl Dis 2022 58 (2) 333-340 Coxiella burnetii is an intracellular bacterial pathogen that can be associated with significant reproductive disease or acute mortality in livestock and wildlife. A novel marine mammal-associated strain of C. burnetii has been identified in pinnipeds of the Northwestern Pacific Ocean. Little is known about C. burnetii infection in regard to reproductive success or population status. Our objective was to characterize the severity and extent of histologic lesions in 117 opportunistically collected placentas from presumed-normal northern fur seals (Callorhinus ursinus) in July 2011 on St. Paul Island, Alaska, where a high placental prevalence of C. burnetii had been reported. Sections were examined by histology and immunohistochemistry and impression smears with modified acid-fast stain. The nature and frequency of histologic changes were compared with target COM1 PCR-confirmed C. burnetii positive and negative placentas. Overall, histologic changes were similar to placental lesions described in aborting ruminants; however, changes were variable within and between placentas. Vasculitis and occasional intracellular bacteria were seen only in C. burnetii PCR-positive placentas. Dystrophic mineralization, edema, and inflammation were seen in PCR-positive and negative placentas, although they were statistically more common in PCR-positive placentas. Results suggest that C. burnetti and associated pathologic changes are multifocal and variable in placentas from these presumably live-born pups. Therefore, multiple sections of tissue from different placental areas should be examined microscopically and screened by PCR to ensure accurate diagnosis, as the genomes per gram of placenta may not necessarily represent the severity of placental disease. These limitations should inform field biologists, diagnosticians, and pathologists how best to screen and sample for pathogens and histopathology in marine mammal placental samples. |
Gonococcal Clinical Strains Bearing a Common gdhR Single Nucleotide Polymorphism That Results in Enhanced Expression of the Virulence Gene lctP Frequently Possess a mtrR Promoter Mutation That Decreases Antibiotic Susceptibility.
Ayala JC , Schmerer MW , Kersh EN , Unemo M , Shafer WM . mBio 2022 13 (2) e0027622 GdhR is a transcriptional repressor of the virulence factor gene lctP, which encodes a unique l-lactate permease that has been linked to pathogenesis of Neisseria gonorrhoeae, and loss of gdhR can confer increased fitness of gonococci in a female mouse model of lower genital tract infection. In this work, we identified a single nucleotide polymorphism (SNP) in gdhR, which is often present in both recent and historical gonococcal clinical strains and results in a proline (P)-to-serine (S) change at amino acid position 6 (P6S) of GdhR. This mutation (gdhR6) was found to reduce GdhR transcriptional repression at lctP in gonococcal strains containing the mutant protein compared to wild-type GdhR. By using purified recombinant proteins and in vitro DNA-binding and cross-linking experiments, we found that gdhR6 impairs the DNA-binding activity of GdhR at lctP without an apparent effect on protein oligomerization. By analyzing a panel of U.S. (from 2017 to 2018) and Danish (1928 to 2013) clinical isolates, we observed a statistical association between gdhR6 and the previously described adenine deletion in the promoter of mtrR (mtrR-P A-del), encoding the repressor (MtrR) of the mtrCDE operon that encodes the MtrCDE multidrug efflux pump that can export antibiotics, host antimicrobials, and biocides. The frequent association of gdhR6 with the mtrR promoter mutation in these clinical isolates suggests that it has persisted in this genetic background to enhance lctP expression, thereby promoting virulence. IMPORTANCE We report the frequent appearance of a novel SNP in the gdhR gene (gdhR6) possessed by Neisseria gonorrhoeae. The resulting amino acid change in the GdhR protein resulted in enhanced expression of a virulence gene (lctP) that has been suggested to promote gonococcal survival during infection. The mutant GdhR protein expressed by gdhR6 had a reduced ability to bind to its target DNA sequence upstream of lctP. Interestingly, gdhR6 was found in clinical gonococcal strains isolated in the United States and Denmark at a high frequency and was frequently associated with a mutation in the promoter of the gene encoding a repressor (MtrR) of both the mtrCDE antimicrobial efflux pump operon and gdhR. Given this frequent association and the known impact of these regulatory mutations, we propose that virulence and antibiotic resistance properties are often phenotypically linked in contemporary gonococcal strains. |
Chlamydia trachomatis variants escaping detection in the Aptima Combo 2® assay in the United States.
Katz SS , Danavall DC , Morris MR , Herrod BP , Dale SE , Nye MB , Kersh EN , Kirkcaldy RD , Raphael BH . Sex Transm Dis 2022 49 (6) 448-452 BACKGROUND: The Aptima Combo 2 (AC2) assay manufactured by Hologic, Inc. detects Neisseria gonorrhoeae (NG) and/or Chlamydia trachomatis (CT) in urogenital and extragenital specimens by targeting either a 16S rRNA (NG) or 23S rRNA (CT) region. In 2019, a mutation (C1515T) in the 23S rRNA region was reported to cause false negative/equivocal results in specimens collected in Finland. Specimens containing this variant (Fl-nvCT) were also discovered internationally. Working with specimens submitted to a large commercial laboratory, we sought to determine if this variant was also present in the United States. METHODS: A subset (N = 401) of specimens tested with the AC2 assay collected during a five-week period in late 2019/early 2020 were evaluated using an updated AC2 assay. RESULTS: While the FI-nvCT variant was not detected within this specimen panel, two CT variants containing 23S rRNA mutations (A1518G, G1526A) were identified. The updated AC2 assay targeting an additional region of the 23S rRNA detected both of these variants. A retrospective study of >18 million AC2 results tested between 2018-2019 did not display a decrease in CT positivity. CONCLUSIONS: Although we did not detect the Fl-nvCT variant among US specimens, we show evidence that the low occurrence of similar diagnostic escape mutants can be detected with an updated AC2 assay using multiple 23S rRNA targets. |
Evaluation of the effect of extended refrigerated storage of serum and plasma specimens on syphilis serologic test results
Sun Y , Shukla MR , Deutsch J , Cao W , Fakile Y , Kersh EN , Pereira LE . Diagn Microbiol Infect Dis 2022 102 (2) 115588 The effect of extended refrigerated storage of 14 serum and plasma specimens on 5 syphilis serologic tests was evaluated for 16 weeks. Higher stability of nontreponemal and treponemal antibodies in serum was recorded compared to plasma. Described work may provide insights on refrigerated specimens' stability and suitability for syphilis tests. |
Global emergence and dissemination of Neisseria gonorrhoeae ST-9363 isolates with reduced susceptibility to azithromycin.
Joseph SJ , Thomas Iv JC , Schmerer MW , Cartee J , St Cyr S , Schlanger K , Kersh EN , Raphael BH , Gernert KM . Genome Biol Evol 2021 14 (1) Neisseria gonorrhoeae multi-locus sequence type (ST) 9363 core-genogroup isolates have been associated with reduced azithromycin susceptibility (AZMrs) and show evidence of clonal expansion in the U.S. Here we analyze a global collection of ST-9363 core-genogroup genomes to shed light on the emergence and dissemination of this strain. The global population structure of ST-9363 core-genogroup falls into three lineages: Basal, European, and North American; with 32 clades within all lineages. Although, ST-9363 core-genogroup is inferred to have originated from Asia in the mid-19th century; we estimate the three modern lineages emerged from Europe in the late 1970s to early 1980s. The European lineage appears to have emerged and expanded from around 1986 to 1998, spreading into North America and Oceania in the mid-2000s with multiple introductions, along with multiple secondary reintroductions into Europe. Our results suggest two separate acquisition events of mosaic mtrR and mtrR promoter alleles: first during 2009-2011 and again during the 2012-2013 time, facilitating the clonal expansion of this core-genogroup with AZMrs in the U.S. By tracking phylodynamic evolutionary trajectories of clades that share distinct demography as well as population-based genomic statistics, we demonstrate how recombination and selective pressures in the mtrCDE efflux operon granted a fitness advantage to establish ST-9363 as a successful gonococcal lineage in the U.S. and elsewhere. Although it is difficult to pinpoint the exact timing and emergence of this young core-genogroup, it remains critically important to continue monitoring it, as it could acquire additional resistance markers. |
Evaluation of a laboratory-developed multiplex real-time PCR assay for diagnosis of syphilis, herpes and chancroid genital ulcers in four public health laboratories in the USA.
Koralur M , Chen CY , Pillay A , White B , Pettus K , Chi KH , Stringer J , Aroh C , Dasu T , Bhattacharyya S , Perkins K , Chen J , Riner D , Soehnlen M , Cao W , Gaynor AM , Kersh EN . Sex Transm Infect 2021 98 (6) 448-450 OBJECTIVE: To evaluate the field performance of a multiplex PCR (M-PCR) assay for detection of herpes simplex virus (HSV)-1 and HSV-2, Treponema pallidum (T. pallidum) and Haemophilus ducreyi (H. ducreyi) in genital ulcer disease (GUD) specimens. METHODS: GUD M-PCR was performed on 186 remnant specimens, previously collected for HSV testing, by four public health laboratories (PHLs) and the Laboratory Reference and Research Branch (LRRB) at the Centers for Disease Control and Prevention. The results from the PHLs were compared with those of LRRB, which served as the reference testing method, and percentage agreement was calculated. RESULTS: HSV was detected in 31 of 52 (59.6%), 20 of 40 (50%), 43 of 44 (97.7%) and 19 of 50 (38.0%) specimens from PHL1, PHL2, PHL3 and PHL4, respectively. There were seven discrepant results for HSV, and the overall percent agreement between the PHLs and the LRRB was 94%-100%, with a kappa value of 0.922, which demonstrates high agreement. T. pallidum was identified in 7 of 51 (13.7%) specimens from PHL1 with 94.1% agreement and in 2 of 40 (5.0%) specimens from PHL2 with 100% agreement. The LRRB identified three additional T. pallidum-positive specimens from PHL1. The kappa value (0.849) for T. pallidum testing suggests good agreement. Consistent with the LRRB results, no T. pallidum was detected in specimens from PHL3 and PHL4, and H. ducreyi was not detected at any of the study sites. CONCLUSIONS: The GUD M-PCR assay performed well in four independent PHLs and 12 suspected syphilis cases were identified in this study. The M-PCR assay could provide improved diagnostic options for GUD infections in state and local PHLs. |
Acute and chronic Q fever national surveillance - United States, 2008-2017
Cherry CC , Nichols Heitman K , Bestul NC , Kersh GJ . Zoonoses Public Health 2021 69 (2) 73-82 Q fever is a zoonotic disease caused by the bacterium Coxiella burnetii and can manifest in an acute or chronic form. Many persons with acute Q fever are asymptomatic, but some develop a febrile illness, pneumonia or hepatitis. Chronic infections are rare and occur in less than 5% of persons exposed. Forms of chronic Q fever include endocarditis, infection of vascular grafts or aneurysms, osteomyelitis and osteoarthritis. Acute and chronic Q fever are nationally notifiable diseases, and presented here are the incidence, demographics and distribution of acute and chronic Q fever in the United States during 2008-2017. We summarized passive surveillance data from the Centers for Disease Control and Prevention's (CDC) National Notifiable Diseases Surveillance System (NNDSS) and supplemental case report forms (CRFs). Health departments reported 1,109 cases of acute Q fever and 272 chronic Q fever cases to NNDSS during this period. The 10-year average annual incidence for acute Q fever was 0.36 cases per million persons, and the average annual incidence for chronic Q fever was 0.09. Males accounted for nearly 75% of both acute and chronic Q fever cases. Average annual incidence was highest among persons aged 60-69 years for both acute and chronic Q fever (0.70 cases per million persons and 0.25, respectively). As reported through CRFs, many Q fever cases did not have a known exposure to C. burnetii; 60% (n = 380) of acute Q fever cases did not report exposure to animals in the 2 months before symptom onset. Almost 90% (n = 558) did not report exposure to unpasteurized milk. Only 40% (n = 247) of persons with reported Q fever were employed in high-risk occupations. Even though Q fever is a rare disease in the United States, incidence doubled from 2008 to 2017. |
Comparison of three Coxiella burnetii infectious routes in mice
Miller HK , Priestley RA , Kersh GJ . Virulence 2021 12 (1) 2562-2570 Evidence suggests that Coxiella burnetii, which is shed in the milk, urine, feces, and birth products of infected domestic ruminants, can lead to Q fever disease following consumption of unpasteurized dairy products; however, C. burnetii is not believed to be a major gastrointestinal pathogen. Most infections are associated with inhalation of aerosols generated from the excreta of domestic ruminants. We recently demonstrated that C. burnetii delivered by oral gavage (OG) resulted in dissemination and an immune response; however, it is unclear how infection via the oral route compares to other well-established routes. Therefore, we delivered three strains of C. burnetii (representing three pertinent sequence types in the United States, such as ST16, ST20, and ST8) to immunocompetent mice in four doses via aerosol challenge (AC), intraperitoneal injection (IP), or OG. Low dose (10^5) of ST16 by OG was insufficient to cause infection, yet doses 1,000- or 100-fold lower by IP or AC, respectively, induced a robust immune response and dissemination. Despite being able to induce an immune response in a dose-dependent manner, administration of C. burnetii via OG is the least efficient route tested. Not only were the immune responses and bacterial loads diminished in mice exposed by OG relative to AC or IP, the efficiency of transmission was also inferior. High doses (10^8) were not sufficient to ensure transmission to 100% of the ST20 or ST8 cohorts. These results may provide some basis for why ingestion of C. burnetii as a mode of Q fever transmission is not often reported. |
Coxiella burnetii infections in mice: Immunological responses to contemporary genotypes found in the US.
Priestley RA , Smith CB , Miller HK , Kersh GJ . Virulence 2021 12 (1) 2461-2473 Coxiella burnetii is an obligate intracellular bacterium that causes the human disease Q fever, which can manifest as an acute flu-like illness or a long-term chronic illness, such as endocarditis. Three genotypes (ST8, ST16, and ST20) of Coxiella burnetii are commonly found in the contemporary US and are associated with specific animal hosts. Although all three genotypes have been isolated from humans with Q fever, studies comparing virulence between C. burnetii sequence types have been rare. Here, groups of mice were infected via aerosol inoculation with isolates derived from cow's milk, environmental, animal, and human samples. Mice were monitored for weight loss and blood samples were takenweekly. Animals were euthanized at 2- and 12-weeks post-infection, and bacterial burden was determined for tissues by real-time PCR. The levels of anti-Coxiella antibodies and selected inflammatory cytokines were determined for serum samples. Weight loss and splenomegaly were observed in mice infected with ST20 and ST16 isolates but were absent in the mice infected with ST8 isolates. Bacterial concentrations in the tissues were lower in the ST8 isolates at 2 weeks post-infection relative to all other isolates. ST16 and ST20 isolates induced robust antibody and cytokine responses, while ST8 isolates produced significantly lower anti-C. burnetii titers early in the infection but saw increased titers in some animals several weeks post-infection. The data suggest that the ST8 isolates are less virulent in this mouse model, as they produce less robust antibody responses that are slow to develop, relative to the ST16 and ST20 isolates. |
Implementation and evaluation of gradient strip antimicrobial susceptibility testing in US public health laboratories to respond to resistant gonorrhea
Raphael BH , Pham CD , Sharpe S , Mauk K , Harvey A , Khubbar M , Triplett L , Soge OO , Denny M , Palavecino EL , Finney R , Olsen A , Carlson J , St Cyr SB , Schlanger K , Kersh EN . Sex Transm Dis 2021 48 S157-S160 BACKGROUND: Gradient strip antimicrobial susceptibility testing (AST) using Etest® is conducted by local public health jurisdictions participating in the Strengthening the U.S. Response to Resistant Gonorrhea (SURRG) program to inform public health responses to resistant gonorrhea. Proficiency testing results across the participating laboratories were analyzed and a comparison of Etest® with the agar dilution method was conducted. METHODS: Laboratories participating in SURRG performed Etest® for azithromycin (AZM), cefixime (CFX), and ceftriaxone (CRO). Concurrence between minimum inhibitory concentrations (MICs) obtained with Etest® versus the agar dilution method using corresponding isolates was defined as +/- 1 double dilution. Specific levels of reduced susceptibility were termed "alerts" and included isolates with the following MICs: ≥ 2.0 μg/ml (AZM), ≥ 0.25 μg/ml (CFX), and ≥ 0.125 μg/ml (CRO). Categorical (alert/non-alert) agreement was calculated for MICs determined using Etest® and agar dilution methods. RESULTS: SURRG laboratories had high proficiency testing scores (≥98%) and low levels of inter-laboratory variations in MICs. The overall concurrence of MICs (essential agreement) determined using agar dilution and Etest® was 96% (CRO), 96% (CFX), and 95% (AZM). Depending on the antibiotic tested, between 27-66% of isolates with alert MICs determined by Etest® also had alert MICs using the reference agar dilution methodology, however most of these alert MICs were detected at threshold levels. CONCLUSIONS: This study demonstrates that MICs produced by SURRG laboratories using Etest® have a high level of concurrence with agar dilution. Although confirmation of specific alert MICs varied, Etest® facilities rapid detection and response to emerging resistant gonorrhea. |
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