Last data update: May 13, 2024. (Total: 46773 publications since 2009)
Records 1-15 (of 15 Records) |
Query Trace: Satola S[original query] |
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Evaluation of asymptomatic Bordetella carriage in a convenience sample of children and adolescents in Atlanta, Georgia, United States
Acosta AM , Simon A , Thomas S , Tunali A , Satola S , Jain S , Farley MM , Tondella ML , Skoff TH . J Pediatric Infect Dis Soc 2023 Few data exist on asymptomatic carriage of Bordetella species among populations receiving acellular pertussis vaccine. We conducted a cross-sectional study among acellular-vaccinated children presenting to an emergency department. B. pertussis carriage prevalence was <1% in this population, a lower prevalence than that found in recent studies among whole-cell pertussis-vaccinated participants. |
Clinical and genomic epidemiology of mcr-9-carrying carbapenem-resistant Enterobacterales isolates in Metropolitan Atlanta, 2012-2017 (preprint)
Babiker A , Bower C , Lutgring JD , Howard-Anderson J , Ansari U , McAllister G , Adamczyk M , Breaker E , Satola SW , Jacob JT , Woodworth MH . medRxiv 2021 2021.10.13.21264308 Colistin is a last-resort antibiotic for multidrug-resistant gram-negative infections. Recently, the ninth allele of the mobile colistin resistance (mcr) gene family, designated mcr-9, was reported. However, its clinical and public health significance remains unclear. We queried genomes of carbapenem-resistant Enterobacterales (CRE) for mcr-9 from a convenience sample of clinical isolates collected between 2012-2017 through the Georgia Emerging Infections Program, a population- and laboratory-based surveillance program. Isolates underwent phenotypic characterization and whole genome sequencing. Phenotypic characteristics, genomic features, and clinical outcomes of mcr-9 positive and negative CRE cases were then compared. Among 235 sequenced CRE genomes, thirteen (6%) were found to harbor mcr-9, all of which were Enterobacter cloacae complex. The median MIC, rates of heteroresistance and inducible resistance to colistin were similar between mcr-9 positive and negative isolates. However, rates of resistance were higher among mcr-9 positive isolates across most antibiotic classes. All cases had significant healthcare exposures. The 90-day mortality was similarly high in both mcr-9 positive (31%) and negative (7%) CRE cases. Nucleotide identity and phylogenetic analysis did not reveal geo-temporal clustering. mcr-9 positive isolates had a significantly higher number of median [range] AMR genes (16 [4-22] vs. 6 [2-15]; p <0.001) compared to mcr-9 negative isolates. Pan genome tests confirmed a significant association of mcr-9 detection with mobile genetic element and heavy metal resistance genes. Overall, the presence of mcr-9 was not associated with significant changes in colistin resistance or clinical outcomes but continued genomic surveillance to monitor for emergence of AMR genes is warranted.Competing Interest StatementThe authors have declared no competing interest.Funding StatementEIP Surveillance of the Multi-site Gram-Negative Surveillance Initiative (MuGSI) was funded through the Centers for Disease Control and Preventions Emerging Infections Program [U50CK000485].Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:Georgia EIP surveillance activities are reviewed and approved by the Emory University Institutional Review Board.I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesAll data produced in the present study are available upon reasonable request to the authors |
Development of a broth microdilution method to characterize chlorhexidine mics among bacteria collected from 2005 to 2019 at three U.S. Sites
Lutgring JD , Grass JE , Lonsway D , Yoo BB , Epson E , Crumpler M , Galliher K , O'Donnell K , Zahn M , Evans E , Jacob JT , Page A , Satola SW , Smith G , Kainer M , Muleta D , Wilson CD , Hayden MK , Reddy S , Elkins CA , Rasheed JK , Karlsson M , Magill SS , Guh AY . Microbiol Spectr 2023 11 (3) e0413422 Chlorhexidine bathing to prevent transmission of multidrug-resistant organisms has been adopted by many U.S. hospitals, but increasing chlorhexidine use has raised concerns about possible emergence of resistance. We sought to establish a broth microdilution method for determining chlorhexidine MICs and then used the method to evaluate chlorhexidine MICs for bacteria that can cause health care-associated infections. We adapted a broth microdilution method for determining chlorhexidine MICs, poured panels, established quality control ranges, and tested Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae complex isolates collected at three U.S. sites. Chlorhexidine MICs were determined for 535 isolates including 129 S. aureus, 156 E. coli, 142 K. pneumoniae, and 108 E. cloacae complex isolates. The respective MIC distributions for each species ranged from 1 to 8 mg/L (MIC(50) = 2 mg/L and MIC(90) = 4 mg/L), 1 to 64 mg/L (MIC(50) = 2 mg/L and MIC(90) = 4 mg/L), 4 to 64 mg/L (MIC(50) = 16 mg/L and MIC(90) = 32 mg/L), and 1 to >64 mg/L (MIC(50) = 16 mg/L and MIC(90) = 64 mg/L). We successfully adapted a broth microdilution procedure that several laboratories were able to use to determine the chlorhexidine MICs of bacterial isolates. This method could be used to investigate whether chlorhexidine MICs are increasing. IMPORTANCE Chlorhexidine bathing to prevent transmission of multidrug-resistant organisms and reduce health care-associated infections has been adopted by many hospitals. There is concern about the possible unintended consequences of using this agent widely. One possible unintended consequence is decreased susceptibility to chlorhexidine, but there are not readily available methods to perform this evaluation. We developed a method for chlorhexidine MIC testing that can be used to evaluate for possible unintended consequences. |
Clinical and Genomic Epidemiology of mcr-9-Carrying Carbapenem-Resistant Enterobacterales Isolates in Metropolitan Atlanta, 2012 to 2017.
Babiker A , Bower C , Lutgring JD , Petit RA3rd , Howard-Anderson J , Ansari U , McAllister G , Adamczyk M , Breaker E , Satola SW , Jacob JT , Woodworth MH . Microbiol Spectr 2022 10 (4) e0252221 Colistin is a last-resort antibiotic for multidrug-resistant Gram-negative infections. Recently, the ninth allele of the mobile colistin resistance (mcr) gene family, designated mcr-9, was reported. However, its clinical and public health significance remains unclear. We queried genomes of carbapenem-resistant Enterobacterales (CRE) for mcr-9 from a convenience sample of clinical isolates collected between 2012 and 2017 through the Georgia Emerging Infections Program, a population- and laboratory-based surveillance program. Isolates underwent phenotypic characterization and whole-genome sequencing. Phenotypic characteristics, genomic features, and clinical outcomes of mcr-9-positive and -negative CRE cases were then compared. Among 235 sequenced CRE genomes, 13 (6%) were found to harbor mcr-9, all of which were Enterobacter cloacae complex. The median MIC and rates of heteroresistance and inducible resistance to colistin were similar between mcr-9-positive and -negative isolates. However, rates of resistance were higher among mcr-9-positive isolates across most antibiotic classes. All cases had significant health care exposures. The 90-day mortality was similarly high in both mcr-9-positive (31%) and -negative (7%) CRE cases. Nucleotide identity and phylogenetic analysis did not reveal geotemporal clustering. mcr-9-positive isolates had a significantly higher number of median [range] antimicrobial resistance (AMR) genes (16 [4 to 22] versus 6 [2 to 15]; P < 0.001) than did mcr-9-negative isolates. Pangenome tests confirmed a significant association of mcr-9 detection with mobile genetic element and heavy metal resistance genes. Overall, the presence of mcr-9 was not associated with significant changes in colistin resistance or clinical outcomes, but continued genomic surveillance to monitor for emergence of AMR genes is warranted. IMPORTANCE Colistin is a last-resort antibiotic for multidrug-resistant Gram-negative infections. A recently described allele of the mobile colistin resistance (mcr) gene family, designated mcr-9, has been widely reported among Enterobacterales species. However, its clinical and public health significance remains unclear. We compared characteristics and outcomes of mcr-9-positive and -negative CRE cases. All cases were acquired in the health care setting and associated with a high rate of mortality. The presence of mcr-9 was not associated with significant changes in colistin resistance, heteroresistance, or inducible resistance but was associated with resistance to other antimicrobials and antimicrobial resistance (AMR), virulence, and heavy metal resistance (HMR) genes. Overall, the presence of mcr-9 was not associated with significant phenotypic changes or clinical outcomes. However, given the increase in AMR and HMR gene content and potential clinical impact, continued genomic surveillance of multidrug-resistant organisms to monitor for emergence of AMR genes is warranted. |
Invasive Nontypeable Haemophilus influenzae Infection Among Adults With HIV in Metropolitan Atlanta, Georgia, 2008-2018.
Collins LF , Havers FP , Tunali A , Thomas S , Clennon JA , Wiley Z , Tobin-D'Angelo M , Parrott T , Read TD , Satola SW , Petit RA3rd , Farley MM . JAMA 2019 322 (24) 2399-2410 Importance: Invasive nontypeable Haemophilus influenzae (NTHi) infection among adults is typically associated with bacteremic pneumonia. Nontypeable H influenzae is genetically diverse and clusters of infection are uncommon. Objective: To evaluate an increase in invasive NTHi infection from 2017-2018 among HIV-infected men who have sex with men in metropolitan Atlanta, Georgia. Design, Setting, and Participants: A population-based surveillance study with a cohort substudy and descriptive epidemiological analysis identified adults aged 18 years or older with invasive NTHi infection (isolation of NTHi from a normally sterile site) between January 1, 2008, and December 31, 2018 (final date of follow-up). Exposures: Time period, HIV status, and genetic relatedness (ie, cluster status) of available NTHi isolates. Main Outcomes and Measures: The primary outcome was incidence of invasive NTHi infection (from 2008-2016 and 2017-2018) among persons with HIV and compared with NTHi infection from 2008-2018 among those without HIV. The secondary outcomes were assessed among those aged 18 to 55 years with invasive NTHi infection and included epidemiological, clinical, and geographic comparisons by cluster status. Results: Among 553 adults with invasive NTHi infection (median age, 66 years [Q1-Q3, 48-78 years]; 52% male; and 38% black), 60 cases occurred among persons with HIV. Incidence of invasive NTHi infection from 2017-2018 among persons with HIV (41.7 cases per 100000) was significantly greater than from 2008-2016 among those with HIV (9.6 per 100000; P < .001) and from 2008-2018 among those without HIV (1.1 per 100000; P < .001). Among adults aged 18 to 55 years with invasive NTHi infections from 2017-2018 (n = 179), persons with HIV (n = 31) were significantly more likely than those from 2008-2018 without HIV (n = 124) to be male (94% vs 49%, respectively; P < .001), black (100% vs 53%; P < .001), and have septic arthritis (35% vs 1%; P < .001). Persons with HIV who had invasive NTHi infection from 2017-2018 (n = 31) were more likely than persons with HIV who had invasive NTHi infection from 2008-2016 (n = 24) to have septic arthritis (35% vs 4%, respectively; P = .01). Pulsed-field gel electrophoresis of 174 of 179 NTHi isolates from 18- to 55-year-olds identified 2 genetically distinct clonal groups: cluster 1 (C1; n = 24) and cluster 2 (C2; n = 23). Whole-genome sequencing confirmed 2 clonal lineages of NTHi infection and revealed all C1 isolates (but none of the C2 isolates) carried IS1016 (an insertion sequence associated with H influenzae capsule genes). Persons with HIV were significantly more likely to have C1 or C2 invasive NTHi infection from 2017-2018 (28/31 [90%]) compared with from 2008-2016 among persons with HIV (10/24 [42%]; P < .001) and compared with from 2008-2018 among those without HIV (9/119 [8%]; P < .001). Among persons with C1 or C2 invasive NTHi infection who had HIV (n = 38) (median age, 34.5 years; 100% male; 100% black; 82% men who have sex with men), 32 (84%) lived in 2 urban counties and an area of significant spatial aggregation was identified compared with those without C1 or C2 invasive NTHi infection. Conclusions and Relevance: Among persons with HIV in Atlanta, the incidence of invasive nontypeable H influenzae infection increased significantly from 2017-2018 compared with 2008-2016. Two unique but genetically related clonal strains were identified and were associated with septic arthritis among black men who have sex with men and who lived in geographic proximity. |
Invasive Methicillin-Resistant Staphylococcus aureus USA500 Strains from the U.S. Emerging Infections Program Constitute Three Geographically Distinct Lineages.
Frisch MB , Castillo-Ramirez S , Petit RA3rd , Farley MM , Ray SM , Albrecht VS , Limbago BM , Hernandez J , See I , Satola SW , Read TD . mSphere 2018 3 (3) USA500 isolates are clonal complex 8 (CC8) Staphylococcus aureus strains closely related to the prominent community- and hospital-associated USA300 group. Despite being relatively understudied, USA500 strains cause a significant burden of disease and are the third most common methicillin-resistant S. aureus (MRSA) strains identified in the U.S. Emerging Infections Program (EIP) invasive S. aureus surveillance. To better understand the genetic relationships of the strains, we sequenced the genomes of 539 USA500 MRSA isolates from sterile site infections collected through the EIP between 2005 and 2013 in the United States. USA500 isolates fell into three major clades principally separated by their distribution across different U.S. regions. Clade C1 strains, found principally in the Northeast, were associated with multiple IS256 insertion elements in their genomes and higher levels of antibiotic resistance. C2 was associated with Southern states, and E1 was associated with Western states. C1 and C2 strains all shared a frameshift in the gene encoding AdsA surface-attached surface protein. We propose that the term "USA500" should be used for CC8 strains sharing a recent common ancestor with the C1, C2, and E1 strains but not in the USA300 group.IMPORTANCE In this work, we have removed some of the confusion surrounding the use of the name "USA500," placed USA500 strains in the context of the CC8 group, and developed a strategy for assignment to subclades based on genome sequence. Our new phylogeny of USA300/USA500 will be a reference point for understanding the genetic adaptations that have allowed multiple highly virulent clonal strains to emerge from within CC8 over the past 50 years. |
Decline in pneumococcal nasopharyngeal carriage of vaccine serotypes after the introduction of the 13-valent pneumococcal conjugate vaccine in children in Atlanta, Georgia
Desai AP , Sharma D , Crispell EK , Baughman W , Thomas S , Tunali A , Sherwood L , Zmitrovich A , Jerris R , Satola S , Beall B , Moore MR , Jain S , Farley MM . Pediatr Infect Dis J 2015 34 (11) 1168-74 BACKGROUND: Streptococcus pneumoniae (SP) serotype distribution among nasopharyngeal (NP) carriage isolates changed significantly after the introduction of the seven-valent pneumococcal conjugate vaccine (PCV7). We evaluated the impact on NP carriage and invasive disease of SP after the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13) in March 2010. METHODS: NP swabs were collected from children 6-59 months of age in an emergency department from July 2010-June 2013. After broth enrichment, samples were cultured for SP and isolates were serotyped. Clinical and immunization records were reviewed. Findings during six sequential 6-month study periods were compared. Surveillance isolates of invasive disease isolates were reviewed. RESULTS: A total of 2,048 children were enrolled and 656 (32%) were SP carriers. Mean age of carriers was 27 months, 54% were males. Carriage was higher among daycare attendees (p<0.01) and children with respiratory tract illnesses (p<0.5) and otitis media (p<0.01). Commonly carried serotypes included 35B (15.2%), 15B/C (14.2%), 19A (9.6%), 11A (8%), 23B (5.6%), 6C (5.3%), 21 (5%), and 15A (5%); 13.9% were PCV13 serotypes. The proportion of children with SP carriage remained stable but the serotype distribution changed over the study period. Among carriers, PCV13 serotypes declined from 29% (36/124) to 3% (3/99) (p<0.0001), predominantly due to decline of serotype 19A from 25.8% (32/124) to 3% (3/99) (p<0.0001); non-PCV13 serotypes (excluding 6C) increased from 68.4% (78/114) to 97% (95/98) (p<0.0001); serotype 35B significantly increased from 8.9% (11/124) to 25.3% (25/99) (p<0.05). Nonsusceptibility to ceftriaxone declined from 22.6% (28/124) to 0% (0/99) (p<0.0001), with a similar decline in penicillin nonsusceptibility. CONCLUSIONS: Introduction of PCV13 for universal infant use was associated with significant reductions in nasopharyngeal carriage of PCV13 serotypes and resistant strains. Carriage of non-PCV13 serotypes increased modestly, particularly serotype 35B. Further investigation is warranted to determine whether non-vaccine pneumococcal serotypes carried in the nasopharynx are associated with significant replacement disease. |
Duration of colonization with methicillin-resistant Staphylococcus aureus in an acute care facility: a study to assess epidemiologic features
Rogers C , Sharma A , Rimland D , Stafford C , Jernigan J , Satola S , Crispell E , Gaynes R . Am J Infect Control 2014 42 (3) 249-53 BACKGROUND: Patients with a history of methicillin-resistant Staphylococcus aureus (MRSA) colonization or infection are often presumed to remain colonized when they are readmitted to the hospital. This assumption underlies the hospital practice that flags MRSA-positive patients so that these patients can be placed in contact isolation at hospital admission and, when necessary, be given the appropriate empirical therapy and/or antibiotic prophylaxis. METHODS: To determine the duration of and factors associated with MRSA colonization among patients following discharge, we designed a cohort study of patients hospitalized between October 1, 2007, and July 31, 2009, at the Atlanta Veterans Affairs Medical Center, a 128-bed acute care facility. We defined 3 cohorts: cohort A; patients with both a MRSA infection during hospitalization and nasal colonization at discharge; cohort B; patients with a MRSA infection but no nasal colonization at discharge; and cohort C; patients only nasally colonized at discharge. We collected information on demographic characteristics, underlying conditions, infections, and antibiotic use. We cultured nasal swabs obtained from patients at home. We calculated hazard ratios (HR), comparing cohorts A, B, and C after controlling for other factors. RESULTS: We obtained 231 swabs (23 in cohort A, 34 in cohort B, and 174 in cohort C). We documented MRSA colonization in 92 (39.9%) of the 231 patients who returned swabs. The median duration of colonization was 33.3 months. Factors significantly associated with persistent MRSA colonization were (1) total duration of hospital stay from previous admissions prior to study entry and (2) a member of cohort A who had a longer duration of colonization compared with cohorts B and C (P < .001). CONCLUSION: Our data suggest that higher initial inocula of bacteria may be an important determinant of persistent colonization with MRSA. |
Pneumococcal carriage and invasive disease in children before introduction of the 13-valent conjugate vaccine: comparison with the pre-7-valent conjugate vaccine era
Sharma D , Baughman W , Holst A , Thomas S , Jackson D , Carvalho MD , Beall B , Satola S , Jerris R , Jain S , Farley MM , Nuorti JP . Pediatr Infect Dis J 2012 32 (2) e45-53 BACKGROUND: Nasopharyngeal (NP) carriage and invasive pneumococcal disease (IPD) due to serotypes in the 7-valent pneumococcal conjugate vaccine (PCV7) declined dramatically after vaccine introduction, whereas non-PCV7 serotypes increased modestly. Characteristics of pneumococcal carriage and IPD among children in Atlanta were compared during two time periods: pre-PCV7 introduction and pre-PCV13 introduction. METHODS: NP swabs from 231 and 451 children aged 6 to 59 months receiving outpatient medical care were obtained in 1995 and 2009, respectively. A total of 202 and 47 IPD cases were identified in children < 5 years of age in 1995 and 2008-2009, respectively, through active, population-based surveillance in Atlanta. Isolates were serotyped, sequence typed (ST), and tested for antimicrobial susceptibility RESULTS: Forty percent (93/231) of children in 1995 and 31% (139/451) in 2009 were colonized with Streptococcus pneumoniae; 60% and 0.7% were PCV7 serotypes, respectively. In 1995, PCV7 serotypes accounted for 83% and 19A 5% of IPD compared with no PCV7 serotypes and 49% 19A among IPD in 2009 [P<0.001]. In 2009, PCV13 serotypes accounted for 22% of carriage (mostly 19A) and 60% of invasive isolates [P<0.001]. ST320 accounted for 66% and 52% of 19A carriage and IPD isolates in 2009, respectively; all ST320 isolates were multi-drug resistant. No ST320 NP or IPD isolates were identified pre-PCV7. CONCLUSIONS: Serotype distribution among NP and IPD isolates in Atlanta has shifted to non-PCV7 serotypes; 19A was the leading serotype for both. The multi-drug resistant ST320 strain was responsible for two-thirds of 19A carriage isolates and nearly half of IPD isolates. The predominance of serotype 19A in carriage and IPD among children in Atlanta highlights the potential direct and indirect benefits anticipated by implementation of PCV13 in the community. |
Haemophilus influenzae type b carriage among young children in metropolitan Atlanta in the context of vaccine shortage and booster dose deferral
Thomas JD , Jackson ML , Sharma D , Mair R , Bach MC , Castillo D , Ejigiri OG , Satola S , Cohn AC , Jerris R , Jain S , Farley MM , Mayer LW , Messonnier NE . Clin Vaccine Immunol 2011 18 (12) 2178-80 Short-term deferral of the Haemophilus influenzae type b (Hib) vaccine booster dose during a recent U.S. Hib vaccine shortage did not result in widespread Hib carriage in Atlanta, as the Hib carriage rate was found to be 0.3% (1/342). Hi colonization was significantly more common among males and daycare attendees. |
sodC-based real-time PCR for detection of Neisseria meningitidis.
Dolan Thomas J , Hatcher CP , Satterfield DA , Theodore MJ , Bach MC , Linscott KB , Zhao X , Wang X , Mair R , Schmink S , Arnold KE , Stephens DS , Harrison LH , Hollick RA , Andrade AL , Lamaro-Cardoso J , de Lemos AP , Gritzfeld J , Gordon S , Soysal A , Bakir M , Sharma D , Jain S , Satola SW , Messonnier NE , Mayer LW . PLoS One 2011 6 (5) e19361 Real-time PCR (rt-PCR) is a widely used molecular method for detection of Neisseria meningitidis (Nm). Several rt-PCR assays for Nm target the capsule transport gene, ctrA. However, over 16% of meningococcal carriage isolates lack ctrA, rendering this target gene ineffective at identification of this sub-population of meningococcal isolates. The Cu-Zn superoxide dismutase gene, sodC, is found in Nm but not in other Neisseria species. To better identify Nm, regardless of capsule genotype or expression status, a sodC-based TaqMan rt-PCR assay was developed and validated. Standard curves revealed an average lower limit of detection of 73 genomes per reaction at cycle threshold (C(t)) value of 35, with 100% average reaction efficiency and an average R(2) of 0.9925. 99.7% (624/626) of Nm isolates tested were sodC-positive, with a range of average C(t) values from 13.0 to 29.5. The mean sodC C(t) value of these Nm isolates was 17.6+/-2.2 (+/-SD). Of the 626 Nm tested, 178 were nongroupable (NG) ctrA-negative Nm isolates, and 98.9% (176/178) of these were detected by sodC rt-PCR. The assay was 100% specific, with all 244 non-Nm isolates testing negative. Of 157 clinical specimens tested, sodC detected 25/157 Nm or 4 additional specimens compared to ctrA and 24 more than culture. Among 582 carriage specimens, sodC detected Nm in 1 more than ctrA and in 4 more than culture. This sodC rt-PCR assay is a highly sensitive and specific method for detection of Nm, especially in carriage studies where many meningococcal isolates lack capsule genes. |
Clinical and laboratory characteristics of invasive infections due to methicillin-resistant Staphylococcus aureus isolates demonstrating a vancomycin MIC of 2 micrograms per milliliter: lack of effect of heteroresistant vancomycin-intermediate S. aureus phenotype
Satola SW , Lessa FC , Ray SM , Bulens SN , Lynfield R , Schaffner W , Dumyati G , Nadle J , Patel JB . J Clin Microbiol 2011 49 (4) 1583-7 We describe clinical and laboratory characteristics of invasive methicillin-resistant Staphylococcus aureus (MRSA) infections with vancomycin MICs of 2 mug/mL and compare hVISA to non-hVISA. Infections were most often healthcare-associated community-onset, demonstrated frequent complications and relapses. hVISA patients were more likely to have been hospitalized in the year prior to MRSA culture. |
Detection of bacterial pathogens in Mongolia meningitis surveillance with a new real-time PCR assay to detect Haemophilus influenzae.
Wang X , Mair R , Hatcher C , Theodore MJ , Edmond K , Wu HM , Harcourt BH , Carvalho MD , Pimenta F , Nymadawa P , Altantsetseg D , Kirsch M , Satola SW , Cohn A , Messonnier NE , Mayer LW . Int J Med Microbiol 2011 301 (4) 303-9 Since the implementation of Haemophilus influenzae (Hi) serotype b vaccine, other serotypes and non-typeable strains have taken on greater importance as a cause of Hi diseases. A rapid and accurate method is needed to detect all Hi regardless of the encapsulation status. We developed 2 real-time PCR (rt-PCR) assays to detect specific regions of the protein D gene (hpd). Both hpd assays are very specific and sensitive for detection of Hi. Of the 63 non-Hi isolates representing 21 bacterial species, none was detected by the hpd #1 assay, and only one of 2 H. aphrophilus isolates was detected by the hpd #3 assay. The hpd #1 and #3 assays detected 97% (229/237) and 99% (234/237) of Hi isolates, respectively, and were superior for detection of both typeable and non-typeable Hi isolates, as compared to previously developed rt-PCR targeting ompP2 or bexA. The diagnostic sensitivity and specificity of these rt-PCR assays were assessed on cerebrospinal fluid specimens collected as part of meningitis surveillance in Ulaanbaatar, Mongolia. The etiology (Neisseria meningitidis, Hi, and Streptococcus pneumoniae) of 111 suspected meningitis cases was determined by conventional methods (culture and latex agglutination), previously developed rt-PCR assays, and the new hpd assays. The rt-PCR assays were more sensitive for detection of meningitis pathogens than other classical methods and improved detection from 50% (56/111) to 75% (83/111). The hpd #3 assay identified a non-b Hi that was missed by the bexA assay and other methods. A sensitive rt-PCR assay to detect both typeable and non-typeable Hi is a useful tool for improving Hi disease surveillance especially after Hib vaccine introduction. |
Evaluation of serum bactericidal antibody assays for Haemophilus influenzae serotype a
Rouphael NG , Satola S , Farley MM , Rudolph K , Schmidt DS , Gomez-de-Leon P , Robbins JB , Schneerson R , Carlone GM , Romero-Steiner S . Clin Vaccine Immunol 2010 18 (2) 243-7 Haemophilus influenzae type a (Hia) is an important pathogen for some American Indian, Alaskan natives and Northern Canada aboriginal populations. Assays to measure serum bactericidal activity (SBA) to Hia have not been developed or validated. Here we describe two methods for the measurement of SBA: SBA with a viability end-point (CFU counts) and SBA with a fluorometric end-point using alamarBlue as metabolic indicator. Both SBA assays measure Hia-specific functional antibody and correlate with anti-Hia IgG ELISA concentration of naturally-acquired antibodies. |
Comparison of detection methods for heteroresistant vancomycin intermediate Staphylococcus aureus (hVISA) using population analysis profile as the reference method
Satola SW , Farley MM , Anderson KF , Patel JB . J Clin Microbiol 2010 49 (1) 177-83 Staphylococcus aureus clinical isolates with vancomycin MICs of 2 mug/mL have been associated with vancomycin therapeutic failure and the heteroresistant vancomycin-intermediate S. aureus (hVISA) phenotype. Population analysis profile (PAP) with an area under the curve (AUC) ratio of ≥ 0.9 compared to hVISA strain Mu3 is most often used for determining hVISA, but it is time consuming and labor-intensive. A collection of 140 MRSA blood isolates with vancomycin MICs of 2 mug/mL by reference broth microdilution and screened for hVISA using PAP-AUC (21/140 [15%] hVISA) were tested by additional methods to detect hVISA. Methods included: 1) Etest macromethod using vancomycin and teicoplanin test strips, Brain Heart Infusion (BHI) agar and a 2.0 McFarland inoculum; 2) Etest GRD using vancomycin-teicoplanin double-sided gradient test strips on Mueller Hinton Agar (MHA) with 5% sheep's blood and 0.5 McFarland inoculum; and 3) BHI screen agar plates containing 4mug/mL vancomcyin and 16 g/L casein using 0.5 and 2.0 McFarland inocula. Each method was evaluated using PAP-AUC as the reference method. The sensitivity of each method for detecting hVISA was higher when read at 48 h. Etest macromethod was 57% sensitive and 96% specific, Etest GRD was 57% sensitive and 97% specific, BHI screen agar was 90% sensitive and 95% specific with 0.5 McFarland inoculum and 100% sensitive and 68% specific with 2.0 McFarland inoculum. BHI screen agar with 4 mug/mL vancomycin and casein and 0.5 McFarland inoculum had the best sensitivity and specificity combination, was easy to perform and may be useful for clinical detection of hVISA. |
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