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Using a nasopharyngeal (NP) or anterior nasal (NS) swab from prospectively collected or retrospective specimens, we assessed the clinical performance of the BD Respiratory Viral Panel (BD RVP) for BD MAX System against FDA-cleared or authorized comparators. Across prospective and retrospective specimens, positive percent agreement (PPA) was ≥ 98.4% for SARS-CoV-2, ≥ 96.7% for influenza (flu) A, ≥ 91.7% for respiratory syncytial virus (RSV), and 100% for flu B (retrospective only) while negative percent agreement (NPA) was ≥ 97.7% across all targets, leading to the assay FDA clearance. A head-to-head comparison of NS versus NP results with BD RVP was also performed; PPA was ≥ 90% and NPA ≥ 98.2% for SARS-CoV-2, flu A and RSV. These findings confirm that the BD MAX RVP assay performs well for detection and differentiation of the three viruses in NP and NS specimens, with strong interrater agreements for NS versus NP comparisons., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Becton, Dickinson and Company reports financial support was provided by Biomedical Advanced Research and Development Authority. Nathan Ledeboer reports a relationship with Copan Italy that includes: consulting or advisory. Nathan Ledeboer reports a relationship with Thermo Fisher that includes: consulting or advisory. Barbara Van Der Pol reports a relationship with Abbott that includes: consulting or advisory and funding grants. Barbara Van Der Pol reports a relationship with Becton, Dickinson and Company that includes: consulting or advisory and funding grants. Barbara Van Der Pol reports a relationship with Biofire Diagnostics Inc that includes: consulting or advisory and funding grants. Barbara Van Der Pol reports a relationship with Cue that includes: consulting or advisory and funding grants. Barbara Van Der Pol reports a relationship with Cepheid that includes: consulting or advisory and funding grants. Barbara Van Der Pol reports a relationship with Detect that includes: consulting or advisory and funding grants. Barbara Van Der Pol reports a relationship with Hologic Inc that includes: consulting or advisory and funding grants. Barbara Van Der Pol reports a relationship with Preventx and FIND that includes: consulting or advisory and funding grants. Barbara Van Der Pol reports a relationship with Rheonix that includes: consulting or advisory and funding grants. Barbara Van Der Pol reports a relationship with Roche that includes: consulting or advisory and funding grants. Barbara Van Der Pol reports a relationship with Visby that includes: consulting or advisory and funding grants. Matthew L. Faron reports a relationship with Becton, Dickinson and Company that includes: consulting or advisory. Sonia Paradis reports a relationship with Becton, Dickinson and Company that includes: employment and equity or stocks. William Laviers reports a relationship with Becton, Dickinson and Company that includes: employment and equity or stocks. Elizabeth Lockamy reports a relationship with Becton, Dickinson and Company that includes: employment and equity or stocks. Karen Yanson reports a relationship with Becton, Dickinson and Company that includes: employment and equity or stocks. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

We conducted a comparative evaluation of the FDA-cleared Simplexa GBS Direct and ARIES GBS molecular assays for the detection of Streptococcus agalactiae (Group B Streptococcus , GBS) in 386 prospectively collected, broth-enriched vaginal/rectal swab specimens. The sensitivity of each test was 96.2% and specificity was ≥98.7% when compared to a combined direct and enriched culture method using chromogenic culture medium. A total of four specimens were called positive by both molecular assays but negative by culture, likely representing specimens with a low burden of GBS in these specimens. Two specimens were reported positive by culture but negative by both molecular assays. One of these specimens demonstrated atypically colored colonies on chromogenic agar; the other yielded typically colored colonies only observed after broth enrichment. Our data demonstrate equivalent performance of Simplexa and ARIES molecular assays for the detection of GBS in clinical specimens.IMPORTANCEClinical laboratories often face decisions regarding which of the multiple available molecular platforms would best fit their needs based on cost, workflow, menu, and diagnostic performance. Therefore, objective clinical comparisons of similar molecular tests are valuable resources to aid these decisions. We provide a clinical comparison of two FDA-cleared tests to routine culture and to each other that can be used by clinical laboratories when determining which of the available molecular platforms would best fit their laboratory in terms of workflow, cost, and performance., Competing Interests: The authors declare no conflict of interest.

The symptomology is overlapping for respiratory infections due to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), influenza A/B viruses, and respiratory syncytial virus (RSV). Accurate detection is essential for proper medical management decisions. This study evaluated the clinical performance of the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay in nasopharyngeal swab (NPS) specimens from individuals of all ages with signs and symptoms of respiratory infection consistent with COVID-19, influenza, or RSV. Retrospective known-positive and prospectively obtained residual NPS specimens were collected during two respiratory seasons in the USA. Clinical performance was established by comparing Panther Fusion SARS-CoV-2/Flu assay results to a three-molecular assay composite comparator interpretation for SARS-CoV-2 and to the FDA-cleared Panther Fusion Flu A/B/RSV assay results for all non-SARS-CoV-2 targets. A total of 1,900 prospective and 95 retrospective NPS specimens were included in the analyses. The overall prevalence in prospectively obtained specimens was 20.7% for SARS-CoV-2, 6.7% for influenza A, and 0.7% for RSV; all influenza B-positive specimens were retrospective specimens. The positive percent agreement of the Panther Fusion assay was 96.9% (378/390) for SARS-CoV-2, 98.0% (121/123) for influenza A virus, 95.2% (20/21) for influenza B virus, and 96.6% (57/59) for RSV. The negative percent agreement was ≥98.5% for all target viruses. Specimens with discordant Panther Fusion SARS/Flu/RSV assay results all had cycle threshold values of ≥32.4 (by comparator or by Panther Fusion SARS/Flu/RSV assay). Only five co-infections were detected in the study specimens. The Panther Fusion SARS-CoV-2/Flu/RSV assay provides highly sensitive and specific detection of SARS-CoV-2, influenza A virus, influenza B virus, and RSV in NPS specimens., Competing Interests: R.S. reports institutional funding from Cepheid, BioFire, Abbott, Bio-Rad, DiaSorin Molecular, Hologic, and Luminex. J.D.D. is a member of the scientific advisory board for DiaSorin Molecular. A.L.G. reports contract testing support from Abbott, Cepheid, Novavax, Pfizer, and Janssen and research support from Gilead. C.V.R., C.L., and R.B. are employed by Hologic Inc., the study sponsor and the manufacturer of the investigational diagnostic test used in this study.

Background: The SARS-CoV-2 pandemic saw the rapid rise, global spread, and diversification of the omicron variant in 2022. Given the overwhelming dominance of this variant globally and its diverse lineages, there is an urgent need to ensure that diagnostic assays are capable of detecting widely circulating omicron sub-lineages., Study Design: Remnant clinical VTM samples from SARS-CoV-2 PCR confirmed infections (n = 733) collected in Wisconsin (n = 94), New York (n = 267), and South Carolina (n = 372) throughout 2022 were sequenced, classified, and tested with m2000 RealTime SARS-CoV-2, Alinity m SARS-CoV-2, ID NOW COVID-19 v2.0, BinaxNOW COVID-19 Ag Card, and Panbio COVID-19 Rapid Test Device assays., Results: Sequences and lineage classifications were obtained for n = 641/733 (87.4%) samples and included delta (n = 6) and representatives from all major SARS-CoV-2 omicron variants circulating in 2022 (BA.1, BA.2, BA.3, BA.4, BA.5, BE, BF, BQ.1, and XBB). Panels of diverse omicron lineages were tested by molecular assays RealTime (n = 624), Alinity m (n = 80), and ID NOW v2.0 (n = 88) with results showing 100% detection for all samples. BinaxNOW and Panbio had sensitivities of 494/533 (92.7%) and 416/469 (88.7%), respectively for specimens with >4 log 10 copies/test, consistent with expected performance for frozen specimens. Furthermore, BinaxNOW demonstrated SARS-CoV-2 detection in clinical samples 1-4 days, and up to 18 days post-symptom onset in BA.1 infected patients with >4 log 10 copies/test., Conclusions: This data highlights the rise and diversification of SARS-CoV-2 omicron variants over the course of 2022 and demonstrate that each of the 5 tested assays can detect the breadth of omicron variants circulating globally., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: MA, VH, BH, AH, AO, TF, GC, and MR are employees and shareholders of Abbott Laboratories., (Copyright © 2023. Published by Elsevier B.V.)

Objectives: To evaluate pre-analytical challenges related to high-volume central laboratory SARS-CoV-2 antigen testing with a prototype qualitative SARS-CoV-2 antigen immunoassay run on the automated Abbott ARCHITECT instrument., Methods: Contrived positive and negative specimens and de-identified nasal and nasopharyngeal specimens in transport media were used to evaluate specimen and reagent on-board stability, assay analytical performance and interference, and clinical performance., Results: TCID50/mL values were similar for specimens in various transport media. Inactivated positive clinical specimens and viral lysate (USA-WA1/2020) were positive on the prototype immunoassay. Within-laboratory imprecision was ≤0.10 SD (<1.00 S/C) with a ≤10% CV (≥1.00 S/C). Assay reagents were stable on board the instrument for 14 days. No high-dose hook effect was observed with a SARS-CoV-2 stock of Ct 13.0 (RLU>1.0 × 10 6 ). No interference was observed from mucin, whole blood, 12 drugs, and more than 20 cross-reactants. While specimen stability was limited at room temperature for specimens with or without viral inactivation, a single freeze/thaw cycle or long-term storage (>30 days) at -20 °C did not adversely impact specimen stability or assay performance. Specificity of the prototype SARS-CoV-2 antigen immunoassay was ≥98.5% and sensitivity was ≥89.5% across two ARCHITECT instruments. Assay sensitivity was inversely correlated with Ct and was similar to that reported for the Roche Elecsys ® SARS-CoV-2 Ag immunoassay., Conclusions: The prototype SARS-CoV-2 antigen ARCHITECT immunoassay is sensitive and specific for detection of SARS-CoV-2 in nasal and nasopharyngeal specimens. Endogenous proteases in mucus may degrade the target antigen, which limits specimen storage and transport times and complicates assay workflow., (© 2023 Walter de Gruyter GmbH, Berlin/Boston.)

Early-onset neonatal sepsis due to Streptococcus agalactiae (group B Streptococcus [GBS]) infection is one of the leading causes of newborn mortality and morbidity. The latest guidelines published in 2019 recommended universal screening of GBS colonization among all pregnant women and intrapartum antibiotic prophylaxis for positive GBS. The updated procedures allow rapid molecular-based GBS screening using nutrient broth-enriched rectovaginal samples. Commercially available molecular assays for GBS diagnosis target mainly the cfb gene, which encodes a hemolysin protein responsible for producing the Christie-Atkins-Munch-Petersen (CAMP) factor. cfb is considered a conserved gene in essentially all GBS isolates. However, false-negative GBS results on Cepheid Xpert GBS and GBS LB tests due to deletions in or near the region that encodes cfb were reported recently. Therefore, the new Xpert GBS LB XC test was developed. This study is a multicenter evaluation of the new test for GBS identification from nutrient broth-enriched rectal/vaginal samples from antepartum women. A total of 621 samples were prospectively enrolled. The samples were tested with the Xpert GBS LB XC test, the composite comparator method, which included the Hologic Panther Fusion GBS test combined with bacterial culture, followed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) identification, and bacterial culture alone, followed by MALDI-TOF MS identification. The respective sensitivity and specificity of the Xpert GBS LB XC test were 99.3% and 98.7% compared to the composite comparator method and 99.1% and 91.8% compared to bacterial culture alone with MALDI-TOF MS identification. Overall, the Xpert GBS LB XC test performed comparatively to the composite comparator method and is equivalent to traditional bacterial culture followed by MALDI-TOF MS.

Within healthcare settings, physicians use antibiograms, which offer information on local susceptibility rates, as an aid in selecting empirical antibiotic therapy and avoiding the prescription of potentially ineffective drugs. While antibiograms display susceptibility and resistance data at hospital, city, or region-specific levels and ultimately enable the initiation of antibiogram-based empirical antibiotic treatment, AST reports at the individual patient level and guides treatments away from broad-spectrum antibiotics towards narrower-spectrum antibiotics or the removal of antibiotics entirely. Despite these advantages, AST traditionally requires a 48- to 72-h turn-around; this window of time can be critical for some antimicrobial therapeutic interventions. Herein, we present a direct-from-specimen AST to reduce the time between patient sampling and receipt of lab AST results. The biggest challenge of performing AST directly from unprocessed clinical specimens with an unknown microbial load is aligning the categorical susceptibility report with CLSI reference methods, which start from a fixed inoculum of 0.5 McFarland units prepared using colonies from a sub-culture. In this pilot clinical feasibility study using de-identified remnant specimens collected from MCW, we observed the high and low ends of microbial loads, demonstrating a final categorical agreement of 87.5% for ampicillin, 100% for ciprofloxacin, and 100% for sulfamethoxazole-trimethoprim., (© 2022. The Author(s).)

The COVID-19 pandemic highlighted the significance of readily available and easily performed viral testing for surveillance during future infectious pandemics. The objectives of this study were: to assess the performance of the Xpert Xpress Flu and/or RSV test, a multiplex PCR assay for detecting influenza A and B virus and respiratory syncytial virus nucleic acids in respiratory tract specimens, relative to the Quidel Lyra Influenza A+B assay and the Prodesse ProFlu+ assay, and the system's ease of use by minimally trained operators. Overall, the Xpert Xpress Flu/RSV test demonstrated a high positive and negative percent agreement with the comparator assays, and was easy to use and interpret results, based on the operators' feedback. We concluded that the Xpert Xpress Flu/RSV test is sensitive, specific, and easy to use for the diagnosis of influenza and RSV by minimally trained operators and can be a valuable tool in future infectious clusters or pandemics., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objectives: Aerococcus spp are Gram-positive cocci increasingly recognized as uropathogens. The Clinical and Laboratory Standards Institute recently published specific breakpoints for Aerococcus spp (M45, third edition); however, the standardized method used for antimicrobial susceptibility testing (AST) requires media not often maintained in clinical laboratories. The purpose of this study was to evaluate and compare alternative methods of AST for Aerococcus isolates., Methods: AST was performed on 134 clinical isolates using the Etest on three different types of agar, Vitek 2, and BD Phoenix. These results were compared with broth microdilution using the Sensititre STP6F., Results: Aerococcus exhibited low minimum inhibitory concentrations to benzylpenicillin, meropenem, linezolid, and vancomycin. Variable resistance was seen to levofloxacin, ceftriaxone, and tetracycline. Meropenem and vancomycin met all acceptance criteria with every alternative method tested. Benzylpenicillin and linezolid did not meet essential agreement on any AST method. Tetracycline met the majority of acceptance criteria with the exception of more than 3% very major error when using the Etest on chocolate agar, the Vitek 2, and BD Phoenix., Conclusions: Overall, the alternate AST method with the highest agreement with broth microdilution was the Etest on Mueller-Hinton agar with 5% sheep blood and may be an optimal alternative to broth microdilution., (© American Society for Clinical Pathology, 2021. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objectives: We conducted an analytic and clinical comparison of a novel high-definition polymerase chain reaction PCR (HDPCR) assay to traditional real-time PCR (RT-PCR) for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in upper respiratory specimens., Methods: Analytic performance of RT-PCR, HDPCR, and extraction-free HDPCR was established through replicate testing of a serially diluted clinical specimen containing SARS-CoV-2. A clinical comparison of all 3 assays was conducted using 351 prospectively collected upper respiratory swab specimens obtained from symptomatic and asymptomatic individuals collected in various transport media., Results: RT-PCR and HDPCR assays using extracted nucleic acid demonstrated similar analytic limits of detection (LoD) and clinical performance, with 100% positive and negative agreement. Extraction-free HDPCR demonstrated a 1.5 to 2.0 log10 increase in LoD based on cycle threshold values. However, clinical performance of extraction-free HDPCR remained high, demonstrating 97.8% positive and 99.6% negative agreement with RT-PCR. An overall increase in "invalid" and "presumptive" results was observed when using the extraction-free method, but this was highly variable based on transport medium used., Conclusions: HDPCR performs similar to RT-PCR for the detection of SARS-CoV-2. The use of an extraction-free HDPCR protocol maintained high clinical performance despite reduced analytic LoD, with the benefit of reduced hands-on time and cost of reagents associated with nucleic acid extraction., (© American Society for Clinical Pathology, 2021. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The emergence and evolution of antibiotic resistance has been accelerated due to the widespread use of antibiotics and a lack of timely diagnostic tests that guide therapeutic treatment with adequate sensitivity, specificity, and antimicrobial susceptibility testing (AST) accuracy. Automated AST instruments are extensively used in clinical microbiology labs and provide a streamlined workflow, simplifying susceptibility testing for pathogenic bacteria isolated from clinical samples. Although currently used commercial systems such as the Vitek2 and BD Phoenix can deliver results in substantially less time than conventional methods, their dependence on traditional AST inoculum concentrations and optical detection limit their speed somewhat. Herein, we describe the GeneFluidics ProMax lab automation system intended for a rapid 3.5-hour molecular AST from clinical isolates. The detection method described utilizes a higher starting inoculum concentration and automated molecular quantification of species-specific 16S rRNA through the use of an electrochemical sensor to assess microbiological responses to antibiotic exposure. A panel of clinical isolates consisting of species of gram-negative rods from the CDC AR bank and two hospitals, New York-Presbyterian Queens and Medical College of Wisconsin, were evaluated against ciprofloxacin, gentamicin, and meropenem in a series of reproducibility and clinical studies. The categorical agreement and reproducibility for Citrobacter freundii, Enterobacter cloacae, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, and Pseudomonas aeruginosa were 100% and 100% for ciprofloxacin, 98.7% and 100% for gentamicin and 98.5% and 98.5% for meropenem, respectively., Competing Interests: As authors of this study [J.C., M.T., V.G.], we declare that we are employed by GeneFluidics, a nonacademic, commercial company. This does not alter our adherence to PLOS ONE policies on sharing data and materials. NYPQ has received a contract under a Master Collaboration Agreement from GeneFluidics. The following authors are employment of NYPQ: Dakai Liu, William Rodgers.

Quantitative reverse transcription polymerase chain reaction (RT-qPCR) assay is the gold standard recommended to test for acute SARS-CoV-2 infection. However, it generally requires expensive equipment such as RNA isolation instruments and real-time PCR thermal cyclers. As a pandemic, COVID-19 has spread indiscriminately, and many low resource settings and developing countries do not have the means for fast and accurate COVID-19 detection to control the outbreak. Additionally, long assay times, in part caused by slow sample preparation steps, have created a large backlog when testing patient samples suspected of COVID-19. With many PCR-based molecular assays including an extraction step, this can take a significant amount of time and labor, especially if the extraction is performed manually. Using COVID-19 clinical specimens, we have collected evidence that the RT-qPCR assay can feasibly be performed directly on patient sample material in virus transport medium (VTM) without an RNA extraction step, while still producing sensitive test results. If RNA extraction steps can be omitted without significantly affecting clinical sensitivity, the turn-around time of COVID-19 tests, and the backlog we currently experience can be reduced drastically. Furthermore, our data suggest that rapid RT-PCR can be implemented for sensitive and specific molecular diagnosis of COVID-19 in locations where sophisticated laboratory instruments are not available. Our USD 300 set up achieved rapid RT-PCR using thin-walled PCR tubes and a water bath setup using sous vide immersion heaters, a Raspberry Pi computer, and a single servo motor that can process up to 96 samples at a time. Using COVID-19 positive clinical specimens, we demonstrated that RT-PCR assays can be performed in as little as 12 min using untreated samples, heat-inactivated samples, or extracted RNA templates with our low-cost water bath setup. These findings can help rapid COVID-19 testing to become more accessible and attainable across the globe.

Objectives: We examined the distribution of reverse transcription polymerase chain reaction (RT-PCR) cycle threshold (CT) values obtained from symptomatic patients being evaluated for coronavirus disease 2019 (COVID-19) to determine the proportion of specimens containing a viral load near the assay limit of detection (LoD) to gain practical insight to the risk of false-negative results. We also examined the relationship between CT value and patient age to determine any age-dependent difference in viral load or test sensitivity., Methods: We collected CT values obtained from the cobas severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) assay corresponding to 1,213 combined nasopharyngeal-oropharyngeal specimens obtained from symptomatic individuals that were reported as positive or presumptive positive for SARS-CoV-2. CT values were stratified by SARS-CoV target and patient age group., Results: In total, 93.3% to 98.4% of specimens demonstrated CT values greater than 3× the assay LoD, at which point false-negative results would not be expected. The mean of CT values between age groups was statistically equivalent with the exception of patients in age group 80 to 89 years, which demonstrated slightly lower CTs., Conclusions: Based on the distribution of observed CT values, including the small proportion of specimens with values near the assay LoD, there is a low risk of false-negative RT-PCR results in combined nasopharyngeal-oropharyngeal specimens obtained from symptomatic individuals., (© American Society for Clinical Pathology, 2020. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introduction: Carbapenemase-producing organisms (CPOs) are a growing threat to human health. Among the enzymes conferring antibiotic resistance produced by these organisms, Klebsiella pneumoniae carbapenemase (KPC) is considered to be a growing global health threat. Reliable and specific detection of this antibiotic resistance-causing enzyme is critical both for effective therapy and to mitigate further spread., Objectives: The objective of this study is to develop an intact protein mass spectrometry-based method for detection and differentiation of clinically-relevant KPC variants directly from bacterial cell lysates. The method should be specific for any variant expressed in multiple bacterial species, limit false positive results and be rapid in nature to directly influence clinical outcomes., Methods: Lysates obtained directly from bacterial colonies were used for intact protein detection using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Bottom-up and top-down proteomic methods were used to characterize the KPC protein targets of interest. Comparisons between KPC-producing and KPC-non-producing isolates from a wide variety of species were also performed., Results: Characterization of the mature KPC protein revealed an unexpected signal peptide cleavage site preceding an AXA signal peptide motif, modifying the molecular weight (MW) of the mature protein. Taking the additional AXA residues into account allowed for direct detection of the intact protein using top-down proteomic methods. Further validation was performed by transforming a KPC-harboring plasmid into a negative control strain, followed by MS detection of the KPC variant from the transformed cell line. Application of this approach to clearly identify clinically-relevant variants among several species is presented for KPC-2, KPC-3, KPC-4 and KPC-5., Conclusion: Direct detection of these enzymes contributes to the understanding of occurrence and spread of these antibiotic-resistant organisms. The ability to detect intact KPC variants via a simple LC-MS/MS approach could have a direct and positive impact on clinical therapy, by providing both direction for epidemiological tracking and appropriate therapy., Competing Interests: W. M. McGee, J. R. Neil, S. R. Kronewitter, and J. L. Stephenson, Jr. are employees of Thermo Fisher Scientific. Also, W.M. McGee, J.R. Neil, and J.L. Stephenson Jr. own stock in Thermo Fisher Scientific. There are two patents that have been filed on resistance marker identification by the authors from Thermo Fisher Scientific. M. L. Faron, B. W. Buchan and N. A. Ledeboer have received research funding from Bruker Daltonics and bioMerieux, and N. A. Ledeboer is a consultant for Thermo Fisher Scientific., (© 2020 The Association for Mass Spectrometry: Applications to the Clinical Lab (MSACL). Published by Elsevier B.V. All rights reserved.)

NG-Test Carba 5 is a rapid in vitro multiplex immunoassay for the phenotypic detection and differentiation of five common carbapenemase families (KPC, OXA-48-like, VIM, IMP, and NDM) directly from bacterial colonies. The assay is simple to perform and has recently received U.S. Food and Drug Administration clearance. A method comparison study was performed at geographically diverse medical centers ( n  = 3) in the United States, where 309 Enterobacterales and Pseudomonas aeruginosa isolates were evaluated by NG-Test Carba 5 (NG Biotech, Guipry, France), the Xpert Carba-R assay (Cepheid, Inc., Sunnyvale, CA), the modified carbapenem inactivation method (mCIM), the EDTA-modified carbapenem inactivation method, and disk diffusion with carbapenems. Colonies from tryptic soy agar with 5% sheep blood (blood agar) and MacConkey agar were tested, and the results were compared to those obtained by a composite reference method. Additionally, a fourth medical center performed a medium comparison study by evaluating the performance characteristics of NG-Test Carba 5 from blood, MacConkey, and Mueller-Hinton agars with 110 isolates of Enterobacterales and P. aeruginosa These results were compared to the expected genotypic and mCIM results. For the multicenter method comparison study, the overall positive percent agreement (PPA) and the overall negative percent agreement (NPA) of NG-Test Carba 5 with the composite reference method were 100% for both blood and MacConkey agars. The medium comparison study at the fourth site showed that the PPA ranged from 98.9% to 100% and that the NPA ranged from 95.2% to 100% for blood, MacConkey, and Mueller-Hinton agars. NG-Test Carba 5 accurately detected and differentiated five common carbapenemase families from Enterobacterales and P. aeruginosa colonies on commonly used agar media. The results of this test will support a streamlined laboratory work flow and will expedite therapeutic and infection control decisions., (Copyright © 2020 American Society for Microbiology.)

Lower respiratory tract infections, including hospital-acquired and ventilator-associated pneumonia, are common in hospitalized patient populations. Standard methods frequently fail to identify the infectious etiology due to the polymicrobial nature of respiratory specimens and the necessity of ordering specific tests to identify viral agents. The potential severity of these infections combined with a failure to clearly identify the causative pathogen results in administration of empirical antibiotic agents based on clinical presentation and other risk factors. We examined the impact of the multiplexed, semiquantitative BioFire FilmArray Pneumonia panel (PN panel) test on laboratory reporting for 259 adult inpatients submitting bronchoalveolar lavage (BAL) specimens for laboratory analysis. The PN panel demonstrated a combined 96.2% positive percent agreement (PPA) and 98.1% negative percent agreement (NPA) for the qualitative identification of 15 bacterial targets compared to routine bacterial culture. Semiquantitative values reported by the PN panel were frequently higher than values reported by culture, resulting in semiquantitative agreement (within the same log 10 value) of 43.6% between the PN panel and culture; however, all bacterial targets reported as >10 5 CFU/ml in culture were reported as ≥10 5 genomic copies/ml by the PN panel. Viral targets were identified by the PN panel in 17.7% of specimens tested, of which 39.1% were detected in conjunction with a bacterial target. A review of patient medical records, including clinically prescribed antibiotics, revealed the potential for antibiotic adjustment in 70.7% of patients based on the PN panel result, including discontinuation or de-escalation in 48.2% of patients, resulting in an average savings of 6.2 antibiotic days/patient., (Copyright © 2020 Buchan et al.)

Group A streptococcus (GAS) species cause bacterial pharyngitis in both adults and children. Early and accurate diagnosis of GAS is important for appropriate antibiotic therapy to prevent GAS sequalae. The Revogene Strep A molecular assay (Meridian Bioscience Canada Inc, Quebec City, QC, Canada) is an automated real-time PCR assay for GAS detection from throat swab specimens within approximately 70 min. This multicenter prospective study evaluated the performance of the Revogene Strep A molecular assay compared to that of bacterial culture. Dual throat swab specimens in either liquid Amies or Stuart medium were collected from eligible subjects (pediatric population and adults) enrolled across 7 sites (USA and Canada). Revogene Strep A and reference testing was performed within 7 days and 48 h of sample collection, respectively. Of the 604 evaluable specimens, GAS was detected in 154 (25.5%) samples by the reference method and in 175 (29%) samples by the Revogene Strep A assay. Revogene Strep A assay sensitivity and specificity were reported to be 98.1% (95% confidence interval [CI], 94.4 to 99.3) and 94.7% (95% CI, 92.2 to 96.4), respectively. The positive predictive value was 86.3% (95% CI, 80.4 to 90.6), negative predictive value was 99.3% (95% CI, 98.0 to 99.8) with a 1.0% invalid rate. Discrepant analysis with alternative PCR/bidirectional sequencing was performed for 24 false-positive (FP) and 3 false-negative (FN) specimens. Concordant results were reported for 17 (FP only) of 27 discordant specimens. The Revogene Strep A assay had high sensitivity and specificity for GAS detection and provides a faster alternative for GAS diagnosis., (Copyright © 2020 Banerjee et al.)

Automation of the clinical microbiology laboratory has become more prominent as laboratories face higher specimen volumes and understaffing and are becoming more consolidated. One recent advancement is the use of digital image analysis to rapidly distinguish between chromogenic growth for screening bacterial cultures. In this study, colony segregation software developed by Copan (Brescia, Italy) was evaluated to distinguish between significant growth and no growth of urine cultures plated onto standard blood and MacConkey agars. Specimens from 3 sites were processed on a WASP instrument (Copan) and incubated on the WASPLab platform (Copan), and plates were imaged at 0 and 24 hours postinoculation. Images were read by technologists following validated laboratory protocols (VLPs), and results were recorded in the laboratory information systems (LIS). Image analysis performed colony counts on the 24-hour images, and results were compared with the VLP. A total of 12,931 urine cultures were tested and analyzed with an overall sensitivity and specificity of 99.8% and 72.0%, respectively. After secondary review, 91.1% of manual-positive/automation-negative specimens were due to expert rules that reported the plate as contaminated or growing only normal flora and not due to threshold counts. Nine specimens were found to be manual-positive/automation-negative; a secondary review demonstrated that the results of 8 of these specimens were due to growth of microcolonies that were programmed to be ignored by the software and 1 were due to a colony count near the limit of significance. Overall, the image analysis software proved to be highly sensitive and can be utilized by laboratories to batch-review negative cultures to improve laboratory workflow., (Copyright © 2020 American Society for Microbiology.)

Previously, we showed that disinfection of sink drains is effective at decreasing bacterial loads. Here, we report our evaluation of the ideal frequency of sink-drain disinfection and our comparison of 2 different hydrogen peroxide disinfectants.

Clostridioides difficile is the leading cause of diarrhea in hospitalized U.S. patients and results in over 400,000 cases of C. difficile infection per year. C. difficile infections have mortality rates of 6 to 30% and significantly increase health care costs, because of increased length of stay and increased frequency of readmissions due to recurrences. Efforts to reduce the spread of C. difficile in hospitals have led to the development of rapid sensitive diagnostic methods. A multicenter study was performed to establish the performance characteristics of the Revogene C. difficile test (Meridian Bioscience, Cincinnati, OH, USA) for use in detection of the toxin B ( tcdB ) gene from toxigenic C. difficile The Revogene instrument is a new molecular platform that uses real-time PCR to detect nucleic acids in up to 8 specimens at a time. A total of 2,461 specimens from symptomatic patients that had been submitted for C. difficile testing were enrolled at 7 sites throughout the United States and Canada for evaluation of the assay. Each stool specimen was tested for the presence of the tcdB gene using the Revogene C. difficile test, and results were compared with those of the reference method, a combination of direct and enriched culture methods. Overall, the Revogene C. difficile test demonstrated a sensitivity of 85.0% (95% confidence interval, 80% to 88%) and a specificity of 97.2% (95% confidence interval, 96% to 98%). The Revogene C. difficile test, using clinical stool specimens for detection of tcdB in C. difficile , demonstrated acceptable sensitivity and specificity, with a short turnaround time., (Copyright © 2020 Mashock et al.)

Urine cultures are among the most common specimens received by clinical laboratories and generate a major share of the laboratory workload. Chromogenic agar can expedite culture results, but technologist review is still needed. In this study, we evaluated the ability of the WASPLab software to interpret urine specimens plated onto chromID CPS Elite (CPSE) agar. Urine specimens submitted for bacterial culture were plated onto CPSE agar with a 1-μl loop using the WASP. Each plate was imaged after 0 and 18 h of incubation, and colonies were enumerated by color using the WASPLab software and a technologist's reading from a high-definition (HD) monitor. The results were reported as negative if <10 colonies/plate were detected. Laboratory information system (LIS) time stamps were used to measure the time to result. A total of 1,581 urine cultures were tested. The sensitivity and specificity of the software were 99.8% and 68.5%, respectively, which included 2 manual-positive/automation-negative (MP/AN) results and 170 manual-negative/automation-positive (MN/AP) results. Of the 170 MN/AP specimens, 116 were caused by microcolonies missed by the technologist. The remaining MN/AP results were caused by either count differences near the 10-colony threshold ( n  = 43) or count differences of >50 CFU ( n  = 11). The use of both CPSE agar and the WASPLab software improved the time to result for urine culture, reducing the average time to result by 4 h 42 min for negative specimens and 3 h 28 min for positive specimens compared to that with standard-of-care testing. These data demonstrate that the use of CPSE agar and automated plate reading has the potential to improve turnaround time while maintaining high sensitivity and reducing urine culture workload., (Copyright © 2019 Faron et al.)

The prevalence of tick-borne infections has been steadily increasing in both number and geographic distribution in the United States and abroad. This increase, in conjunction with the continued recognition of novel pathogens transmitted by ticks, has made accurate diagnosis of these infections challenging. Mainstay serologic tests are insensitive during the acute phase of infection and are often cross-reactive with similar pathogenic and nonpathogenic organisms. Further, they are unable to reliably differentiate active versus past infection which can lead to misdiagnosis and incorrect understanding of the epidemiology and incidence of specific tick-borne pathogens. We evaluated a novel multiplexed high-definition PCR (HDPCR) Tickborne Panel (TBP) assay (ChromaCode, Carlsbad, CA) for the detection of nine tick-borne pathogens or groups associated with human illness. The HDPCR technology enables multiplex identification of multiple targets in a single fluorometric channel based on fluorescent signal modulation using a limiting probe design. A collection of 530 whole-blood specimens collected from patients being evaluated for tick-borne infections, in addition to a panel of 93 simulated specimens, were used to challenge the HDPCR TBP. The results were compared to a clinically validated traditional multiplexed PCR test with additional sequence analysis and clinical history collected to aid in resolving discrepancies. Among clinical specimens the TBP demonstrated 100% sensitivity for the identification of Anaplasma phagocytophilum , Borrelia miyamotoi , Borrelia mayonii , and Rickettsia rickettsii The sensitivity for identification of B. burgdorferi was 44.4% compared to a composite gold standard. Among simulated specimens containing single or multiple targets present at 10 3 to 10 5 copies/PCR, the sensitivity of TBP was 100% for all targets, with a combined specificity of 99.5%. Of note, an increased rate of false-positive results was observed among simulated specimens that contained multiple targets. Based on these data, we find the HDPCR TBP to be a useful adjunct for the diagnosis of tick-borne infections in patients with suspected tick-borne illness., (Copyright © 2019 Buchan et al.)

Early initiation of effective antibiotics for septic patients is essential for patient survival. Matrix-assisted desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has revolutionized clinical microbiology for isolate identification and has the possibility to impact how blood culture testing is performed. This review discusses the various uses of MALDI-TOF MS for the identification and susceptibility testing of positive blood cultures, the performance of these methods, and the outcomes involved with its implementation., (Copyright © 2017 American Society for Microbiology.)

Liquid-based microbiology (LBM) devices incorporating flocked swabs and preservation medium ease transport of specimens and improve specimen yield compared to traditional fiber wound swabs; however, the performance of LBM collection devices has not been evaluated in many molecular assays. It is unclear how the differences in matrix and specimen loading with an LBM device will affect test performance compared to traditional collection devices. The purpose of this study was to evaluate the performance of specimens collected in FecalSwab transport medium (Copan Diagnostics, Murrieta, CA) compared to unpreserved stool using the Cepheid Xpert C. difficile assay (Cepheid, Sunnyvale, CA). Results equivalent to unpreserved stool samples were obtained when 400 μl of FecalSwab-preserved stool was employed in the Xpert assay. The positive and negative percent agreement of specimens inoculated with FecalSwab medium ( n = 281) was 97.0% (95% confidence interval [CI], 90.9 to 96.4%) and 99.4% (95% CI, 96.4 to 99.9%), respectively, compared to reference results obtained using unpreserved stool. Throughout this study, only four discrepant results occurred when comparing preserved specimens to unpreserved stool specimens in the Xpert C. difficile PCR assay. Post discrepant analysis, using the BD MAX Cdiff assay, the specificity and sensitivity both increased to 100%. The high positive and negative percent agreements observed in this study suggest that stool preserved in FecalSwab media yields equivalent results to using unpreserved stool when tested on the Xpert C. difficile assay, allowing laboratories to adopt this liquid-based microbiology collection device., (Copyright © 2017 Mashock et al.)

Objectives: A report on the multicenter evaluation of the Bruker MALDI Biotyper CA System (MBT-CA; Bruker Daltonics, Billerica, MA) for the identification of clinically important bacteria and yeasts., Methods: In total, 4,399 isolates of medically important bacteria and yeasts were assessed in the MBT-CA. These included 2,262 aerobic gram-positive (AGP) bacteria, 792 aerobic gram-negative (AGN) bacteria 530 anaerobic (AnA) bacteria, and 815 yeasts (YSTs). Three processing methods were assesed., Results: Overall, 98.4% (4,329/4,399) of all bacterial and yeast isolates were correctly identified to the genus and species/species complex level, and 95.7% of isolates were identified with a high degree of confidence. The percentage correctly identified and the percentage identified correctly with a high level of confidence, respectively, were as follows: AGP bacteria (98.6%/96.5%), AGN bacteria (98.5%/96.8%), AnA bacteria (98.5%/97.4%), and YSTs (97.8%/87.6%). The extended direct transfer method was only minimally superior to the direct transfer method for bacteria (89.9% vs 86.8%, respectively) but significantly superior for yeast isolates (74.0% vs 48.9%, respectively)., Conclusions: The Bruker MALDI Biotyper CA System accurately identifies most clinically important bacteria and yeasts and has optional processing methods to improve isolate characterization., (© American Society for Clinical Pathology, 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com)

Bloodstream infections are a leading cause of morbidity and mortality in the United States and are associated with increased health care costs. We evaluated the Portrait Staph ID/R blood culture panel (BCP) multiplex PCR assay (Great Basin Scientific, Salt Lake City, UT) for the rapid and simultaneous identification (ID) of Staphylococcus aureus , Staphylococcus lugdunensis , and Staphylococcus species to the genus level and the detection of the mecA gene directly from a positive blood culture bottle. A total of 765 Bactec bottles demonstrating Gram-positive cocci in singles or clusters were tested during the prospective trial at 3 clinical sites. The Portrait Staph ID/R BCP results were compared with results from conventional biochemical and cefoxitin disk methods performed at an independent laboratory. Discordant ID and mecA results were resolved by rpoB gene sequencing and mecA gene sequencing, respectively. A total of 658 Staphylococcus species isolates ( S. aureus , 211 isolates; S. lugdunensis , 3 isolates; and Staphylococcus spp., 444 isolates) were recovered from monomicrobial and 33 polymicrobial blood cultures. After discrepant analysis, the overall ratios of Portrait Staph ID/R BCP positive percent agreement and negative percent agreement were 99.4%/99.9% for Staphylococcus ID and 99.7%/99.2% for mecA detection., (Copyright © 2017 American Society for Microbiology.)

The Shiga Toxin Direct molecular assay (ST Direct) relies on nucleic acid amplification and solid array-based amplicon detection to identify Shiga toxin-producing Escherichia coli (STEC) in preserved stool specimens. Genes encoding Shiga toxin (stx 1 and stx 2 ), as well as the E. coli serotype O:157-specific marker rfbE, are simultaneously detected within 2 h. ST Direct was evaluated using 1,084 prospectively collected preserved stool specimens across five clinical centers. An additional 55 retrospectively collected, frozen specimens were included to increase the number of positive specimens evaluated. Results were compared to results from routine culture and an enzyme immunoassay (EIA) specific for the recovery and identification of STEC. ST Direct was found to be 93.2% sensitive and 99.3% specific for detection of stx 1 and stx 2 and 95.7% sensitive and 99.3% specific for detection of E. coli serotype O:157. All specimens with false-positive results were found to contain stx 1 or stx 2 or were found to be positive for serotype O:157 when analyzed using alternative molecular methods. All 4 false-negative stx 1 or stx 2 results were reported for frozen, retrospectively tested specimens. In all cases, the specimens tested positive for stx by an alternative FDA-cleared nucleic acid amplification test (NAAT) but were negative for stx 1 and stx 2 following nucleic acid sequence analysis. Based on these data, culture and EIA-based methods for detection of STEC are only 33% sensitive compared to molecular tests. A retrospective cost analysis demonstrated 59% of the cost of routine stool culture to be attributable to the identification of STEC. Taken together, these data suggest that ST Direct may provide a cost-effective, rapid molecular alternative to routine culture for the identification of STEC in preserved stool specimens., (Copyright © 2017 American Society for Microbiology.)

Infections attributable to vancomycin-resistant Enterococcus (VRE) strains have become increasingly prevalent over the past decade. Prompt identification of colonized patients combined with effective multifaceted infection control practices can reduce the transmission of VRE and aid in the prevention of hospital-acquired infections (HAIs). Increasingly, the clinical microbiology laboratory is being asked to support infection control efforts through the early identification of potential patient or environmental reservoirs. This review discusses the factors that contribute to the rise of VRE as an important health care-associated pathogen, the utility of laboratory screening and various infection control strategies, and the available laboratory methods to identify VRE in clinical specimens., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)

Vancomycin-resistant enterococci (VRE) are an important cause of health care-acquired infections (HAIs). Studies have shown that active surveillance of high-risk patients for VRE colonization can aid in reducing HAIs; however, these screens generate a significant cost to the laboratory and health care system. Digital imaging capable of differentiating negative and "nonnegative" chromogenic agar can reduce the labor cost of these screens and potentially improve patient care. In this study, we evaluated the performance of the WASPLab Chromogenic Detection Module (CDM) (Copan, Brescia, Italy) software to analyze VRE chromogenic agar and compared the results to technologist plate reading. Specimens collected at 3 laboratories were cultured using the WASPLab CDM and plated to each site's standard-of-care chromogenic media, which included Colorex VRE (BioMed Diagnostics, White City, OR) or Oxoid VRE (Oxoid, Basingstoke, United Kingdom). Digital images were scored using the CDM software after 24 or 40 h of growth, and all manual reading was performed using digital images on a high-definition (HD) monitor. In total, 104,730 specimens were enrolled and automation agreed with manual analysis for 90.1% of all specimens tested, with sensitivity and specificity of 100% and 89.5%, respectively. Automation results were discordant for 10,348 specimens, and all discordant images were reviewed by a laboratory supervisor or director. After a second review, 499 specimens were identified as representing missed positive cultures falsely called negative by the technologist, 1,616 were identified as containing borderline color results (negative result but with no package insert color visible), and 8,234 specimens were identified as containing colorimetric pigmentation due to residual matrix from the specimen or yeast (Candida). Overall, the CDM was accurate at identifying negative VRE plates, which comprised 84% (87,973) of the specimens in this study., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)

Herpes simplex virus (HSV) causes acute and relapsing symptoms characterized by ulcerative lesions. Laboratory diagnosis of HSV in cutaneous or mucocutaneous lesions has historically been performed with the use of viral cell culture systems; however, these tests are laborious and suffer decreased sensitivity for advanced-stage lesions. The recent availability of FDA-cleared moderately complex assays has resulted in the increased use of molecular diagnostics for the routine detection of HSV in superficial swab specimens. We performed a clinical evaluation of the recently FDA-cleared illumigene HSV 1&2 loop-mediated isothermal amplification (LAMP) assay (Meridian Bioscience, Cincinnati OH) for the detection and differentiation of HSV-1 and HSV-2 in cutaneous and mucocutaneous swab specimens. A total of 1,153 clinical swab specimens were collected and tested at 7 different clinical centers. Each specimen was tested for the presence of HSV-1 and HSV-2 using the illumigene assay, and results were compared to those of the enzyme-linked virus-inducible system (ELVIS) as the reference method. Overall, the illumigene assay demonstrated a sensitivity and specificity of 94.8% and 95.5%, respectively, for the detection of HSV-1. Detection of HSV-2 was similar, with a sensitivity of 98.9% and a specificity of 95.5%. Discrepant analysis was performed using an alternative molecular test (AmpliVue HSV1+2 assay; Quidel Molecular, San Diego, CA) on 91/99 specimens that were recorded as false positive (FP) or false negative (FN) compared to the reference method. In total, 57/78 (73%) FP and 9/13 (69%) FN illumigene results were supported by the AmpliVue result. The illumigene HSV 1&2 assay demonstrated high sensitivity and specificity to detect and differentiate HSV in clinical specimens and identified 57 additional specimens that were positive for HSV compared to culture. The use of LAMP eliminates the need for the cycling of temperatures and provides results in less than 60 min, with approximately 2 min of hands-on time per specimen., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)

Recently, systems have been developed to create total laboratory automation for clinical microbiology. These systems allow for the automation of specimen processing, specimen incubation, and imaging of bacterial growth. In this study, we used the WASPLab to validate software that discriminates and segregates positive and negative chromogenic methicillin-resistant Staphylococcus aureus (MRSA) plates by recognition of pigmented colonies. A total of 57,690 swabs submitted for MRSA screening were enrolled in the study. Four sites enrolled specimens following their standard of care. Chromogenic agar used at these sites included MRSASelect (Bio-Rad Laboratories, Redmond, WA), chromID MRSA (bioMérieux, Marcy l'Etoile, France), and CHROMagar MRSA (BD Diagnostics, Sparks, MD). Specimens were plated and incubated using the WASPLab. The digital camera took images at 0 and 16 to 24 h and the WASPLab software determined the presence of positive colonies based on a hue, saturation, and value (HSV) score. If the HSV score fell within a defined threshold, the plate was called positive. The performance of the digital analysis was compared to manual reading. Overall, the digital software had a sensitivity of 100% and a specificity of 90.7% with the specificity ranging between 90.0 and 96.0 across all sites. The results were similar using the three different agars with a sensitivity of 100% and specificity ranging between 90.7 and 92.4%. These data demonstrate that automated digital analysis can be used to accurately sort positive from negative chromogenic agar cultures regardless of the pigmentation produced., (Copyright © 2016 Faron et al.)

Norovirus is the most common cause of sporadic gastroenteritis and outbreaks worldwide. The rapid identification of norovirus has important implications for infection prevention measures and may reduce the need for additional diagnostic testing. The Xpert Norovirus assay recently received FDA clearance for the detection and differentiation of norovirus genogroups I and II (GI and GII), which account for the vast majority of infections. In this study, we evaluated the performance of the Xpert Norovirus assay with both fresh, prospectively collected (n = 914) and frozen, archived (n = 489) fecal specimens. A Centers for Disease Control and Prevention (CDC) composite reference method was used as the gold standard for comparison. For both prospective and frozen specimens, the Xpert Norovirus assay showed positive percent agreement (PPA) and negative percent agreement (NPA) values of 98.3% and 98.1% for GI and of 99.4% and 98.2% for GII, respectively. Norovirus prevalence in the prospective specimens (collected from March to May of 2014) was 9.9% (n = 90), with the majority of positives caused by genogroup II (82%, n = 74). The positive predictive value (PPV) of the Xpert Norovirus assay was 75% for GI-positive specimens, whereas it was 86.5% for GII-positive specimens. The negative predictive values (NPV) for GI and GII were 100% and 99.9%, respectively., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

The prompt and accurate identification of bacterial pathogens is fundamental to patient health and outcome. Recent advances in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) have revolutionized bacterial identification in the clinical laboratory, but uniform incorporation of this technology in the U.S. market has been delayed by a lack of FDA-cleared systems. In this study, we conducted a multicenter evaluation of the MALDI Biotyper CA (MBT-CA) System (Bruker Daltonics Inc, Billerica, MA) for the identification of aerobic gram-negative bacteria as part of a 510(k) submission to the FDA. A total of 2,263 aerobic gram negative bacterial isolates were tested representing 23 genera and 61 species. Isolates were collected from various clinical sources and results obtained from the MBT-CA System were compared to DNA sequencing and/or biochemical testing. Isolates that failed to report as a "high confidence species ID" [log(score) ≥2.00] were re-tested using an extraction method. The MBT-CA System identified 96.8% and 3.1% of isolates with either a "high confidence" or a "low confidence" [log(score) value between 1.70 and <2.00] species ID, respectively. Two isolates did not produce acceptable confidence scores after extraction. The MBT-CA System correctly identified 99.8% (2,258/2,263) to genus and 98.2% (2,222/2,263) to species level. These data demonstrate that the MBT-CA System provides accurate results for the identification of aerobic gram-negative bacteria.

We evaluated the clinical performance (sensitivity and specificity) of the AmpliVue group A Streptococcus (GAS) isothermal helicase-dependent amplification assay using 1,192 pharyngeal swab specimens. AmpliVue GAS assay results were compared to the results of routine throat cultures on selective streptococcal blood agar plates. The sensitivity and specificity of the AmpliVue GAS assay were 98.3% (95% confidence interval [CI], 95 to 100%) and 93.2% (95% CI, 91 to 95%), respectively., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

Neonatal infection with Streptococcus agalactiae (group B Streptococcus [GBS]) is a leading cause of sepsis and meningitis in newborns. Recent guidelines have recommended universal screening of all pregnant women to identify those colonized with GBS and administration of peripartum prophylaxis to those identified as carriers to reduce the risk of early-onset GBS disease in neonates. Enriched culture methods are the current standard for prenatal GBS screening; however, the implementation of more sensitive molecular diagnostic tests may be able to further reduce the risk of early-onset GBS infection. We report a clinical evaluation of the Xpert GBS LB assay, a molecular diagnostic test for the identification of GBS from broth-enriched vaginal/rectal specimens obtained during routine prenatal screening. A total of 826 specimens were collected from women undergoing prenatal screening (35 to 37 weeks' gestation) and tested at one of three clinical centers. Each swab specimen was tested directly prior to enrichment using the Xpert GBS assay. Following 18 to 24 h of broth enrichment, each specimen was tested using the Xpert GBS LB assay and the FDA-cleared Smart GBS assay as a molecular diagnostic comparator. Results obtained using all three molecular tests were compared to those for broth-enriched culture as the gold standard. The sensitivity and specificity of the Xpert GBS LB assay were 99.0% and 92.4%, respectively, compared to those for the gold standard culture. The Smart GBS molecular test demonstrated sensitivity and specificity of 96.8% and 95.5%, respectively. The sensitivities of the two broth-enriched molecular methods were superior to those for direct testing of specimens using the Xpert GBS assay, which demonstrated sensitivity and specificity of 85.7% and 96.2%, respectively., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)