Diagnostic accuracy of the Cepheid GeneXpert vanA/vanB assay ver. 1.0 to detect the vanA and vanB vancomycin resistance genes in Enterococcus from perianal specimens

Marner, Erin S.; Wolk, Donna M.; Carr, Jeanne; Hewitt, C.; Dominguez, Lee B.; Kovacs, Thomas O.; Johnson, Desiree R.; Hayden, Randall T.

doi:10.1016/j.diagmicrobio.2010.11.005

Cited by 41 publications

(32 citation statements)

References 38 publications

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“…In the two studies that reported a PPV greater than 90%, VRE prevalence was 30% and 47% among the specimens tested, whereas both studies reporting low PPVs of 1.4% and 2.6% had VRE prevalence of 1.3% and 1.4%, respectively (68,69,71,73). These data suggest that the utility of molecular assays to serve as a "rule-in" test is limited; however, these assays can still be effectively used to identify noncolonized patients with a high NPV.…”

Section: Laboratory Considerations For Vre Screeningmentioning

confidence: 90%

“…The Roche LightCycler VRE detection kit demonstrated a high negative predictive value (NPV) of 99.9% for VRE but suffered low positive predictive values (PPV) of 1.4% for vanB and 68.5% vanA when results were compared to direct culture using Enterococcosel agar (68). A significantly higher PPV of 92.0% was reported using the Cepheid Xpert vanA and vanB assay, but reference culture was performed using a broth enrichment step prior to plating, which may increase the recovery of VRE in culture (71). Interestingly, a similar study evaluating the Xpert vanA and vanB assay using broth-enriched culture reported a PPV of only 32% (72).…”

Section: Laboratory Considerations For Vre Screeningmentioning

confidence: 99%

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Resistance Mechanisms, Epidemiology, and Approaches to Screening for Vancomycin-Resistant Enterococcus in the Health Care Setting

2016

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bInfections 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. Hospital-acquired infections (HAIs) are a serious threat for patient care and carry a significant cost to hospitals, since treatment of these infections is no longer reimbursable. In addition, regulations requiring hospitals to report HAIs creates further pressure to reduce incidence rates. Screening patients at admission for methicillin-resistant Staphylococcus aureus (MRSA) has been a successful approach in reducing MRSA HAIs in some health care systems and may be a successful strategy for controlling other health care-associated pathogens, including Clostridium difficile, carbapenem-resistant Enterobacteriaceae (CRE), and vancomycin-resistant Enterococcus (VRE) (1). However, there is debate about the optimal approach to screening and infection control, which may differ between pathogens of interest.Members of the genus Enterococcus are well-documented pathogens associated with various clinical manifestations, including bacteremia, infective endocarditis, intra-abdominal and pelvic infections, urinary tract infections, and, in rare cases, central nervous system infections (2-4). Infection with vancomycin-resistant Enterococcus is associated with an increased mortality rate, illustrated by a 2.5-fold increase in mortality for patients suffering from VRE bacteremia (5). Vancomycin resistance in Enterococcus spp. has been increasing in prevalence since it was first encountered in 1986 (6, 7). Currently, 30% of Enterococcus species isolates from the United States are vancomycin resistant, and infection with these organisms causes an estimated 1,300 deaths each year (8). The majority of VRE are associated with the species E. faecium (77%) and E. faecalis (9%), with the remaining 14% of isolates representing species less frequently implicated in serious infections, including E. gallinarum, E. casseliflavus, E. avium, and E. raffinosus (8).The optimal approach to reducing VRE infections is multifactorial, requiring antimicrobial stewardship to reduce the selection of VRE in colonized patients, appropriate infection control practices to reduce transmission, and reliable sensitive laboratory methods for the detection of VRE in a timely manner. ANTIMICROBIAL RESISTANCE MECHANISMS AND APPROACHES TO THERAPYUnderstanding the mechanism be...

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Section: Laboratory Considerations For Vre Screeningmentioning

confidence: 90%

Section: Laboratory Considerations For Vre Screeningmentioning

confidence: 99%

Resistance Mechanisms, Epidemiology, and Approaches to Screening for Vancomycin-Resistant Enterococcus in the Health Care Setting

2016

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“…As part of the infection control measures that have to be taken by the hospital, especially during outbreaks, these time-consuming methods have a high economic impact (3). Several studies evaluated PCR-based methods for rapid detection of VRE, including the Cepheid Xpert vanA/vanB assay (4)(5)(6)(7). This assay runs on the Cepheid GeneXpert system, a fully automated processor that combines DNA extraction, real-time PCR amplification, and detection, providing results within an hour.…”

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confidence: 99%

Evaluation of the Xpert vanA / vanB Assay Using Enriched Inoculated Broths for Direct Detection of vanB Vancomycin-Resistant Enterococci

et al. 2014

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Rapid and accurate detection of VRE (vancomycin-resistant enterococci) is required for adequate antimicrobial treatment and infection prevention measures. Previous studies using PCR for the detection of VRE, including Cepheid's Xpert vanA/vanB assay, reported accurate detection of vanA VRE; however, many false-positive results were found for vanB VRE. This is mainly due to nonenterococcal vanB genes, which can be found in the gut flora. Our goal was to optimize the rapid and accurate detection of vanB VRE and to improve the positive predictive value (PPV) by limiting false-positive results. We evaluated the use of the Xpert vanA/vanB assay on rectal swabs and on enriched inoculated broths for the detection of vanB VRE. By adjusting the cycle threshold (C T ) cutoff value to <25 for positivity by PCR on enriched broths, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 96.9%, 100%, 100%, and 99.5% for vanB VRE, respectively. As shown in this study, C T values of <25 acquired from enriched broths can be considered true positive. For broths with C T values between 25 and 30, we recommend confirming the results by culture. C T values of >30 appeared to be true negative. In conclusion, this study shows that the Cepheid's Xpert vanA/vanB assay performed on enriched inoculated broths with an adjusted cutoff C T value is a useful and rapid tool for the detection of vanB VRE.

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“…Esto podría estar asociado a una mayor sensibilidad del método RPC, descrita en la literatura científica 11 ; el estudio no fue diseñado, sin embargo, para evaluar sensibilidad de la técnica.…”

Section: Discussionunclassified

“…Permite obtener resultados oportunos, en el plazo de una hora, luego de ser cargado con las muestras clínicas 8 . Ha sido validado en distintos escenarios clínicos, tanto para SARM 5,9,10 como para ERV 7,11 . Las ventajas comparativas de estas técnicas son su rapidez en los resultados, el ser operador En todos ellos se obtuvo muestras por hisopado nasofaríngeo e hisopado rectal y se indicó desde la admisión a la unidad, medidas de precaución adicional de contacto, las que se mantuvieron hasta disponer de resultados de cultivos negativos.…”

Section: Introductionunclassified

Impacto de una técnica automatizada rápida en la identificación de SAMR/ERV en pacientes trasladados desde otros centros hospitalarios

Rojas

Potı́n

Corla

et al. 2013

Rev. chil. infectol.

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Diagnostic accuracy of the Cepheid GeneXpert vanA/vanB assay ver. 1.0 to detect the vanA and vanB vancomycin resistance genes in Enterococcus from perianal specimens

Cited by 41 publications

References 38 publications

Resistance Mechanisms, Epidemiology, and Approaches to Screening for Vancomycin-Resistant Enterococcus in the Health Care Setting

Resistance Mechanisms, Epidemiology, and Approaches to Screening for Vancomycin-Resistant Enterococcus in the Health Care Setting

Evaluation of the Xpert vanA / vanB Assay Using Enriched Inoculated Broths for Direct Detection of vanB Vancomycin-Resistant Enterococci

Impacto de una técnica automatizada rápida en la identificación de SAMR/ERV en pacientes trasladados desde otros centros hospitalarios

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