Evaluation of Vancomycin Resistance 3 Multiplexed PCR Assay for Detection of Vancomycin-Resistant Enterococci from Rectal Swabs

BACKGROUND: Active screening for vancomycin-resistant enterococci (VRE) using rectal specimens is recommended to limit the spread of antimicrobial resistance within certain high-risk populations. We evaluated the diagnostic performance of Vancomycin Resistance 3 Multiplexed Tandem PCR assay (AusDiagnostics, Australia), a rapid multiplex real-time PCR assay that detects vanA and/or vanB. METHODS: Two-hundred-and-eleven rectal swabs from Hematology and Oncology unit were submitted for VRE surveillance via direct detection of vanA and/or vanB by culture and by using Vancomycin Resistance 3 Multiplexed Tandem PCR assay. Enterococci were identified to the species level by using standard biochemical tests and BD Phoenix Automated Microbiology System (BD Diagnostic Systems, USA). Vancomycin susceptibility of enterococci was determined using Etest (BioMerieux, France). RESULTS: Compared to the culture method, Vancomycin Resistance 3 Multiplexed Tandem PCR assay had a sensitivity of 84.0%, specificity of 98.8%, positive predictive value (PPV) of 91.3%, and negative predictive value (NPV) of 97.6%. The assay failed to detect 18 (8.5%) specimens because of the presence of PCR inhibitors; of the remaining 193 specimens, 25 (12.9%) were positive, 23 for vanA, and 2 for vanB. Although both sensitivity and specificity for vanA VRE was 100% compared to the culture method, all vanB-positive specimens tested negative by VRE culture. CONCLUSIONS: Vancomycin Resistance 3 Multiplexed Tandem PCR assay is a rapid and laborsaving option for VRE surveillance for direct use on rectal swabs. However, the high rate of PCR failure owing to the inhibitors in the specimens and the low specificity for vanB should be considered when interpreting the results.

Detection of high risk human papilloma viruses [HR-HPV] in endocervical scrapes from women with abnormal cytology in a Turkish university hospital

To assess the utility of a commercial PCR based HPV test for evaluating patients before colposcopy and colposcopic biopsy sampling in a Turkish hospital and to compare its efficacy with histology in preventing unnecessary colposcopic biopsy sampling. Case control study. Akdeniz University, Faculty of Medicine, Antalya, Turkey. One hundred and seventy-four women with abnormal Pap smear results [40 with high-grade squamous intraepithelial lesions [HSIL] and 134 with low-grade squamous intraepithelial lesions [LSIL] and 34 women with normal cytologic test results were included. Papanicolaou stainings and high risk HPV DNA [HR-HPV DNA] detections were done for all endocervical scrape specimens. Colposcopic evaluation and endocervical sampling were done for 52 patients. Papanicolaou stainings, HR-HPV DNA detections and histologic examination from endocervical samplings were evaluated. Human beta-globin was not detected in 40 samples. All of the 13 samples from patients with HR-HPV DNA positivity and HSIL were diagnosed as CIN2+ lesions [100%], whereas 23.2% [4/17] of patients with HR-HPV DNA negativity and HSIL were found to have CIN2+ lesions. HR-HPV DNA test, which also amplifies a genomic fragment as an internal control, seems to be a good screening tool. Besides the benefit of an early diagnosis of cervical cancer, HR-HPV DNA assay may also lead to a marked decrease in unnecessary invasive cervical samplings