Diagnostic Evaluation of a Multiplex Quantitative Real-Time PCR Assay for Bacterial Vaginosis

Abstract

Background: Quantitative multiplex PCR assay for Bacterial Vaginosis (BV) based on the detection of the predominant contributory targets was evaluated against the conventional Nugent Score that is laborious and subjective due to morphological assessment bias of BV-associated bacteria. Methods: 125 dual vaginal specimens were collected from patients aged ≥18 years at the time of presentation at the provider office to perform real time PCR and Nugent Testing. PCR assessment of BV was performed by quantitation of DNA amounts of Gardnerella vaginalis, Atopobium vaginae, Lactobacillus spp., and total amount of bacterial DNA using a multiplex RT-PCR kit (ATRiDA, Netherlands). Discordant results were resolved by the Amsel criteria or ancillary testing such as BD Affirm, when available. Results: Nugent score classified 36.36% of the patients in BV and 15.45% in transitional BV categories. In contrast, the PCR method called 48.18% as BV and 12.72% as transitional BV or BV of unspecified origin categories. The overall concordance between the two methods was 81.81%. None of the BV positives by Nugent method were missed by the PCR. There were only 2 intermediates by Nugent that were called normal by PCR. PCR method was more sensitive than the Nugent and picked an additional 11% positives. Conclusions: PCR based molecular BV diagnosis can standardize women health testing by removing the bias due to subjective interpretation of Nugent scoring. Our study shows that PCR method is more sensitive than conventional testing and may be a promising replacement for laborious Nugent scoring method in an era of shrinking microbiology expertise.

Bacterial vaginosis - diagnostic dilemma and implications

“…Compared to genomic sequencing, culture sensitivity was 29.9%, Amsel method 61.5%, Nugent criteria and BD MAX Vaginal Panel 63.9%, while the RT-PCR test showed sensitivity of 80.6% 23 . In their study, Dhiman et al 24 compared Nugent score and RT-PCR for BV detection in 125 patients of reproductive age and they achieved results of total agreement similar to our results (81.8%).…”

Evaluation of Various Diagnostic Strategies for Bacterial Vaginosis, Including a New Approach Based on MALDI-TOF Mass Spectrometry

“…Both diagnostic tools have obvious limitations, such as the need for good technical skills to prepare good quality smears and to analyze the results accurately for the Nugent score. Although new molecular biology tools were introduced several years ago, their use remains limited and expensive [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ].…”