Accuracy of a commercial multiplex PCR for the diagnosis of bacterial vaginosis

Abstract

Purpose: Bacterial vaginosis (BV) is a common clinical condition characterized by odorous vaginal discharge, vaginal itching and/or burning. BV can occur when vaginal lactobacilli are depleted and replaced by diverse anaerobic bacteria. We evaluated a commercial multiplex PCR (ATRiDA) for the diagnosis of BV.

Methods: Cervicovaginal samples were included from women reporting urogenital symptoms and from women notified for sexually transmitted infections (STI) - who were not (necessarily) symptomatic. Clinical BV diagnoses were obtained from electronic patient files. The ATRiDA test measures the loads of Gardnerella vaginalis, Atopobium vaginae and Lactobacillus species in relation to overall bacterial load. The ATRiDA test outcome was compared to the clinical BV diagnosis and to vaginal microbiota composition, determined by 16SrRNA gene sequencing.

Results: We included samples from 185 women reporting urogenital symptoms, of whom 81 had BV and 93 women who were notified for an STI, of whom 16 had BV. Overall, compared to the clinical BV diagnosis, the ATRiDA test demonstrated high sensitivity (96.9 %) and moderate specificity (70.2 %). The negative predictive value was high (>97.3). The positive predictive value differed by study group and was highest in women reporting urogenital symptoms (78.2 %). Sequencing showed that 54 % of women who had an ATRiDA BV-positive test outcome, but who were not clinically diagnosed with BV, had diverse anaerobic vaginal microbiota (asymptomatic vaginal dysbiosis).

Conclusion: The ATRiDA test is a sensitive method for the detection of BV but, given the high occurrence of asymptomatic vaginal dysbiosis, a positive test outcome should be interpreted together with clinical symptoms.

Keywords: bacterial vaginosis; molecular diagnostics; multiplex PCR; vaginal microbiota.

Fig. 1.

Heatmap depicting microbial species (y-axis) per sample (x-axis) of a) women reporting urogenital symptoms and b) women notified for an STI. Microbial relative abundance is illustrated by the colour key. Sidebars above the heatmap depict vaginal microbiome clusters (top bar), BV clinical parameters and clinical BV diagnosis as recorded in the electronic patient file (middle bars) and ATRiDA test outcome (bottom bar).