Molecular diagnosis of bacterial vaginosis: Prevalence of Gardnerella vaginalis and Atopobium vaginae in pregnant women

Abstract

Introduction/Objective. Bacterial vaginosis (BV) is defined as disequilibrium of vaginal microbiota due to proliferation of Gram-negative/variable anaerobes and reduction/depletion of vaginal lactobacilli. Difficulties in interpreting microscopically categorized findings in diagnosis of BV need a molecular analysis of bacteria present in vaginal discharge of patients. In this regard, we performed real-time qPCR analysis of vaginal discharge samples with the goal to explore in which extent prevalence and amount of anaerobes, Gardnerella vaginalis and Atopobium vaginae, are related to findings obtained by microscopy. Methods. This study enrolled 111 asymptomatic pregnant women between 24 and 28 weeks of pregnancy. Gram-stained vaginal smears were evaluated microscopically. Afterwards, DNA of bacteria was extracted from Gram slides and real-time qPCR was performed with the aim to detect and quantify G. vaginalis and A. vaginae. Results. The data of our study showed that 53.2% of patients had normal results, while 20.7% and 26.1% of patients had intermediary (IMD) and BV results, respectively. G. vaginalis and A. vaginae were more frequently found in IMD and BV than in healthy patients; also, the average bacterial number of G. vaginalis and A. vaginae were significantly higher in BV and IMD than in the group with normal findings (p = 0.000). Comparing mutual relation of G. vaginalis and A. vaginae, the prevalence and number of G. vaginalis were in all groups significantly higher than A. vaginae. Conclusion. The data of our study have shown that in distinguishing normal from BV findings, quantification of bacteria may be more important than just molecular detection of bacteria.