Rapid Quantitative PCR Assay for the Detection of the Three Vaginal Pathogens <i>Candida</i>, <i>Gardnerella</i> and <i>Atopobium</i> as well as the Commensal <i>Lactobacillus</i> Genera

The vaginal microbiota balance is quite fragile and susceptible to the development of vaginosis and candidiasis. The current diagnostic method for bacterial vaginosis relies on the evaluation of different bacterial morphotypes using the Nugent score. This method is only partially in correlation with a DNA sequencing-based diagnostic or Amsel criteria used by clinicians, suggesting the need for new molecular approaches dedicated to the diagnosis of BV. The objective of this study was to develop and validate a quantitative polymerase chain reaction (qPCR) assay for the specific and rapid detection of three vaginal pathogens, <i>i.e</i>. <i>Candida, Gardnerella</i> and <i>Atopobium</i> and the commensal Lactobacillus genera. For this purpose, four oligonucleotide primer pairs were designed and tested to obtain optimal amplification of the four target genera. The qPCR assay was also tested on the non-target genera and on human DNA. The designed primers allowed specific amplification of the target organisms <i>in vitro</i> and in clinical vaginal samples. The qPCR assay designed in this study is effective to specifically detect these genera in clinical samples as a molecular technique complementary to the Nugent score. It can be used in epidemiological studies for understanding the role of these pathogens and to follow their abundance in the microbiota in disease processes such as the development of vulvovaginal candidiasis and bacterial vaginosis.