Diagnosis of bacterial vaginosis by a new multiplex peptide nucleic acid fluorescence in situ hybridization method

Bacterial vaginosis (BV) is one of most common vaginal infection and its diagnosis by classical methods reveals low specificity. Our goal was to compare the accuracy of BV diagnosis between the gold standard method, Nugent score, and our novel Peptide Nucleic Acid Fluorescence in situ Hybridization (PNA-FISH) methodology, which targets Lactobacillus and Gardnerella vaginalis populations. Epidemiological characteristic of the population under study (n=150) mirrored what has been described before in other major studies. Our results have shown a sensitivity of 84.6% (95% confidence interval (CI), from 64.3 to 95.0%) and a specificity of 97.6% (95% CI, from 92.6 to 99.4%), which attests the clinical value of this PNA-FISH approach. This methodology combines the specificity of PNA probes for Lactobacillus species and G. vaginalis visualization, and the criteria defined by Nugent score, allowing a trustful evaluation of the bacteria present in vaginal microflora and avoiding the occurrence of misleading diagnostics. Therefore, the PNA-FISH methodology represents a valuable alternative for BV diagnosis.