Comparison of methods for detecting biofilm syndrome in bacterial vaginosis

In bacterial vaginosis, Gardnerella vaginalis and Fannyhessea vaginae form highly structured, dense biofilm consortia. Key cells serve as markers of biofilm organization within bacterial communities.

Objective: To compare microbiological methods for detecting biofilm syndrome in bacterial vaginosis.

Materials and methods: Twenty-eight women with complaints of vaginal discharge were examined. Vaginal discharge was used as the clinical material. Microscopy of preparations stained with Gram and methylene blue, as well as fluorescent in situ hybridization (FISH) or the RiGinaM method, were used. The Femoflor test was used for molecular analysis.

Results: The diagnosis of bacterial vaginosis in the Nugent study was established in 89.3% (25/28) of women. The microscopic evaluation of vaginal microbiocenosis using aniline dyes and the RiGinaM method yielded identical results (L:E ratio less than 4:1, with clue cells detected). Clue cells were not identified by any of the methods in only three cases. Among the 25 patients diagnosed with bacterial vaginosis by the Femoflor test, G. vaginalis was detected in all clinical samples, with an average logarithmic value of 7.55, whereas F. vaginae was detected in 22 cases. In three instances of physiological vaginal microbiocenosis, the total bacterial mass was predominantly represented by lactobacilli. G. vaginalis was found among these women, but their total bacterial mass was low (3.6, 4.1, and 6.8 lg), and F. vaginae was detected in only one case (2.1 lg).

Conclusion: Clue cells, as markers of biofilm bacterial vaginosis, can be detected using Gram staining, methylene blue staining, and the RiGinaM method. Microscopic methods using aniline dyes do not differentiate the types of bacteria present in the clue cells, whereas the RiGinaM method requires specific probes to identify microorganisms. The multiplex PCR method in real time can be utilized for the diagnosis of bacterial vaginosis in conjunction with microscopy methods.