Significance of Gardnerella vaginalis genotyping in diagnosis of recurrent bacterial vaginosis

Abstract

Objective. To assess the importance of identifying different genotypes of Gardnerella vaginalis in the diagnosis of recurrent bacterial vaginosis.

Materials and methods. The study involved 299 women of reproductive age. All patients were divided into three groups (healthy women, women with the first episode of bacterial vaginosis, and women with recurrent bacterial vaginosis). DNA of Gardnerella vaginalis in vaginal discharge was detected by real-time PCR. The detection of four genotypes of G. vaginalis was performed using real-time multiplex PCR. To quantify the amplified PCR fragments, quantitative standard samples were constructed. Statistical analysis of the results was carried out using the statistical package NCSS 11 (NCSS, LCC).

Results. In 38.2 % of healthy women, any one genotype of G. vaginalis was identified in the vaginal biotope, most often it was genotype 4 (35.2 %), while the concentration of G. vaginalis DNA was low (102–103 geqs/ml). When several genotypes of gardnerella were detected simultaneously in healthy women, the DNA concentration did not exceed 104 geqs/ml. A completely different picture was observed among women with bacterial vaginosis (BV). In the first episode of BV, genotype 4 of G. vaginalis prevailed, both as a single genotype and in combination with 1 or 2, or 3 genotypes. In the recurrent course of BV, only 3–4 genotypes of G. vaginalis were detected at once, and in 78 % of cases it had place is a combination of 1, 2 and 4 genotypes, and the DNA concentration was 107–108 geqs/ml.

Conclusion. To diagnose recurrent forms of BV, it is necessary to develop and introduce into practice laboratory diagnostics a test system for detecting different genotypes of G. vaginalis by real-time PCR.