Vaginal microbiota in healthy women and patients with bacterial vaginosis and nonspecific vaginitis

Abstract

According to Russian classification, bacterial vaginosis (BV) and nonspecific vaginitis (NSV) are two different clinical conditions. The vaginal microbiota was evaluated in 200 women (50 healthy pregnant women (HPW) during the first trimester, 100 patients with BV and 50 patients with NSV). The samples received from both healthy women (121 samples) and patients (BV 241 samples, NSV 136 samples) contained lactobacilli (96.5%), peptostreptococci (52.2%), streptococci (36.4%), bifidobacteria (48.2%), and propionibacteria (34.3%). Other microorganisms (bacteroides, enterobacteria, yeasts, staphylococci) were recovered by culture in 1.2-27.8% of samples. The most common microorganisms found in the vaginal discharge samples of women with BV and NSV were opportunistic pathogens (staphylococci 32.3%, enterococci 17.5%, enterobacteria 28.2%, candida 21.3%, peptostreptococci 64.2%, peptococci 38.8%, gram-negative anaerobic bacteria 29.4%). In most cases, more than one species of microorganisms were present (simultaneously representatives of 1-3 (NSV) or 3-5 (BV) species). The vaginal lactobacillus content in healthy women was log 7-9 cfu/ml. The total number of vaginal lactobacilli in the samples from BV and NSV women was reduced by up to log 6-7 cfu/ml and log 3-4 cfu/ml, respectively; 41.9% of NSV samples contained 3 cfu/ml of lactobacilli. All vaginal aerobic microorganisms isolated from the patients were resistant to 9 or more of 22 antibiotics tested. Microorganisms isolated were evaluated for their ability to restore nitrate and nitrite (Grees reagent) and to produce arginine decarboxylase (Moeller medium with arginine). Nitrate and nitrite reductases were produced by 25-28% of vaginal microbe strains isolated from HPW, 61-64% strains isolated from patients with NSV and 51-55% of those with BV (mostly belonging to enterobacteria, peptostreptococci, bacteroides, candida, and some others). Arginine decarboxylase activity was found in 41%, 53.4%, and 49.5% of strains isolated from these groups of women, respectively. The results obtained allow us to suppose that the determination of activity of enzymes investigated in vaginal strains or vaginal discharges may be used as additional diagnostic or screening tests for the predictive value of vaginal microbial ecology imbalance in BV and NSV. Key words: vaginal microbial ecology, vaginosis, nonspecific vaginitis, antimicrobial resistance, nitrate reductase, nitrite reductase, arginine decarboxylase