Aspectos diagnósticos, epidemiológicos, microbiológicos e moleculares de Gardnerella vaginalis em mulheres atendidas na rede pública e particular de Juiz de Fora, MG

Abstract

Bacterial vaginosis (BV) is a polymicrobial syndrome characterized by an imbalance in the vaginal microbiota associated with the replacement of the vaginal bacterial population predominantly aerobic (Lactobacillus spp.) by an anaerobic population (especially Gardnerella vaginalis) leading to abnormal vaginal discharge in women of reproductive age. The aim of this study was to evaluate physiological and molecular aspects of G. vaginalis in patients with and without BV, treated at public (SUS) and private services in Juiz de Fora/MG, in addition to determining the antimicrobial susceptibility patterns. Vaginal secretion samples were collected and processed for selective isolation, as described in the literature. G. vaginalis was presumptively identified by 13-hemolysis or diffuse hemolysis and oxidase and catalase negative tests. The bacterial identity was confirmed by PCR. The encoding gene for vaginolisin (vly) was detected by PCR. Antimicrobial susceptibility patterns were determined by agar dilution method, according to CLSI guidelines for anaerobic microorganisms. Genotyping was performed by AP-PCR. Out of 89 patients, G. vaginalis was isolated from 42 by cultivation in culture medium, 35 of which with VB, 02 with intermediate clinical and 05 healthy. In 47 patients it was not possible to perform the isolation of G. vaginalis by cultivation method, with a positive PCR result for 26 of these patients. To classify patients in symptomatic and healthy, Nugent score was performed. All 204 isolates of G. vaginalis subjected to PCR reaction had its identity confirmed and, of these, vly gene was detected in 96.5%. Regarding antimicrobial susceptibility patterns, high sensitivity to ampicillin/sulbactam, clindamycin and chloramphenicol was observed, and high resistance was observed to ampicillin, metronidazole, secnidazole and tinidazole. The positive culture of G. vaginalis, per se, does not ensure the diagnosis of BV, as the microorganism may be considered resident microbiota. It was not possible to correlate vly gene detection as a marker for determination of pathogenic strains. Bacterial resistance against antimicrobial drugs commonly used in clinical corroborate with others studies, and warn to the risks of empiric therapy routine. The genotyping technique used did not allow G. vaginalis grouping, according to their source of isolation, suggesting, therefore, a heterogeneous population. This observation is sustained by the impossibility of grouping using the bacterial typing by antimicrobial susceptibility profile too, although other genotyping techniques have not been used. In addition, specific primers for genotyping G. vaginalis by AP-PCR have not been described yet. It is expected that these results can serve as basis for raising discussions related to empiric treatment of bacterial vaginosis, considering limitations in the availability of diagnostic or antimicrobial therapy.