Diversidade bacteriana e determinação da carga de Gardnerella vaginalis, Atopobium vaginae, Mobiluncus spp., Mycoplasma hominis e Lactobacillus spp. em amostras de secreção vaginal de mulheres com e sem diagnóstico clínico de vaginose bacteriana

Abstract

The vaginal microbiota is considered a complex environment where several bacterial species coexist and develop complex relationships. Bacterial vaginosis (BV) is a syndrome characterized by a depletion of Lactobacillus species prevalent in healthy vaginal microbiota and an increase in other species, especially Gardnerella vaginalis and Atopobium vaginae. The aim of this study was to evaluate the vaginal microbiota of patients with and without BV, attended at the gynecology service of the SUS and the private service of health of Juiz de Fora/MG, as its bacterial diversity and quantify the major genera and species involved in the disease pathogenesis. Vaginal secretions of patients with and without BV were collected and transported to the laboratory in a specific medium. Slides were stained by the Gram method in order to establish the Nugent Score for evaluation of patients between healthy and sick. The total DNA of secretions was extracted and Real-time Polymerase Chain Reaction (qPCR) was performed using specific primers for Lactobacillus spp., G. vaginalis, A. vaginae, Mobiluncus spp. and Mycoplasma hominis. From the total DNA extracted from conventional PCR also was performed using specific primers to Bacteria domain and Actinobacteria and Firmicutes phyla, and then Denaturing Gradient Gel Electrophoresis (DGGE) was performed. The identification and quantification of bacteria belonging to the phyla Actinobacteria, Firmicutes, α-Proteobacteria, β-Proteobacteria and γ-Proteobacteria were performed by the technique of Fluorescence in situ Hybridization (FISH). Among the healthy and diseased (VB) groups statistically significant difference was observed in the quantification of Lactobacillus spp., G. vaginalis, A. vaginae, Mobiluncus spp. and M. hominis. Lactobacillus spp. was present in higher concentration in the healthy group while G. vaginalis, A. vaginae, Mobiluncus spp. and M. hominis were present in higher concentrations in the patient group (VB). In general, the concentration of G. vaginalis, and Mobiluncus spp. increased with the increment in the Nugent Score; however, the concentration of Lactobacillus spp decreased with the raise of the Nugent score. The cluster analyses showed that, with few exceptions, the profiles from patients with the same health status grouped together in separate clusters and there was a distinct separation based on the health status of the patients. The richness and diversity showed complex profiles and principal component analysis (PCA) showed that the samples within the VB group grouped together on the analysis of the phyla Firmicutes and Actinobacteria. No statistically significant difference was observed between healthy and diseased groups (VB) for quantification of the phyla Actinobacteria, Firmicutes, α-Proteobacteria, β-Proteobacteria and γ-Proteobacteria. The combined use of techniques DGGE, FISH and real-time quantitative PCR represent a successful strategy for qualitative and quantitative monitoring of changes in vaginal microbiota related to infectious diseases such as Bacterial Vaginosis.This may contribute to both the development of tools that aid in the diagnosis of women affected by BV, especially asymptomatic patients, and may also contribute to the improvement and optimization of therapeutic regimes adopted in clinical practice for the treatment of BV.