Comparison of the total cervical vaginal bacterial counts between the different bacterial communities determined by the vaginal microbiome

Abstract

The development of techniques for determining the microbiome began a major advance in the understanding of bacterial species that makes up the human microbiota. In this sense, the study of vaginal microbiome allowed the identification of numerous bacteria fastidious and non-culturable, hitherto unknown, colonizing this environment. The literature is consistent in showing a strong association between changes in vaginal microbiota and the development of numerous obstetric and gynecological complications, among which the increased risk of acquisition and transmission of Human Immunodeficiency Virus (HIV). The normal microbiota is defined by the predominance of Lactobacillus sp. and, when altered, for replacement of these species by other bacteria, anaerobic mostly. Bacterial vaginosis is the main alteration of vaginal microbiota and it has been shown that, in his presence, there is an increase both in the bacterial diversity and the number of colony forming units (CFU) in the vaginal content of culture. However, such findings on the increased bacterial load in bacterial vaginosis is not confirmed by the total bacterial count using flow cytometry. Thus, the relationship between the pattern of vaginal microbiota and bacterial load in this environment still remains largely unknown, making it impossible to determine whether such a feature plays a role in the relationship between altered microbiota and its associated complications. Whereas the determination of the vaginal microbiome by sequencing the 16S ribosomal RNA bacterial gene, is the most accurate way of characterizing the local microbiota, the aim of this study is to compare the total bacterial count in the different types of vaginal communities determined by the microbiome. It is a cross-sectional study to be carried out with 108 women participating in the project "Characterization of the vaginal microbiome of Brazilian women of reproductive age" (Process FAPESP 2012 / 16800-3), who presented the five types of vaginal bacterial community described by Ravel et al. (2011) and confirmed in this population for the analysis of the microbiome. The total bacterial count of cervical smears will be performed by flow cytometry (FACSCalibur, BD, San Jose, CA) as the methodology standardized by our research group (Luchiari et al., 2015) .The statistical analysis will be performed in accordance with the conditions established for the results obtained and the significance level is 5%.