| Congresso Brasileiro de Microbiologia 2023 | Resumo: 656-1 | ||||
Resumo:The vaginal microbiome is a complex environment that consists of many microorganisms, some commensal, others symbiotic and some pathogens. The main genus that constitutes the vaginal microbiota is Lactobacillus sp, which contribute to vaginal health in several ways, including maintaining a low pH (3.5-4.5) through the production of lactic, producing bacteriocins, biosurfactants and H2O2, inhibiting the growth of pathogenic bacteria and competing for adhesion to the vaginal epithelia. The most common species is Lactobacillus crispatus. One of the most important pathogens that can commensally inhabit the vaginal microbiome is Group B Streptococcus (GBS). Streptococcus agalactiae, or GBS, is the major cause of newborn sepsis worldwide. In this project we explore the ability of L. crispatus (LC), one of the most abundant Lactobacilli of the vaginal microbiota, to inhibit GBS growth or stunt its capacity to colonize the vaginal epithelia. We obtained six GBS strains from vaginal swabs of pregnant women, LC strains were acquired commercially. GBS strains were characterized according to capsular serotype, virulence factors, resistance to antibiotics, Restriction Fragment Length Polymorphism (RFLP) and Multi-Locus Sequence Types (MLST). We also built an 8h-growth-curve for each GBS strain. The interaction between GBS and LC was evaluated with co-culture assays, where both growth and biofilm formation were measured. GBS and LC interactions when in human cell culture (HeLa) was also observed. We obtained six GBS strains that belong to serotypes Ia, II, III and V. RFLP analysis showed that the varying levels of similarity between strains. Growth curves showed that GBS reaches static phase after approximately 3h of growth, with exception of serotype II, with showed low growth throughout the 8h assay. Biofilm formation assays showed that LC affected GBS capacity of biofilm formation, but each strain was affected in different ways, increasing, or decreasing it. Competition assays indicate that GBS growth is minimally affected by the presence of LC, regardless of initial LC concentration. In conclusion, L. crispatus can affect GBS growth and metabolism. Future research will show which mechanisms are in play during their interaction. Palavras-chave: interaction, streptococcus, microbiome, infection, lactobacillus Agência de fomento:FAPESP | |||||