Diversidade genética e características fenotípicas do estreptococo do grupo B do trato anogenital de gestantes

• Autor(a) principal: Feuerschuette, Otto Henrique May
• Data de Publicação: 2018
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Universitário da Ânima (RUNA)
• Texto Completo: https://repositorio.animaeducacao.com.br/handle/ANIMA/15156
• topic: Gravidez; Estreptococo do grupo B; Sorotipagem; Reação em cadeia da polimerase multiplex; Genotipagem; Multi Locus Sequence Typing; Multi Locus Variable Number of Tandem Repeat Analysis

Introduction: Colonization of the anogenital tract of pregnant women by Group B Streptococcus (GBS) is the main risk factor for early-onset neonatal sepsis. Identification of maternal colonization allows antimicrobial prophylaxis and prevention of vertical transmission. Objectives: To identify the genetic diversity and phenotypic characteristics of GBS using molecular biology techniques and culture in specific medium, and the epidemiological aspects of pregnant women colonized by this bacterium. Methods: It was performed a cross-sectional study, anogenital samples of 316 pregnant women were collected between 35 and 37 weeks and submited to culture in specific medium, antimicrobial susceptibility test, multiplex PCR, multi locus sequence typing (MLST) and multi locus variable number of tandem repeat analysis (MLVA). The epidemiological aspects of colonized and non-colonized pregnant women were also investigated. Results: It was obtained a prevalence of 36.4% by culture and 38.6% by PCR. Multiplex PCR had sensitivity of 100%, specificity of 96.5%, positive predictive value of 94.3% and negative predictive value of 100%. The most common serotypes were Ia, V, II and III. Resistance genes were identified in 34 samples. Sensitivity to penicillin was universal, 24.3% presented resistance to erythromycin and 14.8% to clindamycin. Evaluating the epidemiological variables, there were no differences between the colonized and non-colonized pregnant women. Diversity index and number of genotypes found by MLST was 0.608 and 6, and by MLVA was 0.840 and 15, respectively. Conclusion: We found a high prevalence of maternal GBS colonization, with serotype distribution similar to the Americas region. Multiplex PCR was more accurate than culture, and maternal epidemiological variables showed no difference when evaluating presence or absence of bacterial colonization, its serotypes and antimicrobial resistance. MLVA showed a higher discrimination capacity among the unrelated strains than MLST.