Description
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)
Background: Group B Streptococcus (GBS) remains a major cause of neonatal sepsis and is also associated with invasive and noninvasive infections in pregnant women and non-pregnant adults, elderly and patients with underlying medical conditions. Ten capsular serotypes have been recognized, and determination of their distribution within a specific population or geographical region is important as they are major targets for the development of vaccine strategies. We have evaluated the characteristics of GBS isolates recovered from individuals with infections or colonization by this microorganism, living in different geographic regions of Brazil.Methods: A total of 434 isolates were identified and serotyped by conventional phenotypic tests. The determination of antimicrobial susceptibility was performed by the disk diffusion method. Genes associated with resistance to erythromycin (ermA, ermB, mefA) and tetracycline (tetK, tetL, tetM, tetO) as well as virulence-associated genes (bac, bca, lmb, scpB) were investigated using PCR. Pulsed-field gel electrophoresis (PFGE) was used to examine the genetic diversity of macrolide-resistant and of a number of selected macrolide-susceptible isolates.Results: Overall, serotypes Ia (27.6%), II (19.1%), Ib (18.7%) and V (13.6%) were the most predominant, followed by serotypes IV (8.1%) and III (6.7%). All the isolates were susceptible to the beta-lactam antimicrobials tested and 97% were resistant to tetracycline. Resistance to erythromycin and clindamycin were found in 4.1% and 3% of the isolates, respectively. Among the resistance genes investigated, tetM (99.3%) and tetO (1.8%) were detected among tetracycline-resistant isolates and ermA (39%) and ermB (27.6%) were found among macrolide-resistant isolates. The lmb and scpB virulence genes were detected in all isolates, while bac and bca were detected in 57 (13.1%) and 237 (54.6%) isolates, respectively. Molecular typing by PFGE showed that resistance to erythromycin was associated with a variety of clones.Conclusion: These findings indicate that GBS isolates circulating in Brazil have a variety of phenotypic and genotypic characteristics, and suggest that macrolide-resistant isolates may arise by both clonal spread and independent acquisition of resistance genes.
Inst Biol Exercito, Rio De Janeiro, Brazil
Univ Estadual Campinas, Sao Paulo, Brazil
Hosp Naval Marcilio Dias, Rio De Janeiro, Brazil
Fundacao Fac Fed Ciencias Med, Porto Alegre, RS, Brazil
Lab Hosp Mae de Deus, Porto Alegre, RS, Brazil
Lab Sabin, Brasilia, DF, Brazil
Lab Sergio Franco, Rio De Janeiro, Brazil
Lab Hermes Pardini, Belo Horizonte, MG, Brazil
Hosp Univ Fed Amazonas, Manaus, Amazonas, Brazil
Hosp Univ Fed Maranhao, Sao Luis, Maranhao, Brazil
Univ Fed Bahia, Salvador, BA, Brazil
Hosp Univ Cuiaba, Cuiaba, Mato Grosso, Brazil
Lab Municipal Saude Publ Recife, Recife, PE, Brazil
Hosp Univ Sao Paulo, Sao Paulo, Brazil
Univ Estadual Paulista, Sao Paulo, Brazil
Univ Fed Triangulo Mineiro, Uberaba, MG, Brazil
Univ Fed Rio de Janeiro, Maternidade Escola, Rio De Janeiro, Brazil
Univ Fed Parana, Hosp Clin, Bacteriol Lab, BR-80060000 Curitiba, Parana, Brazil
Univ Fed Rio de Janeiro, Inst Microbiol Paulo Goes, Dept Med Microbiol, Rio De Janeiro, Brazil
Univ Estadual Paulista, Sao Paulo, Brazil
