ABSTRACT
Streptococcus agalactiae (GBS) is a leading cause of serious neonatal infection. In this study we determine the prevalence, serotype distribution and genomic diversity of GBS in vagina of pregnant women.Vaginal swabs of 531 pregnant women were cultured on Columbia Agar Base Blood, GBS Agar Base and Todd Hewitt Broth. GBS were characterized by group and type-specific agglutination. Genomic polymorphism was studied by random amplification of DNA (RAPD). Seventeen patients (3.2 percent) were positive for GBS, resulting serotype III the most frequent. RAPD detected 16 different RAPD profiles from 21 GBS studied, revealing a good discriminatory power. In this sense, this method showed different genotype from GBS serotype III recovered from successive samples of two patients, suggesting reinfection. In conclusion, the combination of RAPD and serotyping appear promising for epidemiological studies. Finally, findings of reinfection after therapy during pregnancy, led us to suggest performing prenatal GBS screening and intrapartum prophylaxis in order to reduce neonatal risk.
Subject(s)
Humans , Female , Pregnancy , Adult , Infant, Newborn , Pregnancy Complications, Infectious/diagnosis , Streptococcal Infections/diagnosis , Streptococcus agalactiae/genetics , Phenotype , Pregnancy Complications, Infectious/microbiology , Pregnancy Trimester, Third , Random Amplified Polymorphic DNA Technique , Streptococcal Infections/microbiology , Streptococcus agalactiae/isolation & purificationABSTRACT
Epidemioiogicai studies of Streptococcus agalactiae strains have been limited by the lack of sensitive and discriminatory methods for comparing clinical isolates. Serotyping, albeit a widely used methodology, has been shown to possess low capability to distinguish between epidemiologically related and unrelated isolates. We have employed here a random amplification of polymorphic DNA (RAPD) assay, using degenerate oligonucleotides as primers, to characterize S. agalactiae isolates from related or unrelated clinical samples. Epidemioiogically-related isolates (mother-infant pairs) showed identical profiles by this methodology. On the contrary, 12 epidemioiogically-unrelated isolates (ciassified into 5 different serotypes) resulted in ll distinct RAPD patterns. This suggests that the proposed modified RAPD assay provides a highly discriminatory tool for the analysis of genomic diversity among isolates from pathogenic organisms.