Prevalence of Streptococcus spp. collected from vaginal samples and their antibiotic resistance

Abstract

Background. Streptococci are a heterogeneous group Gram positive bacteria, predominantly anaerobes. They are classified by growth characteristics, hemolysis on blood and antigenic composition.Among the most pathogenic streptococci are ß-hemolytic Streptococcus group B (GBS) responsible for pneumonia, meningitis and sepsis in newborn. In order to prevent infections that might involve not only the female but also but also the future newborn, a bacterial culture have to be performed during pregnancy. Objectives. This study aims to assess the prevalence of GBS and their resistance to antibiotics among bacteria collected from vaginal samples. Methods. During the considered period of study: May 2008 - May 2009, 384 vaginal samples from young women were microbiologically investigated. Swabs were sown on CNA (bioMérieux) plates and incubated under CO2 environment for 24-48 hours. For the identification of group and the evaluation of their susceptibility to antibiotics the kit Slidex streptococcal Plus (bioMérieux) and the ATB Strep (bioMéieux) respectively were used. Breakpoint values were as suggested by CLSI. Results. GBS was the most frequently pathogen found with 59.5% (69) on a total of 116 positive samples, followed by Group D streptococci with 34.5% (40), and Group A with 4.3% (5), Group C and F, accounted for 0.8% (1). Moreover, all the isolates, with the exception of group D, resulted susceptible to penicillin, amoxicillin, vancomycin and cefotaxime, 45% to erythromycin, 47% to clindamycin, 75% to cotrimoxazole. Conclusions. The data from this survey show that GBS is the prevalent pathogen, among Streptococcus spp collected from the vagina.The percentage of antibiotic resistant strains found confirms the importance of the Clinical Pathology Laboratory in the surveillance of streptococcal infections for the control and prevention.

Keywords

• Vaginal swabs, Streptococcus, GBS