Presumptive identification & antibiotic susceptibility of group B Streptococci

Three presumptive identification tests were conducted on 60 strains of beta haemolytic group B streptococci (GBS) & evaluated for their sensitivity as compared to the standard serological grouping. The GBS were further subjected to serotyping and antibiotic sensitivity testing. Hippurate was hydrolysed by 96.6%, the CAMP test was positive in 83.3% & pigment was produced by 95%. The commonest serotype was la (33.3%) followed by lb (30%). Hundred percent strains were sensitive to Penicillin, Ampicillin, Erythromycin & Cephlexin. 76.7% showed MIC of 50 ug/ml or more for Tetracycline & 66.7% were inhibited by 3.2 ug/ml or less of Gentamicin.