Masoumeh Navidinia1*, Marjan Rashidan2, Ali Rahimipour3 and Mehdi Goudarzi4

1Medical Bacteriology (PhD), School of Allied Medical Sciences,
Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
2Medical Microbiology(PhD), School of Medicine,
Shahroud University of Medical Sciences, Shahroud,IR Iran.
3Clinical Biochemistry (PhD), School of Allied Medical Sciences,
Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
4Medical Microbiology (PhD), Faculty of Medical Sciences, Shahid
Beheshti University of Medical Sciences, Tehran, IR Iran.

ABSTRACT

Group B Streptococcus (GBS) is an opportunistic harmless bacterium which the leading cause of neonatal infections. Our purpose was to determine capsular genotypes distribution and antibiotic resistance pattern of GBS isolated from clinical samples. Two hundred and twenty two GBS strains isolated from clinical samples from different hospitals in Tehran, Iran. After identification by specific cultures and biochemical tests, broth microdilution method was used to determine the minimal inhibitory concentration (MIC) of antibiotics based on standard protocol. The erythromycin-clindamycin double-disk test was used to determine the inducible resistance phenotypes. Capsular genotypes were identified by PCR method. The high rates of antibiotic resistance in GBS were related to gentamycin 89.18%, tetracycline 87.38%, kanamycin 62.16%, clindamycin (67.1%), erythromycin 57.2%, and chloramphenicol 32.8%. All strains were sensitive to vancomycin, penicillin, and ampicillin. Between eleven capsular antigens, serotypes such as III(50.9%) ,V(27.47%) ,Ib(17.76%) ,Ia(15.54%) , Ic (5.85%)were the highest. The genotypes distribution and the patterns of resistance phenotypes of GBS may vary in different areas. Thus, it is required to be considered in each region to work out strategies for prevention. The PCR method is recommended as a rapid and reliable technique for identification and molecular epidemiology study of GBS.

Keywords: Group B Streptococcus (GBS), Genotypic characterization, Antibiotic Resistance.