Antibiotic resistance profile and capsular serotyping of Streptococcus agalactiae isolated from pregnant women between 35 to 37 weeks of pregnancy

Streptococcus agalactiae (streptococcus group B (GBS)) is the natural inhabitants of the gastrointestinal and genitourinary tract and frequently is isolated from female reproductive tract. It is the most common cause of bacterial sepsis, meningitis, pneumonia and severe diseases in the newborn. Sixty Streptococcus agalactiae isolates were collected from 500 vaginal smear samples from pregnant women in their 35 to 37 weeks of pregnancy. The antibiotic susceptibility testing was performed by using disk diffusion method on Mueller Hinton agar medium with 5% sheep blood followed by capsular serotyping and PCR for 16Sr RNA, for final approval. Antibiotic susceptibility test showed the lowest resistance was belong to Penicillin, ampicillin, vancomycin (0%), cefazolin (3/33%) and ceftazidime (5%).While the highest resistance was found for erythromycin (28/33%), clindamycin (15%) and tetracycline (96/66%) antibiotics. The frequency of capsular serotypes was as following: III=45%, Ia=18/33%, II=16/66%, V=13/33% and Ib=5%. Based on the current study, high raise in GBS isolates resistance to erythromycin and clindamycin in pregnant women (within the 35-37th weeks of pregnancy) is alarming and Markazi province demands for an expanded screening program in the ground of their GBS preventative plan.