Prevalence and antimicrobial susceptibility pattern of anorectal and vaginal group B Streptococci isolates among pregnant women in Jimma, Ethiopia

BACKGROUND: Streptococcus agalactiae (group B Streptococcus, GBS) is the most frequent pathogen isolated from neonates with invasive bacterial disease and responsible for serious infections in newborns such as pneumonia, septicemia and meningitis. Infection is primarily acquired vertically from mothers colonized with GBS. However, the prevalence and antimicrobial susceptibility pattern of GBS among pregnant women in Ethiopia are less studied. METHODS: This cross-sectional study involved 126 pregnant women at 35–37 weeks of gestation attending the antenatal clinic at Jimma University Hospital. Anorectal and vaginal swabs were cultured on to Todd-Hewitt broth medium supplemented with Gentamicin and Nalidixic acid and subsequently sub-cultured on 5 % sheep blood agar followed by identification of isolates based on colonial morphology, Gram stain, catalase reaction, hippurate hydrolysis and Christie, Atkins, Munch-Petersen (CAMP) test, and testing for their susceptibility to antimicrobial agents using the Kirby–Bauer method. RESULTS: The overall carriage rate of GBS was 19.0 % (24/126), and the rectal and vaginal carrier rates were 14.3 % (18/126) and 10.4 % (13/126), respectively. Concomitant vaginal and anorectal colonization was recorded in 29.2 % (7/24) of the women who were culture positive. All GBS isolates were susceptible to penicillin G, ampicillin, and vancomycin, but a considerable proportion was resistant to clindamycin (3.2 %), erythromycin (6.5 %), ciprofloxacin (9.7 %), ceftriaxone (9.7 %), norfloxacin (12.9 %), cotrimoxazole (29 %), and tetracycline (45.2 %). CONCLUSION: This study reveals high carriage rate of GBS among pregnant women compared to some previous studies in Ethiopia. However, further epidemiological investigations should be done in different parts of the country in order to know the actual GBS colonization rate of pregnant women and to consider the possibility of implementing prophylactic treatment to prevent potential adverse maternal and neonatal outcomes. Future studies should be conducted to reveal serotype distributions of GBS in this community.