Objective: Group B streptococci (GBS), which can colonize in the intestinal and vaginal flora of healthy adults, cause meningitis and sepsis in newborns, soft tissue infections and urinary tract infections in pregnant women and adults with underlying diseases. Penicillins are the first choice in the treatment of GBS infections. However, it is important to know the antibiotic sensitivities to manage the treatment due to recently reported decreased penicillin sensitivity, increased resistance to alternative agents and patients with penicillin allergy. In this study, we aimed to determine the antibiotic susceptibility profile of GBS strains isolated in our laboratory.

Method: Antibiotic susceptibilities of 166 GBS strains, isolated from various clinical samples sent to our laboratory between January 2017 and June 2018 were evaluated. Bacterial identification was performed using conventional methods and VITEK® 2 (BioMérieux, France) testing system. Antibiotic susceptibility was determined by disk diffusion method according to EUCAST criteria. In case of resistance to macrolides, double disc synergy method was used to determine resistance phenotypes.

Results: All GBS isolates were susceptible to penicillin, vancomycin, tigecycline and linezolid. The susceptibility levels to nitrofurantoin, levofloxacin and norfloxacin was 94.5%, 78.3% and 77.7%, respectively. Erythromycin and clindamycin resistance rates were 35.5% and 30.7%, respectively; iMLSB was detected as 73%.

Conclusion: In our study, penicillin resistance was not determined in GBS isolates. Resistance to erythromycin, clindamycin and levofloxacin suggests that caution should be exercised when using these drugs for prophylaxis and treatment. Thus, antibiotic susceptibility tests are recommended for the selection of drugs to be used in the clinic and to determine the resistance profile.