Determination of capsule serotypes and antibiotic resistance of Streptococcus agalactiae isolated from urine samples of patients referred to medical centers in Yazd

Background and Aim : Streptococcus agalactiae (group B streptococcus, GBS) is commonly found in the vagina, rectum and urinary tract of pregnant and non-pregnant women. This bacterium not only causes neonatal infections but also causes invasive diseases including urinary tract infections in pregnant women and non-pregnant adults. Penicillin and macrolides are the main antibiotics in the treatment of GBS infections but the prevalence of resistant strains is increasing. On the other hand, the distribution of bacterial capsule serotypes varies depending on the sampling time, geographical location and type of sample. The aim of this study was to investigate the antimicrobial resistance and capsular serotypes in group B streptococci isolated from urine samples of patients referred to Yazd medical centers.Methods : This descriptive cross-sectional study was performed on ۸۵ GBS isolates from ۶۰۶۸ urine positive culture samples for phenotypic survey and determine pattern of antibiotic resistance to antibiotic disks by Kirby-Bauer method. Also, capsular serotypes of isolates were determined by multiplex PCR.Results : The frequency of GBS in urinary samples was ۱.۴%. Antibiotic resistance of GBS to tetracycline, erythromycin, clindamycin and levofloxacin was ۹۷.۶%, ۳۸.۸%, ۳۱.۸% and ۹.۴%, respectively. All GBS isolates were sensitive to penicillin. The predominant capsular serotype was serotype III (۵۰.۶%) followed by serotypes Ib (۱۴.۱%), V (۱۲.۹%), IV (۷.۱%) and II (۵.۹%). ۹.۴% of isolates were non-typeable.Conclusion : The prevalence of GBS in urinary specimens was low and capsular serotype III was predominant as in previous studies. Antibiotic resistance is increasing in urinary GBS isolates.

کلیدواژه ها:

Group B streptococcus ، Urinary tract infection ، Serotyping ، Antibiotic susceptibility