Frequency of pilus islands and antibiotic resistance in Streptococcus agalactiae isolated from urine of pregnant women

Background and Aim : Group B Streptococcus (GBS) is one of the most important causes of neonatal mortality and postpartum fever. Group B Streptococcus infection can be transmitted from the infected mother to her baby during delivery. Pilus island is one of the most important virulence factors of Streptococcus agalactiae after capsule. The aim of this study was to evaluate the frequency of pilus islands and antibiotic resistance in Streptococcus agalactiae isolated from urine of pregnant women in Yazd, Iran.Methods : In this cross-sectional study, ۳۳ GBS samples isolated from the urine of pregnant women were studied by the multiplex polymerase chain reaction (PCR) method for the presence of pilus islands PI-۱, PI-۲a and PI-۲b. Antibiotic resistance phenotype of tetracycline, penicillin, gentamycin, erythromycin, levofloxacin and clindamycin antibiotics was determined by disk diffusion method. Data analysis was performed using SPSS, version ۱۶. Results : PI-۱+PI-۲a was most frequent pilus island in the GBS isolates (۲۸ [۸۴.۸%]) and the frequency of PI-۲b was ۵ (۱۵.۲%). The frequency of PI-۱+PI-۲a was ۸۳.۳۳% in serotype III and ۱۰۰% in serotypes II, Ia, Ib and V (P=۰.۴۹۲). All the GBS isolates were susceptible to ceftriaxone (۱۰۰%) and cefotaxime (۱۰۰%) antibiotics. However, GBS isolates showed the highest resistance to erythromycin (۷۹%) and clindamycin (۷۶%).Conclusion : Our results showed that most of the GBS isolates examined carried the PI-۱+PI-۲a gene, which increases bacterial potency in colonization and resistance to the immune system. The PI-۲b gene was also observed in a lower frequency. Pilus is suggested as a unique vaccine candidate.

کلیدواژه ها:

Group B Streptococcus ، Pregnant women ، Pilus islands ، Antibiotic resistant