Characteristics of Streptococcus agalactiae causing urinary tract infections: Emergence of new sequence types ST۷۴ and ST۳۸ in Iran

Objective(s): Difficult-to-treat Streptococcus agalactiae infections are increasingly described in patients with urinary tract infections (UTIs). This occurrence could be due to the production of virulence determinants. This study aimed to characterize the molecular features of S. agalactiae responsible for UTIs.Materials and Methods: In this cross-sectional study, ۷۰ S. agalactiae isolated from UTIs were examined. Antibiotic susceptibility testing was performed using the disk diffusion method. All S. agalactiae isolates were confirmed by atr and dltS PCR assays. Virulence, alpha protein-like, and pilus island genes were detected by PCR. Isolates were characterized using the multilocus sequence typing method. Results: Multidrug resistance was observed in ۸۰% of isolates. Five virulence profiles were detected, wherein cylE, lmb, bca, rib (۳۵.۷%), cylE, lmb, alp۳ (۲۷.۱%), and cylE, lmb, bac, rib, alp۲ (۲۱.۴%) were the most frequent detected profiles. S. agalactiae was isolated and categorized within three clonal complexes (CCs) including CC۲۲ (۴۰%), CC۱۷ (۲۵.۷%), and CC۲۳ (۲۰%). The main sequence types (STs) found were ST۲۲ (۲۷.۱%), ST۲۳ (۱۷.۱%), ST۱۷ (۱۲.۹%), ST۳۱ (۸.۷%), ST۴۰ (۸.۷%), ST۷۴ (۷.۱%), ST۴۸ (۴.۳%), ST۸۹۰ (۴.۳%), ST۱۸۹ (۲.۸%), ST۳۸ (۲.۸%), ST۵۲ (۲.۸%), and ST۱۵۵ (۱.۴%). ST۷۴ and ST۳۸ were reported for the first time in Tehran-Iran. Conclusion: This study highlights the predominance of the CC۲۲ lineage among S. agalactiae strains isolated from UTIs in Tehran, Iran, and highlights the significant penetration of this lineage into hospitals. MDR patterns among these strains appear to be becoming a major concern in the management of infections.

Keywords:

Drug resistance , Group B streptococci , Multilocus sequence typing , Multiplex polymerase chain - reaction , Polymerase chain reaction , Urinary tract infection Vancomycin