O-serogrouping of Escherichia coli strains isolated from patients with Urinary tract infection by using PCR method

Background and Aim: Urinary tract infection (UTI) is one of the most common infections, and Escherichia coli is so far the most common causative agent of this disease. The O antigen, consisting of many repeats of an oligosaccharide unit, is part of the lipopolysaccharide (LPS) in the outer membrane of Gram-negative bacteria. The variability of the O antigen provides the major basis for serological schemes of Gram-negative bacteria. The aim of this study was to investigate the prevalence of O-serogroups among E. coli isolated from patients with UTI. Materials and Methods: During three months, ۲۱۰ patients with urinary tract infection, referred to three hospitals of Tehran, Sanandaj and Boroujerd. E. coli isolates were identified using standard methods then serogrouping was performed by using PCR method. Results: A total of ۱۵۰ E. coli strains were isolated from the urine samples. The most common types of O antigens were O۱ (۱۳.۳۳%), O۱۶ (۸%), O۸ (۵.۳۳%) and O۲۱ (۴%). There was no positive isolate for O۲۲ and O۸۳ genes. Conclusions: The present study revealed that serogroup O۱ was isolated with maximum frequency followed by O۱۶, O۸ and O۲۱, respectively. In UPEC, the O-serogroups can be related to the virulence factor profile of each strain. Further studies from other parts of Iran and on other serogroup are recommended.