Evaluation of Relationship between Phylogenetic Typing and Antibiotic Resistance of Uropathogenic Escherichia coli

Urinary tract infections (UTI) are among the most common infectious diseases. Nowadays, Escherichia coli (E. coli) is counted as the predominant cause of urinary tract infection in 80-90% of patients. Due to increase in the rate of antibiotic usage and subsequent drug resistance, this study was performed to evaluate the antimicrobial resistance pattern of E. coli isolated from patients with suspected urinary tract infection and phylogenetic grouping of these strains. This cross sectional study was conducted on 600 samples of suspected urinary tract infection from Hasheminejad super specialty kidney hospital. To isolate E. coli strains, all samples were examined with biochemical and microbial tests. Then using the standard disc diffusion method (Kirby-Bauer), drug susceptibility test was performed on 8 different antibiotics. Multiplex PCR technique and specific primers of chuA, yjaA genes and TSPE4.C2 fragment were used for phylogenetic grouping of the isolated E. coli strains. In this study the highest rates of resistance to antibiotics were seen against ampicillin (83.83%) and nalidixic acid (71.42%). Also, the lowest rates of resistance were reported against nitrofurantoin (3.12%) and ceftizoxime (11.22%). Based on phylogenetic studies, 65%, 19% and 16% of the isolated strains belonged to group B2, group D and group A, respectively. Also, the majority of antibiotic resistant strains and multi-drug resistant strains belonged to the phylogenetic group B2. As same as other reports around the world, most of the E. coli strains isolated from this region belonged to phylogenetic group B2.