Detection of Fimbrial Genes, Antibiotic Resistance Profile and Phylogenetic Background of Uropathogenic E. coli Isolated from Clinical Samples in Karaj City, Iran

The aim of the present study was to determine the prevalence of phylogenetic groups/subgroups, fimbrial genes, and antibiotic susceptibility of E. coli isolated from urinary tract infections in Karaj city, Iran.
A total of 107 E. coli isolates were confirmed by standard bacteriological tests. The phylogenetic group, fimbrial genes and antibiotic resistance genes was determined by PCR method. Antibiotic resistance of all the isolated E.coli against nine antimicrobial agents was determined by disk diffusion method.
PCR assays showed the prevalence of fimbrial genes among the studied isolates were 31.7% and 9.3% for papEF and afaBC, respectively. Most of papEF genes were placed in D phylogroup (18.6%) and D1 subgroup (14.01%) and the percentage of afaBC (2.8%) were similar in B1, B2 and D phylogroups. The frequency of tetA and tetB genes were 22.4% and 17.7%. Isolates which contained tetA were distributed mainly in D group (14.01%) and those which contained tetB were divided in D group (7.48%). Antimicrobial susceptibility testing showed the maximum resistance rate to cephalexin (CN: 100%) and the minimum resistance level to ciprofloxacin (CP: 36.5%).
The present study showed that phylogenetic groups A and D were predominant. Virulence factors such as papEF and afaBC belonged to D phylogenetic group. Multidrug resistance E. coli isolates tends to be in the non-B2 phylogenetic groups. Due to high antibiotic resistance, appropriate control should be considered in medicine to control the development of novel resistant isolates.