Background and Aim : Genes encoding
virulence factors (VFs) such as toxins and adhesins are often encoded on
pathogenicity islands (PAIs) which contribute in Escherichia coli (E. coli) pathogenicity and the development of
urinary tract infection (UTI). Also, global increase in the
extended-spectrum beta-lactamase (ESBL)-producing E. coli is an important public health concern. Molecular characterization of PAI genetic markers and its correlation with virulence traits of the ESBL producers can assist in better understanding of theirs evolution, epidemiological surveillance, and future preventive intervention. This study investigated the prevalence rate of virulence genes and PAIs in non-ESBL E. coli and ESBL producing E. coli isolates.Methods : Current study was carried out in ۲۰۱۸ on ۱۰۰ ESBL producing E. coli and ۶۰ non-ESBL E. coli isolated from patients with UTI in Tehran. Sixteen genes encoding VF, and ۸ PAI markers were screened by PCR method.Results : We illustrated that ۶۵% (n=۱۰۰/۱۵۵) of isolates were ESBL producers. PAI IV۵۳۶ (۸۶?%), genes of fimH (۹۴%) and iroN (۹۵%) were the most prevalent traits in most of isolates. PAI IJ۹۶ marker was not detected in any isolate studied. A significant association (p <۰.۰۵) in papA, hlyA, sat, and usp genes with ESBL producers, and also in afa gene with non-ESBL E. coli isolates was observed. ESBL producers had a higher number of PAI markers compared to non-ESBL E. coli. There was a significant positive association between the presences of PAI III۵۳۶ in ESBL producers vs. non-ESBL isolates (۵۷% vs. ۲۹%). The sat gene was detected in non-ESBL and non-ESBL isolates carrying more than three and four PAI markers. Increased VFs and high resistance in ESBL producers can give a fitness advantage in the pathogenic niche and promote progression to pyelonephritis, septicemia, and septic shock, and as well as reduced the therapeutic options for UTI.Conclusion : Our study suggests a correlation between ESBL production and some VFs. The ESBL producers associated with high virulence leads to increase in severity of UTI, and treatment failure.