Comparison of the Frequencies of traT, ompT, hlyD and cnf1 virulence genes in Escherichia coli Isolates from hospitalized and non-hospitalized Patients with Urinary Tract Infections

Introduction and Objectives: Global studies revealed that 80-90% of community acquired urinary tract infections (UTIs) and 30-50% of hospital acquired UTIs were due to uropathogenic E. coli (UPEC). UPEC have multiple virulence factors that are essential for stability, colonization and pathogenicity in urinary tract. The aim of this study was comparison of frequencies of some virulence genes in E. coli isolates from the community acquired and hospital acquired UTIs patients. Materials and Methods: On hundred E. coli were isolated from urines of 49 hospitalized and 51 non- hospitalized UTIs patients that referred to laboratory of Shahid Faghihi hospital in Shiraz. Genomes of these isolates were extracted using the boiling method. Frequencies of traT, ompT, hlyD and cnf1 genes were evaluated by PCR technique. Statistical analysis of the data was performed using SPSS software. Results: Overall, the highest frequency (71%) was obtained for traT gene which encodes conjugal transfer surface exclusion protein TraT and is responsible for serum resistance against phagocytosis. Thereafter, frequency of ompT which encodes an outer membrane protease and is responsible for protection of UPEC against antimicrobial protamines of immune system was 54%. Frequencies of genes encoding toxins that contribute to pathogenicity of these strains were 18% and 12% for α-hemolysin (hlyD) and cytotoxic necrotizing factor 1 (cnf1) genes, respectively. In isolates of hospitalized and non- hospitalized UTIs patients the frequencies of traT, ompT, hlyD and cnf1 genes were 65.3% vs. 76.5%, 51% vs. 56.9%, 16.3% vs. 19.6%, and 12.2% vs. 11.8%, respectively. Comparison of the virulence genes’ frequencies in these two groups revealed no significant difference (P > 0.05). Conclusion: Existence of several virulence genes in UPEC has influence on UTIs severity. So evaluation of the frequencies of virulence genes can be helpful for prediction of UPEC pathogenicity and the severity of the resulted UTIs.

کلیدواژه ها:

hogenic E. coli ، Virulence gene ، Hospital and community acquired UTIs.