Virulence factor diversity between imipenem resistant and imipenem susceptible strains of Escherichia coli isolated from hospitalized patients with severe urinary tract infections

From a clinical perspective, it is imperative to discern the differences in the distribution of virulence factors between imipenem resistant and imipenem susceptible strains of uropathogenic Escherichia coli isolated from hospitalized patients. The present study was carried out to find this purpose. One-hundred and sixty urine specimens of children and seniors were collected from the Educational Hospital of Tehran, Iran. The urine samples were cultured immediately and those that were E. coli-positive were analyzed for the antimicrobial susceptibility pattern against imipenem using disk diffusion method. Imipenem resistant and imipenem susceptible strains were analyzed for the presence of sfa, afa, pap, hly, cnf 1 and fim virulence factors using the PCR technique. Fifty out of 70 (71.42) children urines and 55 out of 90 (61.11) seniors urine samples harbored E. coli. The incidence of resistance against imipenem in children and seniors were 6 and 9.09, respectively. In the other hand, 99.39 of tested strains were susceptible to imipenem. Total prevalence of pap, cnf 1, hly, sfa, afa and fim genes in the imipenem resistant strains were 12.5 25, 50, 75, 62.5 and 25, respectively. Prevalence of the sfa, afa and hly genes was lower in the imipenem susceptible strains of E. coli, while the pap, cnf 1 and fim genes was entirely higher in the imipenem susceptible strains. This finding suggests that imipenem resistance could be directly associated with decreased prevalence of pap, cnf 1 and fim virulent genes. However, the findings of the present study are novel and valuable but more courtesy studies are necessary to authorize them