Characterisation of Class 1 Integron among Escherichia coli Isolated from Mansoura University Hospitals in Egypt

Extensive use of antibacterials in clinical practice has been associated with increasing frequency of multi-resistant E. coli strains. Genetic elements such as Class 1 integrons have an important role in resistance development. In the current study, a total of 84 E. coli clinical isolates from Mansoura hospitals patients in Egypt were screened for antibacterial susceptibility against 12 different antibacterials. High resistance rates were identified for Ampicillin (92.9%) and sulfamethoxazole/ trimethoprim (84.5%). Class 1 integron was investigated in E. coli isolates by PCR. As a result, Class 1 integron was identified in 51.2% of these isolates. The contents of amplified integron varriable regions, were digested by Alu I restriction endonuclease. Cluster analysis of Class 1 integron digested varriable regions revealed that RFLP digested fragments generated could be classified into 9 different patterns, namely A, B, C, D, E, F, G, H and I. The most prevalent genotype was identifed in Group D. PCR and sequencing were used for detection of antimicrobial resistance genes harbored in integrons of Group D. As a result, main phylogenetic group identified harbored integron cassette carrying resistance gene for two antimicrobial groups namely aminoglycoside and trimethoprim. Multiresistance profiles in Group D exhibited association between antimicrobial resistance and integron presence. These findings suggest that the strategy for treatment of patients with E. coli infections needs to be revised. Furthermore, the high prevalence of Class 1 integron carrying gene confirms the importance of integron-mediated antimicrobial gene cassettes.