Analysis of the relationship between antimicrobial resistance and integrons of Escherichia coli isolated from community patients with urinary tract infections / 中华检验医学杂志

ABSTRACT

Objective:To explore the distribution of integrons in Escherichia coli isolated from community patients with urinary tract infections and their relationship with the phylogenetic groups and antimicrobial resistance. Methods:From November 2015 to December 2018, 152 isolates of E. coli that collected without repetition from the urine samples of outpatients in nephrology of Fengxian District Central Hospital in Shanghai, were studied retrospectively. Bacterial identification and antimicrobial susceptibility analysis was carried out by Phoenix 100 automatic microbiological analyzer. Class 1, 2 integron integrase genes, variable regions of integrons and the phylogenetic groups of isolated E.coli were screened by PCR. The type of promoters and gene cassette arrays of variable regions were determined by sequencing. The relationship of intergon with the phylogenetic groups and antimicrobial resistance was also analyzed. Results:The resistance rate of 152 E. coli to ampicillin was 70.39% (107/152), and the resistance rates to other antibacterial drugs were all less than 40.00%. Among the 152 E. coli isolates, class 1 integron integrase gene intI1 was detected in 65 isolates (42.76%), 8 gene cassette arrays and 14 antimicrobial resistance gene cassettes were detected in 68 class 1 integrons. The most popular gene cassette array was dfrA17-aadA5 (51.47%, 35/68), while the variable regions of class 1 integrons were failed to detected in 12 intI1-positive isolates. Five variable region promoters were detected in 68 class 1 integrons, with the relative weak promoter PcH1 to be the most popular type (77.94%, 53/68). The gene cassette array arr- 2-cmlA5-bla OXA-10-aadA1 was also detected in this study. 65 intI1-positive isolates were mainly belonged to group B2 and D. The class 2 integron integrase gene intI2 was detected in 4 isolates (2.63%,4/152), and their variable region gene cassette arrays were all dfrA1-sat2-aadA1. Conclusions:Class 1 integrons were closely related to antimicrobial resistance in E. coli isolated from community patients with urinary tract infection. Most of the variable region promoters of class 1 integrons were relatively weak promoters. The distribution of each phylogenetic group in the intI1-positive isolates was consistent with the distribution of the overall isolates. The gene cassette array arr-2-cmlA5-bla OXA-10-aadA1 was detected in E. coli.