Shahcheraghi Farzad, Rahmati Ghezelgeh Fatemeh, Nobari Saman, Torabi Elham, Mousavi Seyed Fazlollah, Aslani Mohammad Mehdi, Shahcheraghi Fereshteh
Special Disease Center, Shiraz University of Medical Science, Shiraz, Iran.
Department of Bacteriology & Microbiology Research Center, Pasteur Institute of Iran, Tehran, Iran.
Iran J Microbiol. 2014 Jun;6(3):156-62.
The therapeutic options for diseases caused by Escherichia coli are limited. In this study we investigated the presence of virulence factors among Enteropathogenic Escherichia coli (EPEC) strains and their antibiotic resistance patterns. The isolates were also checked for the presence of class1 integrons and gene cassettes.
This study included 70 EPEC strains isolated from children. Antimicrobial resistance patterns were determined using diffusion methods. The broth microdilution methods was used to determine the minimum inhibitory concentration. PCR was used to detect eaeA, bfpA genes. The 5' and 3' conserved sequences (CSs) of class 1 integrons and intI gene were amplified to investigate the presence of integrons and gene cassettes.
Antimicrobial susceptibility testing showed that 4 (5.7%), 3 (4.2%), and 2 (2.8 %) isolates were resistant to ampicillin, trimethoprim-sulfamethoxazole, and ceftazidime, respectively. Resistance rates to ciprofloxacin and aztreonam were 1.4%. Thirteen (18.5%) isolates showed resistance to tetracycline, and 4 (5.7%) were kanamycin resistant. Class I integron detected in 22 (31.4%) isolates. All the gene cassettes found in class I integrons corresponded to different variants of dfr and aadA genes.
Prevalence of class I integrons in EPEC strains was high. Presence of aadA and dfr gene cassettes in integrons represents high distribution of resistance determinants in EPEC strains.
大肠杆菌所致疾病的治疗选择有限。在本研究中，我们调查了肠致病性大肠杆菌（EPEC）菌株中毒力因子的存在情况及其抗生素耐药模式。还检查了分离株中1类整合子和基因盒的存在情况。
本研究纳入了从儿童中分离出的70株EPEC菌株。采用扩散法测定抗菌药物耐药模式。用肉汤微量稀释法测定最低抑菌浓度。采用聚合酶链反应（PCR）检测eaeA、bfpA基因。扩增1类整合子的5'和3'保守序列（CSs）以及intI基因，以研究整合子和基因盒的存在情况。
药敏试验显示，分别有4株（5.7%）、3株（4.2%）和2株（2.8%）分离株对氨苄西林、甲氧苄啶 - 磺胺甲恶唑和头孢他啶耐药。对环丙沙星和氨曲南的耐药率为1.4%。13株（18.5%）分离株对四环素耐药，4株（5.7%）对卡那霉素耐药。在22株（31.4%）分离株中检测到1类整合子。在1类整合子中发现的所有基因盒均对应于dfr和aadA基因的不同变体。
EPEC菌株中1类整合子的流行率较高。整合子中aadA和dfr基因盒的存在表明EPEC菌株中耐药决定因素的分布广泛。
