Karami Pejman, Bazmamoun Hassan, Sedighi Iraj, Mozaffari Nejad Amir Sasan, Aslani Mohammad Mehdi, Alikhani Mohammad Yousef
Department of Microbiology, Hamadan University of Medical Sciences, Hamadan, Iran.
Department of Paediatric, Hamadan University of Medical Sciences, Hamadan, Iran.
Arab J Gastroenterol. 2017 Dec;18(4):206-209. doi: 10.1016/j.ajg.2017.11.004. Epub 2017 Dec 7.
This study aimed to determine the antibacterial resistance patterns of extended spectrum β-lactamase (ESBL)-producing enteropathogenic Escherichia coli (EPEC) isolated from Iranian children and to investigate its genetic patterns.
192 non-repeats EPEC isolates were collected from stool samples of the children with and without diarrhoea. The EPEC strains were isolated from 1355 stool specimens obtained from 247 children with diarrhoea (0-10 years old; mean age, 5.5 years) and 1108 children without any gastrointestinal symptoms (0-10 years old; mean age, 6.8 years) during the summer months in three Iranian provinces, Tehran, Ilam and Mazandaran. Strains biochemically identified as E. coli were selected and were identified by the presence of eaeA and bfpA as EPEC virulence genes. Antimicrobial susceptibilities were determined by disc diffusion method. The isolates were confirmed to be ESBL producers by the double disk synergy test (DDST). The β-lactamase genes (blaTEM, blaSHV, blaCTX-M, blaOXA) and insertion sequence ISEcp1 were detected by PCR method.
The highest antibiotic susceptibility was detected to imipenem (100%), followed by gentamicin (82.3%) and ciprofloxacin (79.2%). The highest resistance was detected to cefpodoxime (97.9%), trimethoprim (60.7%), and tetracycline (58.4%), respectively. Totally, 153 EPEC strains (79.7%) were ESBL-producing by DDST test. The PCR showed that 84 (43.8%) EPEC isolates were positive for ESBLs encoding genes. Among 153 ESBLs-producing EPEC, TEM was present in 9.2% of isolates. Also, CTX-M and SHV genes were detected in 7.2% and 7.8%, respectively. The SHV positive strains were associated with the highest resistance rate to tetracycline (56.5%), although the TEM and OXA were associated with the highest resistance rate to gentamicin (23.1%) and ciprofloxacin (21.4%).
The study revealed that 79.7% of EPEC isolates from Iranian children were ESBL-producing and were comparable with the non ESBL-producing isolates regarding susceptibility to the antibiotics.
本研究旨在确定从伊朗儿童中分离出的产超广谱β-内酰胺酶（ESBL）的肠致病性大肠杆菌（EPEC）的抗菌耐药模式，并研究其基因模式。
从腹泻和未腹泻儿童的粪便样本中收集了192株非重复的EPEC分离株。这些EPEC菌株是在夏季从伊朗三个省份德黑兰、伊拉姆和马赞德兰的247名腹泻儿童（0至10岁；平均年龄5.5岁）和1108名无任何胃肠道症状的儿童（0至10岁；平均年龄6.8岁）的1355份粪便标本中分离得到的。选择经生化鉴定为大肠杆菌的菌株，并通过检测eaeA和bfpA这两种EPEC毒力基因来进行鉴定。采用纸片扩散法测定抗菌药物敏感性。通过双纸片协同试验（DDST）确认分离株为ESBL产生菌。采用PCR方法检测β-内酰胺酶基因（blaTEM、blaSHV、blaCTX-M、blaOXA）和插入序列ISEcp1。
对亚胺培南的抗生素敏感性最高（100%），其次是庆大霉素（82.3%）和环丙沙星（79.2%）。对头孢泊肟、甲氧苄啶和四环素的耐药性最高，分别为97.9%、60.7%和58.4%。通过DDST试验，共有153株EPEC菌株（79.7%）产ESBL。PCR结果显示，84株（43.8%）EPEC分离株的ESBL编码基因呈阳性。在153株产ESBL的EPEC中，9.2%的分离株含有TEM基因。此外，分别检测到7.2%的CTX-M基因和7.8%的SHV基因。SHV阳性菌株对四环素的耐药率最高（56.5%），而TEM和OXA基因分别与对庆大霉素（23.1%）和环丙沙星（21.4%）的最高耐药率相关。
该研究表明，从伊朗儿童中分离出的79.7%的EPEC分离株产ESBL，并且在抗生素敏感性方面与非产ESBL的分离株相当。
