BACKGROUND The treatment of Enterobacteriaceae family including diarrheagenic E. coli (DEC) has been increasingly complicated due to the emergence of resistant strains. Here we report on the phenotypic resistance profiles and ESBL genotype and virulence profiles of Enteroaggregative E. coli (EAEC) and Enteropathogenic E. coli (EPEC) isolated from children hospitalized with acute gastroenteritis in Qatar (AGE). RESULTS E. coli were isolated and characterized from 76 diarrheagenic stool positive samples, collected from hospitalized children less than 10 years old. Isolates were tested for antibiotic susceptibility against eighteen clinically relevant antibiotics using E-test method. Conventional PCR was performed to detect genes encoding ESBL and virulence factors. Chi-square test was performed to compare the individual antibiotic resistance between EPEC and EAEC. A significant percentage (73.7%) of isolates were resistant to at least one antibiotic. Overall, high resistance (70%) was reported to the first-line antibiotics such as ampicillin, tetracycline (46.4%), and sulfamethoxazole-trimethoprim (42.9%). Further, 39.5% of the isolates were multidrug resistant (MDR), with 22.4% being ESBL producers. On the other hand, all isolates were susceptible to carbapenem, fosfomycin, amikacin and colistin. The incidences of resistance to the 18 antibiotics between EPEC and EAEC were not significantly different by Pearson chi -square test (P > 0.05). Genetic analysis revealed that 88.23% of ESBL production was blaCTX-M-G1 (blaCTX-M-15, blaCTX-M-3) - encoded. Several different combinations of virulence markers were observed, however, there was no specific trend among the isolates apart from absence of the bundle-forming pilus (bfpA) gene, which encodes the type IV fimbriae in EPEC adherence factor (EAF) plasmid (pEAF), among all EPEC (atypical). 15% of the EAEC strains were positive for a combination of astA, aap & capU, while 10% were positive for three different combinations. The aap, aatA, capU and aggR virulence genes showed the highest frequency of 65, 60, 55 and 55% respectively. Others genes, east, astA, and aai, showed frequencies of 35, 30 and 20% respectively. CONCLUSIONS Atypical EPEC and EAEC were the primary etiological agents of diarrhea in children among DEC pathotypes. Our results indicated high rate of antimicrobial resistance pattern of DEC strains, which necessities the development of regulatory programs and reporting systems of antimicrobial resistance in DEC and other AGE-associated bacteria to insure effective control of diarrheal diseases. Results from this study demand a further research on identifying the phenotypic and genotypic profiles of more DEC pathotypes in various clinical samples.

中文翻译：

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卡塔尔儿童急性肠胃炎相关病原性大肠杆菌菌株的抗生素耐药性和毒力模式。

背景技术由于耐药菌株的出现，包括腹泻性大肠杆菌（DEC）的肠杆菌科的治疗变得越来越复杂。在这里，我们报告了从卡塔尔（AGE）患急性胃肠炎住院的儿童中分离出来的肠聚集性大肠杆菌（EAEC）和肠致病性大肠杆菌（EPEC）的表型耐药性，ESBL基因型和毒力谱。结果从76例腹泻的粪便阳性样品中分离并鉴定了大肠杆菌，这些样品是从小于10岁的住院儿童中收集的。使用E-test方法测试了分离物对18种临床相关抗生素的敏感性。进行常规PCR以检测编码ESBL和毒力因子的基因。进行卡方检验以比较EPEC和EAEC之间的个体抗生素耐药性。很大比例（73.7％）的分离株对至少一种抗生素有抗药性。总体而言，对一线抗生素（如氨苄青霉素，四环素（46.4％）和磺胺甲恶唑-甲氧苄氨嘧啶（42.9％））的耐药率较高（70％）。此外，有39.5％的分离株是耐多药（MDR）的，其中22.4％是ESBL的生产者。另一方面，所有分离株均对碳青霉烯，磷霉素，丁胺卡那霉素和粘菌素敏感。经皮尔逊卡方检验，EPEC和EAEC之间对18种抗生素的耐药性发生率无显着差异（P> 0.05）。遗传分析显示，ESBL产量的88.23％是blaCTX-M-G1（blaCTX-M-15，blaCTX-M-3）编码的。观察到了几种不同的毒力标记组合，但是，除了缺乏形成束缚菌毛（bfpA）基因（在EPEC粘附因子（EAF）质粒（EAF）质粒中编码IV型菌毛）的分离株外，没有任何特定趋势。 ，在所有EPEC（非典型）中。EAEC菌株中15％的astA，aap和capU组合呈阳性，而10％的三种不同组合呈阳性。aap，aatA，capU和aggR毒力基因的最高频率分别为65、60、55和55％。其他基因，east，astA和aai的频率分别为35％，30％和20％。结论非典型的EPEC和EAEC是DEC病因中小儿腹泻的主要病因。我们的结果表明DEC菌株的耐药率很高，因此，必须制定有关DEC和其他AGE相关细菌的抗菌素耐药性的管理计划和报告系统，以确保有效控制腹泻病。这项研究的结果需要进一步的研究，以鉴定各种临床样品中更多DEC病态型的表型和基因型谱。