The aim of this study was to assess the virulence, antimicrobial resistance and biofilm production of Escherichia coli strains isolated from healthy broiler chickens in Western Algeria. E. coli strains (n = 18) were identified by matrix-assisted laser desorption–ionization time-of-flight mass spectrometry. Susceptibility to 10 antibiotics was determined by standard methods. Virulence and extended-spectrum β-lactamase (ESBL) genes were detected by PCR. The biofilm production was evaluated by microplate assay. All the isolates were negative for the major virulence/toxin genes tested (rfbE, fliC, eaeA, stx1), except one was stx2-positive. However, all were resistant to at least three antibiotics. Ten strains were ESBL-positive. Seven carried the β-lactamase bla_TEM gene only and two co-harbored bla_TEM and bla_CTX-M−1 genes. One carried the bla_SHV gene. Among the seven strains harboring bla_TEM only, six had putative enteroaggregative genes. Two contained irp2, two contained both irp2 and astA, one contained astA and another contained aggR, astA and irp2 genes. All isolates carrying ESBL genes were non-biofilm producers, except one weak producer. The ESBL-negative isolates were moderate biofilm producers and, among them, two harbored astA, two irp2, and one aggR, astA and irp2 genes. This study highlights the spread of antimicrobial-resistant E. coli strains from healthy broiler chickens in Western Algeria.

中文翻译：

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阿尔及利亚西部健康肉鸡分离株的大肠杆菌的毒力、抗菌素耐药性和生物膜产生

本研究的目的是评估从阿尔及利亚西部健康肉鸡中分离的大肠杆菌菌株的毒力、抗菌素耐药性和生物膜产生。大肠杆菌菌株（n = 18）通过基质辅助激光解吸电离飞行时间质谱法进行鉴定。通过标准方法确定对 10 种抗生素的敏感性。PCR检测毒力和超广谱β-内酰胺酶（ESBL）基因。通过微孔板测定评估生物膜的产生。所有分离株的主要毒力/毒素基因（rfbE、fliC、eaeA、stx1）均呈阴性，只有一个是stx2-积极的。然而，所有人都对至少三种抗生素有抗药性。十个菌株是 ESBL 阳性的。七个仅携带 β-内酰胺酶bla _TEM基因和两个共同携带的bla _TEM和bla _CTX-M-1基因。一个携带bla _SHV基因。在仅包含bla _TEM的 7 个菌株中，6 个具有推定的肠道聚集基因。两个包含irp2，两个包含irp2和astA，一个包含astA，另一个包含aggR，astA和irp2 。基因。除了一个弱生产者外，所有携带 ESBL 基因的分离株都是非生物膜生产者。ESBL 阴性分离株是中等生物膜生产者，其中两个含有astA、两个irp2和一个aggR、astA和irp2基因。这项研究强调了来自阿尔及利亚西部健康肉鸡的抗微生物大肠杆菌菌株的传播。