Extended-Spectrum Beta-Lactamase Producing Strains of Escherichia Coli Isolated from Avian Cellulitis Lesions

ABSTRACT Avian cellulitis causes significant losses to the poultry industry. Avian-pathogenic Escherichia coli (APEC) is the etiological agent of that disease. This microorganism has zoonotic potential and may act as reservoir of antimicrobial-resistance genes. In this context, the production of extended-spectrum B-lactamase (ESBL) is one of the main antimicrobial resistance mechanisms. The objective of this study was to determine the production of ESBL in an Escherichia coli (E. coli) strain isolated from avian cellulitis lesions. Twenty-two E. Coli isolates were harvested from cellulitis lesions in chicken carcasses in a commercial processing plant. Isolates were then submitted to virulence genotypic profile (iutA, hlyF, iss, ironN, ompT) analysis, antimicrobial susceptibility test, and detection of ESBL production. The results showed that 22.7% of the isolates presented five virulence genes, 9.1% four genes, 36.4% three genes, 13.6% two genes, and 18.2% one gene. The tested isolates showed resistance to ampicillin (90.9%), ceftiofur (54.5%), gentamicin (45.5%), tetracycline (72.1%), sulfamethoxazole/trimethoprim (54.5%), and enrofloxacin (54.5%). Furthermore, 77.3% of the isolates presented multidrug resistance (MDR) profile and 72.7% were positive for ESBL production. This study is the first description of ESBL-producing APEC isolated from avian cellulitis lesions, which suggests the need to establish efficient APEC control measures and programs to prevent flock productivity losses due to colibacillosis and public health risks.

【摘要】禽蜂窝织炎给家禽养殖业造成了显著经济损失。禽致病性大肠杆菌（Avian-pathogenic Escherichia coli, APEC）是该疾病的病原。该微生物具备人畜共患潜力，且可作为抗菌耐药基因的储存宿主。在此背景下，超广谱β-内酰胺酶（extended-spectrum β-lactamase, ESBL）的产生是主要的抗菌耐药机制之一。本研究旨在检测从禽蜂窝织炎病灶中分离得到的大肠杆菌（Escherichia coli, E. coli）菌株中超广谱β-内酰胺酶的产生情况。研究人员从某商业屠宰加工厂的鸡胴体蜂窝织炎病灶中分离得到22株大肠杆菌分离株，随后对这些分离株开展了毒力基因型谱（iutA、hlyF、iss、ironN、ompT）分析、抗菌药物敏感性试验以及超广谱β-内酰胺酶产生情况检测。结果显示，22.7%的分离株携带全部5种毒力基因，9.1%携带4种，36.4%携带3种，13.6%携带2种，18.2%携带1种。受试分离株对氨苄西林（耐药率90.9%）、头孢噻呋（54.5%）、庆大霉素（45.5%）、四环素（72.1%）、复方磺胺甲噁唑（54.5%）以及恩诺沙星（54.5%）均表现出耐药性。此外，77.3%的分离株呈现多重耐药（Multidrug resistance, MDR）表型，72.7%的分离株超广谱β-内酰胺酶检测呈阳性。本研究为首次报道从禽蜂窝织炎病灶中分离得到产超广谱β-内酰胺酶的禽致病性大肠杆菌，这提示亟需建立高效的禽致病性大肠杆菌防控措施与方案，以预防由禽大肠杆菌病导致的鸡群生产性能损失以及公共卫生风险。