Department of Microbiology, Faculty of Veterinary Medicine, Cairo University, Cairo, Egypt.
Department of Zoonoses, Faculty of Veterinary Medicine, Cairo University, Cairo, Egypt.
Acta Vet Scand. 2024 Oct 3;66(1):54. doi: 10.1186/s13028-024-00774-6.
The upsurge of diarrheagenic E. coli pathotypes carrying extended-spectrum beta-lactamases (ESBLs)/plasmid-mediated AmpC β-lactamase (pAmpC) among animals constitutes an emerging threat for humans and animals. This study investigated the burden of ESBL-/pAmpC-producing diarrheagenic E. coli among diarrheic foals and its potential public health implications. Rectal swabs were collected from 80 diarrheic foals. These swabs were processed to isolate and identify ESBL/pAmpC-producing E. coli using a selective culture medium, biochemical tests, phenotypic identification, and molecular identification of ESBL- and pAmpC-encoding genes. Moreover, all ESBL-/pAmpC-producing E. coli isolates were examined for different virulence genes related to diarrheagenic E. coli pathotypes.
Out of 80 examined foals, 26 (32.5%) were confirmed as ESBL-/pAmpC-producing E. coli, of which 14 (17.5%) animals carried only ESBL-producing E. coli, whereas 12 (15%) animals possessed ESBL-pAmpC-producing E. coli. The only detected diarrheagenic pathotype was enterotoxigenic, encoded by the heat-stable enterotoxin gene (ST) with a prevalence rate of 80.8% (21/26). The ST gene was further characterized where STa, STb, and STa + STb were found in one, four, and 16 strains, respectively. Moreover, all enterotoxigenic E. coli (ETEC) isolates exhibited a multidrug-resistance pattern. The phylogenetic analysis of 3 obtained partial STb sequences revealed high genetic relatedness to ETEC isolates retrieved from humans, conferring such sequences' public health significance.
These findings highlight that diarrheic foals could serve as a potential reservoir for multidrug-resistant ESBL-/pAmpC-producing enterotoxigenic E. coli.
动物中携带超广谱β-内酰胺酶（ESBL）/质粒介导的 AmpC 内酰胺酶（pAmpC）的致腹泻性大肠杆菌的流行，对人类和动物构成了新的威胁。本研究调查了腹泻驹中 ESBL-/pAmpC 产致腹泻性大肠杆菌的负担及其对公共卫生的潜在影响。从 80 头腹泻驹中采集直肠拭子。这些拭子经过处理，使用选择性培养基、生化试验、表型鉴定和 ESBL 和 pAmpC 编码基因的分子鉴定，从分离和鉴定 ESBL/pAmpC 产大肠杆菌。此外，所有 ESBL-/pAmpC 产大肠杆菌分离株均检测与致腹泻性大肠杆菌相关的不同毒力基因。
在 80 头受检驹中，26 头（32.5%）被确认为 ESBL-/pAmpC 产大肠杆菌，其中 14 头（17.5%）动物仅携带产 ESBL 大肠杆菌，而 12 头（15%）动物携带 ESBL-pAmpC 产大肠杆菌。唯一检测到的致腹泻病型为肠毒素型，由耐热肠毒素基因（ST）编码，流行率为 80.8%（21/26）。ST 基因进一步特征化，其中发现一个、四个和 16 个菌株分别携带 STa、STb 和 STa+STb。此外，所有肠毒素型大肠杆菌（ETEC）分离株均表现出多药耐药模式。从 3 个获得的部分 STb 序列的系统发育分析表明，与从人类中分离出的 ETEC 分离株具有高度遗传相关性，这表明这些序列具有公共卫生意义。
这些发现强调，腹泻驹可能是多药耐药性 ESBL-/pAmpC 产肠毒素性大肠杆菌的潜在储主。
