Abstract Neonatal calf diarrhea remains one of the most important problems faced by livestock, causing great economic losses. This study investigated the prevalence of Salmonella and Escherichia coli, especially enterotoxigenic E. coli (ETEC), in diarrheic calves. Fecal samples were collected from 127 diarrheic calves up to 3 months of age at 12 farms from different governorates in Egypt. 119 bacterial isolates (93.7%) were recovered and the prevalences of Salmonella and E. coli in diarrheic calves were 18.1% and 75.6%, respectively. Serotyping of Salmonella isolates revealed that S. Enteritidis and S. Typhimurium were the most prevalent serotypes, representing 60.9% and 30.4%, respectively, while S. Dublin was 8.7%. Serogrouping of E. coli isolates showed that 10 O-serogroups were obtained where O26 and O103 were the most prevalent (17.7% of each). Salmonella serotypes showed positive results with PCR test using oligonucleotide primer amplifying 521 bp fragment of invA gene of Salmonella while 70% of E. coli serogroups possessed ETEC virulent gene (K99). The in-vitro antibiotic sensitivity test indicated that Salmonella serotypes showed high sensitivity against enrofloxacin, spectinomycin and neomycin while E. coli isolates showed high sensitivities against marbofloxacin, spectinomycin and neomycin only.

中文翻译：

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新生儿腹泻犊牛沙门氏菌和大肠杆菌的患病率

摘要 新生犊牛腹泻仍然是牲畜面临的最重要问题之一，造成了巨大的经济损失。本研究调查了腹泻小牛中沙门氏菌和大肠杆菌的流行情况，尤其是产肠毒素大肠杆菌 (ETEC)。从埃及不同省份的 12 个农场的 127 头 3 个月大的腹泻小牛身上收集了粪便样本。回收到 119 株细菌（93.7%），腹泻犊牛中沙门氏菌和大肠杆菌的流行率分别为 18.1% 和 75.6%。沙门氏菌分离株的血清分型显示肠炎沙门氏菌和鼠伤寒沙门氏菌是最普遍的血清型，分别占 60.9% 和 30.4%，而都柏林沙门氏菌为 8.7%。大肠杆菌分离株的血清群分析表明，获得了 10 个 O 血清群，其中 O26 和 O103 最为普遍（17. 各占 7%）。沙门氏菌血清型用寡核苷酸引物扩增沙门氏菌 invA 基因的 521 bp 片段进行 PCR 检测显示阳性结果，而 70% 的大肠杆菌血清型具有 ETEC 毒力基因（K99）。体外抗生素敏感性试验表明，沙门氏菌血清型对恩诺沙星、大观霉素和新霉素表现出高敏感性，而大肠杆菌分离株仅对马波沙星、大观霉素和新霉素表现出高敏感性。