Instituto de Investigación en Recursos Cinegéticos, CSIC-UCLM-JCCM, Ciudad Real, Spain.
Foodborne Pathog Dis. 2011 Dec;8(12):1313-5. doi: 10.1089/fpd.2011.0923. Epub 2011 Aug 5.
We investigated the prevalence of Escherichia coli O157:H7 in free-ranging red deer in south-central Spain, to assess their potential as reservoir hosts of sorbitol-fermenting (SF) E. coli O157:H7 strains, which are emerging causes of hemolytic uremic syndrome in Europe. Fecal samples from 264 hunter-harvested Iberian red deer (Cervus elaphus) were collected in 25 different game estates and examined for E. coli O157:H7 by culture and PCR. E. coli O157:H7 was detected and isolated in 4 of the 25 game estates sampled (16%) and the isolates obtained (four in total) were further phenogenotypically characterized. One of them was biochemically typical of E. coli O157:H7, that is, neither fermented sorbitol nor exhibited β-glucuronidase (GUD) activity, and carried genes encoding Shiga toxins (Stx) 1 and 2, the intimin subtype γ1, the enterohemorrhagic E. coli (EHEC)-hemolysin, and the ter gene cluster. The rest of the isolates (three of four) fermented sorbitol, exhibited GUD activity after 18-24 h incubation, and carried genes encoding the intimin subtype γ1 and the EHEC-hemolysin, although no Stx-encoding genes were detected. All these atypical isolates carried the sfp gene cluster, lacked the ter gene cluster, and were unable to grow on cefixime tellurite sorbitol MacConkey agar, which are typical features of SF E. coli O157:H7 strains isolated from patients. In total, SF, GUD-positive, Stx-negative E. coli O157:H7 strains were isolated in 3 of the 25 game estates sampled (12%), with an overall sample-level prevalence of 1.1% (3/264). Our findings indicate that free-ranging red deer may be one of the possible reservoir hosts of Stx-negative derivatives of SF E. coli O157:H7.
我们调查了西班牙中南部自由放养的红鹿中大肠杆菌 O157:H7 的流行情况，以评估它们作为糖醇发酵（SF）大肠杆菌 O157:H7 菌株的潜在宿主的潜力，这些菌株是欧洲新兴的溶血性尿毒症综合征的原因。在 25 个不同的狩猎场采集了 264 只猎人捕获的伊比利亚红鹿（ Cervus elaphus ）的粪便样本，并通过培养和 PCR 检查大肠杆菌 O157:H7。在 25 个采样的狩猎场中有 4 个（16%）检测到并分离出大肠杆菌 O157:H7，并且对获得的分离株（总共 4 个）进行了进一步的表型特征分析。其中一个在生化上是典型的大肠杆菌 O157:H7，即既不发酵山梨糖醇，也不表现出β-葡萄糖醛酸酶（GUD）活性，并且携带编码志贺毒素（Stx）1 和 2、肠出血性大肠杆菌（EHEC）-溶血素和 ter 基因簇的基因。其余的分离株（4 个中的 3 个）发酵山梨糖醇，在 18-24 小时孵育后表现出 GUD 活性，并且携带编码 intimin 亚型 γ1 和 EHEC-溶血素的基因，尽管没有检测到编码 Stx 的基因。所有这些非典型分离株都携带 sfp 基因簇，缺乏 ter 基因簇，并且无法在头孢克肟 tellurite 山梨醇 MacConkey 琼脂上生长，这是从患者中分离出的 SF 大肠杆菌 O157:H7 菌株的典型特征。总的来说，在 25 个采样的狩猎场中有 3 个（12%）分离出 SF、GUD 阳性、Stx 阴性的大肠杆菌 O157:H7 菌株，总体样本水平流行率为 1.1%（3/264）。我们的发现表明，自由放养的红鹿可能是 SF 大肠杆菌 O157:H7 的 Stx 阴性衍生物的潜在宿主之一。
