Boukhors Karima, Pradel Nathalie, Girardeau Jean-Pierre, Livrelli Valérie, Ou Saïd Ahmed Mohamed, Contrepois Michel, Martin Christine
Laboratoire de Microbiologie, INRA, St-Genès-Champanelle, France.
Vet Res. 2002 Jul-Aug;33(4):405-12. doi: 10.1051/vetres:2002026.
The gastrointestinal tract of ruminants is the main reservoir for Shiga toxin-producing Escherichia coli (STEC) strains, potentially pathogenic for humans. We used for the first timerumen fluid in which no exogenous carbon source or other supplement was added to compare acid resistance and growth of STEC in physiological physico-chemical conditions. We showed that acidic conditions resulting from the combination of high volatile fatty acid concentration and moderately acidic pH did not alter the survival of STEC, and that human non-O157:H7 STEC isolates were able to persist in the rumen contents in spite of acid stress, low oxygen availability and nutrient deprivation, in the same manner as bovine STEC isolates do. Furthermore, our results support the hypothesis that a grain-rich diet may induce mechanisms of STEC acid resistance in the rumen that allow STEC survival in the abomasum.
反刍动物的胃肠道是产志贺毒素大肠杆菌（STEC）菌株的主要储存库，这些菌株对人类具有潜在致病性。我们首次使用未添加外源碳源或其他补充剂的瘤胃液，在生理物理化学条件下比较STEC的耐酸性和生长情况。我们发现，高挥发性脂肪酸浓度和适度酸性pH值共同导致的酸性条件不会改变STEC的存活率，并且人类非O157:H7 STEC分离株能够在瘤胃内容物中持续存在，尽管存在酸应激、低氧可用性和营养剥夺，其方式与牛STEC分离株相同。此外，我们的结果支持这样一种假设，即富含谷物的饮食可能会在瘤胃中诱导STEC的耐酸机制，使STEC能够在皱胃中存活。
