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Abstract：
E. coli is considered one of the most important zoonotic pathogens worldwide. Highly virulent and antimicrobial-resistant strains of E. coli have been reported in recent years, making it essential to understand their ecological origins. In this study, we analyzed the characteristics of E. coli strains present in the natural population of American bison (Bison bison) in Mexico. We sampled 123 individuals and determined the presence of E. coli using standard bacteriological methods. The isolated strains were characterized using molecular techniques based on PCR. To evaluate the diversity of E. coli strains in this population, we analyzed 108 suggestive colonies from each fecal sample. From a total of 13,284 suggestive colonies, we isolated 33 E. coli strains that contained at least one virulence gene. The virotypes of these strains were highly varied, including strains with atypical patterns or combinations compared to classical pathotypes, such as the presence of escV, eae, bfpB, and ial genes in E. coli strain LMA-26-6-6, or stx2, eae, and ial genes in E. coli strain LMA-16-1-32. Genotype analysis of these strains revealed a previously undescribed phylogenetic group. Serotyping of all strains showed that serogroups O26 and O22 were the most abundant. Interestingly, strains belonging to these groups exhibited different patterns of virulence genes. Finally, the isolated E. coli strains demonstrated broad resistance to antimicrobials, including various beta-lactam antibiotics.
摘要：
大肠杆菌被认为是世界上最重要的人畜共患病原体之一。近年来已经报道了大肠杆菌的高毒力和抗微生物菌株,了解它们的生态起源至关重要。在这项研究中,我们分析了墨西哥美洲野牛自然种群中存在的大肠杆菌菌株的特征。我们对123个个体取样并使用标准细菌学方法确定大肠杆菌的存在。使用基于PCR的分子技术表征分离的菌株。为了评估该人群中大肠杆菌菌株的多样性，我们分析了来自每个粪便样本的108个提示菌落。在总共13,284个暗示性殖民地中，我们分离了33个大肠杆菌菌株，含有至少一个毒力基因。这些菌株的病毒类型是高度不同的，包括与经典病理类型相比具有非典型模式或组合的菌株，比如escV的存在，EAE,bfpB,和大肠杆菌菌株LMA-26-6-6或stx2，eae，和大肠杆菌菌株LMA-16-1-32中的ial基因。这些菌株的基因型分析揭示了以前未描述的系统发育组。所有菌株的血清分型表明，O26和O22血清群最丰富。有趣的是,属于这些组的菌株表现出不同的毒力基因模式。最后,分离的大肠杆菌菌株表现出对抗菌药物的广泛抗性，包括各种β-内酰胺抗生素。
