产志贺毒素的大肠杆菌(STEC)是引起严重疾病的食源性病原体。STEC产生疾病的能力与志贺毒素(Stx)的产生有关。我们调查了牛和猪肉尸体以及运输卡车墙壁上STEC的发生情况,并鉴定了STEC菌株的毒力基因和血清型。在这项工作中,我们比较了从牛car体分离的STECO157:H7菌株和从HUS儿童分离的STECO157:H7菌株的全基因组测序,都在2019年隔离。我们研究了这些分离株与数据库中收集的其他分离株之间的关系。结果显示了40%的STEC和两个不同的血清群(O130和O157)。STECO157:H7从牛尸体中分离出来,并保存了stx2,eae,ehxA,katP,espP,stcE,ECSP_0242/1773/2687/2870/2872/3286/3620被分类为谱系I/II。在STEC非O157分离物中,从牛尸体中分离出三个分离株,并带有O130血清群,从猪肉尸体中分离出的一个菌株是O-不可分型的。所有STEC非O157都带有sxt1基因。全基因组分析表明,STECO157:H7菌株均属于高毒力进化枝8,ST11,系统群E,携带等位基因tir255T>AT,它们不是克隆的。对信息的分析使我们得出结论,STEC菌株在到达运输的猪肉和牛尸体中循环。这种情况对消费者来说是一种风险,需要在食物链中实施综合STEC控制。
Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens causing severe diseases. The ability of STEC to produce disease is associated with Shiga toxin (Stx) production. We investigated the occurrence of STEC on bovine and pork carcasses and walls of trucks where they were transported, and we characterized virulence genes and serotypes of STEC strains. We compared the whole genomic sequencing of a STEC O157:H7 strain isolated from a bovine carcass in this work and a STEC O157:H7 strain isolated from a child with HUS, both isolated in 2019. We studied the relationship between these isolates and others collected in the database. The results show a 40% of STEC and two different serogroups were identified (O130 and O157). STEC O157:H7 were isolated from bovine carcasses and harbored stx2, eae, ehxA, katP, espP, stcE, ECSP_0242/1773/2687/2870/2872/3286/3620 and were classified as lineage I/II. In STEC non-O157 isolates, three isolates were isolated from bovine carcasses and harbored the serogroup O130 and one strain isolated from pork carcasses was O-non-typeable. All STEC non-O157 harbored sxt1 gene. The analysis from the whole genome showed that both STEC O157:H7 strains belonged to the hypervirulent clade 8, ST11, phylogroup E, carried the allele tir 255 T > A T, and they were not clonal. The analysis of information allows us to conclude that the STEC strains circulate in pork and bovine carcasses arriving in transport. This situation represents a risk for the consumers and the need to implement an integrated STEC control in the food chain.