Hormeño Lorena, Ugarte-Ruiz María, Palomo Gonzalo, Borge Carmen, Florez-Cuadrado Diego, Vadillo Santiago, Píriz Segundo, Domínguez Lucas, Campos Maria J, Quesada Alberto
Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Veterinaria, Universidad de Extremadura, Cáceres, Spain.
Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense Madrid, Madrid, Spain.
Front Microbiol. 2018 Oct 23;9:2515. doi: 10.3389/fmicb.2018.02515. eCollection 2018.
Thermotolerant species and are actually recognized as the major bacterial agent responsible for food-transmitted gastroenteritis. The most effective antimicrobials against are macrolides and some, but not all aminoglycosides. Among these, susceptibility to streptomycin is reduced by mutations in the ribosomal RPSL protein or by expression of ANT(6)-I aminoglycoside O-nucleotidyltransferases. The presence of streptomycin resistance genes was evaluated among streptomycin-resistant isolated from humans and animals by using PCR with degenerated primers devised to distinguish , and other -like genes. Genes encoding ANT(6)-I enzymes were found in all possible combinations with a major fraction of the isolates carrying a previously described -like gene, distantly related and belonging to the new sub-family . Among isolates, was uniquely found functional in , as shown by gene transfer and phenotype expression in , unlike detected coding sequences in that were truncated by an internal frame shift associated to RPSL mutations in streptomycin resistant strains. The genetic relationships of isolates with ANT(6)-Ie revealed one cluster of strains presented in bovine and humans, suggesting a circulation pathway of strains by consuming contaminated calf meat by bacteria expressing this streptomycin resistance element.
耐热菌实际上被认为是导致食源性肠胃炎的主要细菌病原体。针对该菌最有效的抗菌药物是大环内酯类以及部分（但并非全部）氨基糖苷类药物。其中，核糖体RPSL蛋白的突变或ANT(6)-I氨基糖苷O-核苷酸转移酶的表达会降低该菌对链霉素的敏感性。通过使用针对区分该菌、其他类似基因而设计的简并引物进行PCR，对从人和动物中分离出的耐链霉素该菌进行了链霉素抗性基因的评估。编码ANT(6)-I酶的基因以所有可能的组合形式被发现，大部分分离株携带一个先前描述的类似基因，该基因与新的亚家族关系较远。在该菌分离株中，如通过基因转移和在其他菌株中的表型表达所示，该基因在特定菌株中被独特地发现具有功能，这与在耐链霉素菌株中检测到的因与RPSL突变相关的内部移码而被截断的编码序列不同。具有ANT(6)-Ie的该菌分离株的遗传关系表明，一组菌株存在于牛和人类中，这表明通过食用表达这种链霉素抗性元件的细菌污染的小牛肉，该菌菌株存在传播途径。
