从奶牛场分离的沙门氏菌对动物健康和生产力有显著影响。沙门氏菌的不同血清群会影响人和牛,从而在两个水库中引起疾病。奶牛和小牛可以是无声的沙门氏菌脱落者,增加在农场内分配沙门氏菌的可能性。这项研究的目的是确定来自奶牛场的沙门氏菌分离株的基因组特征,并检测毒力和抗菌素抗性基因的存在。在一项横断面研究中,共从小牛收集了377个样本,围产期奶牛粪便,来自阿瓜斯卡连特斯州的55个奶牛场的产妇病床,下加利福尼亚州,吉娃娃,Coahuila,杜兰戈,墨西哥,瓜纳华托,伊达尔戈,哈利斯科州,克雷塔罗,圣路易斯波托西,Tlaxcala,还有萨卡特卡斯.选择20个沙门氏菌分离株作为全基因组测序的代表性菌株。菌株的血清学分类只能将12个分离株分配给组,但其中只有5个与基因组血清分型一致。最普遍的血清变型是蒙得维的亚沙门氏菌,其次是麦片沙门氏菌。所有分离株均呈现染色体aac(6')-Iaa基因,该基因赋予对氨基糖苷的抗性。抗生素抗性基因qnrB19,qnrA1,sul2,aph(6)-Id,aph(3)-ld,dfrA1,tetA,tetC,flor2,sul1_15,mph(A),aadA2,blaCARB,并确定了qace。确定了十个致病性岛,最普遍的质粒是Col(pHAD28)。肠道沙门氏菌的主要来源是产妇区,围产期脱落者是污染物,并使粪便中的乳品中的病原体永存,沙子,和混凝土表面。这项研究表明,有必要实施一项健康控制措施,以减少包括沙门氏菌在内的抗生素耐药性和毒性病原体的流行。
Salmonella isolated from dairy farms has a significant effect on animal health and productivity. Different serogroups of Salmonella affect both human and bovine cattle causing illness in both reservoirs. Dairy cows and calves can be silent Salmonella shedders, increasing the possibility of dispensing Salmonella within the farm. The aim of this study was to determine the genomic characteristics of Salmonella isolates from dairy farms and to detect the presence of virulence and antimicrobial resistance genes. A total of 377 samples were collected in a cross-sectional study from calves, periparturient cow feces, and maternity beds in 55 dairy farms from the states of Aguascalientes, Baja California, Chihuahua, Coahuila, Durango, Mexico, Guanajuato, Hidalgo, Jalisco, Queretaro, San Luis Potosi, Tlaxcala, and Zacatecas. Twenty Salmonella isolates were selected as representative strains for whole genome sequencing. The serological classification of the strains was able to assign groups to only 12 isolates, but with only 5 of those being consistent with the genomic serotyping. The most prevalent serovar was Salmonella Montevideo followed by Salmonella Meleagridis. All isolates presented the chromosomal aac(6\')-Iaa gene that confers resistance to aminoglycosides. The antibiotic resistance genes qnrB19, qnrA1, sul2, aph(6)-Id, aph(3)-ld, dfrA1, tetA, tetC, flor2, sul1_15, mph(A), aadA2, blaCARB, and qacE were identified. Ten pathogenicity islands were identified, and the most prevalent plasmid was Col(pHAD28). The main source of Salmonella enterica is the maternity areas, where periparturient shedders are contaminants and perpetuate the pathogen within the dairy in manure, sand, and concrete surfaces. This study demonstrated the necessity of implementing One Health control actions to diminish the prevalence of antimicrobial resistant and virulent pathogens including Salmonella.