Weng Rui, Gu Yihai, Zhang Wei, Hou Xuan, Wang Hui, Tao Junqi, Deng Minghui, Zhou Mengrong, Zhao Yifei
Department of Microbiology, School of Medicine, Xi'an Jiaotong University, Hanzhong, China.
Department of Medical Technology, Shaanxi University of Chinese Medicine, Xianyang, China.
Front Microbiol. 2022 Jun 9;13:899024. doi: 10.3389/fmicb.2022.899024. eCollection 2022.
is a major zoonotic pathogen, which usually contaminates food resulting in salmonellosis in humans. Exploring the characteristics and origins of is essential in formulating prevention and control measures for infection. We used slide agglutination, antimicrobial susceptibility testing, and whole-genome sequencing to analyze and compare 's phenotype, genotyping diversity, and genetic relatedness from livestock meat and diarrhea patients in Hanzhong, China, from 2018 to 2020. Totally 216 enterica isolates were screened from frozen whole chicken carcasses (44.3%, 70/158), frozen raw ground pork (36.2%, 59/163), and diarrhea patients (4.4%, 87/1964). Typhimurium was the dominant serotype. Notably, compared with other sources, isolates obtained from frozen whole chicken carcasses showed significant resistance to third-generation cephalosporin and fluoroquinolones ( < 0.05). All strains were assigned into 36 sequence types (STs) and two novel STs, and an excellent consistency was observed between ST and serotype. Genomic data revealed that extended-spectrum β-lactamase genes were responsible for third-generation cephalosporin resistance in 52 strains, and the most predominant resistance determinant was . Furthermore, of the 60 ciprofloxacin-resistant isolates, five single-base mutations in quinolone resistance-determining regions were identified in or , and the plasmid-mediated quinolone resistance gene was most often detected. The cgMLST clusters show that five clusters among four serotypes (including . Typhimurium, . London, . Derby, and . Agona) cover samples from diarrhea patients and livestock meat pathway isolate, indicating a possibility of cross-host transmission. In conclusion, the livestock meat isolates have a higher level of resistance than diarrhea patients' isolates and could be an essential source of human infection.
是一种主要的人畜共患病原体，通常污染食物导致人类感染沙门氏菌病。探索其特征和起源对于制定感染的预防和控制措施至关重要。我们使用玻片凝集试验、药敏试验和全基因组测序，对2018年至2020年中国汉中地区畜禽肉和腹泻患者中的该菌的表型、基因分型多样性及遗传相关性进行分析和比较。共从冷冻全鸡胴体（44.3%，70/158）、冷冻生碎猪肉（36.2%，59/163）和腹泻患者（4.4%，87/1964）中筛选出216株肠炎沙门氏菌分离株。鼠伤寒沙门氏菌是主要血清型。值得注意的是，与其他来源相比，从冷冻全鸡胴体中获得的分离株对第三代头孢菌素和氟喹诺酮类药物表现出显著耐药性（P<0.05）。所有菌株被分为36个序列型（STs）和两个新的STs，ST与血清型之间具有良好的一致性。基因组数据显示，52株菌株中，超广谱β-内酰胺酶基因导致对第三代头孢菌素耐药，最主要的耐药决定簇是blaCTX-M。此外，在60株耐环丙沙星分离株中，在gyrA或parC中鉴定出喹诺酮耐药决定区的5个单碱基突变，且最常检测到质粒介导的喹诺酮耐药基因qnrS。cgMLST聚类显示，四种血清型（包括鼠伤寒沙门氏菌、伦敦沙门氏菌、德比沙门氏菌和阿哥纳沙门氏菌）中的五个聚类涵盖了腹泻患者和畜禽肉途径分离株的样本，表明存在跨宿主传播的可能性。总之，畜禽肉分离株比腹泻患者分离株具有更高的耐药水平，可能是人类感染该菌的重要来源。
