1 Department of Infectious Diseases, Children's Hospital of Fudan University, Shanghai, China.
2 Department of Microbiology, Shanghai Municipal Center For Disease Control and Prevention, Shanghai, China.
Foodborne Pathog Dis. 2019 Apr;16(4):244-255. doi: 10.1089/fpd.2018.2557. Epub 2019 Feb 19.
This study aimed to trace the transmission source of Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Enteritidis strains associated with enteric infections in Shanghainese children, and understand the molecular mechanism of resistance to third-generation cephalosporins and ciprofloxacin.
The profiles of pulsed-field gel electrophoresis (PFGE) were compared among the isolates from children, animal, and environment. Antimicrobial susceptibility was determined using the minimal inhibitory concentrations and Kirby-Bauer disk diffusion method. Extended-spectrum β-lactamase (ESBL) producing isolates mediated by resistance genes were identified using polymerase chain reaction and sequencing.
Based on PFGE patterns, 49 (33.1%) of 148 human Salmonella Typhimurium isolates located in the dominant PFGE clusters were genetically related to the isolates from poultry source, environment water, aquatic products, and reptiles, whereas 97 (97.0%) of 100 human Salmonella Enteritidis isolates were genetically related to isolates from poultry and water. The rates of resistance to ceftriaxone among clinical Salmonella Typhimurium and Salmonella Enteritidis isolates were 42.0% and 14.2%, respectively. Besides, 35.1% of Salmonella Typhimurium isolates displayed resistance to ciprofloxacin; 64.9% of Salmonella Typhimurium isolates and 97.0% of Salmonella Enteritidis isolates displayed reduced susceptibility to ciprofloxacin. Of 64 ESBL/AmpC-producing strains, CTX-M, TEM, DHA, and CMY were detected at frequencies of 86.0%, 62.5%, 7.8%, 3.1%, and 3.1%, respectively.
The transmission sources of Salmonella Typhimurium and Salmonella Enteritidis infections in Shanghainese children were diverse. The high prevalence of resistance to third-generation cephalosporins and ciprofloxacin mediated by multiple molecular mechanisms needs continuous monitoring and intervention.
本研究旨在追溯与上海儿童肠内感染相关的肠炎沙门氏菌血清型 Typhimurium 和肠炎沙门氏菌血清型 Enteritidis 菌株的传播源，并了解第三代头孢菌素和环丙沙星耐药的分子机制。
比较儿童、动物和环境分离株的脉冲场凝胶电泳（PFGE）图谱。采用最小抑菌浓度和 Kirby-Bauer 纸片扩散法测定抗菌药物敏感性。采用聚合酶链反应和测序鉴定耐药基因介导的产超广谱β-内酰胺酶（ESBL）的分离株。
根据 PFGE 图谱，148 株人源肠炎沙门氏菌 Typhimurium 分离株中有 49 株（33.1%）位于优势 PFGE 簇中，与禽类来源、环境水、水产品和爬行动物的分离株具有遗传相关性，而 100 株人源肠炎沙门氏菌 Enteritidis 分离株均与禽类和水的分离株具有遗传相关性。临床分离的肠炎沙门氏菌 Typhimurium 和肠炎沙门氏菌 Enteritidis 对头孢曲松的耐药率分别为 42.0%和 14.2%。此外，35.1%的肠炎沙门氏菌 Typhimurium 分离株对环丙沙星耐药；64.9%的肠炎沙门氏菌 Typhimurium 分离株和 97.0%的肠炎沙门氏菌 Enteritidis 分离株对环丙沙星的敏感性降低。在 64 株产 ESBL/AmpC 菌株中，CTX-M、TEM、DHA 和 CMY 的检出率分别为 86.0%、62.5%、7.8%、3.1%和 3.1%。
上海儿童肠炎沙门氏菌和肠炎沙门氏菌感染的传播源多样。多种分子机制介导的第三代头孢菌素和环丙沙星耐药率较高，需要持续监测和干预。
