1 Department of Food Science and Technology, School of Agriculture and Biology, Shanghai Jiao Tong University , Shanghai, China .
2 Joint Institute for Food Safety and Applied Nutrition, University of Maryland , College Park, Maryland.
Foodborne Pathog Dis. 2018 Dec;15(12):770-775. doi: 10.1089/fpd.2018.2468. Epub 2018 Nov 29.
Salmonella producing β-lactamases has spread rapidly worldwide and poses a serious threat to human and animal health. In this study, we characterized 220 ceftriaxone (CRO)-resistant isolates identified among 3153 Salmonella from humans, animals, food, and water collected in Shanghai, China. They were assessed for antimicrobial susceptibility, phenotypic identification of extended-spectrum β-lactamases (ESBLs), and β-lactamase genes and integrons. CRO resistance in Salmonella increased from 5.0% in 2011 to 8.4% in 2013. Salmonella Enteritidis (45.5%), Salmonella Typhimurium (20.9%) from humans, and Salmonella Indiana (14.5%) from poultry represented the majority of the CRO-resistant isolates. Many isolates were also resistant to other antimicrobials, including nalidixic acid (84.5%), sulfisoxazole (70.5%), and tetracycline (61.8%). Resistance to ciprofloxacin was also found in 33.6% of the isolates. Most isolates (98.2%) were confirmed as ESBL producers. Resistance genes such as bla, bla, and bla were detected in 207 (94.1%), 99 (45%), and 53 (24.1%) isolates, respectively. Three types of integron I and one type of integron II were identified in 13 (5.9%) and 2 (0.9%) isolates, respectively. The integrons encompassed 10 different genes: dfrA1/12/17/25, aadA1/2/5, sat2, orfF, and ybeA. Our study underscores concern for increasing CRO resistance, and highlights the widespread ESBL genes in Salmonella enterica.
产β-内酰胺酶的沙门氏菌在全球范围内迅速传播，对人类和动物健康构成严重威胁。本研究对 2011 年至 2013 年期间从中国上海采集的 3153 株人源、动物源、食品源和水源沙门氏菌中分离的 220 株头孢曲松（CRO）耐药株进行了特征分析。对这些菌株的药敏性、超广谱β-内酰胺酶（ESBL）表型鉴定以及β-内酰胺酶基因和整合子进行了评估。沙门氏菌对 CRO 的耐药率从 2011 年的 5.0%上升至 2013 年的 8.4%。人源分离的肠炎沙门氏菌（45.5%）、鼠伤寒沙门氏菌（20.9%）和禽源分离的印第安纳沙门氏菌（14.5%）是 CRO 耐药株的主要菌型。许多分离株还对其他抗菌药物（包括萘啶酸 84.5%、磺胺二甲嘧啶 70.5%和四环素 61.8%）具有耐药性。33.6%的分离株对环丙沙星也具有耐药性。98.2%的分离株被确认为 ESBL 产生菌。在 207 株（94.1%）、99 株（45%）和 53 株（24.1%）分离株中分别检测到 blaCTX-M-15、blaTEM-1 和 blaCTX-M-27 耐药基因。在 13 株（5.9%）和 2 株（0.9%）分离株中分别发现了 3 种和 1 种整合子 I 和整合子 II。整合子包含 10 个不同的基因：dfrA1/12/17/25、aadA1/2/5、sat2、orfF 和 ybeA。本研究强调了对 CRO 耐药性不断增加的关注，并突出了沙门氏菌中广泛存在的 ESBL 基因。
