College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, China.
Foodborne Pathog Dis. 2012 Mar;9(3):232-8. doi: 10.1089/fpd.2011.1012. Epub 2012 Jan 27.
Salmonella enterica serovar Enteritidis (S. Enteritidis) is a major serovar associated with human salmonellosis. A total of 425 clinical S. Enteritidis isolates of human origin were collected between June 2009 and September 2010 from North Carolina. The isolates were further characterized for antimicrobial susceptibility, antimicrobial resistance coding determinants, virulence genes, and fingerprint profiles to determine whether they were similar or different to the S. Enteritidis strain responsible for the human outbreak due to consumption of contaminated eggs. Ten different antimicrobial resistance phenotypes were observed with the highest frequency of resistance exhibited to ampicillin (n=10; 2.35%). The isolates were predominantly pansusceptible (n=409; 96.23%); however, seven isolates were multidrug resistant (MDR; i.e., resistant to three or more antimicrobials). Extended spectrum β-lactamase (ESBL) coding genes (bla(TEM) and bla(PSE)) were detected in the ampicillin-resistant isolates, whereas a single MDR isolate tested positive for class 1 integron (1 kb). The majority of the isolates (n=422; 99.3%) carried the invA, mgtC, stn, sopB, sopE1, and sefA virulence genes. However, 37 (8.7%) and 46 (10.82%) S. Enteritidis isolates tested negative for the plasmid encoded genes spvC and rck, respectively. Pulsed-field gel electrophoresis (PFGE) typing of 118 S. Enteritidis isolates by restriction enzymes XbaI and BlnI resulted in seven clusters, each with a discriminatory index (DI) of 0.715 and 0.785, respectively. The combination of XbaI-BlnI patterns generated a dendrogram with 14 clusters and a higher DI of 0.914. The PFGE profile of 80 isolates matched 100% with the S. Enteritidis strain that has been cited for the recent outbreak in the United States due to consumption of contaminated eggs. In conclusion, we identified a genotypic similar S. Enteritidis population in our study based on antimicrobial susceptibility, virulence gene, and PFGE fingerprint profiles.
肠炎沙门氏菌血清型肠炎（S. Enteritidis）是与人类沙门氏菌病相关的主要血清型。2009 年 6 月至 2010 年 9 月期间，从北卡罗来纳州共收集了 425 株来自人类的临床肠炎沙门氏菌分离株。为了确定这些分离株是否与因食用受污染鸡蛋而导致人类爆发的肠炎沙门氏菌菌株相似或不同，对这些分离株进行了抗菌药物敏感性、抗菌药物耐药编码决定因素、毒力基因和指纹图谱的进一步特征分析。观察到十种不同的抗菌药物耐药表型，对氨苄西林的耐药率最高（n=10；2.35%）。分离株主要为全敏感（n=409；96.23%）；然而，有 7 株分离株为多重耐药（MDR；即对三种或更多种抗菌药物耐药）。在氨苄西林耐药分离株中检测到扩展谱β-内酰胺酶（ESBL）编码基因（bla(TEM)和 bla(PSE)），而单个 MDR 分离株对 1 类整合子（1 kb）呈阳性。大多数分离株（n=422；99.3%）携带 invA、mgtC、stn、sopB、sopE1 和 sefA 毒力基因。然而，37（8.7%）和 46（10.82%）株肠炎沙门氏菌分离株的质粒编码基因 spvC 和 rck 检测结果为阴性。用 XbaI 和 BlnI 两种限制酶对 118 株肠炎沙门氏菌分离株进行脉冲场凝胶电泳（PFGE）分型，得到 7 个聚类，每个聚类的区分指数（DI）分别为 0.715 和 0.785。XbaI-BlnI 图谱组合生成了一个具有 14 个聚类和更高 DI（0.914）的系统发育树。80 株分离株的 PFGE 图谱与因食用受污染鸡蛋而导致美国近期爆发的肠炎沙门氏菌菌株完全匹配。总之，我们根据抗菌药物敏感性、毒力基因和 PFGE 指纹图谱，在研究中发现了一个具有相似基因型的肠炎沙门氏菌群体。
