Antimicrobial-drug susceptibility of human and animal Salmonella typhimurium, Minnesota, 1997-2003

We compared antimicrobial resistance phenotypes and pulsed-field gel electrophoresis (PFGE) subtypes of 1,028 human and 716 animal Salmonella enterica serotype Typhimurium isolates from Minnesota from 1997 to 2003. Overall, 29% of human isolates were multidrug resistant. Predominant phenotypes included resistance to ampicillin, chloramphenicol or kanamycin, streptomycin, sulfisoxazole, and tetracycline (ACSSuT or AKSSuT). Most human multidrug-resistant isolates belonged to PFGE clonal group A, characterized by ACSSuT resistance (64%), or clonal group B, characterized by AKSSuT resistance (19%). Most animal isolates were from cattle (n = 358) or swine (n = 251). Eighty-one percent were multidrug resistant; of these, 54% were at least resistance phenotype ACSSuT, and 43% were at least AKSSuT. More than 80% of multidrug-resistant isolates had a clonal group A or B subtype. Resistance to ceftriaxone and nalidixic acid increased, primarily among clonal group A/ACSSuT isolates. Clonal group B/AKSSuT isolates decreased over time. These data support the hypothesis that food animals are the primary reservoir of multidrug-resistant S. Typhimurium.     

一起罗米他沙门菌引起大学生食物中毒的病原学调查

目的 对某高校发生的一起食物中毒开展流行病学调查及病原学检索和溯源,探讨其中毒原因、传染源、传播途径。方法 对相关病例的流行病学特征进行调查,同时对腹泻病原进行检索,对病原菌进行生物学特征研究,利用脉冲场凝胶电泳(PFGE) 技术进行分子流行病学溯源。结果 有流行病学相关病例15例,共分离出9株罗米他沙门氏菌(Salmonella romita,6,7:e,h:1,5),其中4株来自病例,1株来自从业人员,4株来自可疑食品西红柿汤汁。9株菌的生化表型、血清型及药敏试验结果一致,PFGE 条带聚类分析显示菌株属于同一克隆。结论 本起食物中毒由罗米他沙门菌引起,PFGE分型技术实现了对不同样品来源的罗米他沙门菌溯源。     

广州市市售食品中部分沙门菌耐药性及分子分型特征

目的 分析近年来广州市市售食品中部分沙门菌的耐药情况和分子分型特征,为广州市沙门菌疾病的防控提供实验室数据.方法 对分离到的沙门菌进行血清分型,药物敏感性试验和脉冲场凝胶电泳(pulsed-field gel electrophoresis,PFGE),并用BioNumerics软件分析菌株间的同源性.结果2016-2...     

Ciprofloxacin-Resistant Salmonella enterica Serovar Kentucky in Canada

We report emergence of ciprofloxacin-resistant Salmonella enterica serovar Kentucky in Canada during 2003–2009. All isolates had similar macrorestriction patterns and were multilocus sequence type ST198, which has been observed in Europe and Africa. Ciprofloxacin-resistant S. enterica serovar Kentucky represents 66% of all ciprofloxacin-resistant nontyphoidal Salmonella sp. isolates observed in Canada since 2003.     

Potential international spread of multidrug-resistant invasive Salmonella enterica serovar enteritidis

In developing countries, Salmonella enterica serovar Enteritidis causes substantial illness and death, and drug resistance is increasing. Isolates from the United Kingdom containing virulence-resistance plasmids were characterized. They mainly caused invasive infections in adults linked to Africa. The common features in isolates from these continents indicate the role of human travel in their spread.     

Rapid Whole-Genome Sequencing for Surveillance of Salmonella enterica Serovar Enteritidis

For Salmonella enterica serovar Enteritidis, 85% of isolates can be classified into 5 pulsed-field gel electrophoresis (PFGE) types. However, PFGE has limited discriminatory power for outbreak detection. Although whole-genome sequencing has been found to improve discrimination of outbreak clusters, whether this procedure can be used in real-time in a public health laboratory is not known. Therefore, we conducted a retrospective and prospective analysis. The retrospective study investigated isolates from 1 confirmed outbreak. Additional cases could be attributed to the outbreak strain on the basis of whole-genome data. The prospective study included 58 isolates obtained in 2012, including isolates from 1 epidemiologically defined outbreak. Whole-genome sequencing identified additional isolates that could be attributed to the outbreak, but which differed from the outbreak-associated PFGE type. Additional putative outbreak clusters were detected in the retrospective and prospective analyses. This study demonstrates the practicality of implementing this approach for outbreak surveillance in a state public health laboratory.     

宝鸡市一起肠炎沙门氏菌食物中毒事件调查及溯源分析

目的 对宝鸡市一起由聚餐引起的食物中毒事件进行现场流行病学调查分析,并且通过对相关病原菌的分离鉴定和溯源分析,有效控制事件的发展。方法 采用描述性流行病学方法描述疾病分布,建立病因假设。采用分析性流行病学方法(病例对照研究),分析相关因素对疾病产生的影响,找出危险因素。对病例、留样食物、水源开展相关的病原菌分离培养,使用脉冲场凝胶电泳(pulse field gel electrophoresis,PFGE)对可疑致病菌进行溯源分析。结果 此次事件共搜索到病例68人,罹患率28.33%(68/240),主要症状为发热、腹泻、腹痛、呕吐。期间无重症及死亡病例出现。流行病学调查分析发现鸡腿为引起此次事件的可疑食物。通过实验室检测,在留样食物、患者粪便中均分离出了肠炎沙门氏菌。并通过PFGE分子溯源分析得到鸡腿、患者均为同一株沙门氏菌感染。结论 这是一起由沙门氏菌污染而引起的食物中毒,应加强对食物储存、运输、销售的管理工作,防止类似食源性疾病的发生。     

Aquariums as reservoirs for multidrug-resistant Salmonella Paratyphi B

Multidrug-resistant Salmonella enterica serovar Paratyphi B dT+ isolates from patients with gastroenteritis were identical with isolates from their home aquariums. Matched isolates had identical phage types, XbaI and IS200 profiles, and Salmonella genomic island 1 (SGI1). Ornamental fish tanks are reservoirs for SGI1-containing S. Paratyphi B dT+.     

Ceftiofur Resistance in Salmonella enterica Serovar Heidelberg from Chicken Meat and Humans, Canada

The Canadian Integrated Program for Antimicrobial Resistance Surveillance describes a strong correlation (r = 0.9, p<0.0001) between ceftiofur-resistant Salmonella enterica serovar Heidelberg isolated from retail chicken and incidence of ceftiofur-resistant Salmonella serovar Heidelberg infections in humans across Canada. In Québec, changes of ceftiofur resistance in chicken Salmonella Heidelberg and Escherichia coli isolates appear related to changing levels of ceftiofur use in hatcheries during the study period, from highest to lowest levels before and after a voluntary withdrawal, to increasing levels after reintroduction of use (62% to 7% to 20%, and 34% to 6% to 19%, respectively). These events provide evidence that ceftiofur use in chickens results in extended-spectrum cephalosporin resistance in bacteria from chicken and humans. To ensure the continued effectiveness of extended-spectrum cephalosporins for treating serious infections in humans, multidisciplinary efforts are needed to scrutinize and, where appropriate, limit use of ceftiofur in chicken production in Canada.     

上海市罕见沙门菌型腹泻的溯源研究

目的了解上海市长宁区2017年肠炎沙门菌的分子分型结果及抗菌药物耐药情况。方法对2017年上海市长宁区的感染性食源性病原菌监测标本进行沙门菌的分离鉴定、血清分型,检出33株肠炎沙门菌,运用国家致病菌识别网技术手册(2017年)的分子分型方法进行脉冲场凝胶电泳(PFGE)分子分型,使用微量肉汤稀释法进行抗菌药物耐药性的测定。结果33株肠炎沙门菌共分为11种带型,优势带型集中在Clade1中,共计30株。耐2种及2种以上抗菌药物的有22株,耐6种及6种以上抗菌药物的19株,并出现2株四代头孢全耐药。结论长宁区肠炎沙门菌多重耐药现象比较普遍,PFGE型别差异较小,相同PFGE型别的菌株多重耐药表型相近。     

波摩那沙门菌耐药及分子流行病学特征研究

目的 研究波摩那沙门菌的耐药分子流行病学特征。方法 基于上海市网络实验室连续性监测腹泻病例和环境食品及广西地区爬行动物监测的波摩那沙门菌进行抗菌药物耐药和脉冲场凝胶电泳（PFGE）分析。结果 2005－2012 年上海市网络实验室诊断临床病例分离沙门菌4 553 株, 居前10 位的20 个血清型均为A～F 群, 波摩那沙门菌在少见的非A～F 群中仅次于旺兹沃思沙门菌排第2 位, 并对低年龄组人群普遍易感, 症状有血样便和二次感染现象。确认食源环境沙门菌1 805 株, 前10 位血清型明显比人源株更具多样性, 波摩那沙门菌在少见型中列第3位, 多源自甲鱼、海水贝壳类和爬行动物。波摩那沙门菌非人源分离株耐药性显著高于人源株, PFGE结果分属A和B不同克隆簇。克隆A为非流行株的多重耐药株, 菌株多源自淡水养殖鱼类;克隆B为不耐药的流行株, 分为B-Ⅰ（分离自低年龄组）和B-Ⅱ（分离自成年组）2 个亚簇, 前者与海水贝壳类动物、陆龟、蜥蜴分离株同源, 后者与海水贝壳类动物分离株同源, 其中1 例人源株对8种抗生素呈多重耐药。结论 波摩那沙门菌属少见菌型, 但对婴幼儿有较高致病性。上海市近期分离的波摩那沙门菌与2005 年病例菌株存在遗传进化关系, 需要对致病克隆加强监测并预警进食海鲜和爬行动物的感染风险。     

Salmonella enterica pulsed-field gel electrophoresis clusters, Minnesota, USA, 2001-2007

We determined characteristics of Salmonella enterica pulsed-field gel electrophoresis clusters that predict their being solved (i.e., that result in identification of a confirmed outbreak). Clusters were investigated by the Minnesota Department of Health by using a dynamic iterative model. During 2001-2007, a total of 43 (12.5%) of 344 clusters were solved. Clusters of ≥4 isolates were more likely to be solved than clusters of 2 isolates. Clusters in which the first 3 case isolates were received at the Minnesota Department of Health within 7 days were more likely to be solved than were clusters in which the first 3 case isolates were received over a period >14 days. If resources do not permit investigation of all S. enterica pulsed-field gel electrophoresis clusters, investigation of clusters of ≥4 cases and clusters in which the first 3 case isolates were received at a public health laboratory within 7 days may improve outbreak investigations.     

CTX-M-producing non-Typhi Salmonella spp. isolated from humans, United States

CTX-M-type beta-lactamases are increasing among US Enterobacteriaceae isolates. Of 2,165 non-Typhi Salmonella isolates submitted in 2007 to the National Antimicrobial Resistance Monitoring System, 100 (4.6%) displayed elevated MICs (≥2 mg/L) of ceftriaxone or ceftiofur. Three isolates (serotypes Typhimurium, Concord, and I 4,5,12:i:-) contained bla(CTX-M-5), bla(CTX-M-15), and bla(CTX-M-55/57), respectively.     

Foreign travel and decreased ciprofloxacin susceptibility in Salmonella enterica infections

To determine antimicrobial drug resistance patterns, we characterized nontyphoidal Salmonella enterica strains isolated in Liverpool, UK, January 2003 through December 2009. Decreased susceptibility to ciprofloxacin was found in 103 (20.9%) of 492 isolates. The lower susceptibility was associated with ciprofloxacin treatment failures and with particular serovars and phage types often acquired during foreign travel.     

Molecular analysis of fluoroquinolone-resistant Salmonella Paratyphi A isolate, India

Salmonella enterica serovar Paratyphi A is increasingly a cause of enteric fever. Sequence analysis of an Indian isolate showed a unique strain with high-level resistance to ciprofloxacin associated with double mutations in the DNA gyrase subunit gyrA (Ser83-->Phe and Asp87-->Gly) and a mutation in topoisomerase IV subunit parC (Ser80-->Arg).     

Extraintestinal Seeding of Salmonella enterica Serotype Typhi,Pakistan

We evaluated Salmonella enterica serotype Typhi strains isolated from all body sites in Pakistan during 2013–2018. Despite an increase in overall number of localized, extensively drug-resistant Salmonella Typhi in organ infections during 2018, there was no increase in the proportion of such isolates in comparison with non–extensively drug-resistant isolates.     

Plasmid-mediated quinolone resistance among non-Typhi Salmonella enterica isolates, USA

We determined the prevalence of plasmid-mediated quinolone resistance mechanisms among non-Typhi Salmonella spp. isolated from humans, food animals, and retail meat in the United States in 2007. Six isolates collected from humans harbored aac(6')Ib-cr or a qnr gene. Most prevalent was qnrS1. No animal or retail meat isolates harbored a plasmid-mediated mechanism.