Occurrence of Salmonella enterica serotype Enteritidis phage types in the Slovak Republic

Phage typing of 741 isolates of Salmonella enterica serotype Enteritidis from the slovak Republic in 1995 has been carried out using the scheme of Ward and colleagues (1987). 202 strains (51 isolated from food) were from 9 outbreaks, 536 isolates were from sporadic cases and 3 isolates were from nosocomial infections of new-born babies. 704 isolates (95%) from all sources were typeable and belonged to 7 different phage types (PTs). PT8 was the phage type most frequently identified (72.6%). Other epidemiologically relevant phage types were PT2 (8.5%), 4 (7.9%) and 1 (4.2%). With an incidence of 1.3--0.1% isolates of PTs 21, 6, 9 were found. 26 (3.5%) isolates were designated RDNC and 11 (1.5%) were untypeable.     

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.     

Salmonella enterica Serotype Enteritidis in French Polynesia,South Pacific, 2008–2013

Outbreaks of Salmonella enterica serotype Enteritidis infections associated with eggs occurred in French Polynesia during 2008–2013. Molecular analysis of isolates by using clustered regularly interspaced short palindromic repeat polymorphisms and multilocus variable-number tandem-repeat analysis was performed. This subtyping made defining the epidemic strain, finding the source, and decontaminating affected poultry flocks possible.     

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.     

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.     

Rapid Emergence and Clonal Dissemination of CTX-M-15–Producing Salmonella enterica Serotype Virchow,South Korea

The prevalence of cefotaxime-resistant Salmonella enterica serotype Virchow has dramatically increased in South Korea since the first isolation in 2011. Of 68 isolates collected over 10 years, 28 cefotaxime-resistant isolates harbored the bla_CTX-M-15 extended-spectrum β-lactamase gene and were closely related genetically, demonstrating the clonal dissemination of CTX-M-15–producing Salmonella Virchow in South Korea.     

A Comparison of Subtyping Methods for Differentiating Salmonella enterica Serovar Enteritidis Isolates Obtained from Food and Human Sources

PurposeTo evaluate the abilities of these subtyping methods, we distinguished Salmonella Enteritidis (S. Enteritidis) isolated from food products and human clinical samples between 2009 and 2010 in Seoul using five subtyping methods.MethodsWe determined the subtypes of 20 S. Enteritidis isolates from food and human sources using phage typing, antimicrobial susceptibility, pulsed-field gel electrophoresis (PFGE), repetitive sequence-based PCR (rep-PCR), and multilocus sequence typing (MLST).ResultsA total of 20 tested isolates were differentiated into six antimicrobial susceptibility patterns, three different phage types, four different PFGE profiles, seven rep-PCR patterns, and one MLST type. Food isolates were considerably more susceptible to antibiotics than human isolates. We were best able to discriminate among S. Enteritidis isolates using rep-PCR, and obtained the highest Simpson's diversity index of 0.82, whereas other methods produced indices that were less than 0.71. PFGE pattern appeared to be more related to antimicrobial resistance and phage types of S. Enteritidis isolates than rep-PCR. MLST revealed identical alleles in all isolates at all seven loci examined, indicating no resolution.ConclusionThe results of this study suggest that rep-PCR provided the best discriminatory power for phenotypically similar S. Enteritidis isolates of food and human origins, whereas the discriminatory ability of MLST may be problematic because of the high sequence conservation of the targeted genes.     

Increasing prevalence of Salmonella enterica serotype Paratyphi-A in patients with enteric fever in a periurban slum setting of Kolkata, India

A sudden rise in the occurrence of Salmonella enterica serotype Paratyphi-A (SPTA) was noted in a longitudinal community-based study in Kolkata, India, during 2004 - 2005. We compared the incidence rate of Salmonella enterica serotype Typhi (ST) and SPTA and their antimicrobial susceptibility pattern. Rate of isolation of SPTA was 1.5 times higher than that of ST, a trend detected for the first time in that particular focus. Almost all the isolates were sensitive to Gentamycin and Norfloxacin. Most of the strains (90%) were sensitive to Ciprofloxacin. Two thirds of the strains were also sensitive to Chloramphenicol. The high occurrence of SPTA in the present study could be the signal of the emergence of SPTA as a pathogen in India. Quinolone derivatives (namely, Ciprofloxacin, Norfloxacin and Chloramphenicol) can be suggested as drugs of choice for treatment of enteric fever caused by SPTA. Future vaccination strategies should include bivalent vaccines with protection capacities against both ST as well as SPTA.     

Increase in extraintestinal infections caused by Salmonella enterica subspecies II-IV

To garner information regarding site of infection and age and sex of persons infected with Salmonella enterica subspecies II-IV, we retrospectively analyzed data on Salmonella spp. infections in California, USA, 1985-2009. These subspecies were found to cause significantly more frequent invasive disease (e.g., bacteremia) than did Salmonella subspecies I strains.     

Transmission of Multidrug-Resistant Salmonella enterica Subspecies enterica 4,[5],12:i:- Sequence Type 34 between Europe and the United States

Multidrug-resistant Salmonella enterica subspecies enterica 4,[5],12:i:- sequence type 34 represents a worldwide public health risk. To determine its origin in the United States, we reconstructed a time-scaled phylogeny with a discrete trait geospatial model. The clone in the United States was introduced from Europe on multiple occasions in the early 2000s.     

鼠伤寒沙门菌临床分离株对喹诺酮类药物耐药机制的研究

目的 研究引起儿童腹泻鼠伤寒沙门菌对喹诺酮类抗菌药物的耐药机制.方法 采用K-B法测定62株鼠伤寒沙门菌对常用抗菌药物的敏感性;应用PCR法和DNA测序法检测喹诺酮耐药决定区(QRDRs)和质粒介导的喹诺酮耐药基因;采用接合试验测定耐药基因的转移性;PFGE法测定耐药菌株的同源性.结果 62株肠伤寒沙门菌中有40株对环丙沙星耐药(MIC≥0.5 μg/ml),其中28株为低水平耐药,12株为高水平耐药,且所有对环丙沙星耐药菌株同时对其他多种抗菌药物耐药;40株环丙沙星耐药菌株分属于4种PFGE型,分别是A型7株、B型4株、E型1株、D型28株;两株对环丙沙星高水平耐药菌株同时存在gyrA和parC两个位点的突变,其余环丙沙星耐药菌株仅发现gyrA 1个位点的突变,未检测到qnr和qepA基因;62株鼠伤寒沙门菌中有23株为aac-(6′)-Ib-cr阳性,其中19株PFGE分型为D型.结论 腹泻患儿分离的肠伤寒沙门菌对环丙沙星耐药率高,喹诺耐耐药决定区gyrA基因的点突变和携带aac-(6′) -Ib-cr基因是导致鼠伤寒沙门菌对环丙沙星耐药的主要原因.     

广州市566株腹泻病例沙门菌的血清型分布及耐药性分析

目的 了解广州市近两年腹泻病例沙门菌分离株的血清型分布及耐药情况。方法 对广州市8家腹泻病监测医院2012年、2013年间上送的566株沙门菌进行血清分型,同时采用纸片扩散法(K- B法)对12种抗菌药物进行敏感性分析。结果 566株沙门菌分为62个血清型,前三位分别为鼠伤寒沙门菌41.52%（235/566）、肠炎沙门菌15.72%（89/566）和斯坦利沙门菌7.95%（45/566）。药敏分析显示菌株对头孢类抗菌药物敏感率达85%以上,对环丙沙星的敏感性也较高,为75.44%,而对氨苄西林、磺胺复合物、四环素、萘啶酸的耐药率达60%。耐3种及以上抗生素的菌株占71.02%（402/566）,出现ACSSuT+耐药谱（对氨苄西林、氯霉素、链霉素、磺胺复合物、四环素等5种或更多药物多重耐药）的总耐药率为27.39%（155/566）。鼠伤寒沙门菌ACSSuT+耐药率达44.68%（105/235）。结论 本地区沙门菌临床分离株以鼠伤寒沙门菌和肠炎沙门菌为主,菌株对头孢类抗菌药物的敏感性较高,但某些血清型菌株存在严重的多重耐药现象,其中鼠伤寒沙门菌是耐药最严重的血清型,应引起重视。     

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。     

Multistate Outbreak of Salmonella enterica Serovar Heidelberg with Unidentified Source,Australia, 2018–2019

We report a multistate Salmonella enterica serovar Heidelberg outbreak in Australia during 2018–2019. Laboratory investigation of cases reported across 5 jurisdictions over a 7-month period could not identify a source of infection but detected indicators of severity and invasiveness. The hospitalization rate of 36% suggested a moderately severe clinical picture.     

上海市肠炎沙门菌流行特征和分子分型研究

[目的]分析上海市2006—2007年肠炎沙门菌菌株,了解上海市肠炎沙门菌分子流行病学特征。[方法]回顾2002—2007年肠炎沙门菌食品株来源并与肠炎沙门菌腹泻株作耐药性比较;对2006—2007年全球沙门菌监测(GSS)病例和食品分离的肠炎沙门菌进行表型验证、药敏试验和脉冲凝胶电泳(PFGE)分析。[结果]2006—2007年肠炎沙门菌在本市非伤寒沙门菌病例中列首位,而80%的食品株源自禽及禽肉制品,食品株的抗生素耐药性高于腹泻株。2007年肠炎沙门菌腹泻株的耐药谱和2006年有较大差异。包括13株食品株在内共76株肠炎菌株可分为21种PFGE带型,遗传同源性接近80%,优势带型依次为3型(34株)、1型(12株)、2型(5株)和5型(5株),除2型外均发现有与腹泻株同型的食源株。2006和2007年的PFGE 1/2型病例分别为4例和12例。[结论]上海市肠炎沙门菌病例与食用污染的鸡肉等禽类制品有密切关系,PFGE 3型肠炎沙门菌是目前上海市肠炎沙门菌流行株的优势菌型,2007年发现由鹅肝传播的1/2型肠炎沙门菌可能是3型的变异株并有取代之成为流行菌株的趋势。开展对腹泻病例和食物链的综合监测和以实验室为主的实时分子分型检测能快速预警肠炎沙门菌散在爆发和追溯污染源。     

重组人乳铁蛋白对小鼠沙门菌感染抑制效果

目的研究转基因水稻来源的重组人乳铁蛋白(rhLF)在小鼠体内抑制沙门菌感染的效果。方法选择Balb/c小鼠建立沙门菌感染模型; 将Balb/c小鼠按体重随机分为2组,即沙门菌对照组和rhLF干预组,每组12只;染菌前2h,rhLF干预组小鼠经口灌胃20 mg/mL rhLF 0.3 mL,对照组小鼠经口灌胃0.3 mL PBS;之后每天灌胃相同量的rhLF(6 mg/d)或PBS;每天观察小鼠一般情况;7 d后,心脏穿刺取小鼠血液观察菌血症,取肝脏和脾脏组织进行细菌计数分析,取肝脏、脾脏、肾脏和小肠进行病理观察。结果各组小鼠体重变化、生存情况在组间无明显差异(P>0.05);2组小鼠的肝脏重和肝体比值、脾脏重和脾体比值相似(P>0.05);rhLF干预组小鼠的血液、肝脏和脾脏的染菌率和染菌量与对照组相比,呈现降低趋势,但差异无统计学意义(P>0.05);病理分析显示rhLF干预组小鼠的炎症程度有减轻,但差异无统计学意义(P>0.05)。结论6 mg/d的rhLF不能明显减轻小鼠沙门菌感染的炎症程度。