兰州地区腹泻患儿沙门菌耐药性与分子分型分析

目的 了解兰州地区腹泻患儿沙门菌的血清型分布特征,耐药状况及分子分型特征,为儿童沙门菌感染的防治提供依据。方法 2018-2020年收集兰州地区哨点医院腹泻患儿粪便标本中分离的149株沙门菌菌株进行血清学分型、药物敏感试验和脉冲场电泳分型。结果 腹泻患儿感染沙门菌以夏秋季为主,1~3岁幼儿居多,占59.73%。149株沙门菌分为33个血清型,其中肠炎沙门菌和鼠伤寒沙门菌为优势血清型,分别占30.87%和28.19%。沙门菌对氨苄西林耐药率最高为79.87%,多重耐药率为78.52%,其中鼠伤寒沙门菌和肠炎沙门菌多重耐药率分别为80.95%、76.09%。经PFGE分子分型将肠炎沙门菌分为20个带型,包含2株及以上的带型有6种;鼠伤寒沙门菌分为30个带型,ST1带型包含2株菌。结论 兰州市腹泻患儿中沙门菌以非伤寒沙门菌为主,耐药率呈上升趋势,多重耐药严重,肠炎沙门菌PFGE分型同源性较高,鼠伤寒沙门菌带型呈多样性分布。     

2013-2014年贵阳市感染性腹泻监测病例中沙门菌的病原学监测分析

目的 了解2013-2014年贵阳市腹泻监测病例中沙门菌的血清型别分布及脉冲场凝胶电泳(Pulse-Field Gel Electrophoresis,PFGE)分型特征,为贵阳市沙门菌病的防控提供科学依据。方法 收集2013-2014年贵阳市4家哨点医院感染性腹泻病例的432份粪便标本,对其进行沙门菌的分离培养、生化鉴定、血清分型及PFGE分型。结果 432例感染性腹泻患者的粪便标本共检出沙门菌35株,检出率为8.10%(35/432),男女检出之比为1.5:1,发病年龄主要集中在0~5岁;各季度间沙门菌检出率经Fisher确切概率法比较无统计学差异(P=0.052)。35株沙门菌分成9种血清型,其中优势血清型为肠炎沙门菌11株(占31.43%)和鼠伤寒沙门菌9株(占25.71%),其次克勒肯威尔沙门菌6株(占17.14%),斯坦利沙门菌3株,德尔卑沙门菌2株,阿贡纳沙门菌、婴儿沙门菌和病牛沙门菌血清型各1株,1株未分型。经XbaⅠ酶切后11株肠炎沙门菌分成8种PFGE型,优势型为JEGX01.CN0007;9株鼠伤寒沙门菌分成9种PFGE型,总体型别呈多样性分布。结论 贵阳市引起感染性腹泻的沙门菌以肠炎沙门菌和鼠伤寒沙门菌为主,PFGE型别呈多样性。     

2015-2021年西安市腹泻患者沙门菌耐药性及分子分型研究

目的 分析2015-2021年西安市腹泻患者沙门菌分离株的血清型分布、耐药情况及分子分型特征，为沙门菌引起腹泻的防治提供科学依据。方法 对分离自2015-2021年西安市感染性腹泻病例的128株沙门菌进行血清学分型，采用微量肉汤稀释法和脉冲场凝胶电泳(PFGE)进行菌株的药物敏感性测定和分子分型分析。结果 128株沙门菌分为23种血清型，优势血清型为沙门菌4,[5],12:i:-、肠炎沙门菌和鼠伤寒沙门菌，占比分别为34.38%、21.88%和17.19%。111株菌(86.72%)对至少1种抗生素耐药，对氨苄西林耐药率最高为78.91%,其次为四环素(69.50%)、链霉素(67.19%)和萘啶酸(53.12%)。共检出41种耐药谱，菌株的耐药谱相对分散，最常见耐药谱为氨苄西林-四环素-链霉素。多重耐药率高达76.56%,沙门菌4,[5],12:i:-和鼠伤寒沙门菌多重耐药现象严重。PFGE聚类分析得到94种带型，相似度为56.8%～100.0%,共聚集形成13个簇。相同血清型菌株PFGE带型相似度较高，同一血清型带型相同或成簇的菌株耐药谱有较高的一致性。结论 西安市腹泻患者沙门菌血...     

2010~2012年深圳市龙岗区致感染性腹泻沙门菌的流行特征和分子分型

目的分析2010~2012年深圳市龙岗区致感染性腹泻沙门菌的流行特征及脉冲场凝胶电泳(PFGE)分子分型,为沙门菌病的防控提供参考依据。方法对147株沙门菌进行生化鉴定和血清分型,利用PFGE进行分子分型,采集相关的流行病学信息并分析。结果龙岗区2010~2012年沙门菌的流行具有明显季节性,第三季度为高峰期(46.3%,96/147);患者主要为婴幼儿(27.9%,41/147)和青壮年(23.1%,37/147),男女比例为1.37︰1(85/62)。147株沙门菌分属于33种血清型,肠炎沙门菌(35.4%,52/147)和鼠伤寒沙门菌(28.6%,42/147)为优势血清型,XbaⅠ酶切将其分为105种带型,肠炎沙门菌和鼠伤寒沙门菌分别有17和34种PFGE型别,优势分子型别分别是XE5、XE1和XP8。AvrⅡ酶切显示本地区可能有数起小型暴发。结论深圳市龙岗区2010~2012年沙门菌PFGE型别较多,菌株来源复杂,主要呈散发状态,偶有局部小型暴发,夏秋季要做好学龄前儿童和青壮年沙门菌病的防控工作。     

2010-2018年安徽省马鞍山市腹泻患者中非伤寒沙门菌的分子分型与耐药性研究

目的 了解马鞍山地区腹泻监测人群非伤寒沙门菌的感染状况、血清学分布、分子分型与耐药性等特征。方法 对2010-2018年腹泻患者中分离的非伤寒沙门菌进行血清学分型、脉冲场凝胶电泳(PFGE)和药物敏感性试验。结果 从2 998例腹泻患者中检出非伤寒沙门菌腹泻263例(8.8%),其中2例为2种非伤寒沙门菌混合感染;6-7月份非伤寒沙门菌感染率较高,05岁年龄组感染率最高(15.9%)(χ²=72.98,P<0.001);265株非伤寒沙门菌分为36个血清型,优势血清型为阿贡纳沙门菌、肠炎沙门菌和鼠伤寒沙门菌;阿贡纳沙门菌的PFGE带型分布较集中,有菌株成簇存在的现象;测试菌株总耐药率为95.6%(66/69),多重耐药率为82.6%(57/69);测试菌株对AMP(79.7%)、STR(75.3%)和Sul(66.6%)耐药率较高,对AMI和AZI 完全敏感;发现2株ESBLs的菌株,均为多重耐药菌株;鼠伤寒沙门菌和肠炎沙门菌对不同药物的敏感性有所不同,前者对喹诺酮类药物较敏感,而后者对四环素类药物较敏感。结论 马鞍山地区优势血清型为阿贡纳沙门菌,与其他地区不同。阿贡纳沙门菌有成簇存在的情况,提示有既往暴发的可能。总耐药及多重耐药现象严重,应谨慎用药并加强对病例的耐药监测。     

泰安市感染性腹泻非伤寒沙门菌耐药监测及分型研究

目的分离鉴定泰安市腹泻病沙门菌的血清型分布、耐药性及PFGE分子分型和同源性特点。方法对分离自泰安市腹泻病人的粪便标本中的31株沙门菌进行生化鉴定和血清分型,采用微量肉汤稀释法对其进行16种抗生素敏感试验,利用PFGE进行分子分型及聚类分析。结果 31株沙门菌分属于10种血清型,肠炎沙门菌占35.5%(11/31)为优势血清型;31株沙门菌对头孢西丁和亚胺培南100%敏感,对磺胺异唑的耐药率为77.42%(24/31);31株沙门菌按照100%的相似度可分为17个PFGE型。结论药敏显示所检测样本存在较为严重的多重耐药性,肠炎沙门菌遗传变异在该地区相对较为保守,且存在散发流行的可能,提示应做好肠炎沙门菌传染病的早期预警及防控。     

84株沙门菌耐药特征及分子分型结果分析

目的分析广东省第二人民医院2012-2014年临床常见沙门菌耐药特性及分子分型特征。方法对分离的84株沙门菌进行血清分型、药物敏感试验。选取不同菌株来源、血清型和耐药谱的51株沙门菌,按照美国PulseNet标准进行脉冲场凝胶电泳(PFGE)分型。应用BioNumerics软件对电泳图谱进行分析,确定菌株间的相关性。结果84株菌分为20种血清型,沙门菌前3位血清型构成比从高到低分别为:鼠伤寒沙门菌占42.86%(36/84)、肠炎沙门菌占15.48%(13/84)、斯坦利沙门菌占8.33%(7/84)。本次分离沙门菌对头孢类抗生素敏感率达84.21%以上,对于环丙沙星与氯霉素的敏感性在66.67%以上,对于甲氧苄啶与庆大霉素的敏感性在50.88%以上,但仍存在多株多重耐药现象。51株沙门菌经过聚类分析可分为 42个PFGE型,表现为较大的遗传多样性。结论临床治疗时,应根据药敏试验结果指导临床,合理使用抗生素,以提高治疗效果。沙门菌耐药谱与 PFGE分型无明显关联。     

2011-2013年河南省鼠伤寒沙门菌耐药与分子分型研究

目的 分析2011-2013年河南省鼠伤寒沙门菌临床分离株的耐药状况与脉冲场凝胶电泳(PFGE)分子分型带型,为以鼠伤寒沙门菌为代表的食源性疾病暴发预警、调查、溯源及公共卫生意义上的抗生素使用策略提供基线与参考数据。方法 根据国际PulseNet 细菌性传染病分子分型监测网络公布的沙门菌PFGE分型技术与美国临床与实验室标准协会(CLSI)沙门菌K-B法药敏测试方案,对2011-2013年分离自我省5个哨点医院的72株鼠伤寒沙门菌进行13种抗生素的药敏测试与PFGE分子分型分析。结果 72株沙门菌对8类13种抗生素均有不同程度的耐药,有65株为多重耐药菌株(90.3%),其中耐3~5种的为6株(8.3%),耐6~8种的为34株(47.2%),耐9~10种的为10株(13.9%)。72株鼠伤寒沙门菌经Xba Ⅰ酶切与脉冲场凝胶电泳后,获得45种带型,每种带型包含菌株数1~9株不等,相似度区间为65.6%~100%。结论 河南省临床分离的鼠伤寒沙门菌耐药状况普遍比较严重,PFGE带型呈现出多样性的同时又具有较显著的优势带型特点,部分带型与其对应的耐药谱具有一定的关联性与相同的聚集性。     

无锡市腹泻病人沙门菌的病原学特征及分子分型研究

目的分析无锡市腹泻人群中分离的沙门菌的流行特征;同时比较主要血清型菌株间的脉冲场凝胶电泳(PFGE)带型差异,为沙门菌感染的防控提供实验数据。方法收集2015年无锡市腹泻病人的粪便标本,分别进行沙门菌的分离鉴定、药敏试验、血清型分型以及PFGE分型分析。结果 756份粪便标本中共分离到32株沙门菌,阳性率为4.23%;检出时间主要集中在5~10月份,感染人群以老年人为主。药敏试验说明无锡地区的沙门菌对氨苄西林的耐药率最高,达56.25%;对环丙沙星和头孢他啶的耐药率最低,均为6.25%。32株沙门菌共鉴定出11种血清型,以肠炎沙门菌和鼠伤寒沙门菌为主,分别占31.25%和21.88%。对这2种血清型的沙门菌进行PFGE分析,显示肠炎沙门菌所有带型的相似度均在85%以上,鼠伤寒沙门菌的带型各不相同。结论无锡市沙门菌的感染具有明显季节和年龄分布差异性,流行的优势血清型为肠炎沙门菌。无锡市需同时加强对食品和环境中沙门菌的监测。     

红嘴鸥中分离的非伤寒沙门菌分子特征分析

目的 非伤寒沙门菌是一类肠道病原体,能引起人的腹泻性疾病。特从每年飞抵云南省昆明市的红嘴鸥中分离的非伤寒沙门菌,作分子分型研究,以反映红嘴鸥对于人群健康的潜在影响。方法 从2013年11月-2014年1月间,分3次分别采集500份红嘴鸥粪便样本,进行沙门菌的分离培养。得到菌株之后开展药敏试验和脉冲场凝胶电泳(PFGE)分析。结果 500份粪便样品分离到78株非伤寒沙门菌,其中鼠伤寒沙门菌75株(96.15%),韦尔克斯沙门菌1株,印第安纳沙门菌2株。药敏试验显示,所有非伤寒沙门菌对于利福平的耐药率高达97.44%,其次为萘啶酸(28.21%)和复方新诺明(25.64%);而对庆大霉素和环丙沙星则完全敏感。PFGE结果显示,75株鼠伤寒沙门菌形成了3个带型,并且带型之间的同源性关系均大于95%,66株表现为完全一致的带型特征。与分离自病人的鼠伤寒沙门菌比较后发现,红嘴鸥中分离的鼠伤寒沙门菌与病人分离的菌株的PFGE带型被区分成了两个聚类群。结论 红嘴鸥有很高的非伤寒沙门菌携带率,以鼠伤寒沙门菌为主;PFGE结果表明,红嘴鸥携带的非伤寒沙门菌可能与其生活环境和食物构成等因素密切相关,但尚未发现这些菌株与人群患病的相关性。     

Prevalence and antimicrobial resistance of non-typhoid Solmonella in military personnel,1988-2013

Objective: To describe the spanning 25 years data for the occurrence,magnitude,and trends regarding antimicrobial resistance of non-typhoidal Salmonella(NTS) isolated from non-immune travelers to Thailand participating in joint military operations.Methods: A total of 355 NTS isolates,obtained from 2 052 fecal samples from US soldiers deployed for military maneuvers in Thailand during 1988-2013,were examined for NTS serogroup/serotypes and tested for antimicrobial susceptibility by disk diffusion to these 10 antibiotics:ampicillin,azithromycin(AZM),ciprofloxacin,colistin,gentamicin,kanamycin,nalidixic acid,streptomycin(STR),tetracycline(TET),and trimethoprim/sulfamethoxazole.Identified AZM-resistant NTS isolates were further evaluated for their minimal inhibitory concentration by the E-test method.Results: NTS infections accounted for 17.3%(355/2 052),including11 serogroups and 50 different serotypes.The most prevalent serogroup was Salmonella group C2-C3(35.8%,127/355) followed by groups B(21.1%,75/355) and C1(18.6%,66/355).Identified serotypes included Salmonella hadar(n=60),Salmonella rissen(n=45),and Salmonella blockley(n=34).Among the predominate serogroups,antimicrobial resistance was consistently high against TET(76.9%,273/355) followed by STR(40.8%,145/355).One Salmonella senftenberg isolate demonstrated decreased ciprofloxacin susceptibility.Most isolates(94.6%) were resistant to one or more antimicrobials,and the most common multidrug resistance was TET-STR-nalidixic acid(11.5%,41/355).Conclusions: The prevalence of NTS serotypes and the growing magnitude of antibiotic resistant bacteria isolated from deployed US military in Thailand are documented from 1988-2013.This study demonstrates the antibiotic resistance profiles,highlighting the effectiveness of AZM that is a first-line treatment for travelers to Southeast Asia.AZM-resistant NTS isolates are periodically observed over a 25-year period.Hence,the ongoing surveillance and prevalence efforts are required to monitor NTS resistant strains causing further treatment failure.     

Class 1 integrons and resistance gene cassettes among multidrug resistant Salmonella serovars isolated from slaughter animals and foods of animal origin in Ethiopia

The present study was undertaken to identify and characterize integrons and integrated resistance gene cassettes among multidrug resistant (MDR) Salmonella isolates from slaughter animals and food products of animal origin in Ethiopia. A total of 98 epidemiologically unrelated Salmonella isolates comprising 13 serovars were characterized using serotyping, phage typing, antimicrobial resistance testing and the pulsed-field gel electrophoresis (PFGE) method. Integron-PCR was used to detect the presence of class 1 and class 2 integrons in the MDR strains. The associated individual resistance gene cassettes were identified using specific PCRs and DNA sequencing. The location of the integrons was determined by Southern blot hybridization analysis. Among the Salmonella serovars, a high level of antimicrobial resistance was found to streptomycin (82.6%), tetracycline (75.5%), sulfamethoxazole (60.2%), spectinomycin (53.1%), ampicillin (42.8%), nalidixic acid (34.7%), nitrofurantoin (30.6%), trimethoprim (27.5%), gentamicin (20.4%) and ciprofloxacin (19.4%). Class 1 integrons were detected in 53.1% of the MDR isolates comprising serovars Anatum, Braenderup, Kentucky, Saintpaul and Typhimurium. Of the class 1 integron positive isolates 61.5% harboured the integron-associated gene cassettes: aadA2, aadA2+bla(PSE-1), dfrA1-aadA1 and dfrA12-orf-aadA2 (amplicon sizes 1000 bp, 1000+1200 bp, 1600 bp and 1900 bp, respectively). The chromosomally located aadA2 and aadA2+bla(PSE-1) resistance gene cassettes occurred exclusively in S. Typhimurium DT104 isolates, the other cassettes were found on large plasmids in several serovars. An aacCA5-aadA7 gene cassette array (amplicon size 1600 bp) was exclusively found in all MDR S. Kentucky strains of R type Str/SpeSmxGenNalAmpTetCipCef and this integron was shown to be chromosomally located. Results of the present study indicate that class 1 integrons carrying gene cassettes, which confer resistance to different classes of antimicrobials such as aminoglycosides, beta-lactams and trimethoprim are widespread among the MDR Salmonella serovars isolated from slaughter animals and food products of animal origin in Ethiopia indicating the important role of these genetic elements in the dissemination of multidrug resistance.     

Antimicrobial drug resistance in isolates of Salmonella enterica from cases of salmonellosis in humans in Europe in 2000: results of international multi-centre surveillance

The Enter-net surveillance system received results of antimicrobial sensitivity tests for isolates from over 27 000 cases of human salmonellosis in 2000 in 10 European countries. Almost 40% of isolates were resistant to at least one antimicrobial, with 18% multiresistant. Resistance to ampicillin, streptomycin, sulphonamides and tetracyclines was common, with over 20% of isolates resistant to at least one of these antimicrobials. Clinical resistance to ciprofloxacin was rare, with only 0.5% of isolates exhibiting such resistance (MIC >1.0 mg/l). Resistance to nalidixic acid coupled with a decreased susceptibility to ciprofloxacin (MIC 0.25-1.0 mg/l) was more common, with 14% of isolates showing these properties. Resistance to third-generation cephalosporins was rare with only 0.6% of isolates resistant to cefotaxime. In all countries multiple resistance was most common in Salmonella enterica serotype Typhimurium, with 51% of isolates multiresistant in total. In England and Wales multiple resistance was also prevalent in S. Virchow and S. Hadar, whereas in other countries multiple resistance was common in serotypes such as S. Blockley.     

Antimicrobial drug resistance in nontyphoid human Salmonella in Belgium: trends for the period 2000-2002

In order to assess antimicrobial resistance in nontyphoid human Salmonella in Belgium, the six most important serovars, representing together more than 90% of laboratory confirmed cases, were randomly sampled. From June 2000 until December 2002, a total of 1756 isolates were screened for their antimicrobial resistance profile by the disc diffusion method. S. Hadar strains showed the highest level of antimicrobial resistance. Simultaneous resistance to ampicillin, nalidixic acid, tetracycline and streptomycin was observed in 81.5, 58 and 76.1% of these isolates in 2000, 2001 and 2002, respectively. All S. Hadar isolates resistant to nalidixic acid also displayed decreased susceptibility to ciprofloxacin (MIC50 values of 0.25 microg/mL in 2000-2001 and 0.19 microg/mL in 2002). In 2000, 2001 and 2002, respectively 44.6, 46 and 36.5% of S. Typhimurium isolates were multiresistant (resistant to 4 or more antimicrobial agents). These multiresistant isolates were preferably associated with a few phage types, such as DT104. Complete resistance to ciprofloxacin was detected in three S. Typhimurium isolates and sequencing of the gyrA gene revealed for each isolate two mutations at codons corresponding to Ser-83 and Asp-87. Multiresistance was also common in S. Virchow (7.7%, 15.9% and 29.7%, in 2000, 2001 and 2002, respectively). Resistance to nalidixic acid in S. Virchow isolates increased from 46.2% in 2000 to 80.9% in 2002 and six S. Virchow isolates were detected as cefotaxime resistant. In contrast, the vast majority of S. Enteritidis, S. Brandenburg and S. Derby isolates remained sensitive to almost all antimicrobial agents tested.     

The epidemiological relationship between Salmonella enterica serovar typhimurium and Salmonella enterica serovar 4,[5],12:i:- isolates from humans and swine in Thailand

A total of 138 isolates of S. Typhimurium and S. 4,[5],12:i:- from humans and swine in Thailand during 2003-2006, were evaluated for antimicrobial sensitivity by the disk diffusion method against 10 antimicrobial drugs and pulsed-field gel electrophoresis (PFGE) with endonuclease Xbal to investigate the epidemiological relationship among isolates. It was found that all isolates were classified into 27 antimicrobial resistance patterns, and 80% of S. Typhimurium and 95.4% of S. 4,[5],12:i:- isolates were resistant to three or more antimicrobial agents. By PFGE testing, the 84 PFGE patterns were categorized into A to Z patterns. Eighty percent of S. Typhimurium and 71.3% of S. 4,[5],12:i:- isolates in 7 major PFGE patterns had close clonal relationships (_85% similarity). Our studies indicate the spread of genetically identical clones of S. Typhimurium and S. 4,[5],12:i:- in humans and swine in Thailand.     

Antimicrobial susceptibility of nontyphoidal Salmonella isolated from humans in Belgium

Human nontyphoidal Salmonella infections are the primary cause of foodborne disease in developed countries, resulting in considerable morbidity and occasionally death, especially in immunocompromised patients. Strains of Salmonella that are resistant to antimicrobial agents have become a world-wide health problem. Fluoroquinolones are drugs of choice for treatment of human invasive salmonellosis, and have been useful for the treatment of infections caused by multi-resistant strains. However, strains resistant to ciprofloxacin have been noted. A random sample of 378 Salmonella strains of human origin was collected during 1998. Their susceptibility to 11 antimicrobial agents was determined by the agar dilution method according to NCCLS standards. In total, 38 serotypes were represented of which S. Enteritidis (20.4%), S. Typhimurium (20.4%), S. Hadar (9.0%), S. Brandenburg (7.9%), S. Infantis (7.7%), and S. Virchow (5.3%) were the most common. All strains were susceptible to ceftriaxone and ciprofloxacin. For nalidixic acid the rate of resistance was 19.0%. Of the 72 strains resistant to nalidixic acid, 31 were S. Hadar, and thus 91.2% (31/34) of the S. Hadar isolates showed resistance to nalidixic acid. Most of the S. Hadar strains were also resistant to ampicillin, tetracycline and sulphamethoxazole, and an elevated MIC50 (0.25 microgram/ml) and MIC90 (1 microgram/ml) was observed for ciprofloxacin. The high rate of resistance to nalidixic acid can be a first step towards the development of resistance to ciprofloxacin.     

Drug sensitivity, conjugative R plasmids and plasmid profiles of Salmonella isolated from humans with infectious enteritis

Using 92 Salmonella strains isolated from patients suspected of having infectious diseases of the intestinal tract who visited 13 hospitals in Japan during the six years between 1991 and 1996, we investigated the drug susceptibility, prevalence of conjugative R plasmid, and the plasmid profiles. 1) Of the bacterial isolates tested, 52.2% showed drug-resistance. Regarding the drug-resistance patterns, 70.8% of the isolates were resistant to a single drug, while 29.2% were multi drug-resistant. 2) Dividing the resistance patterns by the serotypes, among Salmonella Enteritidis isolates, single-drug resistance to SM was the most frequent, being detected in 27 isolates. Single-drug resistance to NA and two-drug resistance to SM/TC were the second-most frequent, each being detected in isolates. Among Salmonella Hadar isolates, four isolates showed two-drug resistance to SM/TC, and one isolate showed single-drug resistance to TC. Among Salmonella Typhimurium isolates, one isolate each showed three-drug resistance to ABPC/CER/KM and KM/TC/CP. Among Salmonella Agona isolates, one isolate each showed two-drug resistance to SM/TC and single-drug resistance to SM. Among Salmonella Derby isolates, two isolates showed single-drug resistance to SM. 3) The prevalence of conjugative R plasmid was investigated in 48 drug-resistant isolates, and six isolates (12.5%) contained the plasmid. 4) The prevalence of the plasmid was investigated in 29 drug-resistant S. Enteritidis isolates, and 22 isolates (75.9%) contained the plasmid. These isolated were classified by the plasmid profiles into types H1 to H7. 5) Regarding the plasmid profiles of the S. Enteritidis isolates, a position corresponding to 60 Kbp was the most frequently detected in 90.5%.     

PFGE, Lior serotype, and antimicrobial resistance patterns among Campylobacter jejuni isolated from travelers and US military personnel with acute diarrhea in Thailand, 1998-2003

Background

Campylobacter jejuni is a major cause of gastroenteritis worldwide. In Thailand, several strains of C. jejuni have been isolated and identified as major diarrheal pathogens among adult travelers. To study the epidemiology of C. jejuni in adult travelers and U.S. military personnel with acute diarrhea in Thailand from 1998-2003, strains of C. jejuni were isolated and phenotypically identified, serotyped, tested for antimicrobial susceptibility, and characterized using pulsed-field gel electrophoresis (PFGE).

Results

A total of 312 C. jejuni isolates were obtained from travelers (n = 46) and U.S. military personnel (n = 266) in Thailand who were experiencing acute diarrhea. Nalidixic acid and ciprofloxacin resistance was observed in 94.9% and 93.0% of the isolates, respectively. From 2001-2003, resistance to tetracycline (81.9%), trimethoprim-sulfamethoxazole (57.9%), ampicillin (28.9%), kanamycin (5.9%), sulfisoxazole (3.9%), neomycin (2.0%), and streptomycin (0.7%) was observed. Combined PFGE analysis showed considerable genetic diversity among the C. jejuni isolates; however, four PFGE clusters included isolates from the major Lior serotypes (HL: 36, HL: 11, HL: 5, and HL: 28). The PFGE analysis linked individual C. jejuni clones that were obtained at U.S. military exercises with specific antimicrobial resistance patterns.

Conclusions

In summary, most human C. jejuni isolates from Thailand were multi-resistant to quinolones and tetracycline. PFGE detected spatial and temporal C. jejuni clonality responsible for the common sources of Campylobacter gastroenteritis.     

Drug resistance and adherence to human intestines of enteroaggregative Escherichia coli.

Clinical isolates of enteroaggregative Escherichia coli (EAggEC) were tested for their in vitro susceptibilities to 27 antimicrobial agents. Marked drug resistance was observed with sulfamethoxazole, ampicillin, and chloramphenicol in contrast to such antimicrobial agents as cefixime, sparfloxacin, and ciprofloxacin. One of the EAggEC strains carried a plasmid that conferred on its host resistance to ampicillin, tetracycline, sulfamethoxazole, streptomycin, and spectinomycin and an ability to adhere to child ileal villi or HeLa cells in the characteristic aggregative pattern. This plasmid also mediated D-mannose-resistant hemagglutinin production and bacterial clump formation (autoagglutination). The data demonstrate appearance of marked drug resistance and an intestine-adherence and drug-resistance plasmid in the newest category of diarrheagenic E. coli.     

Evolution of antibiotic resistance of non-typhoidal salmonellae in Greece during 1990-97

Susceptibility to 15 antibiotics was determined in 1548 non-typhoidal salmonella strains isolated in Greece from l990 to l997. The overall prevalence of resistance of both Salmonella enterica serotype Enteritidis and Salmonella enterica serotype Typhimurium increased during the first years of the study. A decrease was observed from 1996, especially for S. Enteritidis, which showed the highest overall antibiotic resistance. S. Typhimurium was the serotype with the highest multiresistance to antibiotics. The rest of the serotypes had very low resistance prevalence compared with both S. Enteritidis and Typhimurium serotypes.