食品及环境阪崎肠杆菌分离株的MLST和PFGE分型方法比较

目的:对PFGE和MLST方法在阪崎肠杆菌分型研究中的分辨力和潜在价值进行了比较研究和论述。方法:采用PFGE和MLST方法对本实验室分离的19株阪崎肠杆菌和一株标准菌株ATCC51329进行分型研究。结果:PFGE方法可将20株阪崎肠杆菌分为6大类群,共16个PFGE型,分辨力为0.9474。而MLST方法可将20株菌株分为12个ST型,分辨力为0.9263。结论:PFGE法较MLST法具有较高的分辨力,可用于阪崎肠杆菌的溯源研究,而MLST分型方法能通过全球比对数据库得到更多的关于进化和亲缘关系的分析资料,在致病研究、流行病学调查、进化研究方面优于PFGE法。     

环介导等温扩增法检测进口宠物乳粉中阪崎肠杆菌

目的:建立并验证一种能够简单,准确和快速检测进口宠物乳粉中阪崎肠杆菌的方法。方法:应用环介导等温扩增技术(LAMP)建立宠物乳粉中阪崎肠杆菌检测方法,并通过常规方法对其结果进行验证。结果:LAMP方法从5种进口宠物乳粉中检出两份阪崎肠杆菌阳性,与VITEK 2生化鉴定结果一致。结论:该方法特异性好、灵敏度高,检测时间短,适用于奶粉及其他食品中阪崎肠杆菌检测。     

阪崎肠杆菌外膜蛋白基因的克隆与序列分析

目的:扩增并分析阪崎肠杆菌外膜蛋白基因。方法:根据肠杆菌外膜蛋白A基因的序列特点,设计引物,扩增阪崎肠杆菌外膜蛋白A(ompA)序列,并通过T载体克隆后测序。结果:序列分析表明其1044 bp的序列全长编码347个氨基酸,具有肠杆菌科细菌外膜蛋白序列的典型特征。同源性分析表明,该序列与其它肠杆菌属细菌的序列进行比较,其核酸序列同源性为86%到99%。结论:结果表明该序列为阪崎肠杆菌外膜蛋白基因。     

肠杆菌目细菌产耐碳青霉烯酶的基因分型检测方法进展

碳青霉烯类耐药肠杆菌科细菌（CRE）已成为全球性的公共卫生问题。有文献报道由CRE引起的感染，尤其是血流感染，会导致患者死亡率较高，为临床治疗带来了极大的挑战。肠杆菌科细菌耐碳青霉烯类药物的主要机制是细菌产生了不同型别的耐碳青霉烯类水解酶。目前只有少数几种新型抗菌药物可以用于CRE的治疗如头孢他啶/阿维巴坦，但头孢他啶/阿维巴坦对持有金属β内酰胺酶的CRE没有活性，所以快速、准确地检测CRE菌株所产碳青霉烯酶种类，对临床合理选择抗菌药物至关重要。本文就目前检测肠杆菌科细菌耐碳青霉烯类药物的基因分型实验方法的优缺点进行总结分析。     

耐碳青霉烯类阴沟肠杆菌整合子分布与多位点序列分析

目的通过检测临床分离耐碳青霉烯类阴沟肠杆菌(Carbapenem-resistant enterobacter cloacae,CRECL)整合子,采用多位点序列分型(Multilocus sequence typing,MLST)了解其流行特点,为医院控制感染提供依据。方法收集并保存临床CRECL 15株;鉴定与药敏试验采用BD phoenix M50全自动细菌鉴定仪;整合子、可变区、MLST和碳青霉烯酶测定采用聚合酶链式反应(Polymerase chain reaction,PCR)和琼脂糖凝胶电泳,并对可变区阳性、七对管家基因和碳青霉烯酶的菌株DNA测序,所得数据与数据库比对分析。结果 15株CRECLⅠ类整合子阳性检出率80.0%(12/15),未检出II类及III类整合子;全部CRECL菌株均扩增出可变区,其中11株检测出耐药基因盒,分别为aacA 4-cr、blaOXA30、CatB 3、ARR-3、QacEdelta 1共5种;15株CRECL菌株检出5种序列分型(ST),其中11株为ST 93型,其余为ST 167型、ST 1108型、ST 136型、ST 4型;12株菌株检测出新德里金属-β-内酰胺酶1基因(NDM-1)。结论Ⅰ类整合子与阴沟肠杆菌耐药存在相关性,可能在耐药基因传播中起重要作用;医院CRECL整合子阳性菌株检出率较高;ST型主要为ST 93型,整合子阳性菌株及NDM-1与ST型有较好一致性。     

Effect of linear alkylbenzene sulfonates on the growth of aerobic heterotrophic cultivable bacteria isolated from an agricultural soil

An enrichment culture technique was used to isolate soil bacteria capable of growing in the presence of two different concentrations of linear alkylbenzene sulfonates (LAS) (10 and 500 microg ml(-1)). Nine bacterial strains, representatives of the major colony types of aerobic heterotrophic cultivable bacteria in the enriched samples, were isolated and subsequently identified by PCR-amplification and partial sequencing of the 16S rRNA gene. Amongst the isolates, strains LAS05 (Pseudomonas syringae), LAS06 (Staphylococcus epidermidis), LAS07 (Delftia tsuruhatensis), LAS08 (Staphylococcus epidermidis) and LAS09 (Enterobacter aerogenes), were able to grow in pure culture in dialysed soil media amended with LAS (50 microg ml(-1)). The three Gram-negative strains grew to higher cell numbers in the presence of 50 microg ml(-1) of LAS, compared to LAS-unamended dialysed soil medium, and were selected for further testing of their ability to use LAS as carbon source. However, HPLC analysis of culture supernatants showed that the three strains can tolerate but not degrade LAS when grown in pure cultures. A higher concentration of soluble phosphates was recorded in dialysed soil media amended with LAS (50 microg ml(-1)) compared to unamended control media, suggesting an effect of the surfactant that enhanced the bioavailability of P from soil. The presence of LAS at a concentration of 50 microg ml(-1) had an important impact on growth of selected aerobic heterotrophic soil bacteria, a deleterious effect which may be relevant for the normal function and evolution of agricultural soil.     

2009～2014年重庆地区儿童感染阴沟肠杆菌的临床分布及耐药性分析

目的 了解重庆地区儿童2009～2014年感染阴沟肠杆菌的临床分布特征及耐药性,为合理应用抗菌药物和预防控制医院感染提供依据.方法 分析2009～2014年检出的阴沟肠杆菌对15种抗菌药物的耐药性,采用BD) Phoenix 100全自动微生物鉴定/药敏系统,以最小抑菌浓度(MIC)结合K-B纸片扩散法进行药敏试验,按美国临床实验室标准化协会(CLSI)标准判断结果.结果 共分离阴沟肠杆菌3 384株,检出率为4.18％;以呼吸道标本多见,占83.04％.阴沟肠杆菌对美洛培南和亚胺培南的耐药率最低,分别为0.88％和0.94％;对左氧氟沙星、环丙沙星、哌拉西林/他唑巴坦的耐药率分别为4.38％、5.17％,26.49％.2009～2014年阴沟肠杆菌对15种抗菌药物的耐药率比较,差异均有统计学意义(P＜0.05).共检出产超广谱p内酰胺酶(ESBLs)阴沟肠杆菌87株,占2.57％.新生儿病房和呼吸病房检出阴沟肠杆菌的构成比高于其他病区,分别为26.92％、24.32％.结论 阴沟肠杆菌的耐药性呈上升趋势,新生儿科与呼吸科是预防控制的重点科室.     

Emergence of Enterobacter aerogenes as a major antibiotic-resistant nosocomial pathogen in Belgian hospitals

Objective: To study the epidemiology of Enterobacter aerogenes infections in Belgian hospitals and determine whether recent trends show an increase in incidence of E. aerogenes infections and antimicrobial resistance.
Methods: Data from the bloodstream infection component of the National Surveillance of Hospital Infections (October 1992 to September 1996 data in 45 hospitals) and from a retrospective study on E. aerogenes clinical isolates (1994 and 1995 data in 41 hospitals) were analyzed.
Results: E. aerogenes was recovered from clinical specimens with a mean incidence of 4.6 isolates per 10 000 patient-days and caused 0.20 bloodstream infections per 10 000 patient-days during the surveyed periods, respectively. Both rates increased significantly throughout the years. The proportion of E aerogenes within the Enterobacter genus was 35.4% in clinical isolates and 41.2% in bloodstream infections. Both proportions significantly increased over time. Incidence was not statistically different by hospital size but showed major differences between geographic regions. Resistance rates to third-generation cephalosporins and fluoroquinolones increased, and imipenem resistance emerged in several hospitals.
Conclusions: This report provides evidence of an increase in E. aerogenes infections in Belgian hospitals and documents an increase in antimicrobial resistance of E. aerogenes strains. These figures provide a baseline for further surveillance data.     

产气肠杆菌连续分离株的耐药性及β-内酰胺类抗生素耐药机制的研究

目的 探讨临床连续分离的产气肠杆菌耐药性及耐碳青霉烯类药物菌株对β-内酰胺类药物耐药的主要机制。方法 用Vitek2-Compact仪对临床连续分离的240株产气肠杆菌进行鉴定和常规药敏试验,并筛选出耐碳青霉烯类药物的菌株;用琼脂稀释法测定其对碳青霉烯类药物的MIC值;用改良的三维试验方法分别检测耐药菌株的ESBLs与AmpC酶;改良Hodge试验法检测碳青霉烯酶;用PCR扩增法检测3种β-内酰胺酶的耐药基因;结果 240株产气肠杆菌对23种常用抗生素的耐药率在3.8%～100%之间,最高为头孢西丁(100%)、最低为亚胺培南(3.8%);筛选出10株耐碳青霉烯类产气肠杆菌;三维试验10株菌ESBLs 及AmpC酶均为阳性,Hodge试验阳性7株。PCR结果示,携带blaKPC基因7株;携带blaCTX-M基因7株,携带blaSHV基因2株;携带blaDHA基因6株,携带blaACT/MIR型ampC基因4株; 16SrRNA基因定量确定ampC基因的表达增加的3株。结论 产气肠杆菌对临床常用抗菌药物具有较高的耐药性,其主要耐药机制为产碳青霉烯酶、ESBLs与AmpC酶。     

重症监护室阴沟肠杆菌感染的耐药监测

目的对近年耐第三代头孢的阴沟肠杆菌进行β-内酰胺酶监测,以指导临床用药。方法收集来自重症监护室的各种标本中对第三代头孢耐药的阴沟肠杆菌165株,用三维试验检测ESBLs与AmpC酶。结果165株阴沟肠杆菌中,产ESBLs120株,占72.7%,产AmpC酶40株,占24.24%。结论我院重症监护室对第三代头孢耐药的阴沟肠杆菌主要产ESBLs,体外试验表明对亚胺培南敏感率为97.66%,对其他抗生素敏感性差。