产超广谱β内酰胺酶大肠埃希菌的耐药性及基因型研究

目的了解我院临床分离的大肠埃希菌中产ESBLs菌株的阳性率、耐药性及ESBLs基因型。方法采用纸片扩散法（K—B法）测定2004年1月2005年12月我院临床分离221株大肠埃希菌对23种抗菌药物的敏感度，用酶抑制剂增强试验（纸片法）进行产ESBLs菌株的检测；用PCR和DNA序列分析检测ESBLs基因型，并用WHONET5．3软件进行统计分析。结果221株大肠埃希菌中共检出89株产ESBLs菌株（40．3％）；产ESBLs菌株对青霉素类、第一、第二代头孢菌素100％耐药，第三代头孢菌素中，除细菌对头孢他啶耐药率为41．6％外，对头孢哌酮、头孢噻肟、头孢曲松的耐药率均在95％以上，对哌拉西林-三唑巴坦、头孢哌酮-舒巴坦的耐药率分别为9．0％、18．0%；对亚胺培南的耐药率为0％；89株产ESBLs菌株中，88株（98．9％）PCR检测ESBLs基因型阳性，且均为CTX—M型，其中CTX—M-14为86．5％（77／89）、CTX—M-3为19．1％（17／89），6株细菌（6．7％）同时产CTX—M-14和CTX—M-3。结论我院大肠埃希菌中产ESBLs菌株阳性率较高；产ESBLs菌株耐药显著，ESBLs基因型以CTX—M-14型为主。未检出其他型ESBLs。     

产超广谱β-内酰胺酶的肺炎克雷伯菌相关耐药基因研究

目的了解常州地区肺炎克雷伯菌耐药状况及β-内酰胺类耐药基因。方法用琼脂稀释法检测氨苄西林、哌拉西林、哌拉西林-他唑巴坦、头孢噻肟、头孢他啶、头孢吡肟、氨曲南和亚胺培南对肺炎克雷伯菌的最低抑菌浓度（MIC）。采用聚合酶链反应（PCR）检测产超广谱β-内酰胺酶（ESBLs）肺炎克雷伯菌16种相关耐药基因,并用DNA测序仪测序。结果120株肺炎克雷伯菌ESBLs阳性率为44．2％（53株）。从53株肺炎克雷伯菌中检出TEM、SHV、CTX—M-1群、CTX—M-9群、OXA-1群、LEN、OKP和DHA8种β-内酰胺酶基因,阳性率分别为75．5％、22．6％、18．9％、7．5％、11．3％、5．7％、3．8％和41．5％,其中2株菌同时检出6种B-内酰胺酶基因。基因测序证实为TEM-1、TEM-11、SHV-13、SHV．28、CTX—M-22、CTX—M-55、OXA-1和OKP-6等。结论本地区肺炎克雷伯菌已携带多种β-内酰胺酶耐药基因,是其对β-内酰胺类抗菌药物耐药的重要原因之一。     

CTX-M型超广谱β内酰胺酶肺炎克雷伯菌的分子流行病学研究

目的了解湖北地区产CTX—M型超广谱β内酰胺酶（ESBLs）肺炎克雷伯菌的流行基因型，为有效预防和控制该类感染提供理论依据。方法临床分离的无重复产ESBLs的肺炎克雷伯菌70株，采用NCCLS表型筛选和确证试验检测ESBLs，采用聚合酶链反应（PCR）检测CTX—M基因型，并采用PCR—RFLP检测blaCTX—M基因分型，质粒接合试验探讨产CTX—M型ESBLs菌株的传播机制。结果70株产ESBLs的肺炎克雷伯菌中，产CTX—M基N型的肺炎克雷伯菌有26株（37％），PCR-RFLP及DNA测序证实其均为CTX—M-1亚组，其中CTX—M-3型最常见，质粒接合试验证实CTX—M型ESBLs介导的耐药可以水平转移。结论湖北地区存在着CTX—M基因的流行，且产CTX—M型ESBLs菌株的传播机制以质粒介导的为主，可以水平传播，应加强湖北地区产CTX—M型ESBLs菌株的分子流行病学检测。     

CTX—M型超广谱β内酰胺酶肺炎克雷伯菌的分子流行病学研究

目的了解湖北地区产CTX—M型超广谱β内酰胺酶（ESBLs）肺炎克雷伯菌的流行基因型，为有效预防和控制该类感染提供理论依据。方法临床分离的无重复产ESBLs的肺炎克雷伯菌70株，采用NCCLS表型筛选和确证试验检测ESBLs，采用聚合酶链反应（PCR）检测CTX—M基因型，并采用PCR—RFLP检测blaCTX—M基因分型，质粒接合试验探讨产CTX—M型ESBLs菌株的传播机制。结果70株产ESBLs的肺炎克雷伯菌中，产CTX—M基N型的肺炎克雷伯菌有26株（37％），PCR-RFLP及DNA测序证实其均为CTX—M-1亚组，其中CTX—M-3型最常见，质粒接合试验证实CTX—M型ESBLs介导的耐药可以水平转移。结论湖北地区存在着CTX—M基因的流行，且产CTX—M型ESBLs菌株的传播机制以质粒介导的为主，可以水平传播，应加强湖北地区产CTX—M型ESBLs菌株的分子流行病学检测。     

产超广谱β内酰胺酶大肠埃希菌与肺炎克雷伯菌的基因型和耐药性分析

目的研究我院住院患儿分离产ESBLs大肠埃希菌及肺炎克雷伯菌的基因型及其相关耐药性分析。方法收集2004年10月-2005年10月我院住院患儿呼吸道分离产ESBLs大肠埃希菌75株，肺炎克雷伯菌45株，PCR限制性片段长度多态性（RFLP）分析及PCR产物克隆测序等方法明确ESBLs基因型，并结合体外抗生素敏感试验研究基因分型与细菌对不同头孢菌素及氨曲南的敏感性的关系。结果上述120株细菌中112株（93．3％）产CTX—M型p内酰胺酶；未能扩增出SHV型、TEM型ESBL基因。CTX—M型基因亚型主要为CTX—M9簇中的CTX—M-14型（78、6％），其次为CTX—M-1簇中的CTX—M-3型（19．6％），仅有1．8％为CTX—M-8型；携带CTX-M-1簇的菌株对头孢他啶、头孢哌酮-舒巴坦、阿莫西林-克拉维酸、头孢吡肟及氨曲南的耐药率均明显高于CTX—M-9型。结论CTX—M基因型为武汉地区儿童分离大肠埃希菌以及肺炎克雷伯菌中最常见的ESBLs，CTX—M-14为最常见基因型，其次为CTX—M-3型；CTX—M-9簇及CTX-M-1簇对头孢他啶、头孢吡肟、头孢哌酮-舒巴坦和氨曲南的水解能力差异明显。     

全自动微生物鉴定药敏分析仪对临床相关细菌药敏测定能力的评估

目的评估Vitek 2 Compact全自动微生物鉴定药敏分析仪对临床相关革兰阴性菌和革兰阳性菌的药敏测定能力。方法选取89株北京协和医院临床菌株（革兰阴性菌48株，革兰阳性菌41株）和66株本实验室保存的参考菌株（革兰阴性菌41株，革兰阳性菌25株）为评估菌株，分别采用Vitek 2 Compact AST-GN09（革兰阴性菌）、AST-P536（葡萄球菌）、AST-P534（肠球菌和无乳链球菌）和AST-P533（肺炎链球菌）药敏卡进行药敏测定，测定结果与参考方法Etest结果进行对照。32株以CLSI纸片确证法检测为ESBL阳性的菌株（其中包括16株经PCR扩增测序确定产SHV或CTX-M型ESBLs的菌株），以Vitek 2 Compact检测其是否产ESBLs。结果根据临床和实验室标准协会（CLSI）规定的药敏折点，对Vitek 2 Compact和Etest法测得的药敏结果进行解释，在全部的1626株细菌一抗生素组合中，Vitek 2 Compact药敏测定的标准符合率（CA）为90．83％，严重错误（VME）为4．91％，重大错误（ME）为2．09％，一般错误（MIE）为6．40％。90％以上的肠杆菌科菌、非发酵糖菌、微球菌科菌和链球菌科菌分别在11、13、11和12h内完成测定。32株ESBL阳性菌以Vitek 2 Compact检测均为阳性。结论Vitek 2 Compact能够对临床相关革兰阴性菌和革兰阳性菌的药物敏感性进行准确、快速的测定，对ESBLs检测的敏感性、特异性高，是临床微生物实验室的有利工具。     

产超广谱β-内酰胺酶革兰阴性杆菌的检测

目的研究大肠埃希菌、肺炎克雷伯菌和阴沟肠杆菌产超广谱β-内酰胺酶情况及耐药谱。方法收集2002年8月至2003年6月间从嘉善县第一人民医院分离的167株大肠埃希菌、154株肺炎克雷伯菌和67株阴沟肠杆菌，用头孢噻肟或头孢他啶药敏纸片筛选产ESBLs可疑株；用头孢噻肟和头孢噻肟加克拉维酸或头孢他啶和头孢他啶加克拉维酸双纸片扩散法检测ESBLs；采用K-B法进行药敏试验。结果符合CTX筛选标准的有158株，符合CAZ筛选标准的有94株，两者都符合的有76株，共176株产ESBLs可疑株。CTX和CTV／CA双纸片检出115株阳性，CAZ和CAZ／CA双纸片检出62株阳性，两种双纸片法都为阳性的有51株，共检出126株产ESBLs菌株。大肠埃希菌、肺炎克雷伯菌和阴沟肠杆菌的ESBLs检出率分别为30%（50／167）、34％（52／156）和36％（24／67）。产ESBLs株对氨苄西林、阿齐霉素和克林霉素的耐药率近乎100％，对阿米卡星、环丙沙星和呋喃妥因的耐药相对较低，除2株产ESBLs肺炎克雷伯菌耐亚胺培南外，其余均为敏感。结论大肠埃希菌、肺炎克雷伯菌和阴沟肠杆菌的产ESBLs率较高，耐药性严重。筛选产ESBLs可疑株的最佳纸片为CTX，表型确证产ESBLs菌株的最佳双纸片为CTX和CTX／CA，阴沟肠杆菌的产ESBLs率超过肺炎克伯菌成为主要产ESBLs菌。     

产超广谱β内酰胺酶49株细菌耐药基因调查

目的 了解49株产超广谱β内酰胺酶（ESBLs）细菌的耐药基因。方法 采用纸片扩散法检测产ESBLs细菌，通过基因扩增、序列分析、脉冲场凝胶电泳技术研究ESBLs基因型以及产ESBLs细菌同源性。结果 产ESBLs大肠埃希菌、肺炎克雷伯菌、产酸克雷伯菌流行率自2000年的20％，增长至2003年的40％。49株产ESBLs细菌中，以CTX-M-14（n=33）亚型最常见，其他亚型包括CTX-M-3、CTX-M-9、CTX-M-12、CTX-M-15、CTX-M-24、SHV-5a，1株细菌同时产CTX—M-3、CTX—M-14两种CTX-M型ESBLs；4株表型确证试验阳性细菌未能分型。除2株大肠埃希菌、2株肺炎克雷伯菌有亲缘性外，其他菌株间无同源性。结论 产ESBLs细菌分离率逐年增高，以CTX—M型酶为主。PFGE试验证明非流行所致。     

临床分离阴沟肠杆菌产超广谱β-内酰胺酶及其基因分析

目的探讨临床分离阴沟肠杆菌对β内酰胺类抗生素的耐药性及其机制。方法采用κ—B法药敏试验检测临床分离阴沟肠杆菌耐药表型;双纸片确认试验和增效试验检测超广谱β-内酰胺酶（ESBLs）或／和高产AmpC酶菌株;PCR方法检测TEM-1、SHV-1、CTX—M型ESBLs编码基因,PCR产物直接测序分析其基因亚型。结果（1）被检菌株对IPM、AK、FEP、CIP耐药率分别是0．0％、14.1％、31.5％、48.4％;对其他常用β-内酰胺类抗生素、CN、SXT等耐药率在50.0％～90.0％以上;（2）88．1％菌株高产AmpC酶或／和产ESBLs;高产AmpC酶、单产ESBLs、同时产AmpC酶和ESBLs的菌株检出率分别为27.38％、16.67％、44.05％。60.70％菌株产ESBLs。（3）TEM-1、SHV-1、CTX-M1组ESBLs编码基因检出率分别为75.00％、23.44％、77.27％。（4）基因序列分析显示存在SHV-12、CTX-M 3.9a、14、22等ESBLs编码基因,以SHV-12、CTX—M14、22为主。结论临床分离阴沟肠杆菌多重耐药严重,对β内酰胺类抗生素的耐药机制复杂,ESBLs编码基因亚型以SHV-12、CTX—M14、22为主。     

产酸克雷伯菌超广谱β内酰胺酶与AmpC酶耐药表型及基因型分析

目的了解呼吸道感染患儿产酸克雷伯菌超广谱β内酰胺酶（ESBLs）与AmpC酶的耐药表型和基因型。方法采用API及VITEK32鉴定菌株；琼脂稀释法检测MIC值；CLSI纸片确认实验检测ESBLs，3-氨基苯酚硼酸（APB）纸片增强法检测AmpC酶；基因芯片技术检测ESBLs与AmpC酶的基因型；并进行肠杆菌基因间共有重复序列（Enterobacterial repetitive intergenic consensus，ERIC）分型。结果165株产酸克雷伯菌ESBLs阳性129株（78．2％），ESBLs与AmpC酶同时阳性16株（9．7％），表型及基因型均未检出AmpC单独阳性株；CTX-M型是其主要基因型（89／109），产AmpC酶株的基因型仅见DHA型；ERIC分型显示多数耐药产酸克雷伯菌具有相同的分子型。产酸克雷伯菌的产酶株及非产酶株对碳青霉烯类100％敏感，但产酶株（尤其是同时产ESBLs与AmpC酶）比非产酶株耐药率高，多重耐药性更常见。结论儿童患者中产酸克雷伯菌产ESBLs分离率较高；ESBLs与AmpC酶的耐药基因型分别主要是CTX-M型和DHA型。     

Rapid dissemination and diversity of CTX-M extended-spectrum beta-lactamase genes in commensal Escherichia coli isolates from healthy children from low-resource settings in Latin America

A survey carried out in 2005 among members of a healthy population of children living in Bolivia and Peru revealed that fecal carriage of Escherichia coli strains resistant to expanded-spectrum cephalosporins was remarkably increased compared to that observed in the same settings in 2002 (1.7% in 2005 versus 0.1% in 2002). In this work, we demonstrated that this phenomenon was mainly related to the dissemination of CTX-M-type extended-spectrum beta-lactamase (ESBL) determinants among commensal E. coli strains. Of 50 ESBL-producing isolates collected in the 2005 survey, 44 harbored a CTX-M-type and 6 an SHV-type (SHV-2 or SHV-12) ESBL. Compared to 2002 results, an increased diversity of CTX-M-type ESBLs was also observed: members of the CTX-M-1 group (CTX-M-15) emerged in Bolivia (where only CTX-M-2 was observed in 2002), while members of the CTX-M-9 group (CTX-M-14 and CTX-M-24) emerged in Peru (where only CTX-M-15 and CTX-M-2 were observed in 2002). A new CTX-M-2 variant named CTX-M-56 was also detected. Molecular characterization of the CTX-M-producing isolates and gene transfer experiments suggested that different mechanisms could be involved in the spreading of different CTX-M group determinants and revealed that additional resistance determinants for non-beta-lactam antibiotics were preferentially carried by plasmids encoding certain CTX-M variants (CTX-M-15 and variants of the CTX-M-2 group). Three CTX-M-15-encoding conjugative plasmids from Peruvian isolates carried the new fluoroquinolone resistance gene aac(6')-Ib-cr. To our best knowledge, this is the first report of the detection of aac(6')-Ib-cr in Latin America.     

产超广谱β-内酰胺酶菌株所致医院获得性泌尿道感染的调查与危险因素分析

目的了解致医院获得性泌尿道感染（HAUTI）的革兰阴性杆菌的分布特点及产超广谱β-内酰胺酶（ESBLs）菌株的耐药性现状,并对产ESBLs菌株所致HAUTI的危险因素进行分析。方法收集2007年1月至2008年12月发生院内革兰阴性菌HAUTI的住院病例共299例,对所采集的革兰阴性菌株进行鉴定,并用纸片琼脂扩散法检测所有革兰阴性菌株的药物敏感性,采用双纸片协同试验进行ESBLs表型确证。结合患者的临床资料进行多因素Logistic回归分析产ESBLs菌株致HAUTI的危险因素。结果 299株病原菌中大肠埃希菌分离率最高（60.87%）,其次为铜绿假单胞菌（16.39%）、肺炎克雷伯菌（15.72%）,299株革兰阴性菌中共检出产ESBLs菌株144株（48.16%）,全部为大肠埃希菌和肺炎克雷伯菌,大肠埃希菌和肺炎克雷伯菌中产ESBLs检出率分别为63.19%和61.70%。产酶菌株对多种抗菌药物的耐药率明显高于非产酶菌株;入住重症监护病房（ICU）、前期第3代头孢菌素类抗菌药物的使用和留置尿管是独立的院内产ESBLs细菌感染的危险因素[比值比（OR）分别为0.07、0.14、4.87,P〈0.001]。结论致HAUTI革兰阴性菌中产ESBLs菌株占据较高比例,与不产酶菌株相比,其对大多数抗菌药物均呈不同程度耐药。因此严格把握入住ICU、第3代头孢菌素及留置尿管使用指征,对防止产ESBLs菌株所致HAUTI具有突出的临床意义。     

Dissemination of extended-spectrum β-lactamase-producing <Emphasis Type="Italic">Klebsiella pneumoniae</Emphasis> and <Emphasis Type="Italic">Escherichia coli</Emphasis> in Thai hospitals

Fifty clinical isolates of Klebsiella pneumoniae and Escherichia coli with reduced susceptibility to third-generation cephalosporins, collected from 11 hospitals in Thailand, were studied. All isolates were found to produce extended-spectrum β-lactamase (ESBL), as judged by double-disk synergy and combination disk methods. Most ESBL-producing K. pneumoniae isolates were resistant to ceftazidime (94%) and aztreonam (90%). In contrast, most ESBL-producing E. coli isolates were resistant to ceftriaxone (95%) and cefotaxime (74%). Plasmid DNA was isolated and β-lactamase genes were identified by PCR and sequencing. We found that SHV-12 and CTX-M-14 were the main ESBLs responsible for resistance in K. pneumoniae and E. coli, respectively. SHV-27, SHV-28, and CTX-M-14 were detected in three, two, and four K. pneumoniae isolates, respectively. A high genetic diversity among ESBL-producing K. pneumoniae and E. coli isolates was observed. In addition, the finding of a few isolates that produced identical restriction patterns on pulsed field gel electrophoresis (PFGE) suggests the clonal spread of resistant bacteria within the hospital.     

抗菌药物对产超广谱β内酰胺酶大肠埃希菌和肺炎克雷伯菌接种效应的研究

目的研究美罗培南、头孢米诺、哌拉西林-他唑巴坦、头孢吡肟、头孢他啶、头孢噻肟和头孢曲松7种常见抗生素对产ESBLs大肠埃希菌和肺炎克雷伯菌的接种效应。方法用微量肉汤稀释法测定7种抗生素对22株产ESBLs大肠埃希菌和肺炎克雷伯菌在标准细菌接种量(5×10~5CFU/mL)和高接种菌量(5×10~7CFU/mL)时的MIC。结果随着接种菌量增加,美罗培南和头孢米诺对所有受试菌株的MIC无接种效应;哌拉西林-他唑巴坦对SHV-12型和1株CTX-M-14菌的MIC表现出接种效应;头孢吡肟、头孢他啶、头孢噻肟和头孢曲松存在接种效应的菌种分别占所有受试菌株的86.4%(19/22)、40.9%(9/22)、10%(22/22)和100%(22/22)。结论对22株产ESBLs大肠埃希菌和肺炎克雷伯菌,美罗培南和头孢米诺不存在接种效应,哌拉西林-他唑巴坦对部分基因型ESBLs菌株(SHV-12型和1株CTX-M-14菌株)存在接种效应,头孢吡肟、头孢他啶、头孢噻肟和头孢曲松存在接种效应。     

产超广谱β-内酰胺酶的大肠埃希菌和肺炎克雷伯菌临床分布及耐药性分析

目的调查分析院内产超广谱β-内酰胺酶(ESBLs)的大肠埃希菌、肺炎克雷伯菌临床分布及耐药情况。方法收集浏阳市中医医院2007年1月至2010年1月临床分离到的大肠埃希菌401株和肺炎克雷伯菌319株,采用纸片扩散法(K-B)对分离株进行抗菌药物敏感试验和ESBLs筛选和确证试验,并对其临床分布及耐药情况进行统计分析。结果 720株大肠埃希菌和肺炎克雷伯菌中,产超广谱β-内酰胺酶阳性率为37.9%;其中大肠埃希菌阳性率为42.1%;肺炎克雷伯菌阳性率为32.6%。产超广谱β-内酰胺酶大肠埃希菌和肺炎克雷伯菌均对第3代头孢菌素和单环β-酰胺类抗菌药物呈现高度耐药性,对氨基糖苷类、氟喹诺酮类、磺胺类抗菌药物也存在较高耐药性,但是对亚胺培南敏感。结论该院大肠埃希菌和肺炎克雷伯菌ESBLs的检出率高并呈多重耐药性,这些产ESBLs菌分布在不同病区的各种标本中,临床应及时掌握它们的临床分布及耐药特点,合理的应用抗菌药物、控制ESBLs菌株的传播和流行。     

多重PCR检测临床产ESBLs阴沟肠杆菌的耐药基因型研究

目的了解产超广谱β-内酰胺酶(ESBLs)阴沟肠杆菌的耐药性、阳性率及基因分布特点。方法改良双纸片法检测80株临床分离阴沟肠杆菌对14种抗生素的耐药性及ESBLs表型,多重PCR检测鉴定ESBLs基因型,DNA测序确认DNA序列。结果 80株阴沟肠杆菌中,29株检出ESBLs,阳性率36.3%。80株阴沟肠杆菌对亚胺培南全部敏感,产ESBLs的阴沟肠杆菌对头孢唑啉、头孢噻肟、头孢曲松、头孢哌酮、头孢他啶等头孢菌素类抗生素的耐药率高达96.1%。29株细菌所产ESBLs中,12株为TEM型,6株为SHV型,24株为CTX-M型。其中CTX-M-1组9株,CTX-M-9组15株,未检出CTX-M-2组及CTX-M-8/CTX-M-25组。结论阴沟肠杆菌ESBLs检出率较高,耐药显著。产ESBLs阴沟肠杆菌的主要基因型为CTX-M型。     

High diversity of extended-spectrum beta-lactamases among clinical isolates of Enterobacteriaceae from Portugal

OBJECTIVES: To investigate the occurrence and the diversity of Ambler class A ESBLs among Enterobacteriaceae from different Portuguese clinical settings over a 2 year period (2002-04). METHODS: One hundred and nine extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae isolates from five geographically distant health institutions in Portugal were studied. ESBLs were characterized by isoelectric focussing, PCR and further sequencing. Antibiotic susceptibility testing, transfer of resistance genes and clonal diversity were determined by standard procedures. Plasmid relatedness was established by comparison of random amplified polymorphic DNA (RAPD) patterns. RESULTS: ESBLs were identified as TEM (46%), SHV (30%), CTX-M (22%) and GES (2%) types; TEM-24, TEM-52, SHV-12 and CTX-M-15 enzymes being the most frequently found. Inter-hospital dissemination of epidemic strains harbouring the most prevalent ESBLs was detected, including the TEM-24-producing Enterobacter aerogenes European epidemic clone. Conjugative transfer of ESBLs was achieved for 67% of isolates and epidemic plasmids containing specific bla genes were detected (bla(CTX-M-15) and bla(TEM-24)). We describe two new ESBLs, SHV-90 (A187T, G238S and E240K) and SHV-91 (P20S and E240K), and a new TEM-type enzyme conferring a phenotype resembling that of a complex mutant TEM beta-lactamase, designated as TEM-154 (M69L and R164S). The broad-spectrum beta-lactamases SHV-26, SHV-36 and TEM-110 were first observed in our country. CONCLUSIONS: We describe a complex ESBL epidemiology in Portugal, including widespread dissemination of known strains and plasmids coding for TEM-24 and CTX-M-15 enzymes as observed in other European countries.     

Frequency and diversity of Class A extended-spectrum beta-lactamases in hospitals of the Auvergne, France: a 2 year prospective study

OBJECTIVES: To evaluate the frequency and diversity of extended-spectrum beta-lactamases (ESBLs) produced by Enterobacteriaceae and Pseudomonas aeruginosa in one French region. METHODS: During 2001-2002, all the non-duplicate isolates of P. aeruginosa resistant to ceftazidime and of Enterobacteriaceae intermediate or resistant to ceftazidime and/or cefotaxime and/or aminoglycosides with an AAC(6') I phenotype were collected in nine hospitals of the area. ESBL isoelectric points were determined, bla genes were amplified and sequenced and epidemic isolates were genotyped with ERIC2-PCR. RESULTS: ESBLs were observed in 297 Enterobacteriaceae (0.8%). The most frequent were TEM-3 like (n=152; 51.2%) and TEM-24 (n=115; 38.7%). Four new enzymes were observed, TEM-112 (pI 5.4), TEM-113 (pI 6.3), TEM-114 (pI 5.9) and TEM-126 (pI 5.4). Other TEMs were TEM-8, TEM-12, TEM-16, TEM-19, TEM-20, TEM-21, TEM-29 and TEM-71. The other ESBLs were SHV-4, SHV-5 and SHV-12, CTX-M-1, CTX-M-3, CTX-M-14 and CTX-M-15. In 37 P. aeruginosa (0.7%) only one ESBL was observed, PER-1. Five epidemic strains were detected, Serratia marcescens TEM-3 and four observed in several hospitals, Enterobacter aerogenes TEM-24, Citrobacter koseri TEM-3, Proteus mirabilis TEM-3 and P. aeruginosa PER-1. CONCLUSION: ESBL frequency was lower than in 1998, and CTX-M-type frequency higher (2.1% of ESBLs in 2001, 4.9% in 2002). This long-term survey detected new sporadic enzymes (TEM-112, TEM-113, TEM-114 and TEM-126) and interhospital epidemic strains while avoiding any overestimation of ESBL frequency that may otherwise have occurred because of acute epidemics.     

质粒介导的志贺菌产超广谱β内酰胺酶及其耐药基因型

目的 探讨产生超广谱β内酰胺酶(ESBLs)志贺菌的特性及与耐药质粒的关系.方法 用K-B法做药敏试验并筛选可疑产ESBLs志贺菌株;ESBLs表型确证试验检测可疑产ESBIs志贺菌;采用TEM、SHV、CTX-M-1组、CTX-M-2组、CTX-M-9组β内酰胺酶通用引物进行PCR检测,TEM、CTX-M-9组全编码基因引物进行PCR测定,对扩增产物进行DNA序列分析;对产ESBLs志贺菌进行接合传递试验,供体菌和接合子用稀释法进行MIC测定.结果 在275株志贺菌中有12株为产ESBLs志贺菌,其中8株志贺菌基因型为CTX-M-14型,4株为CTX-M-3型;产ESBLs志贺菌接合传递试验全部阳性,其接合子只对β内酰胺类抗生素耐药.结论 本地区志贺菌对β内酰胺类抗生素的严重交叉耐药是由ESBLs所致,产ESBLs志贺菌可通过质粒传递耐药性.