吉林地区大肠埃希菌和肺炎克雷伯菌ESBLs的基因分型

目的对产超广谱β-内酰胺酶(ESBLs)的大肠埃希菌和肺炎克雷伯菌携带的ESBLs耐药基因进行分型,为临床合理应用抗生素提供理论依据。方法收集住院患者标本中分离出的51株大肠埃希菌和32株肺炎克雷伯菌,经PCR对上述菌株所携带的ESBLs耐药基因进行分型。结果产ESBLs大肠埃希菌中耐药质粒编码TEM型、SHV型和非TEM非SHV型超广谱β-内酰胺酶基因的百分率依次为80.4%,7.8%和11.8%;而在肺炎克雷伯菌中的百分率依次为78.1%,71.9%和25.0%。多数产ESBLs肺炎克雷伯菌同时产生一种以上的β-内酰胺酶。结论获得了吉林地区大肠埃希菌和肺炎克雷伯菌ESBLs的不同基因型,ESBLs基因型具有地区性差异。     

深圳市大肠埃希菌超广谱β-内酰胺酶的基因分型

目的分析深圳市大肠埃希菌超广谱β-内酰胺酶（ESBLs）的主要基因型。方法对50株产ESBLs大肠埃希菌分别用TEM、SHV、CTX-M和OXA-1群基因引物进行PCR扩增,并对PCR产物进行序列分析。结果 92%菌株检出CTX-M型ESBLs,测序结果显示,以CTX-M-14型ESBLs为主,其次为CTX-M-55型。结论 CTX-M-14型和CTX-M-55型是深圳地区大肠埃希菌ESBLs的主要基因型。     

华南地区质粒介导超广谱β-内酰胺酶的基因分型研究

目的：了解华南地区质粒介导超广谱β－内酰胺酶（ESBLs）的发生率及基因型特征。方法：收集2001年4月－9月革兰阴性菌临床分离无重复株共1184株，采用NCCLS表型筛选和确认试验进行了ESBLs产酶的识别，E-test法检测各亚型ESBLs的MICs值，质粒接合及电转化实验，耐药质粒提取及酶切指纹分析，等电聚焦电泳，PCR通用引物扩增TEM、SHV、CTX－M、VEB、PER、SFO基因及其克隆测序进行ESBLs基因分型和质粒定位。结果：革兰阴性苗ESBLs的检出率为14．6％（173／1184）；获得产ESBLs接合子67株，电转化子11株，其中产CTX－M－14型ESBLs为33．3％（26／78）、CTX－M－3为23．1％（18／78）、CTX－M－9为14．1％（11／78）及SHV-2a为2．6％（2／78），未定型为5．1％（4／78）；29．5％（23／78）野生株伴广谱酶TEM－1或SHV－1型；各型ESBLs基因约定位在35－190kb大小的可接合性低执行者拷贝数天然质粒上；CTX－M型ESBLs以对头孢噻肟高水平高耐为特征。结论：华南地区质粒介导的ESBLs以CTX－M型衍生酶为主，其次是SHV型酶。     

儿科产超广谱β-内酰胺酶志贺菌的基因型和耐药性研究

目的 探讨儿科临床分离志贺菌产超广谱β-内酰胺酶(ESBLs)的基因型及其耐药特点.方法 收集2004年1月至2008年12月北京儿童医院细菌性痢疾住院患儿粪便标本中分离出志贺菌共59株,按照美国临床和实验室标准协会推荐的表型确证试验检测ESBLs,用琼脂稀释法进行最低抑菌浓度(MIC)测定,对产ESBLs菌株进行PCR扩增明确其基因型,对扩增产物进行DNA序列分析确定基因亚型.结果 59株志贺菌中共检出产ESBLs者21株,占35.6%.21株产ESBLs志贺菌PCR均扩增到CTX-M型ESBLs,包括CTX-M-1型6株,CTX-M-9型15株,其中有4株同时伴有TEM型酶,6株伴有OXA型酶.DNA序列分析证实6株CTX-M-1型分别为CTX-M-3亚型(1株)、CTX-M-15亚型(2株)、CTX-M-57亚型(3株),15株CTX-M-9型均为CTX-M-14亚型,伴随存在的TEM型及OXA型耐药基因分别为TEM-1型广谱酶、OXA-1型广谱酶.药敏结果显示对产ESBLs菌株敏感性较好的抗生素有亚胺培南、美罗培南、哌拉西林/他唑巴坦、头孢哌酮/舒巴坦和头孢西丁,其耐药率均小于15%.产不同CTX-M基因亚型的菌株对头孢他啶的耐药性不同.结论 本地区儿科分离志贺菌产ESBLs阳性率高,均为CTX-M型,其中以CTX-M-14亚型为主,少部分为CTX-M-3、CTX-M-15和CTX-M-57亚型.大部分产ESBLs菌株呈多重耐药,碳青霉烯类抗生素应作为治疗产ESBLs志贺菌的首选.     

焦磷酸测序检测铜绿假单胞菌的SHV基因点突变

目的:通过焦磷酸测序技术检测产超广谱β-内酰胺酶(ESBLs)铜绿假单胞菌的SHV基因点突变,探讨一种快速、准确的ESBLs基因分型方法。方法:双纸片法确定产ESBLs的铜绿假单胞菌,纸片扩散法(K-B法)进行药敏试验,聚合酶链反应(PCR)法扩增ESBLs的SHV基因片段,用焦磷酸测序法检测16株产ESBLs铜绿假单胞菌的SHV基因35位和43位密码子点突变。结果:焦磷酸测序发现,本地区分离出的16株产ESBLs铜绿假单胞菌有10株扩增出SHV基因片段,且在43位密码子基因没有突变,35位密码子有基因突变,核苷酸由T突变为A,亮氨酸变为谷氨酰胺,突变发生率达到70%(7/10)。16株产ESBLs的菌株对亚胺培南全部敏感。结论:焦磷酸测序技术可快速检测产ESBLs铜绿假单胞菌的SHV基因点突变,具有准确、快速、实时和高通量等优点,可应用于产ESBLs菌株的ESBLs基因分型。     

肠杆菌科产CTX-M酶细菌耐药性与β-内酰胺酶基因型的关系

目的 :了解我院肠杆菌科产CTX M酶细菌耐药性与 β 内酰胺酶基因型的关系。方法 :对 2 0 0 1年 1 0月～ 2 0 0 2年 5月我院临床分离的 4 0株产ESBLs肠杆菌科细菌琼脂对倍稀释法测定 1 0种抗菌药物的最低抑菌浓度 :用针对SHV、TEM、CTX N基因的特异性引物进行PCR扩增确定 β 内酰胺酶基因型 :对扩增的CTX M基因进行DNA序列分析。结果 :产CTX M酶菌中有 93～ 75 %产 2种或 2种以上 β 内酰胺酶。产CTX M酶菌株多重耐药率为 1 0 0 % ,对头孢噻肟、头孢吡肟、头孢他啶、头孢哌酮 /舒巴坦的耐药率分别为 81 .2 5 %、75 %、31 .2 5…     

产超广谱β—内酰胺酶菌表型和TEM基因型配对检测的研究

对临床分离的13株产超广谱β-内酰胺酶菌进行表型和TEM基因型配对检测的研究。结果发现该13株菌对氨苄西林,头孢噻吩,头孢唑啉,头孢呋新均表现为耐药;部分菌对头孢他啶,头孢噻肟和氨基糖苷类,环丙沙星表现为耐药,但该13株菌对亚胺培南均表现为敏感。13株菌经TEM基因套式PCR检测均呈阳性,表明该13株菌至少存在TEM型质粒,该13株菌TEM亚型分型和是否同时存在SHV型质粒等仍在研究中。     

革兰阴性菌对头孢替坦的耐药性分析

目的了解临床分离革兰阴性菌对头孢替坦的耐药性。方法收集2012年1月至2013年6月从医院各种临床标本中分离的革兰阴性菌,使用VITEK2-compact微生物全自动分析仪进行鉴定和药敏试验,对结果进行回顾性调查。结果分离出革兰阴性菌1 045株,其中肠杆菌科细菌627株,占60.0%;非发酵菌402株,占38.5%。分离前3位的细菌分别为大肠埃希菌（27.7%）、铜绿假单胞菌（20.2%）、肺炎克雷伯菌（14.5%）。肠杆菌科细菌对头孢替坦耐药率低,53.3%的大肠埃希菌和29.6%的肺炎克雷伯菌产超广谱β-内酰胺酶（ESBLs）、产ESBLs大肠埃希菌和肺炎克雷伯菌对头孢替坦耐药率均低于6.0%。非发酵菌中铜绿假单胞菌和鲍曼不动杆菌对头孢替坦的耐药率均高于90.0%。结论头孢替坦可以作为临床治疗产ESBLs细菌感染性疾病的一种经验性治疗方案。     

与植入物感染相关大肠埃希菌的耐药特征

背景:生物材料植入人体后,往往会发生感染引起植入物松动、脱落甚至造成菌血症。以往研究未注重植入物相关感染中的细菌耐药性问题。目的:了解与植入物感染相关大肠埃希菌的耐药特征,为预防和更有效治疗该类感染提供策略。方法:以大肠埃希菌ATCC25922、金黄色葡萄球菌ATCC25923和铜绿假单胞菌ATCC27853为质控菌株,选取17种临床常用抗生素进行药敏试验,计算耐药率,分析耐药特征。用表型确证试验筛选产AmpC酶和产ESBLs菌株,明确产酶率。抽提耐药质粒,以聚合酶链反应扩增检测耐药基因,分析基因型分布情况。结果与结论:17种抗生素中耐药率最低的是亚胺培南,其次为阿米卡星、头孢哌酮/舒巴坦、哌拉西林/他唑巴坦和头孢吡肟,大部分菌株对其他抗生素均有较高耐药率,且呈多重耐药。筛选出42株(61.8%)产ESBLs菌株和27株(39.7%)产AmpC酶菌株,同时产ESBLs和AmpC酶菌株有23株(33.8%)。产ESBLs菌株中以携带CTX-M型基因最为多见占66.7%,有19株(45.2%)同时携带两种以上基因,产AmpC酶中大多数是产DHA型,有5株(18.5%)同时携带两种基因。提示与植入物感染相关的大肠埃希菌菌株耐药水平高、耐药谱扩大,且多呈多重耐药,耐药基因复杂多样。建议使用敏感药物联合阿米卡星治疗该类感染。     

产质粒介导AmpC酶和ESBLs细菌的耐药性及β-内酰胺酶基因型研究

目的　了解我院同时产质粒介导AmpC酶和超广谱 β 内酰胺酶 (ESBLs)肺炎克雷伯菌与大肠埃希菌的耐药性及其 β 内酰胺酶的基因型特征。方法　 110株临床分离无重复肺炎克雷伯菌与大肠埃希菌耐药株 ,采用酶提取物三维实验检测AmpC酶 ,美国临床实验室标准委员会 (NCCLS)表型筛选和确认实验检测ESBLs ;琼脂二倍稀释法测定抗生素对同时产AmpC酶和ESBLs菌株的最低抑菌浓度 (MICs) ;等电聚焦实验测定 β 内酰胺酶等电点 (pIs) ;质粒接合实验定位耐药基因 ;PCR通用引物扩增AmpC酶与ESBLs基因及其序列测定以确定其基因亚型。结果　同时产AmpC酶和ESBLs菌株在肺炎克雷伯菌与大肠埃希菌中的检出率分别为 7.7% (5 6 5 )、8.9% (4 4 5 )。该类产酶菌株产 2～ 3种pI5 .4～ 9.0 β 内酰胺酶 ,对第三代头孢菌素、氨曲南、头孢美唑和含酶抑制剂复合制剂的敏感性极低 ,但对亚胺培南均敏感。 9株质粒中均检出AmpC酶基因DHA 1亚型 ,其中 1株同时检出ACT 1亚型 ;ESBLs基因亚型分别为CTX M 14、CTX M 3、CTX M 9,各有 4、3、2株 ;有 3株还携带广谱酶TEM 1基因。结论　我院存在同时产质粒介导DHA 1、ACT 1型AmpC酶和CTX M型ESBLs肺炎克雷伯菌、大肠埃希菌流行株 ,药敏检测结果显示对大多数新型广谱 β 内酰胺类抗生     

Multiplex PCR amplification assay for the detection of blaSHV, blaTEM and blaCTX-M genes in Enterobacteriaceae

Extended-spectrum beta-lactamases (ESBLs) are often mediated by (bla-)SHV, (bla)TEM and (bla)CTX-M genes in Enterobacteriaceae and other Gram-negative bacteria. Numerous molecular typing methods, including PCR-based assays, have been developed for their identification. To reduce the number of PCR amplifications needed we have developed a multiplex PCR assay which detects and discriminates between (bla-)SHV, (bla)TEM and (bla)CTX-M PCR amplicons of 747, 445 and 593 bp, respectively. This multiplex PCR assay allowed the identification of (bla-)SHV, (bla)TEM and (bla)CTX-M genes in a series of clinical isolates of Enterobacteriaceae with previously characterised ESBL phenotype. The presence of (bla)SHV, (bla)TEM and (bla)CTX-M genes was confirmed by partial DNA sequence analysis. Apparently, the universal well-established CTX-M primer pair used here to reveal plasmid-encoded (bla)CTX-M genes would also amplify the chromosomally located K-1 enzyme gene in all Klebsiella oxytoca strains included in the study.     

CTX-M型超广谱β-内酰胺酶基因在头孢他啶诱导的阴沟肠杆菌中的表达

目的 对比临床耐药株与经头孢他啶诱导形成的耐药株(诱导耐药株)CTX-M型超广谱β-内酰胺酶(ESBL)基因在阴沟肠杆菌中的表达情况.方法 取临床分离的对头孢他啶敏感的10株阴沟肠杆菌,应用不同浓度梯度头孢他啶[1/2×最小抑菌浓度(MIC)、1× MIC、2×MIC、4×MIC并呈倍数到128 mg/L]逐级诱导并使其成为耐药株.分别培养诱导耐药株及临床敏感株、临床耐药株各10株,并提取其DNA.采用PCR检测诱导耐药株及临床敏感株、临床耐药株CTX-M型ESBL基因的表达情况.结果 成功诱导出对头孢他啶耐药的阴沟肠杆菌形成诱导耐药株.PCR结果显示在10株诱导耐药株中,有5株表达CTX-M型ESBL基因,可见约900 bp的条带形成;在10株临床耐药株中,则有4株可见约900 bp的条带形成;在10株临床敏感株中则未见此条带形成.结论 头孢他啶可以诱导CTX-M型ESBL基因的表达,临床头孢他啶的不合理使用可能是诱导其产生的重要原因之一.     

Molecular characteristics of extended-spectrum beta-lactamases among gram-negative isolates collected in Cairo University Hospital

Phenotyping is commonly used for detection of extended-spectrum beta-lactamase (ESBL) production in gram-negative isolates. ESBLs are mainly coded for by four important genes, namely bla (TEM), bla (SHV), bla (CTX-M), and bla (OXA). Our aim in this study is to assess use of a multiplex PCR as a rapid method to identify four common genes responsible for ESBL production in different gram-negative isolates. All 793 clinical isolates are subjected to both screen and confirmatory testing for ESBL production using double disc synergy testing (DDST). Two hundred isolates with the ESBL phenotype are subjected to multiplex PCR for detection of the four genes bla (TEM, SHV, CTX-M, and OXA). The isolates were obtained from various clinical specimens: 68 (34 %) were isolated from urine cultures, 43 (21.5 %) from sputum, 26 (13 %) from wounds, 34 (17 %) from blood culture, 20 (10 %) from stool of healthy carrier and nine (4.5 %) from bronchoalveolar lavages. In this study, 83 isolates (41.5 %) were from outpatients (urine and stool specimens only), and the remaining 117 isolates (58.5) were from inpatients. By PCR technique, 181 isolates were found to be ESBL producers. blaTEM was the commonest genotype (39.2 %), followed by blaSHV (32.5 %) and blaCTX-M (30.9 %), either alone or in combination. Acinetobacter baumannii isolate had none of the ESBL genes. Eighteen (9.9 %) out of 181 isolates carried more than one type of beta-lactamase genes. Our study demonstrated rapid detection of bla (TEM, SHV, CTX-M, and OXA) in isolates belonging to Enterobacteriaceae and other nonfermenting clinical isolates using multiplex PCR. This genotypic method provided a rapid and efficient differentiation of ESBLs in the laboratory.     

Prevalence of extended-spectrum β-lactamases in isolates of the Enterobacter cloacae complex from German hospitals

In 2002, 119 isolates of the Enterobacter cloacae complex were collected randomly from 11 German laboratories nationwide. Antibiotic susceptibilities were tested by disk-diffusion tests according to CLSI guidelines, and MICs were determined using Etests. PCRs were performed to amplify all TEM and SHV, and most CTX-M and OXA beta-lactamase genes. PCR products were sequenced to identify the precise extended spectrum beta-lactamase (ESBL) types. Isoelectric focusing (IEF) and PM/PML Etests were used to confirm production of the respective ESBLs. According to susceptibility tests and CLSI criteria, 49 (40%) isolates were resistant to extended-spectrum cephalosporins. Seven (5.8%) isolates were positive in at least one of the PCR assays. Sequencing identified production of TEM-1 beta-lactamase genes by three (2.9%) isolates, and ESBL genes of the CTX-M and SHV beta-lactamase families by five (4.2%) isolates. IEF confirmed the production of beta-lactamases in the expected pI ranges of the respective ESBLs, and four of the five ESBL-producers were detected using the PM/PML Etest. All ESBL-producing isolates showed co-resistance to sulphonamides.     

Recent evolution and characterization of extended-spectrum beta-lactamase producing enterobacteria in the CHU of Nice (2005-2007)

AIM OF THE STUDY: ESBL producing enterobacteria (E-ESBL+) are always a public health concern, mainly due to increase of CTX-M beta-lactamase. So, 542 new strains were isolated in the CHU de Nice during the 2005-2007 period. The aim of this work was to characterize the ESBL and to type isolates suspected to be implicated in outbreaks. METHODS: Every first E-ESBL+ was studied, the antibiotype was defined by the agar diffusion technique. Type of ESBL was determined by PCR, followed by sequencing for CTX-M and SHV enzymes. Typing was performed when several strains of one species had same antibiotype and beta-lactamase. RESULTS: CTX-M type ESBL are predominant (45% of all E-ESBL+), mainly in Escherichia coli (34.5%). The TEM24 ESBL was the second predominant type (34.5%), mainly in Enterobacter aerogenes (18.6%) and Klebsiella pneumoniae (9.4%). SHV5/12 ESBL was found mainly in Enterobacter cloacae (7.5%). Several epidemic situations were identified, with CTX-M15 in Escherichia coli (2005/2006: 27 patients), SHV5/12 in Enterobacter cloacae (2006: 10 patients) and TEM in Proteus mirabilis (2007: nine patients). Enterobacter aerogenes is still endemic (101 patients) while an epidemic clone of TEM24 producing K. pneumoniae persists especially in an intensive care unit (26 patients during the three years). CONCLUSION: Caracterization of E-ESBL+ is essential to better understand their mode of dissemination, monitor the emergence of new enzymes and adapt the efforts against BMR cross transmission.     

Frequency of extended spectrum β-lactamase producing urinary isolates of Gram-negative bacilli among patients seen in a multispecialty hospital in Vellore district,India

Extended-spectrum beta-lactamase (ESBL) producing strains of Coliform bacilli are on the rise and present a major threat especially in India. We assessed the frequency of ESBL producers among urinary isolates from patients presenting urinary tract infections. ESBL screening was done using Double Disk Synergy Test (DDST) and confirmed using E-test and Polymerase Chain Reaction (PCR). With E-test, 92.2% were positive for ESBL. In PCR, 100% strains were positive for any of the three gene targets tested. CTX-M was positive in majority of the strains followed by TEM and SHV. Two (3.22%) strains were positive for all the three genes; 21% strains were positive for both TEM and CTX-M genes. There was no statistically significant difference in the findings of E-test and PCR testing in the determination of ESBL producers (Fisher exact test P = 0.15). The strength of agreement between them was ‘fair’ (k = 0.252). Continuous monitoring of ESBL producers among Indian strains is important to rationalize the antibiotic policy to be followed.     

下呼吸道感染产AmpC酶和超广谱β-内酰胺酶肺炎克雷伯菌耐药基因检测及亲缘性分析

分析下呼吸道感染患者气道分泌物或痰液标本分离的产AmpC酶和超广谱β-内酰胺酶(ESBL)肺炎克雷伯菌耐药基因的特点及亲缘性。方法 2009年1月至2010年8月由本院呼吸病区住院的下呼吸道感染患者气道分泌物或痰液标本分离得到53株肺炎克雷伯菌,采用K-B纸片扩散法测定其对常用抗菌药物的敏感性;三维实验检测AmpC酶;PCR检测ESBL、质粒介导的AmpC酶、喹诺酮类耐药基因、耐消毒剂-磺胺基因qacE△1-sul1、Ⅰ类整合酶基因Int Ⅰ 1的携带情况,并进行聚类分析。结果 53株肺炎克雷伯菌未发现对亚胺培南、美罗培南、厄他培南耐药;对环丙沙星、左旋氧氟沙星耐药率均＞80％;对其他抗菌药物也有不同程度的耐药。53株肺炎克雷伯菌中Int Ⅰ 1基因阳性率60.4％(32/53),qnrA基因阳性率54.7％ (29/53),qnrS基因阳性率13.2％ (7/53),qnrB基因阳性率5.7％(3/53),qacE△1-sul1基因阳性率71.7％(38/53),TEM基因阳性率92.5％ (49/53),CTX-M基因阳性率100％(53/53),SHV基因阳性率9.4％(5/53),AmpC基因阳性率92.5％(49/53);其中4株同时携带qnrA、qnrS、intⅠ 1、qacE△1-sul1、AmpC、CTX-M基因。聚类分析显示40、41、10与18号,25与42号,8与35号菌株有亲缘关系。结论 产ESBL肺炎克雷伯菌的多重耐药与整合子相关,且携带多种耐药基因,聚类分析显示存在克隆传播和医院内感染。