Prevalence characterization of extended‐spectrum β‐lactamases among Escherichia coli isolates collected in Zhengzhou

Objectives: To determine the prevalence and the diversity of extended‐spectrum β‐lactamases (ESBLs) among Escherichia coli isolates in Zhengzhou, China. Methods: Clinical isolates were collected and investigated from the first affiliated hospital of Zhengzhou University and its associated health‐care facilities in Zhengzhou, China, during the period from January 2006 to June 2008. Antibiograms were performed on Mueller–Hinton agar plates with the disc‐diffusion method and MICs were determined by the agar‐dilution method. Total DNA was extracted with a Qiagen mini kit and screened by PCR. Results: Of 94 nonduplicate ESBL‐positive isolates, TEM‐type was encoded in 74 and 79% of the ESBL isolates. Fifty‐six isolates were SHV type ESBLs. CTX‐M‐1, CTX‐M‐14, CTX‐M‐25, and CTX‐M‐38 types were encoded in 30, 54, 6, and 4, respectively. OXA‐1‐type β‐lactamases were encoded in six and OXA‐20‐type was encoded in two isolates. Conclusions: We describe a complex ESBL epidemiology. The study revealed a high rate of ESBL‐producing E. coli isolates. TEM and CTX‐M enzymes dominated in ESBL‐positive E. coli isolates in Zhengzhou, China. J. Clin. Lab. Anal. 23:404–407, 2009. © 2009 Wiley‐Liss, Inc.     

3所医院铜绿假单胞菌中ESBLs基因的检测

目的了解昆明3所医院临床分离的铜绿假单胞菌中超广谱β-内酰胺酶（ESBLs）基因的分布情况。方法收集昆明3所医院临床标本中分离的铜绿假单胞菌110株,用VITEK32型全自动细菌鉴定仪进行细菌鉴定,用聚合酶链反应法对其进行基因检测,靶基因为TEM、SHV、OXA、PER、VEB、GES、CTX-M-1共7种ESBLs基因,对检测的阳性产物进行测序,并对照GenBank确定其基因型。结果 110株PA中7种主要的ESBLs基因型（PER、VEB、GES、TEM、SHV、OXA、CTX-M）均有检出,其中TEM型检出率占77.3%。结论 110株PA中ESBLs基因型分布较广,TEM是其中流行的主要基因型,各医院应规范临床用药,并加强联合动态监测。     

铜绿假单胞菌β-内酰胺类抗生素耐药基因的研究

目的调查佛山地区铜绿假单胞菌对β-内酰胺酶类抗生素的耐药情况,并研究其β-内酰胺酶编码基因的存在情况。方法用法国梅里埃ATBExpression细菌分析系统鉴定微生物分析仪进行菌种鉴定和药敏试验,采用表型确证试验确认产ESBLs的菌株。应用聚合酶链式反应（PCR）技术检测耐药基因。结果50株产ESBLs铜绿假单胞菌中9株具有AmpC酶基因（18％）,TEM和VIM-1阳性菌各6株（12％）,SHV类（SHVI、SHV2、SHV3、SHV4）阳性菌3株（6％）,CTX-M9和IMP-2阳性菌各2株（4％）,其余PER、CTX-MI、CTX-M2、VEB、IMP-1和VIM-2基因检测均为阴性。结论质粒型AmpC基因、TEM、VIM-1、SHV、CTX-M9及IMP-2基因是导致本地区临床分离的铜绿假单胞菌对β-内酰胺酶类抗生素耐药的主要原因,且呈多重耐药。     

铜绿假单胞菌超广谱β-内酰胺酶、质粒介导AmpC酶基因分布及流行特征分析

目的研究临床分离铜绿假单胞菌超广谱β-内酰胺酶(ESBLs)和质粒介导AmpC酶的基因分布及流行特性,为细菌耐药性的监控提供依据。方法回顾性调查5年间临床分离的铜绿假单胞菌的分布和耐药情况。选取每年同一时间段的临床连续分离株共169株,用聚合酶链反应(PCR)检测TEM、SHV、VEB、PER、GES、TLA、IBC、CTX-M、OXA等β-内酰胺酶基因和AmpC酶基因。使用脉冲场凝胶电泳技术(PFGE)分析菌株间的同源性。结果铜绿假单胞菌主要分离自呼吸道(痰标本),占75.7%;对复方磺胺甲噁唑和头孢曲松耐药情况严重,耐药率分别为91.9%和91.7%;对其他主要抗菌药物的耐药率分别为头孢他啶46.7%、亚胺培南38.2%、左旋氧氟沙星30.2%、环丙沙星28.3%、阿米卡星5.0%。169株铜绿假单胞菌中产TEM、CTX-M、OXA和GES型β-内酰胺酶菌株84株(49.7%);质粒介导AmpC酶23株(13.6%)。PFGE结果显示铜绿假单胞菌仅3株具有同源性,呈散发流行。结论铜绿假单胞菌临床感染率高,呈多重耐药且散发流行趋势。     

粘质沙雷菌β-内酰胺类耐药基因研究

目的 调查粘质沙雷菌临床分离株β-内酰胺类耐药基因的携带情况,研究其对β-内酰胺类抗菌药物的耐药机制.方法 采用Vitek2-Compact全自动微生物系统对临床分离菌进行鉴定,检出粘质沙雷菌287株,同时进行药敏试验,选出多重耐药粘质沙雷菌135株;采用双纸片确证试验对所有287株粘质沙雷菌进行ESBLs检测、三维试验法检测AmpC酶,采用PCR法对135株多重耐药粘质沙雷菌进行β-内酰胺类抗菌药物相关基因SHV、TEM、OXA、PER、VEB、GES、IMP、VIM、FOX、CTX、KPC、DHA、MOX和oprD2检测.结果 粘质沙雷菌对氨苄西林、头孢曲松、头孢吡肟、头孢噻肟、氨曲南、庆大霉素、环丙沙星以及哌拉西林等临床常用抗菌药物的耐药率较高,耐药率均大于60％,对亚胺培南、美罗培南、舒普深的耐药率较低,耐药率均小于10％.在287株粘质沙雷菌中,共有32株产ES-BLs,检出率为11.1％,产AmpC酶44株,检出率为15.3％,同时产ESBLs和AmpC酶细菌16株,占5.6％;PCR结果显示,在135株多重耐药的粘质沙雷菌中,检出含CTX-M基因菌株91株、TEM基因25株、SHV基因19株、DHA基因48株、KPC基因10株、MOX基因3株、OXA基因1株、oprD2基因7株.结论 本地区粘质沙雷菌多重耐药现象较为严重,其耐药基因型主要为CTX-M型和DHA基因型.     

95株致泌尿道感染大肠埃希菌耐药性及耐药基因表型分析

目的了解广东医科大学附属医院泌尿系感染患者大肠埃希菌超广谱β-内酰胺酶型(ESBLs)基因型特征和临床耐药情况。方法收集2015年1~10月该院住院或门诊患者的泌尿系感染患者尿液标本中分离培养获得的大肠埃希菌菌株,双纸片协同试验确定产ESBLs大肠埃希菌,PCR扩增技术进行基因分型。结果 95株大肠埃希菌以CTX-M-14型46例最多;TEM型32例;SHV型30例;CTX-M-1型26例;OXA-1型7例;OXA-2型4例;OXA-10型3例。ESBLs阴性菌株TEM型仅5例阳性,其余基因型别为阴性。ESBLs阳性株对多种抗菌药物的耐药率(碳青霉烯类除外)明显高于ESBLs阴性株,而CTX-M-14、CTX-M-1、TEM、SHV四种基因型别大肠埃希菌对18种抗菌药物的耐药性之间差异无统计学意义(P0.05)。结论广东医科大学附属医院泌尿系感染患者产ESBLs大肠埃希菌以CTXM型为主,对常用抗菌药物耐药率高于ESBLs阴性菌株。不同基因型别产ESBLs大肠埃希菌对抗菌药物耐药率没有明显差异。     

17株耐亚胺培南肺炎克雷伯菌和大肠埃希菌相关耐药基因及分子流行病学分析

目的了解17株亚胺培南耐药肺炎克雷伯菌和大肠埃希菌相关耐药基因及分子流行病学状况。方法采用Hodge试验检测碳青霉烯酶表型;采用PCR法检测碳青霉烯酶、I类头孢菌素酶(AmpC)和超广谱β-内酰胺酶(ESBLs)耐药基因,进行测序及网上比对确定基因型;采用肠杆菌科基因间重复序列(ERIC)和多位点序列分型(MLST)对菌株进行同源性和遗传相关性分析。结果 15株肺炎克雷伯菌检出KPC-2、TEM-1、SHV和CTX-M型基因,SHV12和CTX-M-24为主要基因亚型;2株大肠埃希菌检出KPC-2基因,其中1株大肠埃希菌检出TEM-1和CTX-M-24基因,另一株大肠埃希菌检出CMY-42和OXA-1基因;17株菌未检测到IMP、VIM和NDM碳青霉烯酶。15株肺炎克雷伯菌分为A、B和C三个ERIC类别,12株A类为ST11型,2株B类为ST290和ST147型,1株C类为ST967型,2株大肠埃希菌是同一ERIC类别。结论 17株菌亚胺培南耐药主要与KPC-2基因有关,产KPC-2肺炎克雷伯菌在本院神经外科病区呈克隆传播流行,ST11型为此次流行的主要型别;17株菌同时也是产ESBLs株或产ApmC酶株;首次在世界范围内发现ST290和ST967型产KPC-2肺炎克雷伯菌;临床科室应加强院内感染控制措施。     

Extended-spectrum beta-lactamases among Enterobacter isolates obtained in Tel Aviv, Israel

The extended-spectrum beta-lactamase (ESBL)-producing phenotype is frequent among Enterobacter isolates at the Tel Aviv Sourasky Medical Center, Tel Aviv, Israel. We examined the clonal relatedness and characterized the ESBLs of a collection of these strains. Clonal relatedness was determined by pulsed-field gel electrophoresis. Isoelectric focusing (IEF) and transconjugation experiments were performed. ESBL gene families were screened by colony hybridization and PCR for bla(TEM), bla(SHV), bla(CTX-M), bla(IBC), bla(PER), bla(OXA), bla(VEB), and bla(SFO); and the PCR products were sequenced. The 17 Enterobacter isolates studied comprised 15 distinct genotypes. All isolates showed at least one IEF band (range, one to five bands) whose appearance was suppressed by addition of clavulanate; pIs ranged from 5.4 to > or = 8.2. Colony hybridization identified at least one family of beta-lactamase genes in 11 isolates: 10 harbored bla(TEM) and 9 harbored bla(SHV). PCR screening and sequence analysis of the PCR products for bla(TEM), bla(SHV), and bla(CTX-M) identified TEM-1 in 11 isolates, SHV-12 in 7 isolates, SHV-1 in 1 isolate, a CTX-M-2-like gene in 2 isolates, and CTX-M-26 in 1 isolate. In transconjugation experiments with four isolates harboring bla(TEM-1) and bla(SHV-12), both genes were simultaneously transferred to the recipient strain Escherichia coli HB101. Plasmid mapping, PCR, and Southern analysis with TEM- and SHV-specific probes demonstrated that a single transferred plasmid carried both the TEM-1 and the SHV-12 genes. The widespread presence of ESBLs among Enterobacter isolates in Tel Aviv is likely due not to clonal spread but, rather, to plasmid-mediated transfer, at times simultaneously, of genes encoding several types of enzymes. The dominant ESBL identified was SHV-12.     

对头孢吡肟敏感的疑似产超广谱β内酰胺酶大肠埃希菌和克雷伯菌属的分子生物学特征

目的 了解初筛试验疑似产超广谱β内酰胺酶(ESBLs)但确证试验未能确认,而对头孢吡肟敏感的大肠埃希菌和克雷伯菌属中的ESBLs和质粒介导的AmpC酶.方法 纸片扩散法检测18株细菌对常用抗菌药物的敏感性;PCR及多重PCR法检测细菌中的ESBLs和质粒AmpC酶基因;质粒转移接合试验检测耐药质粒的可传递性;细菌基因间重复一致序列(ERIC)-PCR法检测供体大肠埃希菌和受体E.coli J53及其接合子的同源性;脉冲场凝胶电泳(PFGE)对11株大肠埃希菌和6株肺炎克雷伯菌进行同源性分析.结果 18株细菌均为2005年1月至12月期间上海华山医院临床分离的菌株,其中大肠埃希菌11株,肺炎克雷伯菌6株,产酸克雷伯菌1株,按常规方法对细菌进行重新鉴定和药敏试验.18株细菌经美国临床和实验室标准协会(CLSI)推荐的ESBLs初筛试验结果均为ESBLs产生可疑菌株,但确证试验未能确认;所有菌株的头孢吡肟抑菌圈直径均在18 mm以上,显示敏感.PCR检测结果显示,11株大肠埃希菌中有9株产CIT型质粒AmpC酶,DNA测序及序列比对结果证实为CMY-2型AmpC酶,未发现TEM、SHV、CTX-M、PER、VEB、SFO等广谱或ESBLs;6株肺炎克雷伯菌中有5株产DHA型质粒AmpC酶,DNA测序及序列比对结果证实为DHA-1型AmpC酶;5株产DHA-1型AmpC酶的肺炎克雷伯菌株中,4株同时伴有广谱或ESBLs:其中2株产SHV-11型广谱酶,另2株分别产CTX-M-14型ESBLs和SHV-62型ESBLs;1株产酸克雷伯菌亦单产DHA-1型AmpC酶;质粒转移接合试验结果表明,携带耐药基因的质粒可从供体菌转移至敏感细胞中;PFGE结果显示,6株肺炎克雷伯菌的谱型各不相同,而11株大肠埃希菌可分为5种谱型,其中B型包含7株细菌,这7株细菌均产生质粒介导的CMY-2型AmpC酶,并分离自外科病房,提示可能存在克隆菌株的流行传播.结论在确证试验未能确认的疑似产ESBLs中,对头孢吡肟敏感的大肠埃希菌和克雷伯菌属细菌主要产生质粒介导的AmpC酶,但尚有少数菌株同时伴有产ESBLs.对同时产生ESBLs和AmpC酶的菌株,临床微生物实验室必须报告这些菌株对头孢吡肟耐药.     

Extended-spectrum and metallo-beta-lactamases among ceftazidime-resistant Pseudomonas aeruginosa in Riyadh, Saudi Arabia

We investigated the extended-spectrum (ESBLs) and metallo-beta-lactamases (MBLs) among Pseudomonas aeruginosa isolates in Saudi Arabia. Disc susceptibility testing was performed on 200 P. aeruginosa isolates collected during 2010 at the Armed Forces Hospital in Riyadh, with MIC testing and phenotypic screening for ESBLs and MBLs carried out on those found to be ceftazidime resistant. Genes for ESBLs and MBLs were sought by PCR. Thirty-nine (19.5%) P. aeruginosa isolates were ceftazidime resistant, mostly with considerable resistance to other antibiotics except colistin. Twenty-three of these 39 (59%) appeared ESBL positive and 16 (41%) had MBLs. bla(VEB), and bla(GES) genes were found in 20 (86.95%), and 5 (21.74%) of 23 ESBL-positive isolates, respectively whilst bla(VIM) was detected in all 16 MBL-producers. bla(OXA-10-like) often accompanied bla(VEB), bla(VIM) or bla(GES). Several isolates had similar antibiogram and β-lactamase profiles, and may represent outbreaks; nevertheless, the collection was not dominated by any single clone. This dominance of acquired ceftazidime-inactivating beta-lactamases, often in combination is in contrast to the situation in Europe and the USA, where most ceftazidime resistance in P. aeruginosa is attributable to AmpC and efflux.     

碳青霉烯类耐药肺炎克雷伯菌β-内酰胺酶检测和基因分型

摘要：目的：探讨碳青霉烯类耐药肺炎克雷伯菌产β-内酰胺酶情况和β-内酰胺酶基因分型研究。 方法：用Vitek-Ⅱ全自动微生物分析仪对本院临床标本中分离的对碳青霉烯类耐药的肺炎克雷伯菌进行菌种鉴定和药物敏感试验;用冻融法提取β-内酰胺酶,三维试验检测β-内酰胺酶［AmpC酶、超广谱β-内酰胺酶（ESBLs）、金属酶;改良Hodge试验检测KPC酶;用PCR扩增TEM、SHV、CTX-M、PER、VEB、DHA、MIR/ACT、KPC、IMP、VIM、SPM、GIM和NDM-1基因,并对阳性基因进行测序分析确定其基因型;REP-PCR检测分析其同源性。 结果: 4株对碳青霉烯类抗生素耐药肺炎克雷伯菌均表现为多重耐药,其中2株菌对所有测试的抗菌药物均耐药;1株菌产金属酶,由IMP-4型金属酶基因编码;4株菌均产生DHA型AmpC酶,2株菌产CTX-M-14型ESBLs;1株菌产TEM-71型ESBLs,均经测序证实;未检测出SHV、PER、VEB、MIR/ACT、KPC、VIM、SPM、GIM和NDM-1基因型。REP-PCR显示4株菌属于3个不同的克隆型。 结论：本院出现碳青霉烯类耐药的肺炎克雷伯菌,属于不同克隆型,产多种β-内酰胺酶（AmpC酶、ESBLs、金属酶）,基因型为DHA、IMP-4、CTX-M-14、TEM-71。     

佳木斯地区大肠埃希菌和阴沟肠杆菌质粒介导头孢菌素酶、超广谱β-内酰胺酶基因型分布

目的 了解佳木斯地区临床分离的大肠埃希菌和阴沟肠杆菌中质粒介导头孢菌素酶(AmpC酶)和超广谱β-内酰胺酶(ESBLs)流行情况及主要的基因型别.方法 127株临床分离无重复大肠埃希菌81株与阴沟肠杆菌46株,采用酶提取物三维实验检测产AmpC酶和ESBLs菌株,聚合酶链反应(PCR)扩增质粒型AmpC酶与ESBLs基因及其序列测定以确定其基因亚型.结果 46株阴沟肠杆菌中,单产AmpC酶者、单产ESBLs者、高产AmpC酶并产ESBLs者分别占21.7％、28.3％、6.5％;81株大肠埃希菌中,单产AmpC酶者、单产ESBLs者、高产AmpC酶并产ESBLs者分别占19.8％、38.3％、9.9％.大肠埃希菌ESBLs基因型为TEM、SHV、CTX-M,质粒AmpC酶基因型为DHA.阴沟肠杆菌ESBLs基因型为TEM、SHV、CTX-M,质粒AmpC酶基因型为DHA.结论 CTX-M型和DHA-1型分别是本地区大肠埃希菌和阴沟肠杆菌ESBLs和质粒介导AmpC酶的主要流行基因型.     

Real-time PCR and melting curve analysis for reliable and rapid detection of SHV extended-spectrum beta-lactamases

Extended-spectrum beta-lactamases (ESBLs), e.g., ESBLs of the TEM or SHV type, compromise the efficacies of expanded-spectrum cephalosporins. An SHV non-ESBL that hydrolyzes only narrow-spectrum cephalosporins can be converted into an SHV ESBL through substitutions at three amino acid positions, 179, 238, or 238--240. In order to improve detection of SHV ESBLs, a novel method, based on real-time PCR monitored with fluorescently labeled hybridization probes and followed by melting curve analysis, was developed. It is able to (i) detect bla(SHV) genes with high degrees of sensitivity and specificity, (ii) discriminate between bla(SHV non-ESBL) and bla(SHV ESBL), and (iii) categorize the SHV ESBL producers into three phenotypically relevant subgroups. This method, termed the SHV melting curve mutation detection method, represents a powerful tool for epidemiological studies with SHV ESBLs. It even has the potential to be used in the diagnostic microbiology laboratory, because up to 32 clinical isolates can be processed in less than 1 h by starting with just a few bacterial colonies.     

Redefining extended-spectrum beta-lactamases: balancing science and clinical need

The current beta-lactamase classifications have reached a high level of complexity, making them less accessible to clinicians, infection control professionals, hospital management and politicians. From the clinical perspective, a revised comprehensible nomenclature scheme is therefore needed. The term extended-spectrum beta-lactamases (ESBLs) has reached a broader audience over time, but is currently restricted to functional class 2be/molecular class A, clavulanic acid inhibited enzymes with activity against extended-spectrum cephalosporins. The proposed new classification expands the definition of ESBL to other clinically important acquired beta-lactamases with activity against extended-spectrum cephalosporins and/or carbapenems. The classical class A ESBLs have been designated ESBLA in this classification, whereas plasmid-mediated AmpC and OXA-ESBLs are classed as miscellaneous ESBLs (ESBLM). Lastly, the carbapenemases have been designated ESBLCARBA, ESBLs with hydrolytic activity against carbapenems. We believe that this simplified classification may encourage new groups of healthcare professionals to engage in the effort to prevent the spread of acquired beta-lactamases.     

Survey of plasmid-associated genetic markers in enterobacteriaceae with reduced susceptibilities to cephalosporins

Clinical isolates of Enterobacteriaceae with reduced susceptibilities to cephalosporins were collected from 1993 to 2000. The organisms were screened for the extended-spectrum beta-lactamase (ESBL) phenotype, and plasmid extracts were screened for genetic markers by hybridization. A bla(TEM) probe was derived from pUC19; other probes were derived from pACM1, the plasmid responsible for the first known appearance of an ESBL in our institution. These probes included bla(SHV), int, aac(3)-Ia, dfrA1, IS6100, tetA, IncM markers, and Anon 13, a marker for the Klebsiella pneumoniae chromosomal sequences that flank bla(SHV-5). There were 42 hybridization patterns among 237 isolates. Patterns designated pACM1-like occurred in 44% of the isolates (eight species) and were always associated with the clavulanic acid (CA)-susceptible ESBL phenotype. The TEM marker was not predictive of the ESBL phenotype. Mapping indicated the presence of an SHV marker and up to 7.5 kb of its flanking chromosomal sequences in three non-IncM plasmids obtained in transformation experiments. We theorize that this DNA segment spread to other plasmids from pACM1-like sources. CA insensitivity became more frequent with time and was usually associated with either the TEM marker or the absence of both bla markers. One plasmid-encoded enzyme with characteristics of an AmpC beta-lactamase was observed in a transformant lacking both TEM and SHV markers. Although SHV type ESBLs were a continuing source of reduced susceptibility to cephalosporins in our institution, organisms with different resistance mechanisms were added to the hospital microflora in later years. These changes might be related, in part, to ESBL control strategies implemented in 1995.     

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.     

Minor extended-spectrum β-lactamases

Over the last few decades, various extended-spectrum β-lactamases (ESBLs), which are remotely related to the classical TEM and SHV families, have emerged. Among these, CTX-M, VEB and PER variants are of particular interest due to their widespread dissemination. This article will focus on these emerging ESBLs. CTX-M was first identified from an Escherichia coli strain in Germany and since then, a rapidly growing family of ESBLs has formed worldwide. There are now more than 90 CTX-M variants. VEB-1 ESBL is widespread in Southeast Asia. It was first identified in an E. coli strain isolated from a Vietnamese boy in 1996. After the initial discovery, it spread to other species. PER-1, now reported from various continents, was restricted to Turkish hospitals for years after the first identification in a strain of Pseudomonas aeruginosa in 1993. The worldwide dissemination of ESBLs is a healthcare crisis that deserves special attention.     

A novel disk-based detection method with superior sensitivity for β-lactamase production in third-generation cephalosporin-resistant Enterobacteriaceae

Objective

Current phenotypic methods for extended-spectrum β-lactamase (ESBL), AmpC β-lactamase (AmpC), and carbapenemases fail to detect isolates that co-produce other classes of β-lactamases. In this study, we have developed a novel assay (Applied Multiplex Disk Method: AMU-DM) for the phenotypic detection and identification of β-lactamases produced by Enterobacteriaceae.

南昌4家教学医院碳青霉烯类耐药肺炎克雷伯菌耐药机制及同源性分析

目的探讨临床分离的碳青霉烯类耐药肺炎克雷伯菌(CRKP)的耐药机制及同源性。方法收集南昌地区4家教学医院耐碳青霉烯类抗菌药物(亚胺培南和/或美罗培南)的肺炎克雷伯菌29株,双纸片增效法检测超广谱β-内酰胺酶(ESBLs)、三维实验检测AmpC酶、改良Hodge实验和双纸片协同法检测碳青霉烯酶,PCR扩增耐药基因,并对扩增产物测序,确定其基因型。脉冲场凝胶电泳(PFGE)对其进行同源性分析。结果 29株分离菌除对阿米卡星的耐药率较低(37.9%)外,对其他13种抗菌药物的耐药率均大于69%,其中对头孢呋辛、亚胺培南的耐药率为100%,多重耐药肺炎克雷伯菌的检出率为62.1%(18/29)。29株分离菌中有19株携带碳青霉烯酶基因,占65.5%(19/29),以blaKPC-2为主(44.8%,13/29),其次为blaNDM-1、blaIMP-26及blaIMP-4,携带率分别为17.2%(5/29)、10.3%(3/29)及6.9%(2/29),另有3株同时携带blaKPC-2和blaIMP-26,1株同时携带blaKPC-2和blaIMP-4。17株除携带碳青霉烯酶基因外,还携带ESBLs基因和(或)AmpC基因,占58.6%。未检测到VIM、GES、SPM及OXA等其他碳青霉烯酶基因。29株分离菌中有27株被PFGE成功分型,分别属于20个不同克隆,其余2株分型不成功。属于同一克隆型且携带blaKPC-2基因的4株菌来自同一医院。结论 CRKP耐药及多重耐药现象严重;携带碳青霉烯酶基因是肺炎克雷伯菌耐碳青霉烯类药物的主要原因,blaKPC-2携带率高,且在局部有短暂流行。本地区已监测到携带blaNDM的肺炎克雷伯菌,值得关注。     

Minor extended-spectrum β-lactamases

Over the last few decades, various extended-spectrum β-lactamases (ESBLs), which are remotely related to the classical TEM and SHV families, have emerged. Among these, CTX-M, VEB and PER variants are of particular interest due to their widespread dissemination. This article will focus on these emerging ESBLs. CTX-M was first identified from an Escherichia coli strain in Germany and since then, a rapidly growing family of ESBLs has formed worldwide. There are now more than 90 CTX-M variants. VEB-1 ESBL is widespread in Southeast Asia. It was first identified in an E. coli strain isolated from a Vietnamese boy in 1996. After the initial discovery, it spread to other species. PER-1, now reported from various continents, was restricted to Turkish hospitals for years after the first identification in a strain of Pseudomonas aeruginosa in 1993. The worldwide dissemination of ESBLs is a healthcare crisis that deserves special attention.