耐碳青霉烯类肺炎克雷伯菌的药敏结果及耐药基因

目的分析某院耐碳青霉烯类肺炎克雷伯菌(CRKP)的药物敏感性及耐药基因携带情况。方法收集2017年1月—2018年6月该院临床分离的CRKP,对菌株进行药物敏感性分析,应用聚合酶链式反应(PCR)检测耐药基因携带情况。结果共收集57株CRKP,主要来源于呼吸道标本,其中痰34株,肺泡灌洗液11株;来源科室主要为神经内科(20株,35.09%)、呼吸内科(15株,26.32%)、重症医学科(9株,15.79%)。CRKP对大部分抗菌药物耐药,部分抗菌药物耐药率相对较低,其中复方磺胺甲口恶唑耐药率最低(15.79%),其次为替加环素(50.88%)、阿米卡星(57.89%)。共检出2种碳青霉烯酶基因(KPC-2、NDM-1),4种超广谱β-内酰胺酶(ESBLs)基因(SHV、CTX-M-9、TEM、CTX-M-1)。57株CRKP均检出ESBLs基因,其中39株(68.42%)检出KPC-2基因,仅有1株检出NDM-1基因。结论临床分离的CRKP耐药形势严峻,并且携带多种耐药基因,其中最常见的产碳青霉烯酶为KPC。     

Carbapenemase-producing Enterobacteriaceae: Overview of a major public health challenge

Bacterial resistance to antibiotics has become a major source of concern for public health. Enterobacteriaceae are among the most common human pathogens, causing community-acquired as well as hospital-acquired infections. Carbapenem-resistant Enterobacteriaceae have been increasingly reported worldwide since their first identification more than 20 years ago. Three main classes of carbapenemases have been identified: Ambler class A beta-lactamase (KPC), class B (metallo-enzymes), and class D (OXA-48 type). Klebsiella pneumoniae carbapenemases (KPC) was first reported in the United States in the late 1990s and since then worldwide, with a marked endemicity in the United States, Greece, and now Italy. Carbapenemase NDM-1 (New Delhi metallo-beta-lactamase-1) is one of the most recently reported metallo-enzymes. It has spread widely in the Indian sub-continent and now worldwide. Carbapenemases of the oxacillinase-48 type (OXA-48) have been identified mostly in Mediterranean and southern European countries with a rapid spread. An early and quick identification of carbapenemase-producing infected patients, but also of carriers, is mandatory to prevent the spread of these highly resistant pathogens. The early identification of carriers and implementing of cohorting strategies is the only means to prevent nosocomial outbreaks caused by carbapenemase, with very few, if any, therapeutic options.     

Transfer of Carbapenem-Resistant Plasmid from Klebsiella pneumoniae ST258 to Escherichia coli in Patient

Klebsiella pneumoniae carbapenemase (KPC) 3–producing Escherichia coli was isolated from a carrier of KPC-3–producing K. pneumoniae. The KPC-3 plasmid was identical in isolates of both species. The patient''s gut flora contained a carbapenem-susceptible E. coli strain isogenic with the KPC-3–producing isolate, which suggests horizontal interspecies plasmid transfer.     

肺炎克雷伯菌的分布与药敏性分析

目的 统计2009-2010年肺炎克雷伯菌的分布、药敏性及流行状况,指导临床用药,控制医院感染.方法 对2010年分离出肺炎克雷伯菌的162例住院患者进行标本、科室分布的统计及药敏分析;对其中多药耐药肺炎克雷伯菌作ESBLs、AmpC酶、碳青霉烯酶、新德里金属β-内酰胺酶(NDM)-1等试验.结果 162株肺炎克雷伯菌主要来自痰液,占76.54％,其次为尿液及伤口分泌物,分别占8.64％、6.79％;主要分布于ICU、呼吸内科,分别占51.23％、22.84％;产ESBLs肺炎克雷伯菌检出84株,检出率为51.85％,产AmpC酶检出20株,检出率为12.355％,产KPC酶检出17株,检出率为10.49％,没有检测到产新德里金属β-内酰胺酶(NDM)-1菌株.结论 肺炎克雷伯菌耐药率比较高并且耐药因子多样,对多药耐药肺炎克雷伯菌有必要进行耐药机制的检测,以便控制医院感染.     

耐碳青霉烯类肺炎克雷伯菌耐药性及耐药基因的研究

目的:研究耐碳青霉烯肺炎克雷伯菌(CRKP)的耐药性及耐药基因类型,为合理使用抗菌药物及监测院内感染等提供有效的科学指导。方法:对医院收治的肺炎患者分离出的29株CRKP,采用改良碳青霉烯类失活(mCIM)试验法检测肺炎克雷伯菌中的碳青霉烯酶,通过聚合酶链反应(PCR)及测序方法对碳青霉烯酶基因KPC、IMP、NDM型、超广谱β内酰胺酶基因(ESBLs)、TEM、SHV、CTX-M型以及AmpC酶基因DHA进行检测。结果:29株耐药菌株对大部分临床常用抗菌药物高度耐药,对氟喹诺酮类抗菌药物和氨基糖苷类抗菌药物有较高的敏感性。表型确认试验中7株改良Hodge实验阳性,18株mCIM试验阳性。20株(占68.97%)菌检测到碳青霉烯酶基因,其中KPC为17.24%(5/29),IMP为13.79%(4/29),NDM为37.93%(11/29)。25株(占86.20%)菌检测到ESBLs菌株的基因,其中TEM型为62.07%(18/29),SHV型为79.31%(23/29),CTX-M型为62.07%(18/29)。3株菌检测到AmpC酶基因,其中DHA为10.34%(3/29)。29株CRKP中有14株既表达了碳青霉烯酶基因又表达了ESBLs的基因,共同表达率为48.28%。对耐药基因抽取其中部分阳性结果进行测序后均为目标基因,其中KPC为KPC-2、NDM为NDM-1。结论:29株CRKP对多种抗生素耐药率均较高,且对碳青霉类抗菌药物的耐药基因型主要为KPC-2和NDM-1,故加强院内感染预防控制措施,防止此类菌株的播散。     

New Delhi Metallo-β-Lactamase–Producing Enterobacterales Bacteria,Switzerland, 2019–2020

Carbapenemase-producing Enterobacterales (CPE) bacteria are a critical global health concern; New Delhi metallo-β-lactamase (NDM) enzymes account for >25% of all CPE found in Switzerland. We characterized NDM-positive CPE submitted to the Swiss National Reference Center for Emerging Antibiotic Resistance during a 2-year period (January 2019–December 2020) phenotypically and by using whole-genome sequencing. Most isolates were either Klebsiella pneumoniae (59/141) or Escherichia coli (52/141), and >50% were obtained from screening swabs. Among the 108 sequenced isolates, NDM-1 was the most prevalent variant, occurring in 56 isolates, mostly K. pneumoniae (34/56); the next most prevalent was NDM-5, which occurred in 49 isolates, mostly E. coli (40/49). Fourteen isolates coproduced a second carbapenemase, predominantly an OXA-48-like enzyme, and almost one third of isolates produced a 16S rRNA methylase conferring panresistance to aminoglycosides. We identified successful plasmids and global lineages as major factors contributing to the increasing prevalence of NDMs in Switzerland.     

First report of Klebsiella pneumonia carbapenemase-producing Pseudomonas aeruginosa isolated from burn patients in Iran: phenotypic and genotypic methods

Wound infection associated with carbapenem-resistant Pseudomonas aeruginosa in burn patients is a growing problem. One of the main mechanisms of resistance to carbapenem antibiotics is the ability of P. aeruginosa to produce carbapenemase enzymes. Klebsiella pneumonia carbapemenase (KPC) is an important type of carbapenemase which can hydrolyze carbapenem antibiotics. The Modified Hodge Test (MHT) and boronic acid as a KPC inhibitor are two phenotypic methods used for detection of carbapenemase. The sensitivity and specificity of these two phenotypic tests for the identification of KPC can be measured by PCR.In this study, 241 P. aeruginosa strains were isolated from wounds of hospitalized burn patients. Carbapenem-resistant P. aeruginosa isolates were determined by the disk diffusion method. KPC-producing carbapenem-resistant strains were examined using the Modified Hodge Test, followed by boronic acid. Further, strains with positive responses to MHT and boronic acid tests were analyzed with the PCR molecular method. One hundred eighty-six of 241 isolates were resistant to carbapenems and 75 were positive in the MHT. Three exhibited an at least 5-mm diameter difference when meropenem was combined with boronic acid vs meropenem alone in the boronic acid test. Two strains had a specific band with primer No.1 after gel electrophoresis. This study showed that MHT, despite excellent sensitivity, has variable specificity independent of bacterial species. Further, the use of KPC inhibitors such as boronic acid did not yield favorable sensitivity and specificity among the specimens from Iranian patients. Thus, it seems that sequencing after PCR should be considered the gold standard for the detection of KPC-producing P. aeruginosa.     

肠杆菌科细菌KPC型碳青霉烯酶的研究

目的了解某院临床分离的肠杆菌科细菌产KPC型碳青霉烯酶情况及其基因型别。方法收集该院2009—2010年临床分离的肠杆菌科细菌1 801株,经药敏试验筛选出耐药性高的菌株,采用改良Hodge试验和聚合酶链反应(PCR)扩增检测细菌产KPC型碳青霉烯酶情况,并测序分析其基因型别。结果 1 801株肠杆菌科细菌中,有783株(43.48%)对第三代头孢菌素耐药,其中4株还对碳青霉烯类抗菌药物耐药;改良Hodge试验初筛出2株耐药菌株,经PCR扩增证实为碳青霉烯酶blaKPC-2基因。结论该院已出现产KPC-2型碳青霉烯酶耐药基因的肠杆菌科细菌,临床与实验室应加强监测和控制。     

耐碳青霉烯类肺炎克雷伯菌分子流行病学研究

目的分析武汉两所医院耐碳青霉烯类肺炎克雷伯菌(CRKP)临床分离株产碳青霉烯酶的情况,以及分子流行病学特征。方法收集武汉两所医院2018年1—10月临床分离的42株非重复CRKP,采用Carba NP试验方法对菌株产碳青霉烯酶情况进行初筛,聚合酶链反应(PCR)检测碳青霉烯酶基因携带情况,采用质粒接合试验分析耐药基因的水平转移情况,应用脉冲场凝胶电泳(PFGE)进行亲缘关系分析。结果 42株CRKP菌株中14株Carba NP试验阳性,其中有10株扩增出NDM-1基因,3株扩增出KPC-2基因。共13株CRKP碳青霉烯基因检测阳性,其中12株质粒接合试验成功。PFGE分析结果显示,携带NDM-1基因的CRKP菌株共分成6型,无明显优势型;携带KPC-2基因的CRKP菌株为同一型别。结论检出产NDM-1和KPC-2的CRKP菌株,质粒接合试验提示质粒介导的水平传播在碳青霉烯酶基因的播散过程中可能起重要作用。     

产肺炎克雷伯菌碳青霉烯酶肺炎克雷伯菌的研究进展

产肺炎克雷伯菌碳青霉烯酶(KPC)细菌在世界范围内广泛流行,此酶不仅见于克雷伯菌属,在诸多革兰阴性细菌中皆可检测到.产KPC细菌除了对β-内酰胺类抗菌药物耐药,对其他类抗菌药物如氟喹诺酮类、氨基糖苷类、四环素类也多表现为耐药,受到广泛关注.此文对产KPC肺炎克雷伯菌的流行病学、检测方法、感染的治疗及控制进行了综述.     

某综合医院重症监护病房耐碳青霉烯类肺炎克雷伯菌环境流行调查

目的 调查重症监护病房（ICU）环境中耐碳青霉烯类肺炎克雷伯菌（CRKP）污染现状,以及CRKP主要耐药基因携带情况。方法 使用mSuper CARBA显色培养基对某院5个外科ICU中高频接触的物体表面、公共区域物体表面、水槽池壁和排水孔等采样标本进行菌株分离,采用MALDI-TOF质谱仪对目标菌进行鉴定,采用双纸片协同法对CRKP进行碳青霉烯酶表型鉴定,聚合酶链反应（PCR）方法检测KPC和NDM耐药基因。结果 CRKP在高频接触的物体表面（1/73）、公共区域物体表面（1/89）、护工的衣物（1/24）分离比例很低,但水槽排水孔（25/29）污染比例较高。碳青霉烯酶表型鉴定显示,5株产A类酶,11株产B类金属酶;PCR结果显示,2株携带KPC耐药基因,3株携带NDM耐药基因。结论 CRKP在ICU高频接触的物体表面定植率较低,而水槽排水孔污染率较高。耐药表型酶鉴定和PCR结果提示,严格执行环境清洁与消毒措施后,ICU内CRKP交叉传播的可能降低。     

Whole-genome sequencing identification of a multidrug-resistant Salmonella enterica serovar Typhimurium strain carrying blaNDM-5 from Guangdong,China

A carbapenem-resistant Salmonella enterica serovar Typhimurium (sequence type 34 [ST34]) strain was isolated from a fecal specimen from a child with acute diarrhea. Whole-genome sequencing revealed that the 84.5-kb IncFII plasmid pST41-NDM carrying the NDM-5 carbapenemase gene possesses a structure identical to that of the IncFII-type plasmid backbone. However, the bla_NDM-5 flanking sequence found in this plasmid is identical to the bla_NDM-5-positive IncX3 plasmids carried by 10 strains of Enterobacteriaceae identified in the same hospital.     

对亚胺培南不敏感菌株的产碳青霉烯酶的情况分析

目的:探讨对亚胺培南不敏感的革兰阴性杆菌产碳青霉烯酶的分布与变迁情况,为临床合理诊治提供指导。方法:收集2005年5月-2009年8月间临床分离的革兰阴性杆菌,用K-B法筛选对亚胺培南不敏感的菌株;改良Hodge试验检测革兰阴性杆菌产碳青霉烯酶的情况;核酸扩增碳青霉烯酶相关基因NDM-1、KPC、VIM、IMP、OXA-23、OXA-24、OXA-51、OXA-58。结果:铜绿假单胞菌和鲍曼不动杆菌是碳青霉烯类药物不敏感的主要病原菌,54株亚胺培南不敏感的菌株中Hodge试验阳性5株,阳性率为9.3%。携带耐药基因包括IMP 2株,VIM 2株,OXA23 3株,OXA51 2株,OXA65 1株。其中有2株同时携带两种耐药基因。结论:我院亚胺培南不敏感分离株与产碳青霉烯酶IMP、VIM、OXA51、OXA23、OXA65耐药基因有关。     

Molecular characterization of NDM-1-producing Klebsiella pneumoniae ST29, ST347, ST1224, and ST2558 causing sepsis in neonates in a tertiary care hospital of North-East India

Geographical differences can manifest in different spectra of microorganisms and patterns of antibiotic resistance. Considering this, Enterobacteriacae isolated from septicemic neonates from a tertiary care centre in Agartala, India were studied with focus on carbapenem resistance. Two hundred non-duplicate Enterobacteriaceae, of which 12 NDM-1-producing Klebsiella pneumoniae were recovered. Antibiotic susceptibility tests and detection of ESBLs and carbapenemases were performed for all Enterobacteriaceae. For NDM-1-producing isolates, plasmid-mediated quinolone resistance genes, addiction systems, genetic environment of bla_NDM-1 and virulence genes was investigated by PCR. Bacterial clonal relatedness was established using REP-PCR, PFGE, and multi-locus sequence typing (MLST). Transferability of bla_NDM-1 was tested by conjugation and transconjugants were characterized.K. pneumoniae was the primary organism causing sepsis in neonates. Resistance to different antimicrobials was high except for aminoglycosides and carbapenems. bla_CTX-M was present in all isolates. All carbapenem-resistant isolates harboured bla_NDM-1 as the only carbapenemase. bla_CTX-M-15 and qnrS1 were detected in all NDM-1-producing isolates. Plasmid analysis of transconjugants revealed that bla_NDM-1 along with bla_CTX-M-15, qnrS1, qnrB1, aac(6′)-Ib, aac(6′)-Ib-cr and ccdAB or vagCD addiction systems were carried on large IncFIIK conjugative plasmids of varied sizes. bla_NDM-1 was associated with ISAba125 or ISEc33 element at its 5′-end. In addition, isolates also harboured wabG, uge, fimH, mrkD, and entB virulence genes. The NDM-1-producing K. pneumoniae belonged to four distinct clones and were distributed in 4 STs (ST347, ST29, ST2558, and ST1224), of which ST347 was predominant. The association of bla_NDM-1 with diverse STs in K. pneumoniae from neonates indicates the promiscuity of the gene and its widespread dissemination.     

改良Hodge试验、CNPt及mCIM筛选肺炎克雷伯菌产碳青霉烯酶的价值

目的探讨改良Hodge试验(MHT)、Carba NP试验(CNPt)及改良碳青霉烯酶灭活试验(mCIM)检测肺炎克雷伯菌产碳青霉烯酶的价值。方法收集某院2016年12月—2017年11月临床分离的117株肺炎克雷伯菌,所有菌株进行药敏试验,其中碳青霉烯类耐药57株,敏感60株。以PCR法检测碳青霉烯酶基因为标准,评价3种方法检测肺炎克雷伯菌碳青霉烯酶的价值。结果 57株对碳青霉烯耐药的菌株中,PCR阳性40株,包括39株KPC,1株NDM-1,未检出其他耐药基因。MHT、CNPt、mCIM阳性率分别为87.7%(50/57)、89.5%(51/57)、91.2%(52/57)。60株敏感菌PCR均未检出碳青霉烯酶基因,3种表型筛选试验结果均为阴性。以PCR为金标准,MHT、CNPt、mCIM灵敏度分别为97.5%(39/40)、100%(40/40)和100%(40/40),特异度分别为85.7%(66/77)、85.7%(66/77)和84.4%(65/77)。结论 CNPt是一种可靠的表型筛选方法,可用于流行病学和医院感染的监测。mCIM操作简单,结果判断明确,更适合临床微生物实验室常规开展。     

某综合医院重症监护病房耐碳青霉烯类肺炎克雷伯菌环境流行调查

目的 调查重症监护病房（ICU）环境中耐碳青霉烯类肺炎克雷伯菌（CRKP）污染现状,以及CRKP主要耐药基因携带情况。方法 使用mSuper CARBA显色培养基对某院5个外科ICU中高频接触的物体表面、公共区域物体表面、水槽池壁和排水孔等采样标本进行菌株分离,采用MALDI-TOF质谱仪对目标菌进行鉴定,采用双纸片协同法对CRKP进行碳青霉烯酶表型鉴定,聚合酶链反应（PCR）方法检测KPC和NDM耐药基因。结果 CRKP在高频接触的物体表面（1/73）、公共区域物体表面（1/89）、护工的衣物（1/24）分离比例很低,但水槽排水孔（25/29）污染比例较高。碳青霉烯酶表型鉴定显示,5株产A类酶,11株产B类金属酶;PCR结果显示,2株携带KPC耐药基因,3株携带NDM耐药基因。结论 CRKP在ICU高频接触的物体表面定植率较低,而水槽排水孔污染率较高。耐药表型酶鉴定和PCR结果提示,严格执行环境清洁与消毒措施后,ICU内CRKP交叉传播的可能降低。     

骨科感染患者病原菌产肺炎克雷伯菌碳青霉烯酶的检测研究

目的对骨科患者感染的大肠埃希菌、阴沟肠杆菌、肺炎克雷伯菌、弗氏柠檬酸杆菌、褪色沙雷菌等进行肺炎克雷伯菌碳青霉烯(KPC)酶检测,为合理使用碳青霉烯类抗菌药物提供依据。方法选择2008年1月-2011年2月骨科感染患者分离的革兰阴性杆菌包括大肠埃希菌110株、阴沟肠杆菌15株、肺炎克雷伯菌145株、弗氏柠檬酸杆菌5株、褪色沙雷菌3株等共278株病原菌采用VITEK-2Compact、K-B纸片法进行药敏试验,以亚胺培南、美罗培南、厄他培南为检测药物,筛选出碳青霉烯类耐药菌株,用改良的Hodge试验筛选、聚合酶链反应(PCR)扩增,确认产KPC酶及基因分型。结果在278株病原菌中,对碳青霉烯类耐药的大肠埃希菌9株、阴沟肠杆菌10株、肺炎克雷伯菌16株,共35株进行改良Hodge试验,肺炎克雷伯菌阳性2株,2株肺炎克雷伯菌PCR扩增出现目的基因片段,其余菌株改良Hodge试验全部阴性。结论该项研究除2株肺炎克雷伯菌中发现目的基因片段,其他病原菌未发现产KPC酶的菌株。     

Emergence of carbapenem resistant Escherichia coli isolates producing blaNDM and blaOXA-48-like carried on IncA/C and IncL/M plasmids at two Iranian university hospitals

The emergence of carbapenem resistance among Escherichia coli is a serious threat to public health. The objective of this study was to investigate resistance genes and clonality of carbapenem resistant E. coli in Iran. Between February 2015 and July 2016, a total of 32 non-duplicate E. coli isolates that were ertapenem resistant or intermediate (R/I-ETP) were collected from patient clinical or surveillance cultures (rectal swabs) at two university hospitals. Resistance genes were identified by PCR and sequencing. Conjugation experiments, PCR-based replicon typing, PFGE and multilocus sequence typing (MLST) were performed. PCR assays showed, among the 32 isolates, twenty-nine strains produced carbapenemase genes. The predominant carbapenemase was bla_OXA-48 (82.8%), followed by bla_NDM-1 (31%), bla_NDM-7 (6.9%) and bla_OXA-181 (3.4%). Seven of the bla_NDM positive isolates co-harbored bla_OXA-48 carbapenemases. The bla_NDM and bla_OXA-48 were found in IncA/C and IncL/M conjugative plasmids, respectively. The bla_CTX-M-15, qnrA and intI1 genes were also present in most isolates. The PFGE revealed genetic diversity among the 28 E. coli isolates, which belonged to six minor PFGE clusters and 14 isolates were singletons. The 26 isolates were distributed into 18 STs, of which two were dominant (ST648 and ST167). We identified one bla_NDM-1-positive ST131 E. coli isolates that harbor the bla_CTX-M-15 and bla_TEM genes. Horizontal transfer of IncA/C and IncL/M plasmids has likely facilitated the spread of the bla_OXA-48 and bla_NDM genes among E. coli. Their clonal diversity and the presence of faecal carriers in isolates suggest an endemic spread of OXA-48 and NDM. Therefore, it emphasizes the critical importance of monitoring and controlling the spread of carbapenem resistant E. coli.     

CRKP碳青霉烯酶基因检测及同源性分析

目的 了解某院耐碳青霉烯类肺炎克雷伯菌（CRKP）碳青霉烯酶基因携带状况,以及菌株间的同源性,为预防和控制CRKP的克隆传播提供实验室依据。方法 收集2017年1-12月该院分离自临床各科室的CRKP 22株（K1~K22）,用药敏纸片扩散法和微量肉汤稀释法对药敏结果进行复核,采用改良Hodge试验和Carba NP试验检测菌株是否产碳青霉烯酶,应用PCR技术扩增产酶菌株常见的碳青霉烯酶基因并测序,运用多位点序列分型（MLST）和肠杆菌科基因间一致重复序列PCR（ERIC-PCR）进行同源性分析。结果 22株CRKP对厄他培南、亚胺培南、美罗培南的耐药率均为100%,对临床其他常见抗菌药物也高度耐药;13株改良Hodge试验阳性,14株Carba NP试验阳性。14株产酶菌株均携带KPC-2基因,K12菌株同时携带NDM-1基因。按MLST法可分为ST11（14株）、ST875（6株）、ST1964和ST571（各1株）,按ERIC-PCR法分型可分为A型（15株）、B型（6株）及C型（1株）。分型结果相同的菌株中K1~K6同属ICU,K7~K10同属脑血管外科,K15~K21同属新生儿科,对应患者有共同住院时间,且患者存在转科情况（K2、K8患者均由脑血管外科转入ICU,K13、K14分别从ICU转入血液内科、肾内科）。结论 该院2017年存在ST11型和ST875型CRKP的克隆流行,需加强医院感染预防与控制措施。     

Molecular characterization of class b carbapenemases in advanced stage of dissemination and emergence of class d carbapenemases in Enterobacteriaceae from Croatia

Carbapenemases involved in acquired carbapenem resistance in Enterobacteriaceae belong to Ambler class A serin β-lactamases, class B metallo-β-lactamases (MBL) or class D OXA-48-like β-lactamases. The aim of the present study was to analyse the molecular epidemiology and the mechanisms and routes of spread of class B and class D carbapenemases in Croatia.In total 68 isolates were analyzed. Antibiotic susceptibility was determined by broth microdilution method. PCR was used to detect antibiotic-resistance genes. Genotyping was performed by rep-PCR and MLST.Sixty-five isolates were found to harbour VIM-1 carbapenemase, seven of which were positive also for NDM-1, while two strains harboured only NDM-1. OXA-48 was detected in three isolates, two of which coproduced VIM-1. Thirty-six strains possessed additional CTX-M-15 β-lactamase whereas 64 were positive for TEM-1. CMY was found in 18 Citrobacter freundii isolates and DHA-1 in one Enterobacter cloacae isolate. Four different plasmid-incompatibility groups were found: A/C, L/M, N and FIIAs. Unlike C. freundii and E. cloacae, Klebsiella pneumoniae showed high diversity of rep-PCR patterns. E. cloacae and C. freundii predominantly belonged to one large clone which was allocated to ST105 and ST24, respectively.Three different types of carbapenemases were identified showing the complexity of CRE in Croatia.