大肠埃希菌和克雷伯菌临床分离株中整合子介导的多重耐药性的相关性分析Ⅰ

目的研究整合子介导的大肠埃希菌和肺炎克雷伯菌的多重耐药性。方法采用聚合酶链反应（PCR）对临床分离的135株大肠埃希菌和59株克雷伯菌进行Ⅰ型和Ⅱ型整合酶基因的检测。结果在135株大肠埃希菌和59株克雷伯菌中，大肠埃希菌产超广谱β-内酰胺酶（ESBLs）率为50．4％，克雷伯菌产ESBLs率为37.3％，共检出105株细菌携带Ⅰ类整合酶基因，72株为大肠埃希菌，占53.33％（72／135），33株肺炎克雷伯菌，占55.93％（33／59）；其中携带Ⅱ类整合酶基因3株，全部为大肠埃希菌，此3株同时携带Ⅰ类整合酶基因并产ESBLs。结论Ⅰ类整合子在大肠埃希菌和克雷伯菌中分布广泛。整合子与大肠埃希菌和克雷伯菌的耐药有关，即整合子阳性菌比整合子阴性菌更容易产生耐药。     

产ESBLs细菌在我地区流行状况及耐药性

目的：了解本地区2000年－2001年产ESBLs肺炎克雷伯菌和大肠埃希菌流行状况，为临床经验用药提供更合理的选择抗生素药物依据。方法：收集我院2000年－2001年各科室送检标本中分离的肺炎克雷伯菌568株，大肠埃希菌649株；选用双纸片协同试验及表型确证试验检测，结果：ESBLs检出，大肠埃希菌164株，肺炎克雷伯菌214株，分离率分别为25．2％和37．6％，总分离率为31％，产ESBLs细菌对抗生素的耐药性比非产ESBLs细菌有不同程度增加，但亚胺培南对所有产ESBLs细菌的是敏感的，结论：我院地处黑龙江中心地区，省内各市县危重患一般都送我院进行治疗，我院耐药率基本代表黑龙江省的耐药率，在ESBLs检测中，肺炎克雷伯菌和大肠埃希菌分离率最高，产ESBLs细菌对18种抗生素耐药比率不产ESBLs高，并出现多重耐药，所有菌株对亚胺培南均敏感。     

大肠埃希菌、肺炎克雷伯菌超广谱β-内酰胺酶的检测和耐药性监测分析

目的了解医院1998年1月至2006年12月期间临床分离的大肠埃希菌和肺炎克雷伯菌产超广谱β-内酰胺酶（ESBLs）的情况，监测并分析大肠埃希菌和肺炎克雷伯菌的耐药特性，为临床合理使用抗生素提供指导。方法对分离的大肠埃希菌和肺炎克雷伯菌采用纸片扩散法进行药物敏感试验，用筛选试验和确证试验确认产ESBLs菌株，用WHONET5．4软件进行数据分析。结果947株大肠埃希菌中，产ESBLs的有311株，占32．8％；293株肺炎克雷伯菌中，产ESBLs的有69株，占23．5％。产ESBLs菌株的耐药性显著高于非产ESBLs菌株（P〈0．05），产ESBLS菌株呈现多重耐药。结论医院产ESBLs菌的阳性率较高，应加强对产ESBLs菌株的耐药性监测，合理使用抗菌药物，防止ESBLs菌株的增长、扩散与流行。     

产超广谱β内酰胺酶肺炎克雷伯菌和大肠埃希菌耐药性检测

【目的】了解临床分离肺炎克雷伯菌和大肠埃希菌超广谱β内酰胺酶（ESBLs）产生情况及耐药性。【方法】用VITEK32型全自动细菌鉴定分析系统对临床标本中分离的123株肺炎克雷伯菌和大肠埃希菌进行鉴定，ESBLs采用双纸片扩散法检测，采用KB纸片法选用13种抗菌药物进行药敏分析。【结果】产ESBLs肺炎克雷伯菌和大肠埃希菌检出率分别为46．2％和40．5％，以呼吸道感染为主占50％。产ESBLs菌对多种抗生素的耐药性较非产酶株显著升高，对β一内酰胺类喹诺酮类和青霉素类抗生素几乎全部耐药，但对亚胺培南的敏感性为100％，对头孢西丁的敏感率〉60％。【结论】治疗产ESBLs肺炎克雷伯菌和大肠埃希菌首选是碳青霉烯类和头霉素类；应重视ESBLs的检测，合理使用抗生素。     

产ESBLs大肠埃希菌和肺炎克雷伯菌Ⅰ类整合子与耐药性关系

目的 研究产超广谱B-内酰胺酶(ESBLs)大肠埃希菌和肺炎克雷伯菌中Ⅰ类整合子的分布,探讨整合子介导的耐药机制在产ESBLs菌耐药性中的作用.方法 用PCR检测100株产ESBLs大肠埃希菌和肺炎克雷伯菌Ⅰ类整合酶基因及blaTEM、blaSHV和blaCTX-M基因,对Ⅰ类整合子阳性菌进行耐药基因盒检测并测序.结果...     

临床可疑产超广谱β-内酰胺酶大肠埃希菌和肺炎克雷伯菌的耐药性分析

目的了解可疑产超广谱β-内酰胺酶（ESBLs）大肠埃希菌和肺炎克雷伯菌的构成比和耐药情况,指导临床合理用药。方法对2008年7～12月住院患者各种临床标本,采用美国临床实验室标准化委员会推荐的表型筛选法分离到可疑产ESBLs大肠埃希菌和肺炎克雷伯菌,再经确认试验检测产ESBLs菌株,统计耐药分布情况。结果从248株阳性标本中共检出可疑产ESBLs菌株117株,其中大肠埃希菌38株,肺炎克雷伯菌79株;确证试验检测出产ESBLs菌82株,总检出率为33．1％,其中大肠埃希菌27株,肺炎克雷伯菌55株。确定为产ESBLs的菌株对氨苄西林、部分第3代头孢菌素的耐药率为100．0％,对磺胺类、喹诺酮类耐药率为60．0％～90．0％,对亚胺培南的耐药率为0．0％。结论产ESBLs的大肠埃希菌和肺炎克雷伯菌对多种抗菌药物的耐药率明显高于非产ESBLs菌株,具有多重耐药性;而碳青霉烯类亚胺培南仍然是对产ESBLs细菌最有效的药物。     

我院对产超广谱β-内酰胺酶细菌的表型监测和耐药性分析

目的：监测分析2004年9月～2005年12月广东省中医院临床标本中分离的大肠埃希菌和肺炎克雷伯菌产ESBLs的状况及其耐药性，为临床的合理用药提供依据。方法：用美国临床实验室标准化委员会（NCCLS）推荐的确证实验进行ESBLs的检测，用纸片扩散法进行药敏分析。结果：从152株大肠埃希菌中检出ESBLs阳性65株（42．76％），从105株肺炎克雷伯菌检出ESBLs阳性41株（39．05％），产ESBLs株对亚胺培南，哌拉西林／他唑巴坦等药的敏感率较高。结论：我院分离的大肠埃希菌和肺炎克雷伯菌产ESBLs的状况较高，临床应该是在药敏试验的基础上针对具体的菌株和病人症状，选用亚胺培南，哌拉西林／他唑巴坦等药物进行治疗。     

广州地区1998～2003年大肠埃希氏和肺炎克雷伯菌耐药性监测

目的：了解广州地区大肠埃希氏和肺炎克雷伯菌的耐药状况。方法：对12家医院1998～2003年从各种临床标本收集的1646株大肠埃希氏菌和1175株肺炎克雷伯菌，用K—B纸片法进行药敏试验，测定这些菌株对21种临床常用抗生素的耐药性。结果：只发现一株大肠埃希氏菌对亚胺培南耐药，对大肠埃希氏菌耐药率在10％以下的抗生素分别为哌拉西林／三唑巴坦（6．2％）、头孢他啶（6．6％）、头孢哌酮／舒巴坦（8．4％）和阿米卡星（8．3％），对肺炎克雷伯菌耐药率在10％以下的抗生素只有头孢舭肟（9．8％）和头孢哌酮／舒巴坦（9．3％）。环丙沙星对大肠埃希氏菌的耐药率在70％左右，而肺炎克雷伯菌只有30％左右，肺炎克雷伯菌对阿米卡星和头孢他啶的耐药率明显高于大肠埃希氏菌，在头孢西丁耐药菌株中这种差异更加突出。结论：5a监测中，两类细菌对临床常用大部分抗生素的耐药性没有明显改变，但对部分抗生素的耐药性各有特性，对本地区细菌进行系统、全面的耐药性监测是很有必要的。     

产超广谱β-内酰胺酶菌株的药敏分析

目的了解肺炎克雷伯菌、大肠埃希菌及产酸克雷伯菌产超广谱β-内酰胺酶（ESBLs）菌株的发生率及耐药特点，指导此类细菌感染的抗菌药物的应用。方法收集2003年6月至2004年6月我院感染患者中分离出来的肺炎克雷伯菌、大肠埃希菌和产酸克雷伯菌218株，用表型确认试验检测ESBLs，用美国Microscan negative panel 21反应板作细菌鉴定和药敏试验。结果218株肺炎克雷伯菌、大肠埃希菌及产酸克雷伯菌中，共检出产ESBLs 70株，检出率为32．11％，其中肺炎克雷伯菌为36．7％，大肠埃希菌为33．33％，产酸克雷伯菌为25．45％；除亚胺培南、哌拉西林／他唑巴坦和头孢西丁外，产ESBLs菌对其他15种抗生素的耐药率均显著高于非产ESBLs菌；亚胺培南、哌拉西林／他唑巴坦和头孢西丁对产ESBLs菌的耐药率最低。结论肺炎克雷伯菌、大肠埃希菌及产酸克雷伯菌产ESBLs情况严重，产ESBLs菌对大多数抗生素耐药性比非产ESBLs菌严重，亚胺培南、哌拉西林／他唑巴坦和头孢西丁是治疗由产ESBLs菌引起感染的有效抗生素。     

重症监护病房患者大肠埃希菌和肺炎克雷伯菌多重耐药性分析

目的 探讨重症监护病房（ICU）患者大肠埃希菌和肺炎克雷伯菌多重耐药性,为临床提供治疗依据.方法 回顾分析ICU病房患者标本中分离的280株大肠埃希菌和肺炎克雷伯菌耐药性.结果 大肠埃希菌和肺炎克雷伯菌多数来自痰标本,其中产超广谱β-内酰胺酶（ESBLs）136株（48.6%）,产AmpC β-内酰胺酶10株（3.6%）,同时产两种酶2株（1.1%）.抗生素耐药显示：携带产 ESBLs和AmpC酶菌株都有较高耐药性;产 ESBLs菌株对亚胺培南较为敏感（94.8%）,其次是哌拉西林/他唑巴坦（36.1%）;而AmpC酶菌株对亚胺培南的敏感率仅为48.4%.结论 ICU病房大肠埃希菌和肺炎克雷伯菌均有较高的耐药性,因此必须合理应用抗生素.     

The role of horizontal gene transfer in the spread of trimethoprim-sulfamethoxazole resistance among uropathogenic Escherichia coli in Europe and Canada

OBJECTIVES: To describe the distribution of trimethoprim-sulfamethoxazole resistance genes and the role of horizontal gene transfer and clonal expansion in recent increases of antibiotic resistance rates among uropathogenic Escherichia coli in Europe and Canada. METHODS: We identified antibiotic resistance alleles sul1, sul2, sul3 and dfr along with type 1 and type 2 integrons among 350 uropathogenic E. coli isolates from a cross-sectional study of acute, uncomplicated, community-acquired urinary tract infections in 16 western European countries and Canada (ECOSENS). RESULTS: Trimethoprim resistance gene distributions showed no regional dependency (P = 0.84). The most common trimethoprim resistance gene was dfrA1, which occurred in 37.9% of dfr containing isolates. Similarly, the sulfamethoxazole resistance gene distributions did not vary significantly by region (P = 0.20). sul2, the most common sulfamethoxazole resistance gene, was found in 77.9% of sulfamethoxazole-resistant isolates. The distribution of type 1 and type 2 integrons varied slightly by region (P = 0.04) with type 1 integrons being the more common (85.9%). We observed 34 combinations of the sul genes, dfr genes and integron types; the most common combinations were broadly disseminated across every region examined. CONCLUSIONS: Horizontal gene transfer plays a larger role than clonal expansion in the increase of trimethoprim-sulfamethoxazole resistance levels in Europe and Canada.     

鲍曼不动杆菌Ⅰ类整合子系统与其耐药性关系的研究

目的了解Ⅰ类整合子系统在鲍曼不动杆菌中的分布状况,探讨其与该菌耐药性之间的关系。方法用琼脂稀释法测定鲍曼不动杆菌对14种抗生素的敏感性。用PCR法检测Ⅰ类整合子系统。结果29.2%(21/72)的菌株检测出Ⅰ类整合子系统。含与不含Ⅰ类整合子系统的菌株在耐药性上存在显著性差异(P<0.05)。不同类型Ⅰ类整合子的耐药表型存在一定的差异。结论Ⅰ类整合子系统与鲍曼不动杆菌多重耐药性以及耐药表型之间有密切的关系。     

Evolution of multidrug-resistant Acinetobacter baumannii isolates obtained from elderly patients with respiratory tract infections

OBJECTIVES: To study the evolution between 1999 and 2002 and mechanisms of antibiotic resistance in a multidrug-resistant Acinetobacter baumannii clone predominant in isolates from elderly patients with respiratory tract infections. METHODS: Susceptibility to antimicrobials was determined using an agar dilution method. Bacterial clones were identified by PCR-fingerprinting and PFGE with ApaI. Carbapenemases were detected by phenotypic tests; by PCR with primers specific for bla (OXA-40), bla(IMP), bla(VIM-1) and bla(VIM-2); and by hybridization with DNA probes. Class 1 integrons were detected using PCR. RESULTS: In 1999 isolates were grouped into two main genotypes: clone I (33%) and clone II (55%). These were also detected in 2002 with a different distribution: clone I (69%), clone II (22%). Resistance to amikacin, meropenem and imipenem increased significantly in clone I over this time, whereas clone II was not affected. In 2002, the incidence of bla(OXA-40) rose to 91% in clone I isolates with some also harbouring bla(VIM-2) and bla(IMP) genes. Different class 1 integrons were detected ranging in size from 550 to 1200 bp. No relationship was found between carbapenemases and class 1 integrons. CONCLUSIONS: In elderly patients, a single clone became predominant among A. baumannii isolates, coinciding with an increase in antibiotic resistance rates. The majority of isolates harboured the bla(OXA-40) carbapenemase gene and some of them also harboured bla(VIM-2) and bla(IMP) genes. The presence of class 1 integrons also increased over time.     

Characterization of class 1 integrons associated with R-plasmids in clinical Aeromonas salmonicida isolates from various geographical areas

Class 1 integrons were found in 26 of 40 antibiotic-resistant isolates of the fish pathogen Aeromonas salmonicida from Northern Europe and North America. Three different dhfr genes, conferring trimethoprim resistance, and one ant(3")1a aminoglycoside resistance gene were identified as gene inserts. The gene cassettes tended to be conserved among isolates from a particular geographical area. Nineteen isolates transferred R-plasmids carrying different tet determinants to Escherichia coli in filter mating assays, and in 15 cases, the class 1 integrons were co-transferred. Transferable sulphadiazine, trimethoprim and streptomycin resistances were invariably encoded by integrons. It thus appears that integron-encoded antibiotic resistance genes contribute substantially to the horizontal spread of antimicrobial resistance within this species, being associated with conjugative plasmids.     

Incidence and characterization of integrons, genetic elements mediating multiple-drug resistance, in avian Escherichia coli

Antibiotic resistance among avian bacterial isolates is common and is of great concern to the poultry industry. Approximately 36% (n = 100) of avian, pathogenic Escherichia coli isolates obtained from diseased poultry exhibited multiple-antibiotic resistance to tetracycline, oxytetracycline, streptomycin, sulfonamides, and gentamicin. Clinical avian E. coli isolates were further screened for the presence of markers for class 1 integrons, the integron recombinase intI1 and the quaternary ammonium resistance gene qacEDelta1, in order to determine the contribution of integrons to the observed multiple-antibiotic resistance phenotypes. Sixty-three percent of the clinical isolates were positive for the class 1 integron markers intI1 and qacEDelta1. PCR analysis with the conserved class 1 integron primers yielded amplicons of approximately 1 kb from E. coli isolates positive for intI1 and qacEDelta1. These PCR amplicons contained the spectinomycin-streptomycin resistance gene aadA1. Further characterization of the identified integrons revealed that many were part of the transposon Tn21, a genetic element that encodes both antibiotic resistance and heavy-metal resistance to mercuric compounds. Fifty percent of the clinical isolates positive for the integron marker gene intI1 as well as for the qacEDelta1 and aadA1 cassettes also contained the mercury reductase gene merA. The correlation between the presence of the merA gene with that of the integrase and antibiotic resistance genes suggests that these integrons are located in Tn21. The presence of these elements among avian E. coli isolates of diverse genetic makeup as well as in Salmonella suggests the mobility of Tn21 among pathogens in humans as well as poultry.     

Molecular characterization of class 1 integrons and antimicrobial resistance in Aeromonas strains from foodborne outbreak-suspect samples and environmental sources in Taiwan

One hundred thirty-three Aeromonas spp. isolates were examined for multiple antibiotic resistance phenotypes and prevalence of class 1 integron sequences. Twenty-four (18.0%) of these isolates contained class 1 integron. Seven different class 1 integrons were found among 24strains, with a total of 10 different gene cassettes encoding for resistance to trimethoprim (dfr12 and dfr2d), aminoglycosides (aadA1 and aadA2), beta-lactam antibiotics (oxa2), chloramphenicol (catB3 and catB8), quaternary ammonium amines (qacE2), and 2 ORFs (orfD and orfF) with unknown function. Rate of antibiotic resistance was different between integron-positive and integron-negative strains. Trimethoprim and trimethoprim-sulphamethoxazole resistances were commonly associated with integron, and all of integron-positive isolates were multiple resistant to more than 3 agents. Resistance to as many as 10 antimicrobial agents were observed in integron-positive strains. Several cassette arrays of class 1 integrons identified in this study were not previously reported in Aeromonas strains. This study demonstrates the wide distribution of class 1 integron in Aeromonas spp. isolated from foodborne outbreak-suspect samples and environmental sources in Taiwan.     

鲍曼不动杆菌整合子相关耐药基因研究

目的了解我院鲍曼不动杆菌整合子流行情况，证实整合子与鲍曼不动杆菌多重耐药性的关系，建立一种快速简便的整合酶聚合酶链反应（PCR）检测方法。方法收集我院2005年9月至2006年2月临床分离的鲍曼不动杆菌共52株，用纸片扩散法检测鲍曼不动杆菌耐药性及用整合酶PCR检测其整合子基因。结果在52株鲍曼不动杆菌中，整合酶PCR检测出Ⅰ类整合子33株（63％），未检测出Ⅱ类整合子。统计学分析结果显示，整合子阴性和阳性的鲍曼不动杆菌对各种抗生素的耐药率存在明显差异，前者仅对几种抗生素耐药而后者对多种抗生素耐药。结论我院多重耐药鲍曼不动杆菌中主要为Ⅰ类整合子，整合酶PCR是一种快速、简便、易在临床开展的检测方法，同时也是控制医院感染的有效检测手段。     

铜绿假单胞菌整合子基因盒的相关研究

目的对北京大学人民医院不同年度临床分离的铜绿假单胞菌进行整合子基因盒检测,分析其变化趋势及其与细菌耐药性的相关性。方法应用PCR对2006—2008年临床分离的420株铜绿假单胞菌进行整合子检测,对阳性PCR产物采用HinfⅠ内切酶作限制片段多态性(RFLP)分析进行整合子分类,并对整合子阳性株进行耐药基因盒的扩增与测序。结果 420株铜绿假单胞菌中116株(27.6%)检出Ⅰ类整合子,未检出Ⅱ、Ⅲ类整合子。对2006年及2008年的整合子阳性菌株可变区基因盒扩增得到7种不同的基因盒图谱,片段大小在710～2526bp,基因盒为介导氨基糖苷类抗生素耐药的aadB、aadA族和介导甲氧苄啶耐药的dfrA1和dhfrXVB。结论该院铜绿假单胞菌中整合子检出率随年度呈上升趋势,携带的基因盒与其耐药表型有相关性。     

整合子介导的大肠埃希菌临床菌株多重耐药研究

目的　了解大肠埃希菌多重耐药菌株中 1、2类整合酶基因的携带情况,研究整合子与抗生素多重耐药的相关性。方法　对 102株大肠埃希菌临床分离株做药物敏感性分析和整合子的PCR基因检测。结果　102株大肠埃希菌对 11种抗生素的耐药率为:氨苄青霉素(94% )、庆大霉素 ( 88% )、环丙沙星 ( 88% )、阿莫西林 /克拉维酸 ( 70% )、头孢唑啉 ( 62% )、头孢他啶(50% )、哌拉西林(41% )、哌拉西林 /他唑巴坦(38% )、头孢哌酮 /舒巴坦(29% )、丁胺卡那 (24% )和泰能 (2% )。102株大肠埃希菌中 51%找到不同插入大小的整合子,插入基因盒大小范围是 650bp到 2 600bp;intⅠ1整合酶基因检出率为 85%,PCR扩增出 280bp大小的intⅠ1基因片段,而未检测到intⅠ2整合酶基因。结论　1类整合子在大肠埃希菌多重耐药菌株中最常见,整合子的存在与细菌的多重抗生素耐药有密切关系。     

Characterization of antimicrobial resistance and class 1 integrons found in Escherichia coli isolates from humans and animals in Korea

OBJECTIVES: Antimicrobial resistance and class 1 integrons found in Escherichia coli isolates from humans and animals in Korea were characterized. METHODS: E. coli isolates were examined for susceptibility to antimicrobial agents. Integrase genes were amplified. Gene cassette regions for classes 1 and 2 integrons were amplified and sequenced. Conjugal transfer and Southern hybridization were performed to determine the genetic localization of class 1 integrons. The clonal relationship of E. coli isolates carrying an identical cassette array was analysed by PFGE. RESULTS: Commensal E. coli isolates from animals were highly resistant to commonly used antimicrobial agents such as tetracycline, sulfamethoxazole, streptomycin, ampicillin and carbenicillin. Integrons were most prevalent in commensal E. coli isolates from poultry (44%), followed by clinical isolates from humans (33%), commensal isolates from swine (23%) and humans (13%). dfrA17-aadA5, dfrA12-orfF-aadA2 and aadA1 were found most frequently in E. coli isolates from humans, poultry and swine, respectively. Class 1 integrons were mostly located in conjugative plasmids. E. coli isolates carrying an identical cassette array were phylogenetically unrelated. CONCLUSIONS: The use of antibiotics is strongly associated with antimicrobial resistance. E. coli isolates from different sources may select a specific gene cassette by antibiotic selective pressure, which results in differences in class 1 integrons. The horizontal transfer of class 1 integrons through conjugative plasmids seems to be responsible for wide dissemination of a particular type of class 1 integron.