产超广谱β-内酰胺酶细菌的检测和耐药性监测

目的:分析我院产超广谱β内酰胺酶(ESBL)菌的流行情况及其对常用抗生素的耐药性,为临床合理选择抗生素提供依据。方法:对我院2003年1月至2004年6月临床标本中分离的肺炎克雷伯氏菌和大肠埃希氏菌,采用Vitek32全自动细菌鉴定和药敏分析仪进行ESBL检测和药敏实验。结果:34.3%(65/189)的肺炎克雷伯氏菌和35.6%(158/444)大肠埃希氏菌产ESBL,产ESBL菌对青霉素类、头孢菌素类和单环类抗生素耐药率在90%以上,对三代头孢菌素、单环类(氨曲南)、氨基糖苷类(庆大霉素)、喹诺酮类(环丙沙星、左旋氧氟沙星)的耐药率明显高于不产ESBL菌(P<0.05);对加酶抑制剂的复合药如阿莫西林/棒酸、哌拉西林/他唑巴坦的耐药率也显著高于不产ESBL菌(P<0.05)。产ESBL和不产ESBL肺炎克雷伯氏菌和大肠埃希氏菌对亚胺培能均未发现耐药。结论:ESBL细菌的监测对临床用药具有重要意义。     

十二岁以内患儿大肠埃希氏菌和肺炎克雷伯氏菌的耐药性监测

目的：了解年龄小于或等于12岁儿童病患儿大肠埃希氏菌和肺炎克雷伯氏菌的超广谱β-内酰胺酶(ESBb)发生率和耐药性，以便结合《抗菌药物临床应用指导原则》指导临床用药。方法：采用纸片扩散法对2003年10月至2004年10月临床分离的，患者年龄小于或等于12岁儿童205株大肠埃希氏菌和肺炎克雷伯氏菌进行药敏试验．采用双纸片增效试验法按NCCLS2000年版标准检测出ESBLs株，并对阿莫西林／克拉维酸、头孢类等抗生素做药敏试验，分析其耐药性。结果：37．3％(31／83)大肠埃希氏菌产ESBLs；16．4％(20／122)肺炎克雷伯氏菌产ESBLs。结论：治疗大肠埃希氏菌和肺炎克雷伯氏菌引起的感染，要充分了解菌株的耐药性和是否产ESBLs菌株，对产ESBLs菌株应用亚胺培南、β-内酰胺类／β-内酰胺抑制复合物、头孢菌素类药物。同时要注意传统抗生素的使用，结合《抗菌药物临床应用指导原则》指导临床用药。     

产ESBLs大肠埃希菌和肺炎克雷伯菌的检测及其基因分析

目的了解临术分离菌中产超广谱β内酰胺酶（ESBLs）大肠埃希菌和肺炎克雷伯菌发生率，分析其耐药表型，探讨其ESBLs基因类别。方法采用美国国家临床实验室标准化委员会（NCCLS）推荐的纸片扩散法，对364株大肠埃希菌和71株肺炎克雷伯菌进行产ESBLs菌株初筛试验，并用双纸片确证试验和双纸片协同试验进行产ESBLs菌株确证。按照NCCLS文件标准，用Kirby-Bauer纸片扩散法进行产ESBLs株21种抗生素药敏试验。用PCR方法扩增168株ESBLs表型阳性菌中blaTEM-1、blaSHV-1、CTX-M-1组、TOHO-1组等4种基因。结果（1）大肠埃希菌和克雷伯菌中产ESBLs的检出率分别为46．7％和32．4％。（2）产ESBLs菌对青霉素类100％耐药；对第1、2代头孢菌素耐药率达85％～100％；对除头孢他定以外的第3代头孢菌素，产ESBLs大肠埃希菌耐药率为80％以上，产ESBLs肺炎克雷伯菌耐药率为65％～75％以上；产ESBLs菌对复方新诺明的耐药率为75％～85％；产ESBLs大肠埃希菌对环丙沙星耐药率为80％～90％、庆大霉素耐药率为50％～75％；产ESBLs菌对阿米卡星、头孢替坦、亚胺培南有较好的敏感性（80％～90％以上）。（3）产ES-BLs大肠埃希菌中，blaTEM-1、blasSHV-1、CTX-M-1组等3种基因扩增阳性率分别为93．9％、7．4％和53．4％。51．4％的菌株同时携带2种耐药基因，2．7％的菌株同时携带3种耐药基因。产ESBLs肺炎克雷伯菌中blatTEM-1、blaSHV-1、CTX-M-1组等3种基因扩增阳性率分别为50．0％、95．0％和20．0％。同时携带2种耐药基因的菌株占35．0%，同时携带3种耐药基因的菌株占15．0％。两种细菌中均未检出TOHO-1组基因。结论大肠埃希菌和肺炎克雷伯菌中产ESBLs的检出率较高，大肠埃希菌中产ESBLs菌比例有逐年上升趋势。产ESBLs菌对头孢噻肟的耐药率远高于头孢他定，且多数菌株对青霉素类，第1、2、3代头孢菌素、喹诺酮类、磺胺类、氨基糖甙类等抗生素呈多重耐药。大肠埃希菌中以TEM型和CTX-M型基因为主。肺炎克雷伯菌以SHV型基因为主，同时存在TEM型和CTX-M型基因。     

对大肠埃希菌产生β-内酰胺酶和超广谱β-内酰胺酶的探讨

目的：探讨大肠埃希菌产β－内酰胺酶和超广谱β－内酰胺酶（ESBL）之间的关系及耐药性。方法：采用纸片扩散法（K－B法）、Nitrocefin法对该字感染标本中分离的108株大肠埃希氏菌分别进行药敏试验、β－内酰胺酶、ESBL的检测。结果：108株大肠埃希氏中60株产β－内酰胺酶（56％）、ESBL发生率为36％（39株），其中产两种酶的有36株，有3株产ESBL而不产β－内酰胺酶。产β－内酰胺酶株对青霉素，一、二代头孢菌素耐药率为62％－100％，对三代头孢菌素的耐药率为39％－40％；产ESBL的菌株，对青霉素类，一、二、三代头孢菌素均耐药。泰能的敏感率为100％，舒普深为95％。结论：常规检测β－内酰胺酶、ESBL，有利于耐药机制的探讨，对指导临床合理用药，控制ESBL菌株的爆发流行有重要价值。     

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。     

临床产超产谱β-内酰胺酶大肠埃希菌和肺炎克雷伯菌耐药性分析

目的了解2006年产超广谱β-内酰胺酶（ESBLs）大肠埃希菌和肺炎克雷伯菌的耐药性，为临床合理使用抗菌药物提供依据。方法采用法国梅里埃公司API细菌鉴定系统对菌株进行鉴定，药敏试验采用KB纸片扩散法，产ESBLs细菌的检测采用双纸片确认法。结果检出产ESBLs菌株290株，检出率为64．3％，其中大肠埃希菌201株，检出率为66．3％，肺炎克雷伯菌89株，检出率为60．1％；产ESBLS菌株对抗菌药物的耐药率高于非产ESBLs菌株；产ESBLs菌株对头孢菌素类、氨基糖甙类、喹诺酮类抗菌药物大多耐药，对碳青霉烯类、含β-内酰胺酶抑制剂复合物耐药率低。结论应重视ESBLs细菌检测，根据药敏结果合理使用抗菌药物，产ESBLs大肠埃希菌和肺炎克雷伯菌感染应首选碳青霉烯类和含β-内酰胺酶抑制剂复合物。     

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-内酰胺酶的大肠埃希菌和肺炎克雷伯菌耐药性分析

目的：了解临床产超广谱β-内酰胺酶（ESBL）大肠埃希菌和肺炎克雷伯菌的情况以及对常用抗生素的耐药现状,为临床合理用药提供依据。方法：对从病人标本中分离的373株菌株用WITEK-60全自动微生物鉴定仪及配套的GNI＋鉴定卡进行菌种鉴定;药敏试验采用K-B法,按美国临床实验室标准化委员会制定的标准判定结果。结果：本组共分离出大肠埃希菌244株,其中产ESBL菌株106株,检出率为43.4%;肺炎克雷伯菌129株,其中产ESBL菌株58株,检出率为45.0%。检出产ESBL菌株标本位于前5位的分别为中段尿液、痰、分泌物、胆汁及血液。产ESBL菌株较非产ESBL菌株对抗生素的耐药率高,除头孢他啶外,对第二、三代头孢菌素的耐药率均〉70%,对其他抗生素均存在不同程度的耐药,两者对亚胺培南-西拉司丁钠、美洛培南均100%敏感。结论：产ESBL的大肠埃希菌和肺炎克雷伯菌检出率高,耐药性强,临床应合理应用抗生素,以避免产ESBL菌株感染的暴发流行。     

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。     

下呼吸道感染产超广谱β-内酰胺酶菌株的耐药情况分析

目的 研究下呼吸道感染患者中大肠埃希菌和肺炎克雷伯菌产超广谱β-内酰胺酶(ESBLs)及产ESBLs菌株的药敏情况。方法 收集2002年1月至2003年12月我院下呼吸道感染患者中分离出的大肠埃希菌和肺炎克雷伯菌137株，用表型确证试验检测ESBLs；用Kirby-Bauer琼脂扩散法作药物敏感试验。结果 137株大肠埃希菌和肺炎克雷伯菌中，共检出产ESBLs菌84株，检出率为61．31％，其中大肠埃希菌75．51％、肺炎克雷伯菌53．41％；对哌拉西林、哌拉西林／他唑巴坦、氯霉素、环丙沙星、复方磺胺甲基异噁唑、亚胺培南和美罗培南耐药率差异无统计学意义，产ESBLs菌株对其他13种抗生素的耐药率均显著高于非产ESBLs菌株(P≤0．01)，亚胺培南和美罗培南的敏感率最高为100％。结论 下呼吸道感染患者中大肠埃希菌和肺炎克雷伯菌产ESBLs情况严重，治疗本地区产ESBLs菌株下呼吸道感染首选碳青霉烯类抗生素。     

In vitro Activity of Tigecycline and Molecular Characterization of Extended-Spectrum Beta-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae Isolates from a University Hospital in South-Western Germany

Background: Extended-spectrum β-lactamase (ESBL)-producing organisms are spreading worldwide in hospital and community settings. Methods: A total of 328 unduplicated ESBL-producing Enterobacteriaceae isolated in 2008 and 2009 at the University Hospital of Tübingen were analysed retrospectively. Results: Escherichia coli (n = 253) and Klebsiella spp. (n = 46) were the most frequent ESBL-producing species. The ESBL rates among E. coli and Klebsiella spp. increased from 3.8 and 2.1%, respectively, in 2008, to 5.2 and 2.4%, respectively, in 2009. Two E. coli and 3 Klebsiella pneumoniae ESBL producers were non-susceptible to ertapenem, most likely due to loss of porins. Antimicrobial susceptibility testing of selected, molecularly characterized ESBL producers revealed susceptibility to tigecycline among 97.9% (191/195) of the E. coli and 78.8% (26/33) of the K. pneumoniae isolates. PCR analysis and sequencing showed the presence of CTX-M-type enzymes in 91.3% of the E. coli and 87.9% of the K. pneumoniae isolates, whereby bla(CTX-M-15) was the most frequent ESBL gene both in E. coli (50.0%) and K. pneumoniae (51.5%). Only 7 single cases of potential patient-to-patient transmissions of E. coli strains were observed. Conclusions: Our data suggest that the increase in ESBL-producing E. coli and K. pneumoniae isolates at our hospital is mainly caused by growing import of Enterobacteriaceae harbouring CTX-M-type ESBLs.     

产ESBLs大肠埃希菌和肺炎克雷伯菌的检测及其基因分析

目的了解临床分离菌中产超广谱β内酰胺酶(ESBLs)大肠埃希菌和肺炎克雷伯菌发生率,分析其耐药表型,探讨其ESBLs基因类别。方法采用美国国家临床实验室标准化委员会(NCCLS)推荐的纸片扩散法,对364株大肠埃希菌和71株肺炎克雷伯菌进行产ESBLs菌株初筛试验,并用双纸片确证试验和双纸片协同试验进行产ESBLs菌株确证。按照NCCLS文件标准,用KirbyBauer纸片扩散法进行产ESBLs株21种抗生素药敏试验。用PCR方法扩增168株ESBLs表型阳性菌中blaTEM1、blaSHV1、CTXM1组、TOHO1组等4种基因。结果(1)大肠埃希菌和克雷伯菌中产ESBLs的检出率分别为46.7%和32.4%。(2)产ESBLs菌对青霉素类100%耐药;对第1、2代头孢菌素耐药率达85%～100%;对除头孢他定以外的第3代头孢菌素,产ESBLs大肠埃希菌耐药率为80%以上,产ESBLs肺炎克雷伯菌耐药率为65%～75%以上;产ESBLs菌对复方新诺明的耐药率为75%～85%;产ESBLs大肠埃希菌对环丙沙星耐药率为80%～90%、庆大霉素耐药率为50%～75%;产ESBLs菌对阿米卡星、头孢替坦、亚胺培南有较好的敏感性(80%～90%以上)。(3)产ESBLs大肠埃希菌中,blaTEM1、blaSHV1、CTXM1组等3种基因扩增阳性率分别为93.9%、7.4%和53.4%。51.4%的菌株同时携带2种耐药基因,2.7%的菌株同时携带3种耐药基因。产ESBLs肺炎克雷伯菌中blaTEM1、blaSHV1、CTXM1组等3种基因扩增阳性率分别为50.0%、95.0%和20.0%。同时携带2种耐药基因的菌株占35.0%,同时携带3种耐药基因的菌株占15.0%。两种细菌中均未检出TOHO1组基因。结论大肠埃希菌和肺炎克雷伯菌中产ESBLs的检出率较高,大肠埃希菌中产ESBLs菌比例有逐年上升趋势。产ESBLs菌对头孢噻肟的耐药率远高于头孢他定,且多数菌株对青霉素类,第1、2、3代头孢菌素、喹诺酮类、磺胺类、氨基糖甙类等抗生素呈多重耐药。大肠埃希菌中以TEM型和CTXM型基因为主。肺炎克雷伯菌以SHV型基因为主,同时存在TEM型和CTXM型基因。     

Prevalence of important pathogens and the antimicrobial activity of parenteral drugs at numerous medical centers in the united states II. Study of the intra- and interlaboratory dissemination of extended-spectrum β-lactamase-producing Enterobacteriaceae

The incidence of extended-spectrum β-lactamases (ESBL)-producing Klebsiella pneumoniae and Escherichia coli has been increasing rapidly, and they are probably even more prevalent than is currently recognized because of difficulties in their detection by the clinical microbiology laboratory. In addition, several outbreaks associated with these multiresistant strains have been reported. In the present study we evaluated 30 clinical isolates (27 K. pneumoniae from 11 hospitals and three E. coli from three hospitals) that were resistant or intermediately susceptible to ceftazidime and/or cefuroxime. The main objective of the study was to evaluate the intra- and interhospital dissemination of ESBL-producing strains. The isolates were tested for susceptibility to ceftazidime, cefuroxime, gentamicin, and ofloxacin, and the ability of various susceptibility testing methods to detect resistance to these β-lactams was evaluated. The production of ESBL was assessed by the disk approximation synergy test, and typing was performed by pulsed-field gel electrophoresis (PFGE) of chromosomal DNA. ESBL production was demonstrated in 15 K. pneumoniae (from seven hospitals) and in one E. coli strain. Most ESBL-producing isolates demonstrated cross resistance with gentamicin and ofloxacin. Chromosomal DNA analysis by PFGE exhibited a great genomic variability among ESBL-producing isolates. Our results also indicated the occurrence of both intra- and interhospital dissemination of these multiresistant strains.     

Prevalence of extended spectrum beta-lactamase (ESBL)-producing clinical isolates in the Asia-Pacific region and South Africa: regional results from SENTRY Antimicrobial Surveillance Program (1998-99)

The frequency of occurrence of ESBL-producing clinical strains varies widely in distinct geographic areas. The objective of this study was to describe the frequency of occurrence, the preferred substrate, and the co-resistance patterns of the ESBL-producing isolates collected from the Asia-Pacific region and South Africa through the SENTRY Antimicrobial Surveillance Program between January 1998 and December 1999. A total of 1,377 Escherichia coli, 678 Klebsiella pneumoniae, and 138 Proteus mirabilis isolates were collected from diverse body sites. Using NCCLS criteria, 139 E. coli (10.1%), 171 K. pneumoniae (25.2%), and 2 P. mirabilis (1.4%) had presumptive ESBL phenotypes; 100, 146 and 1 strain respectively were confirmed to be ESBL producers on clavulanate enhancement testing. The frequency of occurrence of confirmed ESBL-producing E. coli by the medical centers varied from 0-1% for centers located in Australia to 13-35% for mainland Chinese centers. The higher prevalence rates (>20%) of ESBL K. pneumoniae phenotypes were observed in all mainland Chinese centers, one Japanese and one Taiwanese center, and in the Philippine, South African, Singaporean and medical centers. The spread of the presumptive ESBL phenotype to the Enterobacter species was observed in nine medical centers. Overall, ceftriaxone and aztreonam were the best substrates for the detection of the ESBL phenotype between both E. coli isolates and K. pneumoniae ESBL phenotypes; however, there was significant variation between countries in substrate preference. Co-resistances to gentamicin, tobramycin, tetracycline, and trimethoprim-sulfamethoxazole were common throughout isolates collected from most medical centers. Ciprofloxacin resistance rates were very high among isolates collected from Hong Kong, mainland China, Singapore, and the Philippines. The best coverage against ESBL-producing isolates was obtained with imipenem (0% resistance), followed by amikacin (6% resistance).     

Evaluation of MicroScan ESBL confirmation panel for Enterobacteriaceae-producing,extended-spectrum beta-lactamases isolated in Japan

We assessed use of the MicroScan ESBL confirmation panel (Dade Behring, Tokyo, Japan) for the detection of eight Enterobacteriaceae-producing extended-spectrum beta-lactamases (ESBL) species. Of 137 bacterial strains isolated from patients in 32 hospitals in the Kinki area of Japan, 91 produced ESBL and comprised 60 bacteria (of E. coli, K. oxytoca, and K. pneumoniae) targeted by the NCCLS ESBL test and 31 non-target bacteria such as chromosomal AmpC-producing bacteria (e.g., Serratia marcescens, Enterobacter spp.). Sensitivity and specificity of the MicroScan panel for the target bacteria were 92% and 93%, respectively; sensitivity and specificity for non-target bacteria were 52% and 100%, respectively. There were 20 ESBL-positive strains that were not inhibited by clavulanic acid in the MicroScan panel (3 of 32 ESBL-producing E. coli strains, 1 of 24 K. pneumoniae, 1 of 4 K. oxytoca, 8 of 13 E. cloacae, and 7 of 14 S. marcescens), and most of them were bacteria not targeted by the NCCLS test. In 19 of the 20 strains, the synergy effect of clavulanic acid was observed in the modified-double-disk synergy test using only the cefepime-disk. Because these strains had high MICs of > or = 16 microg/ml for cephamycins such as cefoxitin and cefmetazole, these strains might produce high levels of AmpC in addition to ESBL. The MicroScan ESBL confirmation panel showed excellent performance in detecting target, but not other bacteria. Addition of cefepime and clavulanic acid to the MicroScan panel may significantly improve detection of non-target bacteria.     

Regional variation in the prevalence of extended-spectrum beta-lactamase-producing clinical isolates in the Asia-Pacific region (SENTRY 1998-2002)

We examined the prevalence of extended-spectrum beta-lactamase (ESBL)-producing strains of Klebsiella pneumoniae, Klebsiella oxytoca, Escherichia coli, Proteus mirabilis, Citrobacter koseri, and Salmonella spp. that were isolated as part of the SENTRY Asia-Pacific Surveillance Program between 1998 and 2002. During the study period, a total of 6,388 strains were gathered from 17 medical centers in 7 countries and examined for ESBL production and hyperproduction of K. oxytoca chromosomal K1 beta-lactamase enzyme. High rates of confirmed ESBL-producing isolates were found in K. pneumoniae strains from Singapore (35.6%), followed by those from mainland China (30.7%), South Africa (28.1%), and the Philippines (21.9%), whereas the rates were less than 10% in Japan and Australia. ESBL-producing E. coli strains were also prominent in mainland China (24.5%), Hong Kong (14.3%), and Singapore (11.3%). ESBL-producing K. oxytoca were common in the Philippines (38.5%), Singapore (33.3%), and China (30.0%). Hyperproduction of K. oxytoca chromosomal K1 beta-lactamase enzyme was common in Australia and Japan. P. mirabilis strains from Singapore produced ESBL (17.9%) despite the low prevalence (0-8.1%) in other countries. Few ESBL-producing C. koseri and Salmonella spp. strains were found in Japan, Singapore, Taiwan, and South Africa. Although there was variation among countries in substrate preference, ceftazidime was more likely to detect presumptive ESBL phenotype in K. pneumoniae and aztreonam more likely in E. coli, whereas ceftriaxone was the best substrate for the confirmation of ESBL production. ESBL-producing strains showed high levels of co-resistance to aminoglycosides, tetracycline, trimethoprim-sulfamethoxazole, and ciprofloxacin. Imipenem retained activity against all ESBL-producing strains. Organisms expressing ESBLs are widely distributed in the Asia-Pacific region, although prevalence rates vary significantly.     

Use of cefepime for the treatment of infections caused by extended spectrum beta-lactamase-producing Klebsiella pneumoniae and Escherichia coli

An investigation to determine the efficacy of cefepime in treating infections caused by extended spectrum beta-lactamase (ESBL)-producing strains of Klebsiella pneumonia and Escherichia coli was performed. Retrospective chart reviews were conducted on patients who received cefepime and had an ESBL-producing E. coli or K. pneumoniae isolated from a clinical specimen. Among 13 patients with 15 episodes and 17 sites of infection, there were 12 episodic clinical cures, 1 clinical improvement, and 2 failures. Bacteriologic eradication of the infecting organism from the original clinical site was seen in 11 of the episodes with an additional presumed eradication. Cefepime is a potential alternative, in many cases, to the carbapenems for the treatment of infections caused by ESBL-producing bacteria.     

Decreased susceptibility to noncarbapenem antimicrobials in extended-spectrum-β-lactamase-producing Escherichia coli and Klebsiella pneumoniae isolates in Toronto, Canada

Retrospective review from 11 Canadian hospitals showed increasing incidence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae from 0.12 per 1,000 inpatient days during 2005 to 0.47 per 1,000 inpatient days during 2009. By 2009, susceptibility rates of ESBL-positive E. coli/K. pneumoniae were as follows: ciprofloxacin, 12.8%/9.0%; TMP/SMX, 32.9%/12.2%; and nitrofurantoin, 83.8%/10.3%. Nosocomial and nonnosocomial ESBL-producing E. coli isolates had similar susceptibility profiles, while nonnosocomial ESBL-producing K. pneumoniae was associated with decreased ciprofloxacin (P = 0.03) and nitrofurantoin (P < 0.001) susceptibilities.     

In vitro activity of fosfomycin against extended-spectrum-beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae: comparison of susceptibility testing procedures

The agar dilution, broth microdilution, and disk diffusion methods were compared to determine the in vitro susceptibility of 428 extended-spectrum-beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae to fosfomycin. Fosfomycin showed very high activity against all ESBL-producing strains. Excellent agreement between the three susceptibility methods was found for E. coli, whereas marked discrepancies were observed for K. pneumoniae.