High prevalence of CTX-M-15-producing Klebsiella pneumoniae isolates in Asian countries: diverse clones and clonal dissemination

The characteristics of 218 Klebsiella pneumoniae isolates from patients with hospital-acquired pneumonia in nine Asian countries were investigated. In total, 92 isolates (42.2%) produced extended-spectrum β-lactamases (ESBLs), amongst which 67 (72.8%) possessed CTX-M ESBL genes; CTX-M-15 was the major ESBL (55 isolates; 59.8%). Multilocus sequence typing (MLST) and plasmid replicon typing were performed to investigate the genetic backgrounds of the 55 CTX-M-15-producing K. pneumoniae isolates. Twenty-five sequence types (STs) were identified. Clonal complex 11 (CC11) including ST11 was the most prevalent clone (20 isolates; 36.4%) and was distributed in all Asian countries except Taiwan. ST15 was the next most frequently identified clone (8 isolates; 14.5%). An IncFIIA-type plasmid was predominantly associated with bla_CTX-M-15 (45 isolates; 81.8%). However, another plasmid type (IncA/C) was also identified and replicon types of seven isolates could not be determined. The high prevalence of CTX-M-15 amongst K. pneumoniae isolates in Asian countries may be due both to the acquisition of plasmids carrying bla_CTX-M-15 and the spread of certain clones such as ST11 and ST15.     

对临床分离的大肠埃希杆菌和肺炎克雷伯菌耐药状况分析

目的：调查和分析上海市杨浦区市东医院临床分离的大肠埃希杆菌和肺炎克雷伯菌分布特征与药敏结果。方法：收集本院2010年临床送检标本所分离的大肠埃希杆菌和肺炎克雷伯菌药敏资料,用WHONET 5.5软件进行数据分析。结果：共获得大肠埃希杆菌696株和肺炎克雷伯菌409株,在菌株总数中排名第一和第三。大肠埃希杆菌检出率较高的科室为普外科（20.3%）、急诊科（14.1%）、风湿肾病科（12.6%）,主要分离自尿（46.3%）、脓液（11.6%）和痰（10.8%）等标本。肺炎克雷伯菌检出率较高的科室为急诊科（17.6%）、呼吸科（14.2%）、肿瘤内科（11.7%）,主要分离自痰（40.8%）、咽拭子（26.4%）和尿（9.5%）等标本。大肠埃希杆菌和肺炎克雷伯菌中产超广谱β-内酰胺酶（ESBLs）菌株检出率分别为56.0%和17.1%,两者的检出率之间具有显著性差异（P〈0.01）,产ESBLs菌株的耐药率明显高于非产ESBLs菌株。结论：本院大肠埃希杆菌和肺炎克雷伯菌在泌尿系统、呼吸系统疾病高发的科室分离率高,其耐药率水平主要受产ESBLs菌株的影响。     

Efficacies of colistin and tigecycline in mice with experimental pneumonia due to NDM-1-producing strains of Klebsiella pneumoniae and Escherichia coli

New Delhi metallo-β-lactamase-1 (NDM-1)-producing Enterobacteriaceae have emerged as a global threat. The aim of this study was to assess the efficacies of colistin and tigecycline in an experimental model of pneumonia caused by NDM-1-producing Escherichia coli and Klebsiella pneumoniae. The susceptibilities of K. pneumoniae NDM, E. coli NDM and K. pneumoniae ATCC 29665 were determined using the broth microdilution technique. The pharmacokinetics of colistin and tigecycline in an experimental model of pneumonia were performed using immunocompetent C57BL/6 mice. Mice were treated with colistin (60 mg/kg/day) or tigecycline (10 mg/kg/day). Mortality, bacteraemia and lung bacterial concentrations were recorded. The strains were susceptible to colistin and tigecycline. The ratio of area under the concentration-time curve/minimum inhibitory concentration (AUC/MIC) for colistin was 158.5 (all three strains) and that for tigecycline was 18.5 (K. pneumoniae NDM) and 37 (K. pneumoniae ATCC 29665 and E. coli NDM). In vivo, colistin decreased bacterial lung concentrations of K. pneumoniae NDM and K. pneumoniae ATCC 29665 by 1.16 log colony-forming units (CFU)/g and 2.23 logCFU/g, respectively, compared with controls (not significant). Tigecycline reduced K. pneumoniae NDM and K. pneumoniae ATCC 29665 load by 2.67 logCFU/g and 4.62 logCFU/g (P<0.05). Colistin and tigecycline decreased lung concentrations of E. coli NDM by 2.27 logCFU/g and 4.15 logCFU/g (P<0.05), respectively, compared with controls, and was more active than colistin (P<0.05). In conclusion, these results suggest that colistin is inappropriate for treating pneumonia due to NDM-1-producing K. pneumoniae and its efficacy was suboptimal against NDM-1-producing E. coli. A high tigecycline dose was efficacious for treating experimental pneumonia due to NDM-1-producing E. coli and K. pneumoniae.     

SLO4, a new interferon inducer isolated from Klebsiella pneumoniae and Escherichia coli

A product isolated from Klebsiella pneumoniae and Escherichia coli, coded SLO4, has been shown to be effective in endogenous interferon induction in vivo in mouse when administered IP or IV, and in vitro with human leukocyte cultures. In these two systems induced interferon was defined. The inducer has not yet been characterized but seems not to belong to any components known to be interferon inducers such as viral particles, nucleic acids or endotoxins. An analytical study will be carried out to specify the constitution of this interferon inducer.     

122株儿童肺炎克雷伯菌药敏试验分析

目的了解我院2007年住院儿童临床分离122株肺炎克雷伯菌的耐药性。方法采用VITEK-32全自动微生物分析鉴定系统和NCCLS（2005年）的判断标准对临床分离菌株行细菌鉴定和药敏试验。结果肺炎克雷伯菌122株，产ESBLs肺炎克雷伯菌62株，检出率为50．82％。所有产ESBLs菌株对亚胺培南和头孢西丁均敏感，对其余药物呈现不同程度地耐药。结论重视产ESBLs细菌的耐药性监测，根据药敏试验结果合理用药。亚胺培南和头孢西丁是治疗产EsBLs肺炎克雷伯菌感染的满意选择。     

CTX-M-1- and CTX-M-15-type beta-lactamases in clinical Escherichia coli isolates recovered from food-producing animals in France

Clinical Escherichia coli strains with resistance or variable susceptibility to third-generation cephalosporins were detected in cattle, swine and poultry in France. These strains were shown to produce extended-spectrum beta-lactamases (ESBLs), with CTX-M-1- and CTX-M-15-type beta-lactamases being responsible for this phenotype. The bla(CTX-M-1) gene was encountered most commonly and was characterised in seven E. coli strains isolated from cattle, swine and poultry, whereas bla(CTX-M-15) was identified in one E. coli isolated from cattle. These genes were located on a conjugative plasmid and were linked to the insertion sequence ISEcp1, which could have contributed to dissemination of the resistance gene. No epidemiological link between the strains was determined by pulsed-field gel electrophoresis, although two plasmids were identical in two strains isolated from swine and in two strains isolated from cattle and poultry. Thus, this study describes the emergence of ESBLs in animals in France, with a probable similar prevalence rate to that observed in humans. This is a major concern because of the possibility of transfer of these genes between animal species as well as to humans, leading to treatment failures in veterinary and human medicine.     

大肠埃希菌和肺炎克雷伯菌耐药机制检测

目的筛查大肠埃希菌与肺炎克雷伯菌膜孔蛋白基因情况,分析其与耐药的关系。方法随机抽取2008—2010年耐3代头孢菌素(头孢他啶)的大肠埃希菌72株和肺炎克雷伯菌57株,56株头孢他啶敏感的大肠埃希菌和肺炎克雷伯菌为对照组;三维试验确定细菌头孢菌素β-内酰胺酶(AmpC酶)的产生情况;超广谱β-内酰胺酶(ESBL)确证试验检测细菌产ESBL的情况;多重聚合酶链反应(PCR)扩增AmpC基因和膜孔蛋白ompF、ompk35、ompk36基因;纸片扩散法检测抗菌药物的敏感性。结果 72株大肠埃希菌中,14株产AmpC酶,23株产ESBL,3株膜孔蛋白基因缺失;57株肺炎克雷伯菌中,13株产AmpC酶,19株产ESBL,5株膜孔蛋白缺失,膜孔蛋白缺失株4代头孢均出现耐药。结论我院大肠埃希菌和肺炎克雷伯菌对头孢类抗生素的耐药机制主要是产AmpC酶和ESBLs,同时膜孔蛋白基因的缺失会造成耐药程度增高。     

Pathogenecity of fosfomycin-resistant strains isolated from Escherichia coli

Two fosfomycin-resistant strains, FRC14 (parent strain, Escherichia coli [E.coli] c73-18) and FRK104 (parent strain, E. coli O124), were isolated from spleens before the bacterial disappearance, after inoculating the parent strains intraperitoneally into mice and treating them with a single oral dose of fosfomycin. The resistant strains were successfully isolated by a replica method from a mass of sensitive cells of respective parent. To elucidate the pathogenesis of the resistant strains, their characteristics were investigated. The MIC of fosfomycin for FRC14 was 25 micrograms/ml (4 times the MIC for the parent) and that for FRK104 was 100 micrograms/ml (8 times the MIC for the parent). The strain FRC14 showed a defective utilization of sn-glycerol 3-phosphate (G3P), but utilization of other carbohydrates was similar to that of the parent strain. Thus, the strain FRC14 seemed to be a glpT mutant. The strain FRK104 did not use variety of carbohydrates including G3P, but used glucose 6-phosphate. The utilization of G3P was recovered in the presence of cAMP. Thus, the strain FRK104 seemed to be a ptsI mutant. These resistant strains were diminished their killing activity for mice in comparison to that of the each parent strain when they were inoculated intraperitoneally. The cell number of FRC14 decreased or disappeared in blood and spleen in mice, while that of the parent increased. The strain FRK104 diminished its ability of producing keratoconjuctivitis in guinea pigs in comparison to that of the parent strain.     

哌拉西林/三唑巴坦对肺炎克雷伯菌和大肠埃希菌的体外敏感性

目的 评价哌拉西林/三唑巴坦对肺炎克雷伯菌和大肠埃希菌的体外敏感性。方法 收集肺炎克雷伯菌和大肠埃希菌426株,用Kirby-Bauer琼脂扩散法作药敏试验;用表型确认试验检测用广谱β-内酰胺酶(ESBLs)。结果 426株肺炎克雷伯菌和大肠埃希菌中,哌拉西林/三唑巴坦的敏感性为99.53％,与亚胺培南(100％)和头孢哌酮/舒巴坦(100％)相当,明显高于青霉素类抗生素哌拉西林(48.83％)和第二代头孢菌素头孢呋新(60.09％),也高于第三代头孢菌素头孢三嗪(62.91％)、头孢噻肟(64.79％)、头孢哌酮(65.73％)和头孢他啶(88.26％),略优于第四代头孢菌素头孢吡肟(94.37％)。142株(33.33％)菌株经表型确认试验证实为产ESBLs菌;哌拉西林/三唑巴坦对产ESBLs菌的体外敏感性为98.59％。结论 哌拉西林/三唑巴坦对肺炎克雷伯菌和大肠埃希菌的体外抗菌活性与亚胺培南和头孢吸酮/舒巴坦相当,高于第三、四代头孢菌素;哌拉西林/三唑巴坦可作为产ESBLs菌感染的治疗选择。     

大肠埃希菌和肺炎克雷伯菌门诊与住院患者分离菌株耐药性比较及临床意义

目的比较大肠埃希菌和肺炎克雷伯菌门诊与住院患者分离菌株耐药性的差异及临床意义。方法用MicroScan Walk-AWay-40全自动微生物分析仪鉴定细菌,用微量液体稀释法测定18种抗菌药物的耐药性,用NCCLS2004推荐的确证试验检测ES-BLs。结果住院患者分离大肠埃希菌对头孢唑啉、头孢噻吩、头孢呋肟、氨苄西林/舒巴坦、庆大霉素、头孢他啶、妥布霉素、头孢西丁、阿米卡星等抗菌药物耐药率显著高于门诊患者（P〈0.05）;住院患者分离肺炎克雷伯菌对氨苄西林/舒巴坦、哌拉西林、头孢唑啉、头孢噻吩、头孢呋肟、环丙沙星、复方新诺明、庆大霉素、头孢他啶、妥布霉素、氨曲南、头孢西丁、头孢曲松、头孢噻肟、阿米卡星、哌拉西林/他唑巴坦等抗菌药物的耐药率显著高于门诊患者（P〈0.05）;两种细菌住院患者分离菌株ESBLs菌株检出率均显著高于门诊患者（P〈0.05）。结论社区感染菌株的药物敏感性较高,可用抗菌药物的范围较广,对门诊患者的治疗要选用不同与住院患者的抗菌治疗方案,尽量使用青霉素类或第一代、第二代头孢菌素,减少第三代头孢菌素和亚胺培南的使用。     

Comparative in vitro activity of ertapenem against extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae isolated in Spain

The in vitro activity of ertapenem was tested against extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae isolated in Spain. Ertapenem activity was similar to that of imipenem and meropenem and better than that of the other antimicrobials tested. No differences in activity were observed regarding the origin of the isolates or type of ESBL produced.     

大肠埃希菌和肺炎克雷伯菌产超广谱β-内酰胺酶的探讨

目的：了解本地区分离的大肠埃希菌和肺炎克雷伯菌产超广谱β-酰胺酶的发生率、耐药性及超广谱β-酰胺酶可能的基因型。方法：用MICs试验和PCR方法研究了从武汉地区医院ICU病房收集的288株大肠埃希菌和103株肺炎克雷伯菌产超广谱β-酰胺酶的发生率、可能的基因型。结果：强产超广谱β-酰胺酶的大肠埃希菌和肺炎克雷伯菌的发生率分别为25．0％（72／288）和46．6％（48／103）。RAPD分析显示一些不同的产超广谱β-酰胺酶的菌株具有相同的RAPD型别，而不同的RAPD型别的菌株可能含有相同的产超广谱β-酰胺酶的基因型。这些菌株耐受绝大部分含β-内酰胺的药物（包括第3代头孢菌素）和不含β-酰胺的药物（例如氨基糖苷、四环素和氯霉素），几乎所有的产超广谱β-内酰胺酶菌株对亚氨培南，头孢美唑和β-酰胺／克拉维酸敏感。TEM是产超广谱β-内酰胺酶的主要基因型，CTX-M型也常见，其中以CTX-M-3为主。产超广谱β-酰胺酶一些的大肠埃希菌和大部分的肺炎克雷伯菌的菌株含不止一个超广谱β-酰胺酶的基因型。产超广谱β-酰胺酶菌株的传播绝大部分依赖质粒的水平转移。结论：这些结果证明在武汉地区分离的大肠埃希菌和肺炎克雷伯菌菌株产超广谱β-酰胺酶很常见，对这些菌株的监测和阻止其传播具有重要意义。     

大肠埃希菌及肺炎克雷伯杆菌血流感染分布及药敏分析

目的回顾性分析大肠埃希菌和肺炎克雷伯杆菌血流感染临床分布及药敏特征。方法收集71例次大肠埃希菌及21例次肺炎克雷伯杆菌血流感染患者的年龄、性别、入住科室、基础疾病及其药敏结果资料。药敏试验采用Kirby-Bauer法。结果急性白血病是高发基础疾病。大肠埃希菌及肺炎克雷伯杆菌产超广谱β-内酰胺酶(ESBLs)阳性率分别为67.6%和42.8%。近3年中,肺炎克雷伯杆菌产ESBLs的比例有上升趋势,产ESBLs菌对除亚胺培南、丁胺卡那霉素外的其它常用抗菌药物敏感率均明显低于非产ESBLs菌(P<0.05)。结论血流感染中,大肠埃希菌、肺炎克雷伯杆菌产ESBLs率高,产酶菌对多种常用抗菌药物高度耐药,亚胺培南仍是经验治疗的首选药物。     

Distribution and antibiotic sensitivity of Escherichia coli and Klebsiella pneumoniae in bloodstream infections

目的 回顾性分析大肠埃希菌和肺炎克雷伯杆菌血流感染临床分布及药敏特征.方法 收集71例次大肠埃希菌及21例次肺炎克雷伯杆菌血流感染患者的年龄、性别、入住科室、基础疾病及其药敏结果资料.药敏试验采用Kirby-Bauer法.结果 急性白血病是高发基础疾病.大肠埃希菌及肺炎克雷伯杆菌产超广谱β-内酰胺酶(ESBLs)阳性率分别为67.6％和42.8％.近3年中,肺炎克雷伯杆菌产ESBLs的比例有上升趋势,产ESBLs菌对除亚胺培南、丁胺卡那霉素外的其它常用抗菌药物敏感率均明显低于非产ESBLs菌(P＜0.05).结论 血流感染中,大肠埃希菌、肺炎克雷伯杆菌产ESBLs率高,产酶菌对多种常用抗菌药物高度耐药,亚胺培南仍是经验治疗的首选药物.     

福州地区肺炎克雷伯氏菌和大肠埃希氏菌的药敏监测

目的监测福州地区肺炎克雷伯氏菌和大肠埃希氏菌对14种常用抗生素的药敏情况，为临床合理选用抗生素提供依据。方法收集2001年3月-10月福州地区4家医院分离的肺炎克雷伯氏菌和大肠埃希氏菌426株，用K-B琼脂扩散法作药敏试验；用表型确认试验检测超广谱β-内酰胺酶(ESBLs)。结果在14种抗生素中，敏感性最高的是亚胺培南(100％)、头孢哌酮／舒巴坦(100％)、哌拉西林／三唑巴坦(99．53％)、头孢吡肟(94．37％)和头孢美唑(91．08％)，敏感性最低的是阿莫西林(12．68％)、哌拉西林(48．83％)和环丙沙星(50．70％)；除头孢他啶外，第三代头孢菌素对肺炎克雷伯氏菌和大肠埃希氏菌的耐药率均在30％以上；产ESBLs菌检出率为33．33％(142／426)；除亚胺培南、头孢哌酮／舒巴坦、哌拉西林／三唑巴坦和头孢美唑外，产ESBLs菌对其它10种抗生素的耐药率均显著高于非产ESBLs菌。结论亚胺培南、头孢哌酮／舒巴坦、哌拉西林／三唑巴坦、头孢吡肟和头孢美唑的敏感性最高，产ESBLs是肺炎克雷伯氏菌和大肠埃希氏菌产生耐药的主要机制之一，临床实验室有必要常规检测肺炎克雷伯氏菌和大肠埃希氏菌是否产ESBLs。     

肺炎克雷伯菌、大肠埃希菌耐药性变迁分析

目的了解临床分离肺炎克雷伯菌、大肠埃希菌对抗生素耐药性变迁。方法采用VITEK-32微生物全自动分析系统进行细菌鉴定和药敏检测。结果4年中肺炎克雷伯菌、大肠埃希菌超广谱β-内酰胺酶（ESBLs）的发生率呈逐年上升的趋势。2005年至2008年肺炎克雷伯菌、大肠埃希菌ESBLs菌发生率分别为36．6％、40．6％、41．5％、41．0％;产ESBLs菌对三代头孢、氨基糖苷类、喹诺酮类和磺胺类交叉耐药,且呈逐年上升趋势。结论肺炎克雷伯菌、大肠埃希菌的发生率呈逐年上升趋势,耐药率升高,临床应及时了解它们的耐药特点和变化,合理使用抗生素,有效控制ESBLs的传播。     

Extended-spectrum beta-lactamase types in Klebsiella pneumoniae and Escherichia coli in two Greek hospitals

Seventy-nine Klebsiella pneumoniae and 124 Escherichia coli clinical strains, isolated consecutively during August-October 2001 in two Greek hospitals, were examined for production of extended-spectrum beta-lactamases (ESBLs). Seventy-one (35%) isolates (46 K. pneumoniae and 25 E. coli) were ESBL-positive by phenotypic methods. Isoelectric focusing of beta-lactamases and PCR assays for bla genes showed that SHV-5-type ESBLs were the most frequent (45 isolates, 22%) followed by CTX-M (24 isolates, 12%) and IBC (three isolates, 1.5%). The latter two ESBL types may have been established recently in this setting.     

Susceptibility of ESBL-producing Escherichia coli and Klebsiella pneumoniae to various antibacterial agents

With the increasing use of broad-spectrum antibacterial agents, the increase in various drug-resistant bacterial strains has become a concern in recent years. Especially, the development of drug-resistance by Enterobacteriaceae which significantly affects therapy and prognosis in sepsis and lower gastrointestinal post-operative infection. The extended spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae strains isolated in the Surveillance Program of Bacterial Resistance in Kinki region of Japan (SBRK) were supplied between November 2000 and March 2003. The susceptibilities of them to 16 kinds of antimicrobial agents were investigated. The number of them was 48 strains consisting of 36 Escherichia coli strains (75%) and 12 Klebsiella pneumoniae strains (25%). Our focus was on carbapenem and the new quinolone antibacterial agents. Among the 16 major antibacterial agents examined, carbapenem had low MIC50/90 values. Meropenem had a MIC50/90 of 0.03/0.06microg/ml, followed by biapenem (0.12/0.5), imipenem (0.25/0.5) and panipenem (0.25/0.5). Among cephem, ceftazidime had the lowest MIC50 at 4 microg/ml. All four of the cephem agents had a MIC90 of greater than 128microg/ml. Among beta-lactamase inhibitors, tazobactam/piperacillin had the lowest MIC50 at 4 microg/ml, and sulbactam/cefoperazone had a MIC50 of 32 microg/ml. Among the new quinolones, prulifloxacin had the lowest MIC50 at 1 microg/ml, and the other drugs had a MIC50 of 2 microg/ml. The resistance rate of ciprofloxacin was 61.1% in E. coli and 16.6% in K. pneumoniae. Comparison of drug-sensitivity to cephem by ESBL-gene type revealed that cefpirome, cefepime and cefozopran had higher MIC50/90 values against the CTX-M group with a MIC50 of greater than 128microg/ml. Ceftazidime and aztreonam had higher MIC50/90 values against the TEM/SHV group than those against the CTX-M group. In the CTX-M group, the MIC50 was 4 and 16microg/ml, respectively.