Dissemination of clonally related Escherichia coli strains expressing extended-spectrum beta-lactamase CTX-M-15

We analyzed 43 CTX-M-15-producing Escherichia coli isolates and 6 plasmids encoding the blaCTX-M-15 gene from Canada, India, Kuwait, France, Switzerland, Portugal, and Spain. Most isolates belonged to phylogroups B2 (50%) and D (25%). An EC-B2 strain of clonal complex sequence type (ST) 131 was detected in all countries; other B2 isolates corresponded to ST28, ST405, ST354, and ST695 from specific areas. EC-D strains were clonally unrelated but isolates from 3 countries belonged to ST405. All CTX-M-15 plasmids corresponded to IncFII group with overrepresentation of 3 HpaI-digested plasmid DNA profiles (A, B and C; 85-120kb, similarity > or =70%). Plasmid A was detected in EC-B2 strains (ST131, ST354, or ST405), plasmid C was detected in B2 and D strains, and plasmid B was confined to worldwide-disseminated ST131. Most plasmids contained blaOXA-1, aac(6')-Ib-cr, and blaTEM-1. Worldwide dissemination of CTX-M-15 seems to be determined by clonal complexes ST131 and ST405 and multidrug-resistant IncFII plasmids.     

Ertapenem resistance of Escherichia coli

An ertapenem-resistant Escherichia coli isolate was recovered from peritoneal fluid in a patient who had been treated with imipenem/cilastatin for 10 days. Ertapenem resistance may be explained by a defect in the outer membrane protein and production of extended-spectrum beta-lactamase CTX-M-2.     

CTX-M ��-Lactamase Production and Virulence of Escherichia coli K1

We report a patient with neonatal meningitis caused by a CTX-M-1–producing Escherichia coli K1 strain. The influence of CTX-M production on virulence was investigated in cell culture and a newborn mouse model of meningitis. CTX-M production had no influence on virulence but was a major factor in clinical outcome.     

产ESBLs大肠埃希菌的检出与耐药趋势分析

目的 了解产超广谱β内酰胺酶（ESBLs）大肠埃希菌的检出及其耐药变化,为临床合理使用抗菌药物提供参考。方法收集某院2006年1--12月间临床标本分离的大肠埃希菌,对其产ESBLs株及耐药情况与2002年进行比较。结果2006年分离的大肠埃希菌中产ESBLs株占65．54％（175／267）,与2002年的47．92％（46／96）比较,显著增加（X^2=9．21,P〈0．05）。产ESBLs大肠埃希菌对氨曲南的敏感率2006年为24．00％,较2002年的52．17％显著下降（X^2=13．80,P〈0．05）;对其他抗菌药物的敏感率差异无统计学意义,亚胺培南仍对产ESBLs大肠埃希菌有良好的抗菌活性。结论产ESBLs大肠埃希菌的检出有增加趋势,且耐药率高,应引起临床重视。     

Cefepime MIC as a predictor of the extended-spectrum beta-lactamase type in Klebsiella pneumoniae, Taiwan

To guide selection of carbapenems or fourth-generation cephalosporins as therapy, 110 Klebsiella pneumoniae isolates with extended-spectrum beta-lactamases from Taiwan were characterized by phenotypic (MICs), molecular, and chemical methods. MIC patterns of ceftazidime and cefepime clearly differentiate strains treatable by cefepime and those capable of efficiently hydrolyzing available cephalosporins (CTX-M series and SHV-types). Continued use of cefepime appears to be a treatment option in cases for which MIC results are available and interpreted by the criteria presented.     

产ESBLs大肠埃希菌、肺炎克雷伯菌的分布及耐药性分析 FREE

目的了解某院大肠埃希菌、肺炎克雷伯菌产超广谱β 内酰胺酶（ESBLs）的分布及耐药特点。方法对该院2007年10月-2008年9月各科送检标本分离的大肠埃希菌和肺炎克雷伯菌,采用双纸片扩散法进行ESBLs确证试验,K B纸片扩散法进行药敏试验。结果分离出大肠埃希菌766株,其中产ESBLs株443株（57.83%）;肺炎克雷伯菌632株,产ESBLs株355株（56.17%）。产酶菌株主要分离自痰（557株,69.80%）、尿（149株,18.67%）等标本。产ESBLs菌对亚胺培南/西司他丁、美罗培南、头孢哌酮/舒巴坦敏感性高,对第一～三代头孢菌素类几乎全部耐药,对喹诺酮类、氨基糖苷类等存在交叉耐药。结论产ESBLs菌感染严重,以下呼吸道感染最多,其次为泌尿道感染;耐药率较高,亚胺培南/西司他丁、美罗培南、头孢哌酮/舒巴坦对其保持较高的抗菌活性。     

某院分离的大肠埃希菌和肺炎克雷伯菌ESBLs基因检测及分型

目的了解某院分离的大肠埃希菌和肺炎克雷伯菌产生的超广谱β 内酰胺酶（ESBLs）基因型。方法采用表型确证试验测定并收集该院产ESBLs大肠埃希菌（40株）和肺炎克雷伯菌（20株）,提取质粒DNA。采用特异性引物扩增TEM、SHV和 CTX M系列基因,测序后进行序列分析。结果60株表型确证试验阳性的大肠埃希菌和肺炎克雷伯菌,聚合酶链反应（PCR）扩增均阳性,包括TEM、SHV、CTX M 3组和CTX M 9组4种基因型。大肠埃希菌中上述4种基因型阳性率分别为37.50%（15株）、2.50%（1株）、62.50%（25株）、50.00%（20株）;肺炎克雷伯菌上述4种基因型阳性率分别为40.00%（8株）、90.00%（18株）、65.00%（13株）、40.00%（8株）。100.00%的大肠埃希菌和80.00%的肺炎克雷伯菌产生blaCTX M,12.50%(5/40)的大肠埃希菌和25.00%(5/20)的肺炎克雷伯菌携带2种CTX M酶基因。23例TEM基因皆为TEM 1型;19例SHV型基因包括SHV 1型6株、SHV 11型6株、SHV 12型5株及SHV 25型2株,仅SHV 12为ESBLs基因,且均来源于肺炎克雷伯菌;66例CTX M型基因,其中CTX M 14在大肠埃希菌和肺炎克雷伯菌的检出率分别为45.00%和35.00%,CTX M 55检出率均为35.00%,CTX M 15检出率分别为20.00%和15.00%,检出少量CTX M 3、CTX M 65、CTX M 101及CTX M 123基因型。结论该院分离的大肠埃希菌和肺炎克雷伯菌ESBLs基因型以CTX M 为主,其次为SHV 12。CTX M基因型中以CTX M 14最为常见,CTX M 101及CTX M 123型ESBLs为山东省首次检出。     

Fosfomycin Resistance in Escherichia coli,Pennsylvania, USA

Fosfomycin resistance in Escherichia coli is rare in the United States. An extended-spectrum β-lactamase–producing E. coli clinical strain identified in Pennsylvania, USA, showed high-level fosfomycin resistance caused by the fosA3 gene. The IncFII plasmid carrying this gene had a structure similar to those found in China, where fosfomycin resistance is commonly described.     

产ESBLs大肠埃希菌CTX—M型耐药基因分析

目的了解某院CTX-M型超广谱β-内酰胺酶（ESBLs）在大肠埃希菌中的检出率，并确定其基因型。方法对该院2005年1—12月临床送检标本中分离的197株大肠埃希菌进行ESBLs表型确证试验和接合试验；采用聚合酶链反应（PCR）检测CTX-M酶基因型，对PCR产物测序并确定其基因型。结果197株大肠埃希菌中有104株（52．79％）ESBLs表型检测阳性，其中91株符合供体菌标准，64株（70．33％）接合成功，接合子均确证产ESBLS。PCR扩增结果示104株产ESBLs大肠埃希菌中共有98株（94．23％）携带CTX-M型基因，其中38株（36．54％）检出blaCTX-M-1组基因，69株（66．35％）检出blaCTX-M-9组基因。64株接合子中共有51株（79．69％）携带CTX-M型基因，其中18株（28．13％）检出blaCTX-M-1组基因，35株（54．69％）检出blaCTX-M-9组基因。基因测序确定存在CTX-M-22、CTX-M-28、CTX-M-15、CTX-M-14、CTX-M-27五种基因亚型，以CTX-M-14为主。结论该院大肠埃希菌产ESBLs和耐药质粒水平传播情况严重，产ESBLs细菌基因型以CTX-M-9组的CTX-M-14亚型为主，同时存在CTX-M-22、CTX-M-28、CTX-M-15和CTX-M-27等多种亚型。     

Extended spectrum ß-lactamase-producing Escherichia coli in neonatal care unit

An outbreak of extended-spectrum β-lactamase–producing Escherichia coli in a neonatal care unit began with transmission from a mother to her newborn twins during vaginal delivery. Subsequently, infection spread by healthcare worker contact with other neonates; a healthcare worker also was infected. Knowledge about transmission may improve infection control measures.     

CTX-M ��-Lactamases in Escherichia coli from Community-acquired Urinary Tract Infections, Cambodia

Despite the recent global spread of CTX-M β-lactamases in Escherichia coli isolates from community-acquired urinary tract infections (CA-UTIs), their dissemination has been little studied in developing countries. In a 2-year prospective study, we documented the prevalence of extended-spectrum β-lactamases (ESBLs) in E. coli that were responsible for CA-UTIs in Phnom-Penh, Cambodia. Ninety-three E. coli strains were included. We observed a high prevalence of resistance to amoxicillin (88.2% of strains), cotrimoxazole (75.3%), ciprofloxacin (67.7%), gentamicin (42.5%), and third-generation cephalosporins (37.7%). A total of 34 strains carried ESBLs, all of which were CTX-M type. CTX-M carriage was associated with resistance to fluoroquinolones and aminoglycosides. U using repetitive extragenic palindromic–PCR, we identified 4 clusters containing 9, 8, 3, and 2 strains. The prevalence of CTX-M β-lactamases has reached a critical level in Cambodia, which highlights the need for study of their spread in developing countries.     

Bacteriophages and diffusion of beta-lactamase genes

We evaluated the presence of various Beta-lactamase genes within the bacteriophages in sewage. Results showed the occurrence of phage particles carrying sequences of bla(OXA-2), bla(PSE-1) or bla(PSE-4) and bla(PSE)-type genes. Phages may contribute to the spread of some Beta-lactamase genes.     

Extended-Spectrum ��-Lactamase Genes of Escherichia coli in Chicken Meat and Humans, the Netherlands

We determined the prevalence and characteristics of extended-spectrum β-lactamase (ESBL) genes of Enterobacteriaceae in retail chicken meat and humans in the Netherlands. Raw meat samples were obtained, and simultaneous cross-sectional surveys of fecal carriage were performed in 4 hospitals in the same area. Human blood cultures from these hospitals that contained ESBL genes were included. A high prevalence of ESBL genes was found in chicken meat (79.8%). Genetic analysis showed that the predominant ESBL genes in chicken meat and human rectal swab specimens were identical. These genes were also frequently found in human blood culture isolates. Typing results of Escherichia coli strains showed a high degree of similarity with strains from meat and humans. These findings suggest that the abundant presence of ESBL genes in the food chain may have a profound effect on future treatment options for a wide range of infections caused by gram-negative bacteria.