下呼吸道感染铜绿假单胞菌流行和耐药现状分析

目的总结下呼吸道感染住院患者铜绿假单胞菌的流行情况及耐药现状,为临床合理应用抗菌药物提供指导依据。方法收集2004年下呼吸道感染住院患者痰培养结果为铜绿假单胞菌的数据,用WHONET 5.3软件统计分析。结果患者痰标本中共检出铜绿假单胞菌152株,其中产ESBLs者20株,占13%。外科ICU和呼吸ICU铜绿假单胞菌所占比例最高,分别为25.5%和21.6%。呼吸ICU中铜绿假单胞菌产ESBLs菌株比例最高(36.3%)。铜绿假单胞菌除对哌拉西林/他唑巴坦敏感率较高为70.1%,对其他加酶抑制剂的β-内酰胺类、碳青霉烯类、氨基糖苷类、氟喹诺酮类和单环酰胺类敏感率都较低,大都低于50%。耐药分析组合结果显示:亚胺培南-哌拉西林/他唑巴坦(IPM-TZP)、阿米卡星-哌拉西林/他唑巴坦(AMK-TZP)、头孢他啶-哌拉西林/他唑巴坦(CAZ-TZP)、阿米卡星-亚胺培南(AMK-IPM)、环丙沙星-哌拉西林/他唑巴坦(CIP-TZP)2者均敏感率较高,在40%以上,且两者均耐药率较低,在20%左右。结论铜绿假单胞菌耐药现象较为严重,耐药机制较为复杂。通过对其目前耐药状况的研究,单一用药推荐哌拉西林/他唑巴坦(TZP),联合用药推荐IPM-TZP、AMK-TZP、CAZ-TZP、AMK-IPM、CIP-TZP。     

Third-Generation Cephalosporin-Resistant Vibrio cholerae, India

Vibrio cholerae resistance to third-generation cephalosporins is rarely reported. We detected a strain that was negative for extended-spectrum β-lactamase and positive for the AmpC disk test, modified Hodge test, and EDTA disk synergy test and harbored the blaDHA-1 and blaNDM-1 genes. The antimicrobial drug susceptibility profile of V. cholerae should be monitored.     

肺炎克雷伯菌中超广谱β-内酰胺酶基因分布及转移研究

目的 研究肺炎克雷伯菌中超广谱β-内酰胺酶（ESBLs）基因类型及转移方式。方法 回顾性分析该院2011年1月至2013年1月收集的460例住院患者菌株的临床资料,并对其ESBLs基因进行分型和研究耐药性。结果 460株β-内酰胺酶的KPN检出6种β-内酰胺酶基因,其中bla TEM占总数的5％,bla SHV占总数的20％,bla CTX—M-1群占总数的5％,bla CTXM-9群占总数的25%,bla OXA-1群占总数的10％,bla DHA占总数的30％等;本研究共发现322种菌株耐药谱,菌株耐药在9种抗菌药物以上。阿莫西林／替卡西林／头孢噻吩等、阿莫西林／克拉维酸和头孢西丁、哌拉西林／克拉维酸、亚胺培南的耐药性分别为100％、60％、45％、35％和0。结论 肺炎克雷伯菌中ESBLs基因类型主要是bla TEM和bla CTX—M-1,并具有较为严重的耐药性。     

Substrate specificity of HMRZ-86 for β-lactamases,including extended-spectrum β-lactamases (ESBLs)

HMRZ-86 was designed as a new chromogenic cephalosporin to detect extended-spectrum β-lactamases (ESBLs) and similar evolved β-lactamases, such as metallo-β-lactamases, derepressed AmpC, and extended oxacillinase. We report here our investigation of the kinetic parameters of several types of β-lactamases to show the enzymatic characteristics of HMRZ-86. The Michaelis constant (K _m values of HMRZ-86 for ESBLs were twice to three and half times as high as those of nitrocefin, and the maximum velocity (Vmax) was one-fifth that of nitrocefin. The K _m and Vmax of HMRZ-86 for AmpC were both smaller than those of nitrocefin. The kinetic parameters of HMRZ-86 for metallo β-lactamase (MBL) were very variable, depending on the type of buffer solution used and the concentration of zinc ions. For MBL, the K _m values of HMRZ-86 were higher than those of nitrocefin, but the Vmax values were almost the same as those of nitrocefin. Although the chemical structure of HMRZ-86 is similar to that of nitrocefin, we think the enzymatic reactivities of the two entities for β-lactamases are very different.     

Clinical characteristics of bacteraemia caused by extended-spectrum β-lactamase-producing Enterobacteriaceae in the era of CTX-M-type and KPC-type β-lactamases

Clin Microbiol Infect 2012; 18: 887-893 ABSTRACT: A multicentre, case-control study was conducted to assess risk factors and patient outcomes of bacteraemia caused by Enterobacteriaceae producing extended-spectrum β-lactamases (ESBLs) and Klebsiella pneumoniae carbapenemases (KPCs). One hundred and five and 20 patients with bacteraemia caused by ESBL-producing and KPC-producing organisms were matched to controls who had bacteraemia caused by non-ESBL/KPC-producing organisms, respectively. Independent risk factors for ESBL production included admission from a nursing home (OR 4.64; 95% CI 2.64-8.16), chronic renal failure (OR 2.09; 95% CI 1.11-3.92), the presence of a gastrostomy tube (OR 3.36; 95% CI 1.38-8.18), length of hospital stay before infection (OR 1.02; 95% CI 1.01-1.03), transplant receipt (OR 2.48; 95% CI 1.24-4.95), and receipt of antibiotics with Gram-negative activity in the preceding 30 days (OR 1.76; 95% CI 1.00-3.08). Twenty-eight-day crude mortality rates for patients infected with ESBL-producing or KPC-producing organisms and controls were 29.1% (34/117) and 19.5% (53/272), respectively (OR 1.70; 95% CI 1.04-2.80). On multivariate analysis, inadequate empirical therapy (OR 2.26; 95% CI 1.18-4.34), onset of bacteraemia while in the intensive-care unit (OR 2.74; 95% CI 1.47-5.11), Apache II score (OR 1.17; 95% CI 1.12-1.23) and malignancy (OR 2.66; 95% CI 1.31-5.41) were independent risk factors for mortality. CTX-M was the most common ESBL type in Escherichia coli, whereas SHV predominated in Klebsiella spp. and Enterobacter spp.     

Extended-spectrum β-lactamase-producing and AmpC-producing Escherichia coli from livestock and companion animals,and their putative impact on public health: a global perspective

The possible zoonotic spread of antimicrobial-resistant bacteria is controversial. This review discusses global molecular epidemiological data combining both analyses of the chromosomal background, using multilocus sequence typing (MLST), and analyses of plasmid (episomal) extended-spectrum β-lactamase (ESBL)/AmpC genes in Escherichia coli present in humans and animals. For consideration of major epidemiological differences, animals were separated into livestock and companion animals. MLST revealed the existence of ESBL-producing isolates thoughout the E. coli population, with no obvious association with any ancestral EcoR group. A similar distribution of major ESBL/AmpC types was apparent only in human isolates, regardless of their geographical origin from Europe, Asia, or the Americas, whereas in animals this varied extensively between animal groups and across different geographical areas. In contrast to the diversity of episomal ESBL/AmpC types, isolates from human and animals mainly shared identical sequence types (STs), suggesting transmission or parallel micro-evolution. In conclusion, the opinion that animal ESBL-producing E. coli is a major source of human infections is oversimplified, and neglects a highly complex scenario.