High clonality and diversity of virulence determinants among blaPSE-positive Salmonella Typhimurim isolates recovered in three geographically distant Spanish hospitals

Molecular typing, the presence of Salmonella genomic island 1 (SGI1), and virulence factors were studied in 45 bla_PSE-positive S. Typhimurium isolates from 3 hospitals. All isolates belonged to sequence type ST19, presented low clonal diversity, and harbored SGI1. The wide diversity of virulence factors was classified into 3 major virulotype groups.     

我院产超广谱β-内酰胺酶大肠埃希菌的耐药性分析

目的:了解我院产超广谱β-内酰胺酶(ESBLs)大肠埃希菌(ECO)的耐药现状,为临床合理用药提供依据.方法:将1999年1月- 2011年9月我院分离ECO的药敏试验结果,应用WHONET 5.5软件进行统计学分析;产ESBLs菌株采用双纸片协同实验测定并经美国临床实验室标准化协会确证试验确认.结果:ECO和产ESBLs ECO的分离率为21.6%和63.9%.产ESBLs菌株的耐药率远高于非产ESBLs菌株.产ESBLs ECO除对亚胺培南、阿米卡星、呋喃妥因和头孢哌酮钠舒巴坦钠敏感率较高外,对其他抗菌药物耐药严重.结论:我院应重视对产ESBLs菌株的监控,临床应合理应用抗菌药物;碳青霉烯类是治疗产ESBLs ECO最有效的药物.     

下呼吸道感染产AmpC酶和超广谱β-内酰胺酶肺炎克雷伯菌耐药基因检测及亲缘性分析

分析下呼吸道感染患者气道分泌物或痰液标本分离的产AmpC酶和超广谱β-内酰胺酶(ESBL)肺炎克雷伯菌耐药基因的特点及亲缘性。方法 2009年1月至2010年8月由本院呼吸病区住院的下呼吸道感染患者气道分泌物或痰液标本分离得到53株肺炎克雷伯菌,采用K-B纸片扩散法测定其对常用抗菌药物的敏感性;三维实验检测AmpC酶;PCR检测ESBL、质粒介导的AmpC酶、喹诺酮类耐药基因、耐消毒剂-磺胺基因qacE△1-sul1、Ⅰ类整合酶基因Int Ⅰ 1的携带情况,并进行聚类分析。结果 53株肺炎克雷伯菌未发现对亚胺培南、美罗培南、厄他培南耐药;对环丙沙星、左旋氧氟沙星耐药率均＞80％;对其他抗菌药物也有不同程度的耐药。53株肺炎克雷伯菌中Int Ⅰ 1基因阳性率60.4％(32/53),qnrA基因阳性率54.7％ (29/53),qnrS基因阳性率13.2％ (7/53),qnrB基因阳性率5.7％(3/53),qacE△1-sul1基因阳性率71.7％(38/53),TEM基因阳性率92.5％ (49/53),CTX-M基因阳性率100％(53/53),SHV基因阳性率9.4％(5/53),AmpC基因阳性率92.5％(49/53);其中4株同时携带qnrA、qnrS、intⅠ 1、qacE△1-sul1、AmpC、CTX-M基因。聚类分析显示40、41、10与18号,25与42号,8与35号菌株有亲缘关系。结论 产ESBL肺炎克雷伯菌的多重耐药与整合子相关,且携带多种耐药基因,聚类分析显示存在克隆传播和医院内感染。     

产DHA-1型AmpC酶和TEM-1型β-内酰胺酶及携带Ⅰ类整合子的鲍氏不动杆菌

目的分析鲍氏不动杆菌临床株(编号0524)的β-内酰胺酶基因(BLA)、质粒介导耐氟喹诺酮基因(qnr)、氨基糖苷类修饰酶基因(AMEs)、消毒剂与磺胺类耐药基因(qacE△1-sul1)和Ⅰ类整合子酶基因(intⅠ1)存在情况。方法对0524株应用K-B法检测其耐药表型,应用三维试验检测其产生的β-内酰胺酶表型,应用聚合酶链反应及序列分析方法分析其BLAs、AMEs、qnr、qacE△1-sul1和intⅠ1基因类型。结果0524株鲍氏不动杆菌对第三代头孢菌素、头孢西丁、环丙沙星、阿米卡星耐药,对头孢吡肟、亚胺培南、头孢哌酮/舒巴坦敏感,产生AmpC酶,携有blaDHA-1基因,同时blaTEM-1型基因,acc(3)-Ⅰ、aac(6′)-Ⅰ、ant(3″)-;ⅠqacE△1-sull和intⅠ1均阳性,其他受试基因均阴性。结论0524号菌株产生DHA-1型AmpC酶和TEM-1型的广谱β-内酰胺酶,且携带Ⅰ类整合子、消毒剂与磺胺类耐药基因和3种氨基糖苷修饰酶基因,其耐药机制复杂。     

脑血栓患者合并肺部感染痰细菌培养和药敏分析

目的：了解脑血栓患者合并肺部感染痰细菌菌裙的分布和体外药敏试验状况、耐药机制、合理指导应用抗生素。方法：脑血栓患者合并肺部感染的痰液做细菌培养，按常规方法分离应用MICROSCAN-4半自动细菌鉴定分析仪进行细菌鉴定到种并作药敏试验采用产色素头孢菌素法检测β-内酰胺酶（ESBLS）和双纸片协同实验做超广谱β-内酰胺酶初筛。结果：319例痰中分离到238例阳性，其中细菌株208株，酵母样真菌47株，合并感染42例，157例革兰氏阴性菌中产β-内酰胺酶（ESBLS）的肺炎克雷伯菌11株和产β-内酰胺酶的大肠杆菌5株，12株金黄色葡萄球菌中检出耐苯唑青霉素（MRCNS）的6株，在42株凝固酶阴性的表皮葡萄球菌中检出耐苯唑青霉素的24株。结论：脑血栓合并肺部感染的细菌种类多，菌谱复杂菌株呈多重耐药性。以非发酵菌感染占多数，铜绿假单胞菌位居首位，二重感染以合并酵母样真菌多见，革兰氏阳性球菌中耐苯唑青霉素的菌株占58．3％。     

临床产超广谱β-内酰胺酶菌的分离情况及耐药性分析

目的 研究临床不同标本中产超广谱β-内酰胺酶(ESBLs)的大肠埃希菌和肺炎克雷伯杆菌的检出情况及其耐药特点.方法 采用全自动细菌鉴定/药敏分析仪结合双纸片确证法对我院2005-2006年微生物室从各类标本中分离的大肠埃希菌和肺炎克雷伯杆菌523株进行检测.结果 大肠埃希菌产ESBLs的发生率为26.1%,肺炎克雷伯杆菌产ESBLs的发生率为23.1%,中段尿、痰、伤口分泌物3种标本中分离的大肠埃希菌、克雷伯杆菌产ESBLs的发生率间差异均无统计学意义(P>0.05);产ESBLs菌在ICU病房所占比例最大,其次为呼吸科病房,儿科病房所占比例最小;产ESBLs菌株对抗菌药物的耐药性较非产ESBLs菌株差异有统计学意义(P<0.05),且呈现多重耐药.目前我院产ESBLs细菌主要为大肠埃希菌和肺炎克雷伯杆菌.结论 产ESBLs菌在我院各个病房、不同标本均有发生,对抗菌药物的耐药性明显高于非产ESBLs菌,除亚胺培南外,产ESBLs菌对多种抗菌药物均出现不同程度的耐药性.     

甲氧西林耐药金黄色葡萄球菌耐药性的研究

甲氧西林耐药金黄色葡萄球菌（ＭＲＳＡ）感染发生率有逐年增加趋势。为了解ＭＲＳＡ耐药特点及合理选用抗菌药物，我们测定了１８种抗菌药物对临床分离金黄色葡萄球菌（ＳＡ）的最低抑菌浓度（ＭＩＣ）、受试菌的β－内酰胺酶及凝固酶分型。结果表明ＭＲＳＡ占临床分离ＳＡ的５０．７％，其中产β－内酰胺酶菌株占８５．１％，ＭＲＳＡ凝固酶均为ＩＩ型。ＭＲＳＡ对多数β－内酰胺类及某些氨基糖甙类抗生素呈多重耐药性。万古霉素、阿贝卡星对ＭＲＳＡ显示最强的抗菌活性；阿米卡星、妥磺沙星、氧氟沙星、亚胺培南亦显示较强抗菌活性，提示上述药物可用于ＭＲＳＡ所致严重感染。     

First Canadian outbreak of Enterobacteriaceae-expressing Klebsiella pneumoniae carbapenemase type 3

BACKGROUND:

Organisms expressing Klebsiella pneumoniae carbapenemase (KPC) are found in several regions worldwide but are rarely detected in Canada. The first outbreak of KPC-expressing strains of Enterobacteriaceae clinical isolates in a university-affiliated hospital intensive care unit (ICU) in Canada is described.

METHODS:

Enterobacteriaceae isolates that were flagged by the Vitek 2 (bioMérieux, France) system as possible carbapenemase producers were subjected to the modified Hodge test. Modified Hodge test-positive organisms were analyzed by pulsed-field gel electrophoresis, tested for KPC and other beta-lactamase genes by polymerase chain reaction analysis and underwent subsequent nucleic acid sequencing. Antimicrobial susceptibility profiles were determined by Vitek 2 and Etest (bioMérieux, France). A chart review was conducted to establish epidemiological links.

RESULTS:

During the study period, 10 unique Enterobacteriaceae isolates expressing KPC were detected from nine ICU patients. Five patients had infections (three pneumonias, one surgical site infection, one urinary tract infection). Isolates included Escherichia coli (5), Klebsiella oxytoca (2), Serratia marcescens (2) and Citrobacter freundii (1). Polymerase chain reaction analysis and sequencing confirmed the presence of KPC-3 in all isolates; four also carried TEM, two CTX-M and one CMY-2. The imipenem minimum inhibitory concentrations as determined by Etest ranged from 0.75 μg/mL to ≥32 μg/mL. Pulsed field gel electrophoresis clonal patterns and patient location in the ICU revealed presumptive horizontal transmission events.

CONCLUSIONS:

In the present study, Enterobacteriaceae isolates with KPC are emerging and can result in serious infections. The KPC gene can spread via plasmids to different genera of the Enterobacteriaceae family. The dissemination of KPC in Enterobacteriaceae and the consequences for treatment and infection control measures warrant a high degree of vigilance among clinicians and microbiologists.     

超广谱β-内酰胺酶肺炎克雷伯菌耐药性研究

目的:超广谱β-内酰胺酶(ESBLs)肺炎克雷伯菌的耐药性调查,更好的指导临床用药。方法:应用双纸片协同试验法检测38株产ESBLs的肺炎克雷伯菌的体外抗生素耐药性。结果:ESBLs肺炎克雷伯菌阳性率为10.3％,产ESBLs肺炎克雷伯菌对头孢噻肟、头孢曲松、头孢唑琳、耐药率高达93％,所有受试菌对亚胺培南均敏感。结论:产ESBLs肺炎克雷伯菌引起的感染,治疗应首选亚胺培南、头孢西汀,其次为β-内酰胺酶抑制剂复合制剂。