1、革兰阳性球菌耐药与治疗,倪语星上海交通大学医学院附属瑞金医院,MDR细菌已成为全球关注的焦点,在全球范围内，“ESKAPE”耐药已成为导致患者发病及死亡的重要原因1,“ESKAPE”耐药现象日益严重，但当前新型抗菌药物的研发逐渐减缓，未来可能面临无药可用的局面3,新药数量,1983-1987,1988-1992,1993-1997,1998-2002,2003-2007,1.Rice LB et al.The Journal of Infectious Diseases 2008;197:1079812.http:/www.who.int/world-health-day/zh/3.Bouch
2、er HW et al.Clinical Infectious Diseases 2009;48:112,我国主要的MDR致病菌,我国，“ESKAPE”耐药菌株检出率高,检出率(%),产ESBL大肠埃希菌,MRSA,产ESBL肺炎克雷伯菌属,不动杆菌属*,铜绿假单胞菌*,耐万古霉素屎肠球菌,*在G-菌中的检出率,朱德妹等.中国感染与化疗杂志.2011;11(5):321-329,13967株,5380株,431株,1733株,1623株,汪复,等.中国感染与化疗杂志.2010;10(5):325-334.,各类标本中的主要病原菌？,血培养排名前10位的临床致病菌,一、药敏监测数据,R.N.Jo
3、nes et al.Diagnostic Microbiology and Infectious Disease.2009;64:191201.,ZAAPS监测项目简介,R.N.Jones et al.Diagnostic Microbiology and Infectious Disease.2009;64:191201.,近6年ZAAPS监测共分离到G+菌34170株,不同国家MRSA耐药率,加拿大：55.7%拉丁美洲：平均为50.1%(29.0%-64.1%)欧洲：平均为28.2%(1.7%-56.2%)亚太地区：平均为44.2%(25.3%-68.0%),R.N.Jones et al
4、.Diagnostic Microbiology and Infectious Disease.2009;64:191201.,常用抗菌药物对金黄色葡萄球菌抗菌活性,R.N.Jones et al.Diagnostic Microbiology and Infectious Disease.2009;64:191201.,2007年ZAAPS项目对3000株金黄色葡萄球菌药敏监测结果,常用抗菌药物对CoNS的抗菌活性,R.N.Jones et al.Diagnostic Microbiology and Infectious Disease.2009;64:191201.,2007年ZAAPS
5、项目对716株CoNS药敏监测结果,2008年CHINET监测网各医院金葡菌MR菌株检出率,2008年CHINET监测网各医院凝固酶(-)葡萄球菌MR菌株检出率,MSSA(1495株)与MRSA(1916株)的耐药率（%）,MRSA的耐药率MSSA仍有75，67菌株对SMZ/TMP、磷霉素敏感MSSA对内酰胺类、氟喹诺酮类、SMZ/TMP、利福平、磷霉素的耐药率10无万古、替考拉宁、利奈唑胺耐药株,MSCNS(555株)和MRCNS(1723株)的耐药率（%）,MRCNS的耐药率MSCNSMRCNS耐药率MRSA，但仍有约90、65菌株对利福平、磷霉素敏感。无万古、替考拉宁、利奈唑胺耐药株,2
6、006-2010年监测数据 耐万古霉素的粪肠球菌与屎肠球菌发生率极少,汪复.2006年中国CHINET细菌耐药性监测.中国感染与化疗杂志 2008;8(1):1-9.汪复等.2007年中国CHINET细菌耐药性监测.中国感染与化疗杂志 2008;8(5):325-333.肖永红等.2006-2007年Mohnarin细菌耐药检测.中华医院感染学杂志 2008;18(8):1051-1056.汪复等.2008年中国CHINET细菌耐药性监测.中国感染与化疗杂志 2009;9(5):321-329.汪复等.2009年中国CHINET细菌耐药性监测.中国感染与化疗杂志 2010;10(5):325-
7、334.朱德妹,汪复,胡付品等.2010年中国CHINET细菌耐药性监测.中国感染与化疗杂志 2011;11(5):321-329.,二、S.aureus and MRSA,Methicillin resistant S.aureusPresence of a mecA geneCarried in a mobile genetic element(SCCmec)Most routine testing antibiotic sensitivity(MRSA id agar),CLSI药敏指南,“金黄色葡萄球菌或所有凝固酶阴性葡萄球菌如对苯唑西林(或甲氧西林)耐药，则对青霉素类、头孢菌素类、碳
8、青霉烯类和含酶抑制剂的复方制剂均应报告耐药，而不考虑其体外药敏结果”。,Cefoxitin Disk Test for mecA-mediated Resistance in Staphylococci Breakpoints(mm),*Report as oxacillin resistant*Report as oxacillin susceptibleCoNS,coagulase-negative staphylococci,OX-R=mecA=MRSA?,Discovery of the new MRSA strains(LGA251),We found S.aureus that w
9、ere highly resistant on one farm(ST425)(Oxacilin MIC=16mg/l,cefoxitin MIC=32mg/l)Looked for mecA gene negative resultsSequenced whole genome to look for the reasonFound a divergent mecA gene inside a new SCCmec,Importance of the new MRSA,Molecular tests(PCR&slide agglutination test)designed to detec
10、t MRSA give a negative result when tested on the new strainThe new MRSA is moving between people and cattleOld MRSA was not found in dairy cowsDivergent MRSA is found in S.aureus strains thought to be restricted to animalsGeographical clustering of human and cow strains of the new MRSADivergent MRSA
11、 mecA gene has not been found in human strainsIsolations of divergent MRSA appear to be increasing,New MRSA isolates by year,三、对糖肽类的耐药机制,VRSA,vanA gene positiveChange of D-alanyl-D-alanyl-D-lactate1000 fold decrease in affinity to vancomycinTypical MIC16mg/L to vancomycin,VRSA,USA 12 caseshttp:/www.
12、cdc.gov/HAI/settings/lab/vrsa_lab_search_containment.htmlFirst discovered in 20028 from Michigan!2 most reccent from Delaware(2010)Iran-1 case THE-2,2005India 6 casesFrom intensive care units in 2 tertiary hospitals in Hydrabad-2008,VISA isolates,Not a single mutation or acquisition of a single gene
13、Complex!Involves a series of changes!Increased cell wall thickening,increased number of free D-alanyl-D-alanin residues,reduced autolytic activity,mutations in regulators of cell wall synthesis(i.e.graRS,vraSR),change in transcription profileTypical MIC 4-8mg/L,hVISA,isolates susceptible by standard
14、 MIC testing but have subpopulations expressing reduced susceptibilitySame types of resistance mechanisms as VISA isolatesTypical MIC 1-2mg/L,Population profile of initial isolate(6000)and after persistant bacteremia/vancomycin therapy(6001),Howden,AAC,2006,Prevalence of VISA/hVISA,Highly variable p
15、revalences are reported in the literature including within countriesIllustrated by data from AustraliaMelbourne(Austin)117 MRSAVISA 2 isolates(2%)Sydney 401 MRSA BSIhVISA 46(11.5%)(almost all ST239)VISA 2(0.5%)Australia general 532 SAB/202 MRSAhVISA 2 isolates 0.4%/1%VISA 0 isolates,Horne AAC,2009.V
16、al Hal,Plosone.Homes,JID 2011.,Summary,The prevalence of VRSA and VISA isolates are still low in most part of the worldThe prevalance of hVISA varies in general relatively low but can locally be up 50%of MRSA isolatesThere are increasing evidence that strains with MIC1mg/L are associated with pooer
17、outcome but large definitive prospective studies is needed,Linezolid-R S.aureus:Review,April June 200812 patients with LRSA6 VAP,3 bacteremia1 predominant clonecfr mediated resistanceHealth care workers and environment Neg,Clinical Outbreak of Linezolid-Resistant Staphylococcus aureus in an Intensiv
18、e Care Unit,Sanchez M,JAMA 2010,Linezolid-R S.aureus outbreak,K-217Clinical and Microbiological characteristics of Linezolid-Resistant Staphylococcus aureus(LRSA)April-June 2008,From July 2001 to May 2011:22 publications,77 patientsMechanism of resistance was aRNA mutation in 37cfr gene in 33Both 1N
19、ot reported 730 ICU-patients,17 patients on hospital words and 18 outpatientsLRSA caused 29 respiratory tract infections,mostly VAP,bacteremia in 7,and SSTI in 6.Six patients were colonized.,M de la Torre,ICAAC,Chicagao 2011,Mechanisms of Linezolid Resistance,Binding to the Petidyl Transferase Cente
20、r(PTC)on the ribosomeMutations of 23S rRNARibosomal proteins L3 and L4Cfr methyl transferase gene,Long KS.AAC 2012.,Resistance to Linezolid Caused by modifications at Its Binding Site on the Ribosome,LR-MRSA outbreak:Results,All LR-MRSA(patients and HCWs)were genotypically identical by PFGEThe cfr g
21、ene was detected in all isolatesNone of the isolates showed mutations in the 235 rRNA subunit,LR-MRSA outbreak:Linezolid Use,Dapto-Resistance:mechanisms,Mutations in genes essential for Membrane phospholipid biosynthesis reduce the net-negative charge of the cell membrane.Electrorepulsion of Daptomy
22、cin,Whole Genome Characterization of the Mechanisms of Daptomycin Resistance in Clinical and Laboratory Derived Isolates of Staphylococcus aureus,Peleg AY.PLoSone 2012.,Dapto-Resistance:mechanisms,Correlation between nonsusceptibility to daptomycin is due to cell wall thickening,Peleg AY.PLoSone 201
23、2.,Daptomycin MIC increase among patients with methicillin-resistant Staphylococcus aureus persistent bacteraemia treated with daptomycin.Prospective study in 22 Spanish hospitals.O.Gasch*,M.Camoez,MA.Dominguez,B.Padilla,Increase in MICs in sequential isolates both to Daptomycin and Vancomycin.Switc
24、h to another drug if BCs do not become negative,Gash O.ECCMID 2012.,四、VRE,肠球菌对万古霉素的耐药可分为低水平耐药（MIC，8-32mg/L）和高水平耐药（MIC，64mg/L）。根据肠球菌对万古霉素和替考拉宁的不同耐药水平及耐药基因，VRE分为四个表型，分别是VanA，VanB，VanC和VanD。,VRE的分型及其耐药表型,类型 万古霉素（g/ml）替考拉宁,VanA 641000 16512 VanB 41024 0.252 VanC 232 0.122 VanD 1664 24,CLSI bp 2,4-8 16 8
25、,16 32,chromID VRE,粪肠球菌,屎肠球菌,VRE筛选试验阳性必须做MIC确认，并观察动力和色素鉴别菌种，以区分获得性耐药（VanA和VanB）及某些菌种存在的固有的中介（8-16）耐药（VanC），后者在感染控制中的意义与VRE不同。,肠球菌的治疗,粪肠球菌：氨苄西林加减庆大霉素 重症，HLAR：万古霉素屎肠球菌：庆大霉素重症，HLAR：万古霉素VRE：VanA：替考拉宁，其他：利奈唑胺泌尿道感染：呋喃妥因,五、经验治疗,以下情况高度提示革兰阳性球菌感染,血流感染，包括导管相关的血流感染，菌血症，脓毒症，细菌性心内膜炎皮肤软组织感染，包括伤口和创面感染手术部位感染，包括植入物感染骨和关节感染，骨髓炎,以下情况有可能革兰阳性球菌感染,HAP（MRSA）VAP（MRSA）复杂UTI（MRSA，肠球菌）,革兰阳性球菌感染？,葡萄球菌占革兰阳性球菌感染第一位金黄色葡萄球菌占葡萄球菌感染第一位MRSA占金黄色葡萄球菌5060%,以下情况考虑糖肽类治疗,脓毒症骨、关节感染手术部位感染血流感染：菌血症、心内膜炎导管相关感染院内肺炎复杂性尿路感染,Thank You!,
