耐碳青霉烯类抗菌药物鲍曼不动杆菌膜蛋白机制研究

目的研究耐碳青霉烯类鲍曼不动杆菌膜蛋白机制并了解其流行型别。方法收集仁济医院、瑞金医院和上海市第六人民医院鲍曼不动杆菌共85株,其中亚胺培南和美罗培南耐药菌49株,敏感菌36株。用细菌基因组回文结构重复序列-聚合酶链反应(REP-PCR)分析其流行型别,PCR扩增检测碳青霉烯类水解酶及金属酶,对阳性扩增菌株进行DNA测序分析,同时用超声波和超速离心法提取细菌的膜孔蛋白并用十二烷基磺酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)进行分析。结果49株耐亚胺培南和美罗培南鲍曼不动杆菌中,REP-PCR分析结果以A型为主,与敏感菌株存在很大差异;耐药菌株中oxa-51均为阳性,45株为oxa-23阳性;36株敏感菌株中检测到1株oxa-58阳性,29株为oxa-51阳性;金属酶(VIM和IMP-1/4型)均阴性;膜蛋白分析显示,在36株耐药株中38 000附近条带缺失,而在30株敏感株中有17株在相应位置处表达该条带。结论耐碳青霉烯类鲍曼不动杆菌主要以A型流行,产oxa-23水解酶和38 000附近膜孔蛋白条带缺失可能是其主要耐药机制。     

Clinical management of cUTI,cIAI, and HABP/VABP attributable to carbapenem-resistant Gram-negative infections in Spain

IntroductionCarbapenem-resistant Gram-negative (CRGN) infections are a major public health problem in Spain, often implicated in complicated, healthcare-associated infections that require the use of potentially toxic antibacterial agents of last resort. The objective of this study was to assess the clinical management of complicated infections caused by CRGN bacteria in Spanish hospitals.MethodsThe study included: 1) a survey assessing the GN infection and antibacterial susceptibility profile in five participating Spanish hospitals and 2) a non-interventional, retrospective single cohort chart review of 100 patients with complicated urinary tract infection (cUTI), complicated intra-abdominal infection (cIAI), or hospital-acquired bacterial pneumonia/ventilator-associated bacterial pneumonia (HABP/ VABP) attributable to CRGN pathogens.ResultsIn the participating hospitals CRGN prevalence was 9.3% amongst complicated infections. In the retrospective cohort, 92% of infections were healthcare-associated, and Klebsiella pneumoniae and Pseudomonas aeruginosa were the most common pathogens. OXA was the most frequently detected carbapenemase type (71.4%). We found that carbapenems were frequently used to treat cUTI, cIAI, HABP/VABP caused by CRGN pathogens. Carbapenem use, particularly in combination with other agents, persisted after confirmation of carbapenem resistance. Clinical cure was 66.0%, mortality during hospitalization 35.0%, mortality at the time of chart review 62.0%, and 6-months-post-discharge readmission 47.7%.ConclusionOur results reflect the high burden and unmet needs associated with the management of complicated infections attributable to CRGN pathogens in Spain and highlight the urgent need for enhanced clinical management of these difficult-to-treat infections.     

烧伤病房鲍曼不动杆菌耐药性及OXA基因型检测

目的:了解烧伤病房患者创面鲍曼不动杆菌的耐药性和OXA碳青霉烯酶基因携带情况,为预防和控制多重耐药鲍曼不动杆菌医院感染提供依据.方法:收集2013年1月—2015年12月皖南医学院第一附属医院烧伤整形外科收治2572例患者创面分泌物进行细菌培养;使用VITEK2 Compact型全自动微生物检测仪鉴定鲍曼不动杆菌,通过药敏实验检测其对18种抗菌药物的敏感性;应用聚合酶链反应(PCR)方法检测4种OXA碳青霉烯酶基因(OXA-23-like、OXA-24-like、OXA-51-like、OXA-58-like)的携带情况,并对其中10株进行OXA-23-like基因测序.结果:分离出44株鲍曼不动杆菌,对亚胺培南耐药率为79.55%(27株),对米诺环素及替加环素的耐药率较低,分别为20.45%(9株)和31.82%(14株),对庆大霉素耐药率高达100%,对其他抗菌药物也具有较高的耐药率(59.09%~97.73%).所有菌株OXA-51-like基因均为阳性,共有35株OXA-23-like基因阳性(阳性率79.55%),均未检测到OXA-24-like基因和OXA-58-like基因.结论:鲍曼不动杆菌呈多重耐药现象,对米诺环素耐药率最低,我院创面鲍曼不动杆菌主要耐药机制可能与OXA-23-like基因有关.     

Antimicrobial activity of plazomicin against Enterobacteriaceae-producing carbapenemases from 50 Brazilian medical centers

Plazomicin is a next-generation aminoglycoside with activity against Enterobacteriaceae, including carbapenemase-producing Enterobacteriaceae (CPE). The aim of this study was to evaluate the activity of plazomicin against CPE (Klebsiella spp., Escherichia coli, Serratia spp., Enterobacter spp., Citrobacter spp., Morganella spp., Proteus spp., Providencia spp.) from different Brazilian hospitals. A total of 4000 carbapenem-resistant Enterobacteriaceae isolates were collected from clinical samples in 50 Brazilian hospitals during 2013–2015. Of these, 499 carbapenem-resistant isolates (CLSI criteria) were selected for further evaluation via broth microdilution to assess for the activity of plazomicin, colistin, tigecycline, meropenem, amikacin, and gentamicin. Additionally, the isolates were assessed for the presence of carbapenemase genes (bla_KPC, bla_NDM, bla_OXA-48-like, bla_IMP, bla_BKC, bla_GES, and bla_VIM) by polymerase chain reaction (PCR). When PCR was positive to bla_OXA-48-like, bla_IMP, bla_GES, and bla_VIM, the carbapenemase genes were sequenced. bla_KPC was the most prevalent carbapenemase gene found (n = 397), followed by bla_NDM (n = 81), bla_OXA-48 (n = 12), and bla_IMP-1 (n = 3). Other genes were identified in only 1 isolate each: bla_BKC-1, bla_GES-16, bla_GES-1, bla_OXA-370, and bla_VIM-1. One isolate had 2 carbapenemase genes (bla_KPC and bla_NDM). Thirty-three percent of the isolates were nonsusceptible to colistin, 24% to tigecycline, 97% to meropenem, 51% to amikacin, and 81% to gentamicin (via EUCAST criteria). The plazomicin MIC_50/90 was 0.5/64 mg/L, with 85% of MICs ≤2 mg/L and 87% of MICs ≤4 mg/L. Elevated MICs to plazomicin were not associated with a specific carbapenemase or bacterial species. The MICs of plazomicin against CPE were lower than those of other aminoglycosides. Plazomicin is a promising drug for the treatment of CPE infections.     

Wastewater drainage system as an occult reservoir in a protracted clonal outbreak due to metallo-β-lactamase-producing Klebsiella oxytoca

We describe the epidemiology of a protracted nosocomial clonal outbreak due to multidrug-resistant IMP-8 producing Klebsiella oxytoca (MDRKO) that was finally eradicated by removing an environmental reservoir. The outbreak occurred in the ICU of a Spanish hospital from March 2009 to November 2011 and evolved over four waves. Forty-two patients were affected. First basic (active surveillance, contact precautions and reinforcement of surface cleaning) and later additional control measures (nurse cohorting and establishment of a minimum patient/nurse ratio) were implemented. Screening of ICU staff was repeatedly negative. Initial environmental cultures, including dry surfaces, were also negative. The above measures temporarily controlled cross-transmission but failed to eradicate the epidemic MDRKO strain that reappeared two weeks after the last colonized patients in waves 2 and 3 had been discharged. Therefore, an occult environmental reservoir was suspected. Samples from the drainpipes and traps of a sink were positive; removal of the sink reduced the rate number but did not stop new cases that clustered in a cubicle whose horizontal drainage system was connected with the eliminated sink. The elimination of the horizontal drainage system finally eradicated the outbreak. In conclusion, damp environmental reservoirs (mainly sink drains, traps and the horizontal drainage system) could explain why standard cross-transmission control measures failed to control the outbreak; such reservoirs should be considered even when environmental cultures of surfaces are negative.     

北京与银川两家医院耐碳青霉烯类肠杆菌科细菌的流行特征研究#br#

目的 调查研究北京与银川两家医院耐碳青霉烯类肠杆菌(carbapenem-resistance Enterobacteriaceae, CRE)的流行病学特征，为CRE的临床诊治及其传播控制提供依据。方法 收集2008年1月至2017年12月间北京地区解放军302医院及银川地区宁夏医科大学总医院的临床标本中分离的CRE，分析其流行趋势、标本来源、病原特点及基因型组成，探讨CRE的流行病学特征。结果 两地区10年间分离鉴定出266株CRE，呈上升趋势，北京地区CRE检出率由2008年为0.45%上升到2017年的5.84%；银川地区CRE检出率由2008年的0.26%上升到2017年的3.1%。CRE感染患者以男性为主(159例，59.77%)，主要来自重症监护病房(intensive care unit，ICU)70例(26.31%)。北京与银川两家医院分离出CRE的主要标本为痰液(29.4%与26.3%)，血液(18.4%与6.5%)和尿液(10.5%与19.7%)，血液和尿液标本占比差异显著(P=0.015和0.045)。北京与银川两家医院CRE菌株以克雷伯菌属(66.32%和44.74%)、埃希菌属(20.00%和9.21%)及肠杆菌属(7.89%和36.84%)为主，差异均具有统计学意义(比较P值分别为0.0012、0.0340和0)。266株CRE总体对碳青霉烯类和头孢类抗生素的耐药率较高，对其他类抗生素包括磷霉素和左氧氟沙星的耐药率达到80%以上，对阿米卡星的耐药率近60%；对头孢他啶/阿维巴坦的耐药率为42.86%，耐药率较低的包括替加环素(4.51%)和多黏菌素B(4.14%)；北京地区CRE对阿米卡星和左氧氟沙星的耐药率显著高于银川地区。北京地区的blaKPC在克雷伯菌、埃希菌属和肠杆菌属中均占绝对优势(93.75%、61.9%和80%)，而blaNDM仅在埃希菌属中检测到；银川地区均以blaNDM基因为主，三个菌属中占比分别为36%、74%和85.71%，两地碳青霉烯酶耐药基因分布差异明显(P=0)。结论 北京与银川两地区的CRE菌株流行呈增长趋势，在标本来源、病原特点、碳青霉烯酶耐药基因分布等方面特征鲜明，临床应根据本地区的CRE流行特点采取针对性治疗。     

产KPC酶肠杆菌科细菌对碳青霉烯类抗菌药物的耐药性分析

目的 评价临床常用的5种药物敏感性（药敏）试验方法对KPC酶介导碳青霉烯类抗菌药物耐药性的检出率.方法 收集2007年10月-2008年9月浙江大学医学院附属第一医院36株经PCR证实产KPC酶的肠杆菌科细菌,包括32株肺炎克雷伯菌、1株大肠埃希菌、1株弗氏枸橼酸杆菌、1株产酸克雷伯菌和1株黏质沙雷菌,用琼脂稀释法、纸片扩散法检测菌株对亚胺培南、美罗培南和厄他培南的耐药性,ATB G-5药敏卡检测亚胺培南、美罗培南的耐药性,BD Phoenix 100NMIC-109药敏卡检测亚胺培南的耐药性,VITEK 2 Compact AST-GN13药敏卡检测亚胺培南、厄他培南的耐药性.结果 ATB、BD Phoenix100、VITEK 2 Compact、琼脂稀释法和纸片扩散法检测亚胺培南耐药率分别为13.9%（5株）、11.1%（4株）、13.9%（5株）、22.2%（8株）和69.4%（25株）;ATB、琼脂稀释法和纸片扩散法检测美罗培南耐药率分别为22.2%（8株）、55.6%（20株）和47.2%（17株）;VITEK 2 Compact、琼脂稀释法和纸片扩散法检测厄他培南耐药率分别为69.4%（25株）、77.8%（28株）和88.9%（32株）.VITEK 2 Compact和琼脂稀释法检测结果显示,厄他培南对所有产KPC酶菌株的MIC均≥2 μg/mL.结论 纸片扩散法和琼脂稀释法能更好地检出KPC酶介导的碳青霉烯类抗菌药物的耐药性,厄他培南可作为筛选产KPC酶菌株的指示药物.     

碳青霉烯类药物耐药的弗劳地枸橼酸杆菌耐药机制研究

目的 对耐碳青霉烯类弗劳地枸橼酸杆菌进行同源性分析及多种耐药基因的检测.方法 用琼脂稀释法测定其最低抑菌浓度( MIC)值,采用脉冲场凝胶电泳(PFGE)分析耐碳青霉烯类弗劳地枸橼酸杆菌的同源性,以聚合酶链反应(PCR)检测β-内酰胺酶、膜孔蛋白的缺失等多种耐药基因.结果 PFGE显示1、2、4、5号菌株均有19个条带,具有同源性;PCR试验检测结果1、4号菌携带blaCTX-M型超广谱β-内酰胺酶(ESBLs);2、3、5号菌携带携带blaDHA,3号携带bla ACT/MIR型AmpC 基因,1、2、4、5号菌携带bla KPC-2碳青霉烯酶基因;2号、4号菌株缺失膜孔蛋白基因ompF,3号菌株同时缺失ompC和ompF;其中3号菌株的16S rRNA基因定量确定AmpC基因的表达为阴性菌的106.7倍.结论 宁波市第一医院碳青霉烯类耐药的弗劳地枸橼酸盐杆菌具有同源性,其耐药机制由KPC酶、AmpC酶、ESBLs、膜孔蛋白缺失等共同作用所形成,多数耐药基因定位在质粒上易引起耐药性的播散,临床应引起高度重视.     

Dissemination of New Delhi metallo-β-lactamase-1-producing Acinetobacter baumannii in Europe

Multidrug-resistant and New Delhi metallo-β-lactamase I (NDM-I) -producing Acinetobacter baumannii are increasingly reported. A collection of five NDM-I-positive A. baumannii isolates recovered in four European countries were analysed. Genotyping was performed by pulsed-field gel electrophoresis, multiplex PCR sequence typing, Diversilab and multilocus sequence typing. Three distinct sequence types were identified. All isolates harboured a chromosomally located bla_NDM-1. gene within a Tn/25-like transposon. One isolate co-expressed another unrelated carbapenemase OXA-23. This report constitutes the first epidemiological study of NDM-I-producing A. baumannii from four countries.