鲍曼不动杆菌及其耐药基因的检测

目的探索一种检测鲍曼不动杆菌及其耐药基因的新方法。方法首先对近几年医院内鲍曼不动杆菌的耐药情况进行分析,选择临床上治疗鲍曼不动杆菌的首选药,再采用聚合酶链反应对鲍曼不动杆菌及其突变株进行检测。结果鲍曼不动杆菌对亚胺培南的耐药率最低,为9.37%,OXA-51基因扩增结果与细菌培养相符,OXA-23基因扩增与鲍曼不动杆菌耐亚胺培南的结果相符。结论采用PCR法对OXA-51基因扩增可以检测是否存在鲍曼不动杆菌,采用PCR法对OXA-23基因扩增可以检测鲍曼不动杆菌是否存在亚胺培南耐药性。从而快速检测鲍曼不动杆菌及其耐药基因,指导临床用药。     

某院2011年12月-2012年12月ICU亚胺培南耐药鲍曼不动杆菌碳青霉烯酶基因型的研究

目的:对重症监护病房(ICU)临床分离的亚胺培南耐药鲍曼不动杆菌的耐药性及碳青霉烯酶基因型进行研究,为临床防治提供理论依据。方法:收集2011年12月-2012年12月青岛市海慈医疗集团ICU临床分离的亚胺培南耐药鲍曼不动杆菌65株,采用K-B琼脂纸片扩散法进行药敏试验,聚合酶链反应(PCR)检测OXA-23、OXA-24、OXA-51、OXA-58、IMP、VIM 6种碳青霉烯酶基因,并对PCR产物进行测序。结果:65株亚胺培南耐药鲍曼不动杆菌除对头孢哌酮/舒巴坦、阿米卡星、多黏菌素B的耐药率较低外,对其他药物的耐药率均在90%以上。65株扩增出OXA-51基因,56株扩增出OXA-23基因,6株扩增出VIM基因,检出率分别为100%、86.15%、9.23%,OXA-24、OXA-58及IMP均未检出;PCR产物测序表明与GenBank相关基因同源性为100%。结论:该单位ICU亚胺培南耐药鲍曼不动杆菌的耐药现象严重;OXA-23型碳青霉烯酶的产生是鲍曼不动杆菌对碳青霉烯类药物耐药的重要机制之一。     

鲍曼不动杆菌耐药性及碳青霉烯酶的研究

目的了解鲍曼不动杆菌耐药谱及碳青霉烯酶的研究。方法用VITEK60型全自动药敏分析系统鉴定药敏系统及纸片扩散法进行药敏实验;PCR扩增和测序分析检测碳青霉烯酶VIM、IMP、OXA-23和OXA-24。结果217株鲍曼不动杆菌中头孢哌酮/舒巴坦耐药率最低,其次是亚胺培南,再者是头孢他啶和哌拉西林/他唑巴坦;头孢哌酮/舒巴坦和头孢他啶的中介率分别是27.6%和19.8%;20株亚胺培南耐药菌中,PCR扩增VIM、IMP和OXA-24均阴性;OXA-23基因扩增显示19株（95%）阳性,PCR产物并经序列分析证实为OXA-23。结论碳青霉烯类抗生素的长期广泛应用使鲍曼不动杆菌的耐药率不断升高;产OXA-23型β-内酰胺酶是本院鲍曼不动杆菌对亚胺培南耐药的重要原因。     

耐亚胺培南鲍曼不动杆菌耐药机制研究

目的 研究鲍曼不动杆菌对亚胺培南的耐药机制。方法 对临床分离的3株耐亚胺培南的鲍曼不动杆菌，采用KB纸片扩散法（CLSI／NCCLS2004年标准）进行药敏试验，三维试验检测ESBLs和AmpC酶，PCR方法检测TEM、SHV、PER、VEB、AmpC、IMP、VIM、OXA-23和OXA-24等9种耐药基因型，PCR阳性产物进行基因测序，结果在GenBank基因库中比对分析。结果 3株鲍曼不动杆菌为多重耐药菌株，三维试验均产生ESBLs，1株产生AmpC酶，耐药基因型检测3株TEM阳性，2株PER阳性，2株AmpC酶阳性及SHV、VEB和IMP、VIM、OXA-24型等均为阴性；3株OXA-23型均阳性；另外27株对亚胺培南敏感鲍曼不动杆菌IMP、VIM，OXA-23和OXA-24型检测结果均阴性。结论 耐亚胺培南鲍曼不动杆菌携带TEM、PER、非诱导AmpC酶、OXA-23型碳青霉烯酶基因，产生OXA-23型碳青霉烯酶是主要耐药机制。     

我院鲍曼不动杆菌携带blaOXA-23基因及其耐药机制研究

目的研究我院分离鲍曼不动杆菌携带bla_OXA-23基因的携带情况及其诱导细菌耐药机制。方法收集江阴市青阳医院2019年1月至2019年12月间临床分离鲍曼不动杆菌,经VITEK-2全自动微生物鉴定及药敏分析系统鉴定耐亚胺培南菌株100株,敏感菌株100株。通过多重PCR法检测上述菌株中bla_OXA-23、bla_OXA-24、blaOXA-51和bla_OXA-58基因携带情况。通过PCR法扩增亚胺培南耐药的鲍曼不动杆菌bla_OXA-23的ORF序列,构建过表达载体bla_OXA-23/pYMAb3并电转化鲍曼不动杆菌(ATCC 17978),以硫酸卡那霉素和美罗培南共同筛选过表达bla_OXA-23基因的菌株。采用稀释法检测转化bla_OXA-23/pYMAb3载体和pYMAb3空载体的菌株对亚胺培南的MIC。结果我院耐亚胺培南的鲍曼不动杆菌均携带bla_OXA-23,敏感株未检出携带该基因。RT-PCR法可检出转化bla_OXA-23/pYMAb3载体菌株表达bla_OXA-23基因,而转化pYMAb3空载体菌株未检出bla_OXA-23基因表达。转化bla_OXA-23/pYMAb3载体菌株对亚胺培南MIC为32μg/mL,转化空载体菌株MIC仅为0.5μg/mL。结论我院耐亚胺培南的鲍曼不动杆菌均携带bla_OXA-23基因,可以作为耐药菌株筛选的分子标记。由质粒携带的bla_OXA-23基因是诱发我院鲍曼不动杆菌耐药的重要原因,在院感工作中需高度重视。     

耐亚胺培南鲍曼不动杆菌耐药性及OXA碳青霉烯酶检测

目的 分析97株临床分离的耐亚胺培南鲍曼不动杆菌的耐药特点及OxA碳青霉烯酶分布.方法 用国际标准平皿二倍稀释法,明确研究菌株的耐药表型;用脉冲场凝胶电泳法,对其进行分型并用PCR的方法,检测OXA碳青霉烯酶.结果 97株耐亚胺培南鲍曼不动杆菌均为多药耐药菌株,其中2株为泛耐药菌株;主要存在7个流行克隆株;有78株菌携带bal-oxa-23基因(80.4%);2株菌携带bal-oxa-58基因(2.1%);未发现携带bal-oxa-24基因的菌株.结论 在我国的亚胺培南耐药的鲍曼不动杆菌中,OXA-23仍为主要分布的碳青霉烯酶.     

鲍曼不动杆菌对亚胺培南耐药分子机制的研究

目的了解鲍曼不动杆菌对亚胺培南产生耐药的分子机制。方法收集对亚胺培南耐药的鲍曼不动杆菌(imipenem resistant Acinetobacter baumannii，IRAB)无重复株共9株，采用琼脂稀释法进行药敏检测，协同抑制试验、质粒接合试验、Southern杂交、等电聚焦电泳、PCR扩增blavIM、blaIMP、baooxA-23、blaoA-24相关基因及整合子编码序列及其分子克隆和测序，以阐述其分子耐药机制。结果本组IRAB具有多重耐药性；耐药基因分子克隆、测序并结合等电聚焦分析证实均产OXA-23型碳青霉烯酶，质粒接合试验、Southern杂交显示其编码基因定位在染色体上。9株细菌均检测出Ⅰ型整合子基因结构(大小约1．2～4kb)；3株菌检测出Ⅱ型整合子基因结构(1．8～2kb)，均携带了多种耐药基因。结论产OXA-23型p内酰胺酶是本组鲍曼不动杆菌对碳青霉烯类抗生素产生耐药性的重要原因；IRAB整合子基因携带的多种耐药基因与其多重耐药性相关。     

重症监护病房耐碳青霉烯酶鲍曼不动杆菌分子流行病学调查

目的 对重症监护病房耐碳青霉烯酶鲍曼不动杆菌之间的同源性进行分子流行病学调查,为制定预防和控制其院内感染提供依据.方法 收集重症监护病房2007年1月至12月分离到的21株亚胺培南耐药鲍曼不动杆菌.采用全自动微生物分析系统PHOENIX 100对其进行鉴定,脉冲场凝胶电泳(PFGE)分析其耐药株的同源性,对碳青霉烯类基因OXA-23型、OXA-24型、IMP型、VIM型基因进行PCR扩增及序列分析.结果 14株鲍曼不动杆菌菌株为同一耐药克隆株,并检出OXA-23型碳青霉烯酶,21株鲍曼不动杆菌菌株均未检出OXA-24、IMP、VIM基因型.结论 相同耐药克隆株在重症监护病房不同患者身上流行,可能与行气管插管、呼吸机、氧气湿化瓶、护士手工操作有关.     

耐碳青霉烯酶鲍曼不动杆菌分子流行病学调查

目的对耐碳青霉烯酶鲍曼不动杆菌之间的同源性进行分子流行病学调查，为防控院内感染提供依据。方法收集河南省人民医院重症监护病房2007年1—12月分离到的21株亚胺培南耐药鲍曼不动杆菌进行鉴定。用E-test法测定10种抗菌药物的最低抑菌浓度（MIC），脉冲场凝胶电泳（PFGE）分析其耐药株的同源性，对碳青霉烯类基因OXA-23型、OXA-24型、IMP型、VIM型基因进行PCR扩增及序列分析。结果14株鲍曼不动杆菌菌株为同一耐药克隆株，并检出OXA-23型碳青霉烯酶，21株鲍曼不动杆菌菌株均未检出OXA-24、IMP、VIM基因型。结论该院相同耐药克隆株在重症监护病房不同患者身上流行，可能与行气管插管、呼吸机、氧气湿化瓶、护士手操作有关。     

AdeC基因与鲍曼不动杆菌耐药性的研究

目的:探讨adeC基因与鲍曼不动杆菌耐药性的关系。方法:K-B法检测30株鲍曼不动杆菌对头孢曲松、利福平、亚胺培南、庆大霉素、环丙沙星5种抗菌药物的耐药性,采用PCR技术扩增adeC基因,观察30株鲍曼不动杆菌adeC基因携带情况。结果:30株鲍曼不动杆菌中,28株为耐药菌;耐药性鲍曼不动杆菌中adeC基因阳性率为96.43%(27/28)。结论:adeC基因是鲍曼不动杆菌耐药的重要机制之一。     

31例鲍曼不动杆菌对碳青霉烯类抗生素的耐药分析及基因型研究

目的通过对我院住院患者的31株鲍曼不动杆菌对耐碳青霉烯类抗生素的药物敏感试验及对碳青霉烯酶基因的分析研究,为临床用药提供参考依据。方法用梅里埃细菌分析仪对细菌鉴定,并对细菌进行药敏试验,同时用碳青霉烯酶4种基因的特异性引物进行基因扩增和基因型的测序分析,再对基因类型与网上GemBank比对,确定编码酶基因的类型。结果 31株鲍曼不动杆菌对多粘菌素B、丁胺卡那霉素、左旋氧氟沙星的耐药率分别为4%、20%、50%。对哌拉西林/他唑巴坦、庆大霉素的耐药率分别为80%、85%。对本试验研究的其他9种抗菌药物的耐药率均在90%以上。携带OXA-51基因有21株(68%),携带D类碳青霉烯酶OXA-23基因有26株(84%),对OXA-24、OXA-58基因引物PCR扩增结果为阴性,并随机各抽取5株OXA-23基因为阳性菌株进行测序,并通过在网上GemBank对比,结果 OXA-23标准株有99%同源,OXA-51基因阳性的菌株与OXA-51标准株97%同源。结论多粘菌素B、丁胺卡那霉素、左旋氧氟沙星对耐碳青霉烯类抗生素的鲍曼不动杆菌的敏感性较好,对其他抗生素有较强的耐药性。基因类型上以携带OXA-23型碳青霉烯酶基因为主,应合理地选用抗生素,防止多重耐药现象产生,对控制院感和疾病的疗效有极其重要意义。     

Multiplex PCR for genes encoding prevalent OXA carbapenemases in Acinetobacter spp

Carbapenem resistance in Acinetobacter baumannii is a growing public health concern and is most often mediated by OXA carbapenemases. We describe a novel multiplex polymerase chain reaction (PCR) assay able to detect and distinguish alleles encoding three subgroups of acquired OXA carbapenemases (OXA-23-like, OXA-24-like and OXA-58-like) that are scattered in Acinetobacter spp., and a fourth subgroup, OXA-51-like, which appears to be intrinsic to Acinetobacter baumannii. Isolates belonging to two prevalent UK A. baumannii 'OXA' clones (OXA-23 clones 1 and 2) had alleles encoding both an intrinsic OXA-51-like and an acquired OXA-23 enzyme, whereas isolates of the 'SE clone' had only an intrinsic bla(OXA-51-like) allele. Genes encoding OXA-58 were detected (with bla(OXA-51-like)) in a cluster of related isolates from a single hospital. This simple assay will assist in monitoring the mechanisms responsible for carbapenem resistance in Acinetobacter spp.     

Characterisation and clonal dissemination of OXA-23-producing Acinetobacter baumannii in Tabriz, northwest Iran

The characteristics and molecular epidemiology of carbapenemase genes amongst 68 imipenem-resistant Acinetobacter baumannii isolated from Imam Reza Hospital (Tabriz, Iran) during a 17-month period were studied. All 68 isolates were typed using sequence group-based multiplex polymerase chain reaction (PCR) to compare the clonal relationship of isolates with known international clonal lineages. Repetitive sequence-based PCR was further performed with representative isolates of each clone. PCR and sequencing were performed to detect OXA-type carbapenemases and class 1, 2 and 3 integron genes as well as to confirm the presence of insertion sequence ISAba1 upstream of bla(OXA-23) and bla(OXA-51-like) genes. Sixty-four isolates (94%) belonged to international clone (IC) II, two isolates (3%) belonged to IC I and two isolates (3%) did not belong to known international clones. All isolates carried bla(OXA-51-like), bla(OXA-23) and class 1 integron genes. No other acquired bla(OXA) genes or class 2 or 3 integron genes were detected. Sequence analysis confirmed the presence of bla(OXA-23) as well as the bla(OXA-51-like) variants bla(OXA-66), bla(OXA-69) and bla(OXA-88). ISAba1 was present upstream of the bla(OXA-23) gene in all of the isolates. Clonal spread of OXA-23-producing A. baumannii emphasises the need for appropriate infection control measures to prevent further spread of these multidrug-resistant organisms.     

Efficacy of monotherapy and combined antibiotic therapy for carbapenem-resistant Acinetobacter baumannii pneumonia in an immunosuppressed mouse model

Acinetobacter baumannii is an important cause of nosocomial infection with increasing carbapenem resistance. The aim of this study was to compare the efficacy of colistin+rifampicin and imipenem+rifampicin combinations with that of several other antibiotic regimens against carbapenem-resistant A. baumannii pneumonia using an immunosuppressed mouse model. Three different A. baumannii strains with diverse resistance mechanisms (OXA-51-, IMP-1- and VIM-2-type beta-lactamases) were used. Among the monotherapy regimens, only rifampicin significantly reduced the bacterial load in lungs 24 h after infection with the OXA-51-producing strain. Addition of rifampicin to either imipenem or colistin yielded synergistic results after 48 h. Rifampicin was bactericidal against the IMP-1-producing strain, and only the imipenem+rifampicin combination yielded synergistic effects. In contrast, rifampicin alone was not effective against the VIM-2-producing strain, but the imipenem+rifampicin combination was bacteriostatic even at 24 h post-infection. Tigecycline and amikacin were not effective against any of the three strains. Rifampicin-based combinations were effective against A. baumannii bacteraemia and improved survival regardless of the strain type. Contrary to the similar minimum inhibitory concentration results, the antibacterial effects of rifampicin were quite different according to the strains; a tailored antibiotic strategy must be considered in treatment. Addition of rifampicin to either imipenem or colistin would be effective.     

bla(OXA-51)-type beta-lactamase genes are ubiquitous and vary within a strain in Acinetobacter baumannii

We investigated the spread of bla(OXA-51)-type beta-lactamase genes in 200 Acinetobacter spp. clinical strains isolated in Argentina from 1982 to 2005. bla(OXA-51)-type genes were present in all Acinetobacter baumannii isolates tested (n=194), whereas they were not detected in two Acinetobacter haemolyticus, two genomic species 10 or two Acinetobacter lwoffii isolates. The bla(OXA-51)-type alleles varied within a strain and were found in six different A. baumannii pulsed-field gel electrophoresis clones that were susceptible or resistant to imipenem, suggesting a controversial role in imipenem resistance. Our findings agree with previous reports showing that bla(OXA-51)-type genes are naturally harboured by A. baumannii isolates from various geographical origins and support the presence of a direct reservoir of beta-lactam resistance genes within the nosocomial environment.     

呼吸内科病房泛耐药鲍曼不动杆菌的耐药性及临床用药分析

目的：了解2010-2012年间本院呼吸科病房泛耐药鲍曼不动杆菌（PDR-Ab）对常用抗菌药物的耐药情况及耐药性变化,指导临床合理用药。 方法：回顾性分析本院呼吸科2010-2012年间分离的283株泛耐药鲍曼不动杆菌的药敏结果及阳性检出率,药敏结果采用K-B纸片琼脂扩散法。 结果：泛耐药鲍曼不动杆菌对临床常用14种抗菌药物均有不同程度的耐药,且呈逐年上升的趋势,对碳青酶烯类上升幅度最大;其中耐药率最高的是头孢他啶,达93.4% ;耐药率最低的是多粘菌素B,仅1.9%;其次,对亚胺培南,头孢哌酮/舒巴坦,氨苄西林/舒巴坦,米诺环素,阿米卡星等耐药率相对较低 结论：来源于本院呼吸内科病房的泛耐药鲍曼不动杆菌对临床常用抗菌药物耐药率很高,临床必需加强耐药监测,以便为临床合理用药提供理论和客观依据。     

重症医学科医院感染病原菌分布及耐药分析

目的 调查分析重症医学科(ICU)医院感染的病原菌分布、耐药状况及变化趋势,为危重患者抗感染治疗提供依据.方法 对ICU2006年9月-2008年8月所分离出的病原菌菌株及其耐药性进行回顾性调查分析,并比较不同时期(A组:2006年9月-2007年8月,B组:2007年9月-2008年8月)病原菌耐药率差异.结果 共检出病原菌255株,其中革兰阴性杆菌183株(71.76%),以非发酵革兰阴性杆菌科和肠杆菌科细菌为主,主要包括铜绿假单孢菌(58/183,31.69%),鲍曼/溶血不动杆菌(39/183,21.31%),大肠埃希菌(32/183,17.49%)等,多见于下呼吸道感染;革兰阳性菌51株(20.0%),以葡萄球菌属和肠球菌属为主,主要见于下呼吸道和腹腔感染;真菌21株(8.24%),包括白色念珠菌(9/21,42.85%)和光滑念珠菌(8/21,38.10%)等.病原菌对常用抗菌药物耐药严重,耐药率呈上升趋势,B组铜绿假单胞菌对美罗培南和亚胺培南的耐药率及鲍曼不动杆菌对亚胺培南的耐药率较A组显著增加(P<0.05). 结论 ICU医院感染最多见于下呼吸道,以革兰阴性杆菌为主,对常用抗菌药物耐药严重,且耐药率呈上升趋势,需严格掌握抗菌药物使用原则,根据药敏选用抗菌药物.     

泛耐药鲍曼不动杆菌β-内酰胺类耐药机制研究

目的调查泛耐药鲍曼不动杆菌(pandrug-resistant Acinetobacter baumannii,PDR-ABA菌)临床分离菌株中β-内酰胺酶基因和膜孔蛋白基因的存在和变异情况。方法收集2010年3月到2010年5月临床标本中分离的PDR-ABA菌20株,采用微量肉汤烯释法进行抗菌药物敏感性试验,聚合酶链反应(PCR)和基因测序方法分析36种β-内酰胺酶基因和carO膜孔蛋白基因。结果本组20株PDR-ABA菌TEM-1、ADC-30-1ike、OXA-23型3种β-内酰胺酶基因全部阳性,CARB-2和DHA-1型阳性率为5.0%。在鲍曼不动杆菌中发现CARB-2型为国内首次报道。膜孔蛋carO基因突变率达100.0%。结论本组PDR-ABA菌对多种β-内酰胺类药物耐药与产TEM、ADC-30-like、OXA-23、CARB-2、DHA-1型5种13-内酰胺酶相关外,还与膜孔蛋白编码基因carO突变有关。     

In vitro activity of doripenem against Acinetobacter baumannii clinical isolates

Doripenem is a carbapenem with activity against Gram-positive and Gram-negative pathogens. This study evaluated the in vitro activity of doripenem against a collection of 87 Acinetobacter baumannii clinical isolates, showing that the activity of doripenem was superior to imipenem and meropenem for strains carrying the bla(OXA-58) gene. A. baumannii clinical isolates expressing the bla(OXA-24) gene were resistant to doripenem, imipenem and meropenem. However, in clinical isolates expressing the bla(OXA-58) gene, the percentage of isolates with a doripenem minimum inhibitory concentration >8microg/mL was much lower than that of imipenem and meropenem. This study shows that the activity of doripenem was superior to imipenem and meropenem for strains carrying the bla(OXA-58) gene.