Molecular typing of Acinetobacter baumannii-Acinetobacter calcoaceticus complex isolates from endemic and epidemic nosocomial infections.

Ribotype, biotype and resistance phenotype were used to characterize 37 Acinetobacter baumannii-A. calcoaceticus complex isolates responsible for nosocomial infections in Buenos Aires. Nineteen isolates were recovered from endemic infections at 2 hospitals and 18 represent an intensive care unit outbreak that occurred in a third hospital. By ribotyping isolates were classified into five different clones of A. baumannii biotype 2, 3 of A. baumannii biotype 9, and 3 of Acinetobacter genospecies 13. Combination of the three epidemiological markers permitted categorization of 18 outbreak isolates into four probable strains: 2 A. baumannii biotype 2, named type I, and II, and 2 A. baumannii biotype 9. Type I (15 isolates) was the most prevalent strain at one hospital and was responsible for the outbreak. In conclusion, combined analysis of biotypes, resistance phenotypes, and ribotypes was an accurate approach for epidemiologic investigation of A. baumannii. Furthermore, ribotyping discriminated Acinetobacter genospecies 13 isolates which were phenotypically difficult to type.     

鲍氏不动杆菌临床分离株的耐药性分析

目的调查分析医院分离的鲍氏不动杆菌流行趋势和耐药特征,指导临床合理使用抗菌药物,延缓多药耐药菌株的出现,为医院感染控制提供依据。方法收集2012年1月-2014年5月从医院临床各种标本中分离出的132株鲍氏不动杆菌,菌种鉴定和药物敏感试验采用全自动微生物分析仪,回顾性分析临床分离的鲍氏不动杆菌耐药性。结果 132株临床分离的鲍氏不动杆菌中有84株分离自痰液占63.6%,22株分离自分泌物占16.7%;大部分分离自ICU、呼吸道、烧伤科分别占45.5%、16.7%、15.2%;分离自50~59岁的患者占7.6%、60~69岁的患者占15.2%、70~79岁患者占27.3%、>80岁患者占24.2%;在132株鲍氏不动杆菌中有112株同时对≥3类抗菌药物耐药,为多药耐药菌株,占84.8%,132株鲍氏不动杆菌除对多黏菌素B、米诺环素耐药率低外,对其他抗菌药物的耐药率高达70.0%以上。结论医院分离的鲍氏不动杆菌耐药性严重,应重视抗菌药物的合理使用。     

Resistance to disinfectants in epidemiologically defined clinical isolates of Acinetobacter baumannii

Decreased susceptibility to biocides may contribute to epidemic spread of Acinetobacter baumannii in the hospital. This study was conducted to evaluate the susceptibility of different clinical A. baumannii strains to disinfectants. Twenty A. baumannii strains were examined, ten of which were outbreak-related and ten that were sporadic. Clinical isolates were selected on the basis of demonstrating a unique pulsed-field gel electrophoresis pattern. The in-vitro activities of propanol, combination of 1-propanol, 2-propanol and mecetronium ethylsulphate, polyvinylpyrrolidone (PVP)-iodine, triclosan and chlorhexidine were determined using a broth macrodilution method. Exposure times to the disinfectant ranged from 15 s to 2 min and concentrations ranged from undiluted to a 1:4000 dilution in order to investigate the impact of inadvertent dilution that might occur in clinical practice. Five American Type Culture Collection (ATCC) type strains (A. baumannii, Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis and Staphylococcus aureus) were used as controls. All disinfectants inhibited growth of all isolates at concentrations and contact times recommended by the respective manufacturer. With most of the disinfectants tested, a relevant number of viable bacteria remained if contact times < 30s or diluted agents were used. No significant differences in susceptibility between outbreak-related and sporadic strains were detected, but larger studies would be required to confirm this. Resistance to currently used disinfectants is probably not a major factor in the epidemic spread of A. baumannii. However, even minor deviations from the recommended procedures leading to decreased concentrations or exposure times may play a role in nosocomial cross-transmission.     

鲍氏不动杆菌临床分离株分布及耐药性分析

目的调查医院住院患者鲍氏不动杆菌感染部位、科室分布,并分析其对抗菌药物的耐药性,以指导临床合理用药。方法选取2012年1月-2012年12月医院感染患者送检标本,采用BACTEC9000培养系统分离培养鲍氏不动杆菌,采用K-B琼脂法进行药敏试验。结果共分离培养出鲍氏不动杆菌183株,其感染部位分布较多的为脓液46株占25.14%、血液35株占19.13%、尿液27株占14.75%及呼吸道22株占12.02%;183株鲍氏不动杆菌的临床科室分布中ICU 55株占30.05%、呼吸内科25株占25.14%、神经内科25株占13.66%、神经外科18株占9.84%、普外科13株占7.10%,中医科9株占4.92%、血液科6株占3.28%及其他科室11株占6.01%;分离培养所得的183株鲍氏不动杆菌对氨苄西林、四环素、红霉素、庆大霉素、阿莫西林、诺氟沙星、氧氟沙星、头孢克肟和头孢哌酮的耐药率较高,均>50.00%;对美罗培南、亚胺培南和替考拉宁的敏感性较高,>80.00%。结论医护工作人员首先应采取措施控制医院鲍氏不动杆菌的感染,若感染发生,及时进行药敏试验,选择敏感性高的抗菌药物进行及时有效的治疗。     

鲍氏不动杆菌临床分离株的耐药性变迁

目的探讨2010-2012年山区医院临床分离的鲍氏不动杆菌(ABA)耐药性变迁,为临床选择抗菌药物提供实验室参考依据。方法对医院2010-2012年分离的353株ABA耐药性进行了回顾性调查分析;ABA分离培养严格按《全国临床检验操作规程》进行;采用法国生物梅里埃公司VITEK-32全自动微生物分析仪和配套鉴定试剂盒进行菌种鉴定;采用CLSI推荐的纸片扩散法(K-B法)进行药敏试验,并依据CLSI标准判读药敏结果,应用WHONET 5.5软件进行数据处理。结果医院ABA在呼吸道标本中检出率最高,占67.1%,其次是脓性分泌物和尿液,分别占11.1%和9.1%;ABA对临床常用抗菌药物的耐药性呈逐年升高趋势,对阿米卡星、亚胺培南、美罗培南、头孢哌酮/舒巴坦、哌拉西林/他唑巴坦耐药率在12.6%²0.6%;2010-2012年泛耐药ABA检出率分别为12.6%、14.4%、16.3%;耐亚胺培南ABA检出率分别为14.9%、17.6%、17.7%。结论医院鲍氏不动杆菌的耐药性总体呈逐年上升态势,应严格执行卫生部《抗菌药物临床应用管理办法》,将ABA列入医院监控的重点菌株,实行医院细菌耐药性预警公示制度,扭转山区医院细菌耐药性上升的不良现状。     

A new trilocus sequence-based multiplex-PCR to detect major Acinetobacter baumannii clones

A collection of 163 Acinetobacter baumannii isolates detected in a large Brazilian hospital, was potentially related with the dissemination of four clonal complexes (CC): 113/79, 103/15, 109/1 and 110/25, defined by University of Oxford/Institut Pasteur multilocus sequence typing (MLST) schemes. The urge of a simple multiplex-PCR scheme to specify these clones has motivated the present study. The established trilocus sequence-based typing (3LST, for ompA, csuE and bla_OXA-51-like genes) multiplex-PCR rapidly identifies international clones I (CC109/1), II (CC118/2) and III (CC187/3). Thus, the system detects only one (CC109/1) out of four main CC in Brazil. We aimed to develop an alternative multiplex-PCR scheme to detect these clones, known to be present additionally in Africa, Asia, Europe, USA and South America. MLST, performed in the present study to complement typing our whole collection of isolates, confirmed that all isolates belonged to the same four CC detected previously. When typed by 3LST-based multiplex-PCR, only 12% of the 163 isolates were classified into groups. By comparative sequence analysis of ompA, csuE and bla_OXA-51-like genes, a set of eight primers was designed for an alternative multiplex-PCR to distinguish the five CC 113/79, 103/15, 109/1, 110/25 and 118/2. Study isolates and one CC118/2 isolate were blind-tested with the new alternative PCR scheme; all were correctly clustered in groups of the corresponding CC. The new multiplex-PCR, with the advantage of fitting in a single reaction, detects five leading A. baumannii clones and could help preventing the spread in healthcare settings.     

2005-2011年临床分离鲍氏不动杆菌耐药性变迁

目的 了解医院感染鲍氏不动杆菌分布特点和变迁趋势,为临床合理使用抗菌药物,减少耐药性提供参考.方法 对2005-2011年临床分离的鲍氏不动杆菌分布构成及耐药性进行统计分析.结果 7年检出鲍氏不动杆菌共1973株,来源标本为呼吸道、尿液、伤口分泌物、血液、引流液,分别占85.4％、3.7％、3.2％、2.1％、2.1％;分离自ICU占35.0％、非ICU占65.0％;鲍氏不动杆菌耐药率及多药耐药菌检出率逐年增加;ICU比非ICU科室的整体耐药水平偏高;鲍氏不动杆菌对头孢哌酮/舒巴坦、亚胺培南和美罗培南的平均耐药率分别为22.4％、28.7％和29.2％,仍是经验用药的首选;对头孢他啶、头孢曲松和头孢吡肟的平均耐药率分别为46.4％和44.5％;对替卡西林/克拉维酸、哌拉西林/他唑巴坦和磺胺甲噁唑/甲氧苄啶的平均耐药率分别为44.3％、37.1％和52.2％;对阿米卡星和左氧氟沙星的平均耐药率分别为28.1％和36.8％.结论 7年鲍氏不动杆菌的构成比及耐药率均呈上升趋势,加强医院感染病例的细菌学监测和动态分析,对制定有效的感染控制措施、杜绝感染暴发流行具有积极意义.     

利福平联合碳青霉烯类药物对多药耐药鲍氏不动杆菌体外抗菌活性研究

目的评价利福平联合亚胺培南、美罗培南对患者呼吸道标本分离的耐碳青霉烯类鲍氏不动杆菌体外抗菌效应,为临床联合用药提供治疗依据。方法收集2011年1月-2012年12月11所医院临床患者送检的105株耐亚胺培南和美罗培南鲍氏不动杆菌,采用琼脂稀释法测定不同浓度组合的抗菌药物最低抑菌浓度,并计算部分抑菌浓度指数(FICI)判定联合效应。结果利福平联合亚胺培南、利福平联合美罗培南联用后,其MIC50和MIC90降低,联合效应主要表现为相加作用,无拮抗作用,与亚胺培南联用后,相加作用为72.64%高于与美罗培南联用52.83%;部分菌株显示协同作用,其中与亚胺培南联用协同作用为3.77%,与美罗培南联用协同作用5.66%。结论利福平与亚胺培南或美罗培南联用后主要表现为相加作用,部分为协同作用,对于严重的多药耐药鲍氏不动杆菌引起的呼吸道感染,可采用利福平和亚胺培南或美罗培南联合治疗方案。     

Genetic relatedness of multidrug-resistant Acinetobacter baumannii endemic to New York City

Multidrug-resistant isolates of Acinetobacter baumannii from New York City generally belong to one of three ribotypes. To assess the accuracy of ribotyping, the relatedness of representative isolates was further assessed by rep-PCR, pulsed-field gel electrophoresis (PFGE), and DNA sequencing of five genes potentially associated with antimicrobial resistance (ampC, ompA, adeB, adeR, and abeM). The isolates fell into several major groups. The first group shared the same ribotype and had common mutations affecting OmpA, AdeR, and AbeM, but consisted of two subtypes with distinctive rep-PCR and PFGE patterns and ampC mutations. The second and third groups shared common alterations in OmpA, AdeR, and AbeM, but had distinct ribotype, rep-PCR, and PFGE patterns. The resistant isolates were unrelated to the beta-lactam susceptible isolates. Many of the resistant strains shared OmpA and AdeB patterns observed in several European clonal groups. Further development of a multilocus sequencing typing scheme will help determine if multidrug-resistant isolates from diverse geographic areas are indeed ancestrally related.     

鲍氏不动杆菌及铜绿假单胞菌的分布与耐药性监测

目的 了解临床分离的鲍氏不动杆菌、铜绿假单胞菌的分布和耐药性,以指导临床合理使用抗菌药物.方法 K-B纸片扩散法测定临床分离菌株对常用抗菌药物的药物敏感性,按CLSI 2009年标准判读,用WHONET 5.4软件分析数据.结果 2011年浙江省人民医院共收集到非重复的鲍氏不动杆菌606株,分离自ICU 237株占39.1％,鲍氏不动杆菌对多黏菌素B敏感率为100.0％,对头孢哌酮/舒巴坦的敏感率为26.3％,哌拉西林/他唑巴坦为30.1％;对亚胺培南、美罗培南的敏感率分别为31.0％和40.8％,耐碳青霉烯类鲍氏不动杆菌(CRAB)为77.2％;2011年医院临床分离铜绿假单胞菌579株,164株分离自医院中心ICU(28.3％),铜绿假单胞菌对多黏菌素B敏感率最好为100.0％、妥布霉素为86.7％、左氧氟沙星为64.3％,对头孢哌酮/舒巴坦、哌拉西林/他唑巴坦的敏感率分别为63.8％、82.4％,对亚胺培南、美罗培南的敏感率分别为55.3％、64.7％;耐碳青霉烯类抗菌药物的铜绿假单胞菌(CRPA)检出率为44.6％.结论 临床分离的鲍氏不动杆菌、铜绿假单胞菌对常用抗菌药物敏感性低,CRPA、CRAB检出率高,应加强抗菌药物的合理使用和医院感染控制.     

Low genetic diversity of the intrinsic OXA-51-like class D carbapenemases among Acinetobacter baumannii clinical isolates in Greece

This study examined the geographical distribution and diversity of the intrinsic OXA-51-like class D carbapenemases among Acinetobacter baumannii clones recovered in three major Greek regions from 2000 to 2005. The blaOXA-66 allele was exclusively detected among clonally distinct A. baumannii isolates recovered in the regions of Thessaloniki and Larissa. This sequence was also the most widespread among A. baumannii isolates in Athens, while less frequent were blaOXA-69 and blaOXA-65 alleles. These findings highlight the high prevalence of a specific blaOXA-51-like allele in Greece, possibly indicating that our A. baumannii clones might have originated from a common ancestor. However, the possibility that blaOXA-51-like variants, with blaOXA-66 predominating, are widely disseminated among several unrelated A. baumannii strains cannot be excluded.     

2009-2011年ICU鲍氏不动杆菌的临床分布及耐药性变迁

目的 了解医院鲍氏不动杆菌的临床分布和耐药性的变迁,为临床感染的预防和治疗提供参考.方法 对医院ICU2009-2011年临床分离的802株鲍氏不动杆菌临床分布及药敏结果进行回顾性分析.结果 2009-2011年共分离鲍氏不动杆菌802株,检出率为19.48％,呈逐年上升趋势;最常见分离自痰标本,占84.4％,其次是排泄物和分泌物,分别占4.1％、3.5％;鲍氏不动杆菌对常用抗菌药物均产生了不同程度的耐药性,对美罗培南和亚胺培南耐药率均逐年上升,2011年分别达到75.7％和76.0％,目前多黏菌素B对鲍氏不动杆菌最为敏感,耐药率＜4.0％,且呈逐年下降趋势.结论 鲍氏不动杆菌是ICU患者呼吸道感染的常见病原菌,且耐药性高,头孢哌酮/舒巴坦足治疗鲍氏不动杆菌较敏感的药物,鲍氏不动杆菌对碳青霉烯类抗菌药物严重耐药,应引起高度重视.     

不同浓度美罗培南对临床分离的鲍氏不动杆菌生物膜形成能力的影响

目的 探究不同浓度美罗培南对临床分离的鲍氏不动杆菌生物膜形成能力的影响。方法 收集2017年9月-2020年9月海南省老年病医院肺部感染患者临床样本分离的鲍氏不动杆菌25株,采用琼脂倍比稀释法检测美罗培南最低抑菌浓度(MIC)和最低杀菌浓度(MBC),分别以不添加美罗培南(空白)及美罗培南1/4 MIC、1/2 MIC、MIC和MBC绘制鲍氏不动杆菌生长曲线,采用结晶紫半染法和激光扫描共聚焦显微技术检测鲍氏不动杆菌生物膜形成的能力,实时荧光定量逆转录聚合酶链式反应(RT-PCR)检测生物膜形成相关调控基因的表达。结果 鲍氏不动杆菌对美罗培南的MIC为2μg/ml, MBC为32μg/ml。24 h的生长周期中,随着给药浓度的增加,对鲍氏不动杆菌生长的抑制作用增强。与空白组比较,1/2 MIC、MIC及MBC组各孔OD_(570nm)值降低,且随药物浓度的增加呈降低趋势(P<0.05)。各组绿色荧光均呈先增强、后减弱的变化趋势,空白组和MBC组分别在24 h和48 h时绿色荧光最强。与空白组比较,1/2 MIC、MIC及MBC组鲍氏不动杆菌bap、filA及pbp-1a基因相对表达量均降低,且随药物浓度的增加呈降低趋势(P<0.05)。结论 美罗培南对鲍氏不动杆菌的生长和生物膜的形成有明显的抑制作用,可能与下调bap、filA及pbp-1a基因表达有关。     

Molecular epidemiology of carbapenem-resistant Acinetobacter baumannii isolates reveals the emergence of blaOXA-23 and blaNDM-1 encoding international clones in India

Acinetobacter baumannii is a nosocomial pathogen increasingly affecting the critically ill patients and represents a major public health challenge. Carbapenem-resistant A. baumannii (CRAB) is found to be associated with International Clones (ICs) and different classes of carbapenemases. The objective of the present study was to investigate the prevalence of carbapenem resistance genes, clonal relationship and genetic structure of clinical isolates of A. baumannii. In the present study, multi-locus sequence typing (MLST^OX) and analysis were carried out using Oxford scheme for 86 clinical isolates of CRAB along with 11 carbapenem sensitive A. baumannii (CSAB) collected over a period of two years (2014–2016) from two tertiary care hospitals of North India. We observed a high prevalence of the bla_OXA-23-like (97.7%) among the CRAB followed by bla_NDM-1 (29.1%) and bla_OXA58-like (3.5%). Forty-seven Sequence Types (STs) were represented by all 97 isolates, out of which, 28 (59.6%) were novel STs that were assigned to 41 isolates. STs 451 (13%), 447 (7%), 195 (6%) and 848 (5%) were the most common STs. The majority of CRAB isolates (44.3%) belonged to the CC92, followed by the CC447 (15.1%), CC109 (9.3%) and CC110 (3.4%), which corresponds to the IC2, 8, 1 and 7 respectively. Phylogenetic and recombination analysis suggested two major and one minor lineage in the population. Further linkage disequilibrium analysis suggested clonal nature of the population as recombination was noticed at a low frequency, which was not enough to split the clonal relationship. The knowledge of genetic structure of CRAB from this study will be invaluable to illustrate epidemiology, surveillance and understanding its global diversity.     

耐替加环素鲍曼不动杆菌的同源性及临床分布

目的了解某院耐替加环素鲍曼不动杆菌的同源性及临床分布。方法选取该院2013—2014年各临床科室送检标本分离的多重耐药鲍曼不动杆菌（88株）,检测其对替加环素的敏感性;应用脉冲场凝胶电泳（PFGE）分析替加环素耐药菌株的同源性,以及感染患者的临床特征和科室分布。结果88例患者在检出多重耐药鲍曼不动杆菌前未曾使用过替加环素。88株多重耐药鲍曼不动杆菌中4株（4.55%）对替加环素耐药,分别为10、31、33和87号菌株。PFGE结果显示,31、33和87号菌株同一基因型,同源性高,分布于医院3个不同的独立病区;31号菌株在综合重症监护病房（ICU）检出,33号菌株在急诊ICU检出,虽在不同科室检出,但在检出前患者有转科情况,曾同时期住胃肠外科和急诊ICU;87号菌株在神经外科ICU检出,此患者从未转科,检出时间距31、33号菌株检出晚7～8个月。10号菌株于急诊ICU检出,该患者未曾转科。结论该院多重耐药鲍曼不动杆菌中替加环素耐药菌株检出率低,检出菌株大部分具有同源性,不同病区可能存在交叉感染。     

Prevalence of Acinetobacter baumannii and Pseudomonas aeruginosa isolates resistant to imipenem by production of metallo-beta-lactamase

Metallo-beta-lactamases (MBL) are enzymes produced by Gram-negative bacilli such as Pseudomonas aeruginosa and Acinetobacter baumannii. These enzymes make these isolates resistant to imipenem. AIM: The aim of this study was to determine the prevalence of this resistance mechanism in Pseudomonas aeruginosa and Acinetobacter baumannii strains identified in the bacteriology laboratory of the Rabat Ibn Sina teaching hospital, Morocco. MATERIALS AND METHOD: Screening for MBL was systematic in all resistant strains and/or strains with decreased sensitivity to imipenem, according to Dongeun Yong et al.'s method, using a sterilized solution of EDTA 0.5 M pH 8. RESULTS: Eighty-five bacterial strains (48 P. aeruginosa and 37 A. baumannii) were identified 23% (11) and 57% (21) of which were respectively resistant to the imipenem. The prevalence of MbetaL producing strains was 27% for P. aeruginosa and 38% for A. baumannii. CONCLUSION: These results show that the frequency of these strains is increases in our hospital and that their emergence represents a serious therapeutic and epidemiological problem. This means that we need to implement the supervision of hospital microbial environment and strictly apply hygiene measures.     

鲍氏不动杆菌耐药性分析

目的 了解鲍氏不动杆菌感染现状及其对临床常用抗菌药物的耐药性,为临床合理应用抗菌药物提供依据.方法 对医院2011年6月-2012年6月住院患者的各类微生物检测标本进行病原菌培养和分离,采用VITEK-2Compact全自动微生物分析仪进行鉴定和药敏分析.结果 从各种临床标本中共分离出158株鲍氏不动杆菌,主要来源为呼吸道分泌物占76.58％,其次为伤口分泌物占13.29％,鲍氏不动杆菌的科室分布以外科ICU、干部科、呼吸内科为主,分别占27.85％、14.56％、10.76％;鲍氏不动杆菌对常用抗菌药物均产生了较严重的耐药性,除对头孢哌酮/舒巴坦耐药率为31.6％外,对其他药物的耐药率在53.8％～90.5％;158株鲍氏不动杆菌中分离出89株泛耐药不动杆菌,占56.33％,对多黏菌素E敏感率达100.0％,对头孢哌酮/舒巴坦耐药率为53.6％.结论 鲍氏不动杆菌对常用抗菌药物均耐药严重,应根据药敏结果选用抗菌药物;针对泛耐药鲍氏不动杆菌的感染可选用多黏菌素与头孢哌酮/舒巴坦或含舒巴坦制剂的药物.     

鲍氏不动杆菌的临床分布与耐药性分析

目的调查住院患者鲍氏不动杆菌的分布和对抗菌药物的耐药性,为指导临床合理用药提供理论依据。方法回顾性分析2009年1月-2013年6月中西医结合医院临床分离的846株鲍氏不动杆菌耐药结果,分析其耐药率及感染因素,数据采用SPSS11.0软件进行统计。结果医院鲍氏不动杆菌的分离率为11.0%;对抗菌药物的耐药率也日趋严重,其中增长较显著的有美洛西林、左氧氟沙星及亚胺培南,耐药率分别由2009年的23.8%、31.3%及23.6%上升至2013年的72.6%、46.7%及64.8%;多药耐药鲍氏不动杆菌感染与年龄、住院时长、入住ICU、联合使用抗菌药物、糖皮质激素、免疫抑制剂使用及侵入性操作有关(P<0.05)。结论鲍氏不动杆菌的耐药形势严峻,应引起临床高度关注。