A nosocomial outbreak of multiresistant Acinetobacter baumannii originating from an intensive care unit.

An outbreak of a multiresistant Acinetobacter baumannii in February through September 1996 affected 103 patients in a regional hospital in Singapore. We describe the effectiveness of closure of the outbreak area and the importance of good teamwork in the management of the outbreak.     

An outbreak due to multiresistant Acinetobacter baumannii in a burn unit: risk factors for acquisition and management.

OBJECTIVES: To describe the investigation and management of an outbreak due to multiresistant Acinetobacter baumannii and to determine risk factors for acquisition of the organism. SETTING: A 14-bed regional burn unit in a Canadian tertiary-care teaching hospital. DESIGN: Case-control study with multivariate analysis of potential risk factors using logistic regression analysis. Surveillance cultures were obtained from the hospital environment, from noninfected patients, and from healthcare providers. RESULTS: A total of 31 (13%) of 247 patients with acute burn injuries acquired multiresistant A. baumannii between December 1998 and March 2000; 18 (58%) of the patients were infected. The organism was recovered from the hospital environment and the hands of healthcare providers. Significant risk factors for acquisition of multiresistant A. baumannii were receipt of blood products (odds ratio [OR], 10.8; 95% confidence interval [CI95], 3.4 to 34.4; P < .001); procedures performed in the hydrotherapy room (OR, 4.1; CI95, 1.3 to 13.1; P = .02); and increased duration of mechanical ventilation (OR, 1.1 per day; CI95, 1.0 to 1.1; P= .02). INTERVENTIONS: Improved compliance with hand hygiene, strict patient isolation, meticulous environmental cleaning, and temporary closure of the unit to new admissions. CONCLUSIONS: Acquisition of multiresistant A. baumannii was likely multifactorial, related to environmental contamination and contact with transiently colonized healthcare providers. Control measures addressing these potential sources of multiresistant A. baumannii were successful in terminating the outbreak. Ongoing surveillance and continued attention to hand hygiene and adequate environmental cleaning are essential to prevent recurrent outbreaks due to antibiotic-resistant bacteria in burn units.     

Post-surgical meningitis due to multiresistant Acinetobacter baumannii. Effective treatment with intravenous and/or intraventricular colistin and therapeutic dilemmas

Post-surgical meningitis and/or ventriculitis caused by Gram-negative bacteria may be difficult to treat due to the emergence of multiresistant strains. Two patients with multiresistant Acinetobacter baumannii central nervous system infection, successfully treated with either intravenous and/or intraventricular colistin are presented. Unresolved issues such as dose and duration of intraventricular colistin are discussed.     

Investigation of an outbreak of multi-drug resistant Acinetobacter baumannii in an intensive care burns unit.

Over a three month period there was an outbreak of infection, due to a multi-drug resistant Acinetobacter baumannii in the intensive care burns unit with spread of infection to other patients, both within the unit and elsewhere in the hospital.Microbiological sampling of the environment and of the healthcare workers' (HCWs) hands were carried out. Strain relatedness of the isolates was confirmed by pulsed field gel electrophoresis.Fifteen patients were involved in the outbreak, whose infections were all hospital-acquired. The burns room environment was contaminated with the A. baumannii, as was the door handle of the door leading from the ante-chamber between both rooms. This allowed the hands of HCWs to be contaminated by A. baumannii despite appropriate handwashing procedures prior to leaving the rooms. Two staff members were colonized with A. baumannii. One HCW who was directly involved in patient care was found to be "heavily" colonized, the other, with less patient contact, was only "lightly" colonized. Review of handwashing practices revealed that chlorhexidine/alcohol hand wash solution was not used by the HCW whose hands were heavily colonized.A combination of a review of handwashing practice, education about the spread of bacteria via hands and contaminated environment, and the revision of infection control procedures in the unit contributed to a prompt termination of the outbreak.     

Risk factors for the isolation of multi-drug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa: a systematic review of the literature

An understanding of the epidemiology of multi-drug-resistant (MDR) Acinetobacter baumannii and Pseudomonas aeruginosa infections is necessary in order to develop strategies to curtail their spread. For this purpose, the evidence linking the isolation of MDR A. baumannii and P. aeruginosa with specific risk factors was evaluated. PubMed was searched for the 20-year period from September 1985 to September 2005, and eligible studies were considered to be those that: (1) linked the isolation of A. baumannii and P. aeruginosa with specific risk factors; (2) described the characteristics of the affected patients in detail; and (3) provided data on the antibiotic resistance profile of the isolated micro-organisms. Fifty-five studies were found referring to A. baumannii (28 with case-control methodology and 27 outbreak investigations without case-control methodology), and 42 studies were found referring to P. aeruginosa (25 with case-control methodology and 17 outbreak investigations without case-control methodology). Although heterogeneous study designs and investigated risk factors limited this analysis, it was concluded that acquisition and spread of these micro-organisms appear to be related to a large number of variables. Among the most important were deficiencies in the implementation of infection control guidelines and the use of broad-spectrum antibiotics. Use of carbapenems and third-generation cephalosporins appear to be related to the development of an MDR phenotype by A. baumannii, while carbapenems and fluoroquinolones are implicated in MDR P. aeruginosa. The diversity of risk factors associated with the development of MDR A. baumannii and P. aeruginosa suggests that a separate outbreak investigation should be performed in each hospital setting. The development of innovative control strategies is needed in order to limit the spread of these pathogens.     

Epidemiology of Acinetobacter baumannii in a university hospital in Turkey.

OBJECTIVE: Molecular epidemiologic surveillance of Acinetobacter baumannii by polymerase chain reaction-randomly amplified polymorphic DNA analysis in a university hospital for 3 consecutive study periods. RESULTS: Twelve different Acinetobacter baumannii genotypes (A-L) were detected. Although only 2 genotypes were detected during the first period and genotype A appeared to be the most common genotype, genotype D was included in these genotypes during the second study period. Genotype A completely disappeared during the third period. Although the presence of genotype C and the genotype D continued during the third period, 9 new genotypes were detected during this period. Genotype A appeared to be the most common genotype in the hospital (detected in 19 different clinics). The distribution of genotypes in clinical samples correlated with patient traffic between them. Some genotypes were found in both clinical and environmental samples. Seventeen different antibiotypes were detected, according to antibiotic susceptibility profiles. CONCLUSIONS: Environmental contamination, airborne transmission, patient transfer, and cross-contamination play important roles in epidemics caused by A. baumannii in our hospital. The distribution of genotypes can change over time, so antibiotyping is not appropriate for the epidemiological analysis of A. baumanii infection.     

An outbreak of Acinetobacter baumannii: the importance of cross-transmission.

OBJECTIVE: To investigate an outbreak of nosocomial infections due to multidrug-resistant (MDR) Acinetobacter baumannii and to analyze the contribution of cross-transmission in the rise in infection rates. DESIGN: Epidemiological investigation; molecular typing using pulsed-field gel electrophoresis (PFGE); matched case-control study to identify risk factors for infection. SETTNG: A 34-bed surgical intensive care unit at a tertiary-care hospital. PATIENTS: Eighteen patients who developed MDRA baumannii nosocomial infection were matched to 36 patients who were admitted to the same surgical intensive care unit (SICU) room and did not develop an infection during the outbreak period. RESULTS: Prior to the outbreak, the baseline attack rate of MDR A baumannii nosocomial infections was 3 per 100 patients per month. From February 1 through March 22, 1998, the attack rate rose to 16 per 100 patients per month, with a total of 18 infections. All isolates had indistinguishable PFGE patterns. Seventy environmental cultures were negative for MDR A baumannii. Following intense infection control education, the attack rate decreased to 4 per 100 patients per month. By conditional logistic regression, cases were exposed to a significantly higher number of patients with MDR A baumannii infections compared to controls (odds ratio, 1.1; 95% confidence interval, 1.01-1.2; P=.02), even after adjusting for length of SICU admission and exposure to antibiotics and invasive devices. CONCLUSION: Cross-transmission between patients contributed to the rise in rates of MDRA baumannii infections. A common environmental source was not detected.     

呼吸道鲍氏不动杆菌耐药研究及防治措施

目的了解呼吸道鲍氏不动杆菌感染现状及耐药性,为临床资料提供参考依据。方法选择2011年10月-2012年9月住院患者呼吸道标本培养出的640株鲍氏不动杆菌进行临床分析。结果泛耐药鲍氏不动杆菌193株,占分离菌株30.16%,鲍氏不动杆菌对米诺环素敏感性最高达72.41%,其次为阿米卡星达50.63%,对美罗培南、左氧氟沙星、亚胺培南、环丙沙星、磺胺甲噁唑/甲氧苄啶及头孢吡肟敏感率>20.00%,对其余抗菌药物敏感性均<20.00%;有212株鲍氏不动杆菌合并>1种其他病原菌,其中金黄色葡萄球菌56株、肺炎克雷伯菌38株、铜绿假单胞菌32株、嗜麦芽寡养单胞菌及大肠埃希菌各20株、白色假丝酵母菌18株及奇异变形菌6株。结论呼吸道鲍氏不动杆菌耐药性严重,临床应选用含米诺环素联合抗菌药物治疗。     

Emergence of carbapenem resistance in Acinetobacter baumannii recovered from blood cultures in Australia.

We describe the first emergence of carbapenem-resistant Acinetobacter baumannii in Australia. Ninety A. baumannii isolates recovered from cultures of blood specimens from 69 patients were analyzed. Overall, 58 isolates (64%) were resistant to meropenem. The chi 2 test for linear trend revealed that emergence of carbapenem resistance was statistically significant during the 32-month study period. Selected isolates were of the same clonal type, and no genes encoding carbapenemases were identified.     

Fatal multidrug-resistant Acinetobacter baumannii sepsis in a patient with travel history and recent onset of systemic lupus erythematosus: a case report

Severe infections are a common cause of death in patients suffering from systemic lupus erythematosus (SLE). We here report on a fatal multidrug-resistant Acinetobacter baumannii sepsis in a patient with newly diagnosed SLE, who had to be treated with immunosuppressants due to lupus nephritis. Detailed analysis of the patient's history revealed that colonisation probably had occurred during a recent hospitalisation of the patient in the Mediterranean region. E-test analysis indicated that resistance to carbapenems was mediated by a plasmid-encoded metallo-ß-lactamase. We conclude that travel history including previously visited health care facilities always should be carefully considered for decisions on anti-infective therapy, as travel activities increasingly facilitate spread of antimicrobial resistances.     

老年慢性阻塞性肺疾病患者鲍氏不动杆菌的分子流行特征

目的 揭示医院老年慢性阻塞性肺疾病(COPD)患者中鲍氏不动杆菌分子流行的主要特征.方法 筛选2009-2011年老年COPD患者中分离的57株鲍氏不动杆菌为试验菌株;使用Whonet5.6软件分析其药敏结果;应用基于序列分型的多重PCR方法鉴定鲍氏不动杆菌的主要流行克隆谱系;利用限制性内切酶ApaI对试验菌株基因组DNA进行酶切和脉冲场凝胶电泳(PFGE)分析;应用PCR及测序方法检测10种耐药相关基因,分析并命名相应的耐药基因谱.结果 鲍氏不动杆菌除了对多黏菌素B的耐药率为8.8％外,对其他15种抗菌药物均具有较高的耐药率,为70.2％～98.2％;主要克隆谱系以RGP1序列型为主,所占的比例高达59.6％;在87.0％的相似性水平上,可大致分为18种PFGE图谱,其中主要型别为A型;共发现存在有15种耐药基因谱,其中多药耐药谱RGP1所占的比例高达52.63％.结论 在老年COPD患者中分离的鲍氏不动杆菌主要的流行克降谱系与欧洲克隆谱系Ⅱ具有高度的同源性;多药耐药相关基因的携带率较高,在具有不同遗传背景的鲍氏不动杆菌中存在有水平转移.     

Isolation of Acinetobacter spp. including A. baumannii from vegetables: implications for hospital-acquired infections.

A. baumannii is rarely recovered from the skin of patients or healthy European subjects as other genospecies predominate, but it isa significant nosocomial pathogen. The natural reservoir of this organism is therefore uncertain. We determined the isolation rates of Acinetobacter spp. from vegetables (as an indicator of the natural environment) using a selective technique and classified the genospecies by amplified ribosomal DNA restriction analysis (ARDRA). Of the 177 samples of vegetables examined, 30 yielded Acinetobacter, with genospecies 2 and 11 being the most common, each with a frequency of 27%. MIC assays showed that strains of genospecies 1, 2, 3, and 13TU (the A. calcoaceticus-A. baumannii complex) were significantly more resistant than other genospecies to ciprofloxacin and gentamicin. Vegetables may therefore be a natural habitat of A. baumannii and provide a route by which these bacteria are introduced into hospitals with obvious implications for infection control.     

Antibiotic resistance is a major risk factor for epidemic behavior of Acinetobacter baumannii.

OBJECTIVE: To study the presence of bacterial factors in clinical isolates of Acinetobacter species in order to identify markers of epidemic potential. DESIGN: Case-control study. METHODS: Forty-six isolates of Acinetobacter species, including 23 epidemic and 23 sporadic strains from different outbreaks in nine European countries, were compared for the presence of the following factors: hemagglutination, presence of capsules and fimbriae, binding to salivary mucins, resistance to drying, and antibiogram typing. Genotyping of all strains was performed by amplified fragment-length polymorphism (AFLP). RESULTS: All outbreak strains except two (91%) were identified as Acinetobacter baumannii. Binding to salivary mucins and resistance to antibiotics were significantly associated with epidemic behavior. Antibiogram typing showed clustering of predominantly A baumannii strains within one group, and these strains were significantly more resistant to antibiotics than sporadic strains. AFLP genotyping revealed a great heterogeneity among the different European Acinetobacter strains. Cluster analysis of AFLP fingerprints showed several small clusters of different A baumannii outbreak strains. AFLP genotyping could not identify a common epidemic marker within the strains studied. CONCLUSIONS: Antibiogram typing can be used in routine clinical laboratories as a screening method to recognize potentially epidemic A baumannii strains. Several other factors were found, both in different outbreaks as well as in sporadic Acinetobacter isolates. These characteristics were unable to predict epidemic behavior and therefore cannot be used as discriminative epidemic markers. AFLP genotyping demonstrated no common clonal origin of European epidemic A baumannii strains. This indicates that any clinical A baumannii isolate with resistance to multiple antibiotics can be a potential nosocomial outbreak strain.     

Genotypic evolution of Acinetobacter baumannii strains in an outbreak associated with war trauma.

The Walter Reed Army Medical Center has experienced an influx of traumatically injured patients either infected or colonized with Acinetobacter baumannii. Using multilocus polymerase chain reaction (PCR) and mass spectrometry to genotype isolates, we found an atypical and evolving strain distribution, distinct from those found at nonmilitary hospitals in the United States.     

2013—2016年老年病医院鲍曼不动杆菌临床分布及耐药性

目的了解2013—2016年某老年病医院鲍曼不动杆菌（AB）临床分布及耐药性变化趋势。方法采用回顾性研究对2013—2016年全院患者分离的AB标本来源、科室分布和耐药性进行分析。结果2013—2016年共分离1 712株AB,2013、2014、2015、2016年AB分离率逐年下降,分别为17.92%、17.17%、15.10%、11.81%;AB标本来源主要为痰（1 524株,89.02%）,其次为尿（79株,4.61%）和血（37株,2.16%）。检出AB居前3位的科室依次为重症监护病房（798株,46.61%）、呼吸内科（507株,29.62%）、神经内科（156株,9.11%）。2013—2016年AB对绝大部分抗菌药物耐药率不断上升,对复方磺胺甲口恶唑的耐药率（25.68%～65.89%）较低,其次为头孢哌酮/舒巴坦（54.74%～68.00%）,对亚胺培南的耐药率为71.40%～77.42%,对其余药物的耐药率均＞60%;2013—2016年AB对头孢吡肟、头孢哌酮/舒巴坦、庆大霉素、妥布霉素、复方磺胺甲口恶唑的耐药率比较,差异有统计学意义（均P＜0.05）。结论该院AB耐药率不断升高,需加强监测,促进抗菌药物合理使用,阻断AB的医院感染和传播。     

Importation of Acinetobacter baumannii into a burn unit: a recurrent outbreak of infection associated with widespread environmental contamination.

A burn patient was infected with Acinetobacter baumannii on transfer to the hospital after a terrorist attack. Two patients experienced cross-infection. Environmental swab samples were negative for A. baumannii. Six months later, the bacteria reemerged in 6 patients. Environmental swab samples obtained at this time were inoculated into a minimal mineral broth, and culture results showed widespread contamination. No case of infection occurred after closure of the unit for disinfection.