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.     

Environmental contamination during a carbapenem-resistant Acinetobacter baumannii outbreak in an intensive care unit

During a three-month period in 1999, 25 strains of carbapenem resistant Acinetobacter baumannii were isolated from 12 of 170 hospitalized intensive care unit (ICU) patients, of which 16 were considered to be clinically significant. These strains were indistinguishable by biotyping and antibiograms, but genotyping was not performed. Appropriate antibiotic treatment, isolation precautions, and infection control education of the staff failed to halt the outbreak. Environmental contamination was therefore investigated, and A. baumannii was found out in 22 (39.3%) of 56 environmental samples obtained by swabbing. Different antibiotic sensitivity patterns were obtained in the majority of these isolates, but four (7.1%) of the strains were found to have the same sensitivity pattern as the strain causing the outbreak. As a result the ICU was closed, equipment and the environment cleaned, with hypochlorite and terminal disinfection carried out. No bacteria were grown on repeat environmental cultures. Environmental contamination has an important reservoir role in outbreaks of A. baumannii in ICUs and must be eradicated in order to overcome such outbreaks.     

综合ICU一起疑似鲍曼不动杆菌感染暴发的调查

目的分析重症监护病房(ICU)多重耐药鲍曼不动杆菌(AB)医院感染暴发流行的流行病学特征,为医院感染预防与控制提供依据。方法采用流行病学调查和环境卫生学监测的方法调查2015年4月1日—26日入住某院ICU后发生肺部感染的患者,分析各种危险因素并采取相应的预防控制措施。结果先后共发生15例泛耐药AB医院获得性下呼吸道感染。15例患者共分离AB15株。1、3、4、5号患者检出AB药敏结果相同;6、7、8、9号患者检出AB药敏结果相同;10、11号患者检出AB药敏结果相同;时间均相对集中。共采集43份环境表面和医务人员手标本,床头柜AB检出率为100.00%(1/1),监护仪按钮为75.00%(6/8)、医务人员手为66.67%(4/6),治疗桌、输液泵按钮、医生鼻拭子均未检出AB。至2015年5月下旬综合ICU内未再出现类似新发病例。结论此次AB医院感染可能通过ICU环境表面和医务人员手播散,患者检出的AB呈广泛耐药性,积极治疗患者和采取严格的消毒隔离措施,可有效控制进一步流行。     

Successful control of an Acinetobacter baumannii outbreak in a neonatal intensive care unit

We describe an outbreak of Acinetobacter baumannii in a neonatal intensive care unit (NICU), and our investigation to determine the source and mode of transmission and identify the population at risk. A case (infected infant) was defined as a patient hospitalized in the NICU during the outbreak period, with clinical signs of sepsis and isolation of A. baumannii. In colonized infants, A. baumannii was isolated from body surfaces without signs of infection. Infected infants were separated and treated by a different medical team. Cultures were taken from working surfaces and along the infant's admission passage from the delivery room to the NICU. The outbreak strain was identified by pulsed-field gel electrophoresis (PFGE). Nine cases and eight colonized infants met the definition criteria. Cases were younger than colonized infants with regard to gestational age and age of diagnosis and had lower birthweights (P<0.01). The outbreak strain was only isolated from hygroscopic bandages used on skin under the ventilation tube and umbilical catheters. Discontinuing the use of the bandages put an end to the outbreak. We conclude that a rapid and thorough investigation of the environment during an outbreak of A. baumannii is essential to finding the source of the infection, and that hygroscopic bandages may be a source of such outbreaks.     

Control of an outbreak of multi-drug-resistant Acinetobacter baumannii in an intensive care unit and a surgical ward

We describe an outbreak of multi-drug-resistant Acinetobacter baumannii (MRAB) that occurred in an intensive care unit (ICU) and a surgical ward from December 2003 to March 2004. Mapping patient movements on a timeline indicated that the outbreak was confined to these two areas. Investigation by the hospital's infection prevention service found that a possible source of spread was improper cleaning methods used on respiratory equipment. Pulsed-field gel electrophoresis analysis of available isolates indicated the presence of two distinct strains. One strain was seen in patients from the ICU and the other strain was seen in the surgical ward patients. Cleaning and environmental decontamination as well as staff education were implemented to halt further immediate spread. The deficiencies identified during the investigation were also resolved. The final outcome was the successful termination of this outbreak.     

Investigation of an outbreak of multidrug-resistant Acinetobacter baumannii in trauma intensive care unit

Between January and June 2002, an outbreak of multidrug-resistant Acinetobacter baumannii occurred in a trauma intensive care unit (TICU) at the Hamad Medical Corporation, Qatar. The outbreak involved 21 patients whose infection/colonization was hospital acquired. All the strains were resistant to all tested antibiotics except amikacin. An A. baumannii strain with a similar antibiogram was isolated from the environment, equipment and hands of healthcare workers (HCWs). The technique of open suctioning probably resulted in aerosilization and contamination of the immediate patient environment. This allowed the hands of HCWs to be contaminated with the outbreak strain, with subsequent transmission to other patients and their environment. Lack of proper hand hygiene between patients and equipment contact facilitated this transmission. A review of hand hygiene practices, extensive environmental cleaning, a closed suctioning system, education and review of other infection-control practices, contributed to the termination of the outbreak.     

某综合ICU耐碳青霉烯鲍曼不动杆菌下呼吸道医院感染暴发调查

目的调查某院综合重症监护病房（ICU）一起由耐碳青霉烯类鲍曼不动杆菌（CRAB）引起的疑似下呼吸道医院感染暴发流行的原因,为有效控制医院感染提供科学依据。方法对2014年3月4-23日该综合ICU CRAB感染病例进行流行病学调查和现场环境卫生学监测,并积极采取预防控制措施。结果共发生CRAB医院感染7例,流行期间总住院日数160 d,下呼吸道CRAB医院感染发病密度为43.75‰（7/160）,02床收治的5例患者中4例发生CRAB下呼吸道医院感染。单因素分析显示,使用常规吸痰是重要的危险因素;物体表面细菌菌落数合格率为31.75%(20/63)。02床吸引装置外架培养出CRAB,该菌与7例患者痰培养CRAB耐药谱相同。通过采取一系列控制措施,2014年3月24日后未再出现CRAB感染病例,此次CRAB暴发流行得到有效控制。结论此次疑似医院感染暴发可能原因为吸引装置外架污染CRAB后消毒不彻底,通过医务人员吸痰操作水平传播。ICU环境物体表面的清洁消毒对于预防医院感染至关重要。     

重症监护病房鲍氏不动杆菌的监测研究

目的监测同济医院ICU鲍氏不动杆菌检出率及耐药性,了解鲍氏不动杆菌流行状况,为ICU预防治疗鲍氏不动杆菌感染提供参考。方法对2011-2015年入住医院ICU患者送检的各类标本中分离鲍氏不动杆菌进行统计分析,应用VITEK-2全自动细菌鉴定药敏仪进行菌株鉴定及药敏试验,参照2015年美国实验室标准化委员会(CLSI M100-S25)标准判断药敏结果,以WHONET 5.6软件进行数据分析。结果 2011-2015年ICU共检出5 084份阳性标本,检出鲍氏不动杆菌1 079株,检出率为21.22%,其中检出耐碳青霉烯类鲍氏不动杆菌(CRAB)1 026株占95.09%,2011-2015年ICU鲍氏不动杆菌检出率呈上升趋势;在所送检的标本来源中,以痰液标本为主占88.88%、血液标本占6.21%、其他各类标本占4.91%;2011-2015年医院ICU检出鲍氏不动杆菌对头孢哌酮/舒巴坦、米诺环素的耐药性发生明显变化,目前对替加环素耐药性较低,对其余抗菌药物的耐药性均>70.00%、且妥布霉素、阿米卡星的耐药性逐年上升。结论医院ICU鲍氏不动杆菌的分离率和耐药状况严峻,总体呈升高趋势。应掌握其流行趋势及特点,根据药敏结果选用敏感的抗菌药物,合理联合使用抗菌药物。     

Molecular findings and antibiotic-resistance in an outbreak of Acinetobacter baumannii in an intensive care unit

We investigated an outbreak of Acinetobacter baumannii in the intensive care unit (ICU) of a hospital in Rome, Italy. The outbreak involved 14 patients whose isolates were most frequently recovered from bronchoalveolar lavage. All isolates were multidrug-resistant and showed diminished susceptibility or resistance to carbapenems. A. baumannii strains with a similar antibiotic susceptibility pattern were isolated from the environment. Pulsed-field gel electrophoresis identified a single clone from both the patients' and environmental isolates. Because of the lack of a single source of infection, the eradication of the epidemic required a broad approach, including contact isolation and cohorting, aggressive environmental disinfection, and close monitoring of the ward staff's performance. Infected patients were successfully treated with combined therapy. Although considered of low virulence, A. baumannii can be particularly aggressive and difficult to treat in ICU patients.     

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.     

Clonal spread of Acinetobacter baumannii in a general intensive care unit

The epidemiological characterization of multiply resistant Acinetobacter baumannii isolates from a six-bed Intensive Care Unit (ICU) is described. Investigations for A. baumannii were performed in three subsequent surveillance studies. In the first study, surveillance cultures were taken from patients, health care personnel and the environment; in the second study surveillance cultures were taken at 0, 4, and 7 days from all patients admitted consecutively to the ward; and in the third study surveillance cultures were taken from patients, health care personnel and the environment. During the first study all four hospitalized patients were found to harbour A. baumannii. Hand cultures did not grow any A. baumannii when staff entered the ward from home, but 7 positive health care workers were identified out of 25 samples taken during work, and two cultures of environmental specimens grew A. baumannii. During the second study, 4 of 86 (4.6%) patients resulted colonized with A. baumannii. In the third epidemiological study, no A. baumannii was cultured from either patients, health care personnel or the environment. All isolates recovered from various patients or sources produced conserved macrorestriction Pulsed-Field Gel Electrophoresis (PFGE) patterns and showed the same antibiotic resistance; therefore, they can be considered indistinguishable. The same antibiotic resistance and macrorestriction patterns were observed in previously isolated A. baumannii strains in the ward during May 1997, suggesting the persistence of a single A. baumannii in the ICU. The present study confirms that molecular typing is an essential tool in the epidemiology and control of nosocomial infections, showing here the persistence of a single A. baumannii clone in the ICU. The origin of this strain remains unknown but, when basic infection control measures were reinforced, emphasizing the importance of hand antisepsis and judicious use of gloves, control of A. baumannii spread in the ward was achieved.     

新生儿室泛耐药鲍氏不动杆菌感染暴发调查

目的 对一起新生儿室泛耐药鲍氏不动杆菌感染暴发进行调查分析,查找原因,以采取有效方法控制感染流行.方法 采用现场采样检测,对采集标本进行细菌鉴定及药物敏感试验,检测结果为泛耐药鲍氏不动杆菌的进一步采用肠杆菌基因组内重复序列聚合酶链反应(ERIC-PCR)基因检测其同源性.结果 医院新生儿室2011年7月15-23日共收治患儿30例,连续发生4例泛耐药鲍氏不动杆菌引起的下呼吸道感染病例,感染率为13.33％;经对室内环境表面采样检测,在共用的喉镜镜片表面分离出与4例感染患儿痰标本耐药模式一致的泛耐药鲍氏不动杆菌,经ERIC-PCR基因检测确定为同一基因型.结论 由泛耐药鲍氏不动杆菌污染的喉镜镜片引起的医院感染暴发.     

Epidemic bacteremia due to Acinetobacter baumannii in five intensive care units

From March 5, 1986 to September 4, 1987, Acinetobacter baumannii (AB) was isolated from blood or vascular catheter-tip cultures of 75 patients in five intensive care units at a hospital in New Jersey. To identify risk factors for AB bacteremia in the intensive care units, a case-control study was conducted. Characteristics of 72 case-patients were compared with those of 37 controls. Case-patients were more likely than controls to have had peripheral arterial catheters (odds ratio (OR) = 7.0, p less than 0.001), mechanical ventilation (OR = 5.8, p less than 0.001), hyperalimentation (OR = 5.7, p less than 0.001), or pulmonary arterial catheters (OR = 3.9, p less than 0.001). Arterial catheters were used with reusable pressure transducers for intravascular pressure monitoring. A logistic regression analysis identified four independent risk factors: transducers, ventilation, hyperalimentation, and days of transducer use at an insertion site. The strongest influence on the risk of AB bacteremia was exerted by number of days of transducer usage. Cultures of 70 transducer diaphragms or domes, 42 in-use and 28 in-storage, were positive for AB in 21% and 46%, respectively. Plasmid analysis showed that patient blood cultures and transducer isolates were identical. Transducers were wiped with alcohol in the units between patient uses. Since reusable transducers appeared to be the source of this outbreak, it is recommended that reusable transducers receive either high level disinfection or sterilization between patient uses.     

Role of environmental cleaning in controlling an outbreak of Acinetobacter baumannii on a neurosurgical intensive care unit

An outbreak of Acinetobacter baumannii colonization and infection occurred in 19 patients over a 14-month period during 1998-1999 on a neurosurgical intensive care unit. During efforts to control the outbreak a significant correlation was observed between the number of environmental isolates of A. baumannii obtained during each monthly screening and the number of patients with A. baumannii colonization/infection in the same calendar month (P < 0.004). Use of 1000 ppm hypochlorite solution and the introduction of new cleaning protocols reduced the number of environmental isolates. Failure to maintain low levels of environmental contamination with A. baumannii resulted in increases in patient colonization. This study showed that high standards of cleaning play an integral role in controlling outbreaks of A. baumannii in the intensive care unit setting.     

Investigation and management of an imipenem-resistant oxa-23 Acinetobacter baumannii outbreak in an intensive care unit

Objectives

The study objectives were to describe the investigation and management of an imipenem-resistant Acinetobacter baumannii outbreak that occurred in the 15-bed ICU of a tertiary care teaching hospital (Brest, France), during the summer 2008.

Patients and methods

Patients harboring an imipenem-resistant A. baumannii strain were defined as case patients. We described case occurrence and steps taken to control the outbreak: contact isolation, reinforcement of hygiene procedures, unit shutdown decision, unit disinfection, and reopening. We also made a case control study and a cost analysis of the outbreak management.

Results

During a 10-day period, five patients were positive for a single clone of imipenem-resistant oxa-23 A. baumannii. Four patients presented with ventilation-acquired pneumonia and one was asymptomatic. The first two patients died one day after the first swab which led to the identification of A. baumannii. No additional case was noted in the ICU or in other hospital units after deciding to close the ICU. The cost of outbreak management was estimated at 264,553 euros. The case control study identified several factors associated with infection or colonization: length of stay in the ICU, chronic respiratory disease, number of previous antibiotic classes used, duration of ventilation, prone position, echocardiography, and presence of a nasogastric tube.

Conclusion

This outbreak occurred during the summer period requiring the shutdown of the ICU and inducing a considerable cost. Rapid reactions of the ICU staff during the outbreak enabled to limit the epidemic.     

Control of an outbreak of pandrug-resistant Acinetobacter baumannii colonization and infection in a neonatal intensive care unit.

OBJECTIVE: To investigate the potential reservoir and mode of transmission of pandrug-resistant (PDR) Acinetobacter baumannii in a 7-day-old neonate who developed PDR A. baumannii bacteremia that was presumed to be the iceberg of a potential outbreak. DESIGN: Outbreak investigation based on a program of prospective hospital-wide surveillance for nosocomial infection. SETTING: A 24-bed neonatal intensive care unit in a 2,200-bed major teaching hospital in Taiwan that provides care for critically ill neonates born in this hospital and those transferred from other hospitals. INTERVENTIONS: Samples from 33 healthcare workers' hands and 40 samples from the environment were cultured. Surveillance cultures of anal swab specimens and sputum samples were performed for neonates on admission to the neonatal intensive care unit and every 2 weeks until discharge. The PDR A. baumannii isolates, defined as isolates resistant to all currently available systemic antimicrobials except polymyxin B, were analyzed by pulsed-field gel electrophoresis. Control measures consisted of implementing contact isolation, reinforcing hand hygiene adherence, cohorting of nurses, and environmental cleaning. RESULTS: One culture of an environmental sample and no cultures of samples from healthcare workers' hands grew PDR A. baumannii. The positive culture result involved a sample obtained from a ventilation tube used by the index patient. During the following 2 months, active surveillance identified PDR A. baumannii in 8 additional neonates, and isolates from 7 had the same electrokaryotype. Of the 9 neonates colonized or infected with PDR A. baumannii, 1 died from an unrelated condition. Reinforcement of infection control measures resulted in 100% adherence to proper hand hygiene protocol. The outbreak was stopped without compromising patient care. CONCLUSIONS: In the absence of environmental contamination, transient hand carriage by personnel who cared for neonates colonized or infected with PDR A. baumannii was suspected to be the mode of transmission. Vigilance, prompt intervention and strict adherence to hand hygiene protocol were the key factors that led to the successful control of this outbreak. Active surveillance appears to be an effective measure to identify potential transmitters and reservoirs of PDR A. baumannii.