Baumannii Outbreak Research Articles

Molecular mechanisms of antimicrobial resistance in Acinetobacter baumannii, with a special focus on its epidemiology in Lebanon.

Acinetobacter baumannii is an opportunistic bacterium involved in several types of infection with high mortality and morbidity, especially in intensive care units. Treatment of these infections remains a challenge due to the worldwide emergence of broad-spectrum resistance to many antibiotics. Following the implementation of molecular techniques to study A. baumannii outbreaks, it has been shown that they are mainly caused by specific clones such as international clones I, II and III. The present work aims to review the available data on the mechanisms underlying antimicrobial resistance in A. baumannii, with a special focus on the molecular epidemiology of this species in Lebanon.

Simultaneous emergence and rapid spread of three OXA-23 producing Acinetobacter baumannii ST208 strains in intensive care units confirmed by whole genome sequencing

Carbapenem-resistant Acinetobacter baumannii (CRAB) is a common nosocomial bacterial pathogen with limited treatment options. CRAB outbreaks are disastrous for critically ill patients. This study investigated carbapenemase-produced A. baumannii outbreaks in a tertiary hospital. Although multiple outbreaks were suggested by pulse-field gel electrophoresis, the genetic lineages and evolution between these isolates were not clear. To investigate the genomic epidemiology of these outbreaks and to reveal possible transmission routes, whole genome sequences (WGS) were compared and analyzed. From the WGS data, thirty isolates had the same sequence type (ST208); acquired resistance genes and chromosome resistant genes were detected and were responsible for multidrug resistance. A phylogenetic tree of single-nucleotide polymorphisms (SNPs) compared to the earliest index isolate found that three outbreaks had emerged and disseminated simultaneously. Of these, <10 SNPs were detected within the cluster, whereas at least 600 SNPs were found between the clusters. The probable transmission routes of outbreaks were generated combined with the genetic distance of isolates and patient epidemiological data. In conclusion, WGS was a convenient and accurate monitoring method for genomic epidemiologic investigation of outbreaks, and the genomic surveillance of multidrug-resistant bacterial pathogens would be a powerful warning system for the surveillance and prevention of outbreaks.

Control of multidrug-resistant Acinetobacter baumannii in Hong Kong: Role of environmental surveillance in communal areas after a hospital outbreak

Environmental reservoir is an important source of multidrug-resistant Acinetobacter baumannii (MRAB) outbreaks. The role of postoutbreak environmental surveillance for guiding sustained infection control effort has not been examined. Enhanced environmental disinfection and regular environmental surveillance of ward communal areas after an outbreak were performed in a university-affiliated hospital. To assess the usefulness of environmental culture in predicting patients with MRAB, weekly surveillance of communal areas was continued for 3 months after the outbreak in intervention wards. The incidence of MRAB in intervention and nonintervention wards (control) was compared, whereas the other infection control measures remained identical. Postoutbreak weekly surveillance of communal areas showed that identification of newly diagnosed MRAB patients was significantly correlated with preceding environmental contamination with MRAB (P = .001). The incidence of nosocomial MRAB infection was significantly lower in the intervention compared with nonintervention wards (0.55 vs 2.28 per 1,000 patient days, respectively; P = .04). All MRAB isolated from the environmental and patients' samples belonged to multilocus sequence typing ST457 and were blaOXA23-like positive. Environmental surveillance may serve as a surrogate marker for the presence of MRAB carriers. Implementation of timely infection control measures should be guided by environmental culture for MRAB to minimize the risk of MRAB outbreak.

Management of an Acinetobacter baumannii outbreak in an intensive care unit

IntroductionAcinetobacter baumannii is a ubiquitous pathogen resistant to desiccation and responsible for healthcare-associated infections (HAI), especially in intensive care units (ICU) where it is responsible for 5–10% of HAIs. An A. baumannii outbreak occurred in the ICU of the University Hospital of Angers, France. ObjectivesTo describe the A. baumannii outbreak and to evaluate the control measures taken. The secondary objective was to evaluate the impact of the electronic alert system on the incidence of multidrug resistance to antibiotics. MethodsWe performed a descriptive study of A. baumannii carriers during the outbreak. Case contacts and carriers were described using the epidemic curve and a case synopsis table. ResultsFrom August 2011 to September 2013, 49 patients presenting with an extended-spectrum beta-lactamase-producing A. baumannii infection were identified: thirty-four were colonized and 15 were infected. No death was due to the outbreak. Measures taken were: geographical and technical isolation of patients, dedicated team implementation, contact precaution implementation including hand hygiene measures, appropriate use of gloves, and reinforcement of bio-cleaning procedures. ConclusionSome patients were re-admitted to hospital while still being carriers; this could explain epidemic peaks. The immersion mission of the hygiene nurse contributed to answering healthcare workers’ queries and led to a better cooperation between the ICU and the hygiene team.

Development and evaluation of a core genome multilocus typing scheme for whole-genome sequence-based typing of Acinetobacter baumannii.

We have employed whole genome sequencing to define and evaluate a core genome multilocus sequence typing (cgMLST) scheme for Acinetobacter baumannii. To define a core genome we downloaded a total of 1,573 putative A. baumannii genomes from NCBI as well as representative isolates belonging to the eight previously described international A. baumannii clonal lineages. The core genome was then employed against a total of fifty-three carbapenem-resistant A. baumannii isolates that were previously typed by PFGE and linked to hospital outbreaks in eight German cities. We defined a core genome of 2,390 genes of which an average 98.4% were called successfully from 1,339 A. baumannii genomes, while Acinetobacter nosocomialis, Acinetobacter pittii, and Acinetobacter calcoaceticus resulted in 71.2%, 33.3%, and 23.2% good targets, respectively. When tested against the previously identified outbreak strains, we found good correlation between PFGE and cgMLST clustering, with 0–8 allelic differences within a pulsotype, and 40–2,166 differences between pulsotypes. The highest number of allelic differences was between the isolates representing the international clones. This typing scheme was highly discriminatory and identified separate A. baumannii outbreaks. Moreover, because a standardised cgMLST nomenclature is used, the system will allow inter-laboratory exchange of data.

Colonization of long term care facility patients with MDR-Gram-negatives during an Acinetobacter baumannii outbreak

BackgroundWe aimed to determine the prevalence of colonization by multidrug-resistant Gram-negative bacteria including ESBL-producing enterobacteriaceae, carbapenem-resistant enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii at two wards caring long term for patients with disorder of consciousness at the Geriatric Health Centers Graz, Austria. During our study we detected two A. baumannii outbreaks.MethodsIn August 2015, we conducted a point-prevalence study. Inguinal and perianal swabs were taken from 38 patients and screened for multidrug-resistant Gram-negative rods using standard procedures. Six months after the initial investigation all patients were sampled again and use of antibiotics during the past 6 months and mortality was registered. Genetic relatedness of bacteria was evaluated by DiversiLab system.ResultsFifty percent of patients were colonized by multidrug-resistant Gram-negative isolates. Five patients harboured ESBL-producing enterobacteriaceae. No carbapenem-resistant enterobacteriaceae were detected. 13/38 patients were colonized by A. baumannii isolates (resistant to ciprofloxacin but susceptible to carbapenems). There was a significant difference in the prevalence of colonization by A. baumannii between ward 2 and ward 1 (60% vs. 5.6%, p < 0.001). Two clusters of A. baumannii isolates were identified including one isolate detected on a chair in a patient’s room.ConclusionsWe detected a high prevalence of two multidrug-resistant A. baumannii strains in patients with disorder of consciousness at a LTCF in Graz, Austria. Our findings strongly suggest nosocomial cross-transmission between patients. An active surveillance strategy is warranted to avoid missing newly emerging pathogens.

Carbapenemase-producing Acinetobacter baumannii: An outbreak report with special highlights on economic burden

ObjectiveWe aimed to describe the management of a carbapenemase-producing Acinetobacter baumannii (CP-AB) outbreak using the Outbreak Reports and Intervention Studies of Nosocomial Infection (ORION) statement. We also aimed to evaluate the cost of the outbreak and simulate costs if a dedicated unit to manage such outbreak had been set-up. MethodsWe performed a prospective epidemiological study. Multiple interventions were implemented including cohorting measures and limitation of admissions. Cost estimation was performed using administrative local data. ResultsFive patients were colonized with CP-AB and hospitalized in the neurosurgery ward. The index case was a patient who had been previously hospitalized in Portugal. Four secondary colonized patients were further observed within the unit. The strains of A. baumannii were shown to belong to the same clone and all of them produced an OXA-23 carbapenemase. The closure of the ward associated with the discharge of the five patients in a cohorting area of the Infectious Diseases Unit with dedicated staff put a stop to the outbreak. The estimated cost of this 17-week outbreak was $474,474. If patients had been managed in a dedicated unit — including specific area for cohorting of patients and dedicated staff — at the beginning of the outbreak, the estimated cost would have been $189,046. ConclusionControlling hospital outbreaks involving multidrug-resistant bacteria requires a rapid cohorting of patients. Using simulation, we highlighted cost gain when using a dedicated cohorting unit strategy for such an outbreak.

Control of carbapenem-resistant Acinetobacter baumannii outbreak in an intensive care unit of a teaching hospital in Southern Italy.

Background Acinetobacter baumannii is an opportunistic pathogen that has become a major cause of concern, since it is a frequent cause of healthcare-associated infections (HAIs). The aim of the study was to describe the occurrence, the management and the control of an outbreak that occurred in an intensive care unit (ICU) of a teaching hospital in Southern Italy caused by multiple strains of extensively drug-resistant A. baumannii (XDRAB).MethodsCase-patient was defined as a patient with an healthcare-associated infection caused by an XDRAB isolate identified in a clinically significant culture. Environmental samples were collected from different surfaces. The isolates were identified by typical Gram stain morphology, using the Vitek 2 system (bioMérieux, France) and by MALDI-TOF MS mass spectrometry (bioMèrieux, France). Genotyping was performed through rep-PCR analysis.ResultsA patient presented an XDRAB ventilator-associated pneumonia at admission and was managed with strict isolation precautions until discharge. Five patients had a ventilator-associated pneumonia and two had a central line-associated bloodstream infection. Of the environmental samples, 1 sample obtained from the side of the bed of an infected patient yielded growth of XDRAB. Infection control measures were adopted. Rep-PCR analysis identified four patterns.ConclusionsThe integration of epidemiological and microbiological data and the application of infection control measures were crucial to bring such an outbreak to a rapid halt. The distinctive characteristic of this study was the complex molecular pattern of the outbreak, which subsided in a short period of time due to adherence to infection-control measures, confirming the fundamental role of molecular typing in the comprehension of outbreaks dynamics and of integrated control interventions for the interruption of epidemic events.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-016-2036-7) contains supplementary material, which is available to authorized users.

Acinetobacter baumannii biofilm resistance mechanisms and prevention and control of progress

At present, the multiple drug resistance of Acinetobacter baumannii outbreaks worldwide and has intensified the trend, especially in the intensive care unit and burn ward. Generic drug resistant Acinetobacter baumannii is known as the 21st century gram-negative bacterium “MRSA”, “Superbugs”. In recent years, researches have shown that this is associated with pathogenic bacteria to form biofilms. In this paper, the status of Acinetobacter baumannii infection, biofilm formation, resistance mechanism and prevention in recent years were summarized.

Head-to-head comparison of two multi-locus sequence typing (MLST) schemes for characterization of Acinetobacter baumannii outbreak and sporadic isolates

Head-to-head comparison of two multi-locus sequence typing (MLST) schemes for characterization of Acinetobacter baumannii outbreak and sporadic isolates

Task force on management and prevention of Acinetobacter baumannii infections in the ICU.

Acinetobacter baumannii constitutes a dreadful problem in many ICUs worldwide. The very limited therapeutic options available for these organisms are a matter of great concern. No specific guidelines exist addressing the prevention and management of A. baumannii infections in the critical care setting. Clinical microbiologists, infectious disease specialists and intensive care physicians were invited by the Chair of the Infection Section of the ESICM to participate in a multidisciplinary expert panel. After the selection of clinically relevant questions, this document provides recommendations about the use of microbiological techniques for identification of A. baumannii in clinical laboratories, antibiotic therapy for severe infections and recommendations to control this pathogen in outbreaks and endemic situations. Evidence supporting each statement was graded according to the European Society of Clinical Microbiology and Infection Diseases (ESCMID) grading system. Empirical coverage of A. baumannii is recommended in severe infections (severe sepsis or septic shock) occurring during an A. baumannii outbreak, in an endemic setting, or in a previously colonized patient. For these cases, a polymyxin is suggested as part of the empirical treatment in cases of a high suspicion of a carbapenem-resistant (CR) A. baumannii strain. An institutional program including staff education, promotion of hand hygiene, strict contact and isolation precautions, environmental cleaning, targeted active surveillance, and antimicrobial stewardship should be instituted and maintained to combat outbreaks and endemic situations. Specific recommendations about prevention and management of A. baumannii infections in the ICU were elaborated by this multidisciplinary panel. The paucity of randomized controlled trials is noteworthy, so these recommendations are mainly based on observational studies and pharmacodynamics modeling.

Infection Control Programs and Antibiotic Control Programs to Limit Transmission of Multi-Drug Resistant Acinetobacter baumannii Infections: Evolution of Old Problems and New Challenges for Institutes.

Background: Acinetobacter baumannii complex (A. baumannii) has been isolated worldwide. The rapid spread of multidrug-resistant A. baumannii complex (MDRAB) in clinical settings has made choosing an appropriate antibiotic to treat these infections and executing contact precautions difficult for clinicians. Although controlling the transmission of MDRAB is a high priority for institutions, there is little information about MDRAB control. Therefore, this study evaluated infection control measures for A. baumannii infections, clusters and outbreaks in the literature. Methods: We performed a review of OVID Medline (from 1980 to 2015), and analyzed the literature. Results: We propose that both infection control programs and antibiotic control programs are essential for control of MDRAB. The first, effective control of MDRAB infections, requires compliance with a series of infection control methods including strict environmental cleaning, effective sterilization of reusable medical equipment, concentration on proper hand hygiene practices, and use of contact precautions, together with appropriate administrative guidance. The second strategy, effective antibiotic control programs to decrease A. baumannii, is also of paramount importance. Conclusion: We believe that both infection control programs and antibiotics stewardship programs are essential for control of MDRAB infections.

A Epidemiological Investigation of a Nosocomial Outbreak of Multidrug-Resistant Acinetobacter baumannii in a Critical Care Center in Japan, 2011-2012.

In 2011, a multidrug-resistant Acinetobacter baumannii (MDRAB) outbreak occurred at a Japanese critical care center (CCC) in a tertiary care hospital. Multidrug-resistance in Japan is defined as resistance to the antimicrobials amikacin, carbapenem, and fluoroquinolone. We conducted a retrospective epidemiological investigation of this outbreak to identify the risk factors for MDRAB respiratory tract acquisition in this hospital. Cases were defined as hospitalized patients with MDRAB-positive cultures at least 3 days post admission to the CCC between June 1, 2011 and April 20, 2012. Fifteen MDRAB cases were identified, including 3 with infection and 12 with colonization. This case-control study demonstrated that hypoalbuminemia along with carbapenem administration were associated with MDRAB respiratory tract acquisition. Pulsed-field gel electrophoresis analysis and multilocus sequence typing using MDRAB isolates suggested a clonal dissemination of MDRAB strains with sequence type 74 occurred primarily among patients admitted to the CCC. From April 16, 2012, a decreased isolation rate of MDRAB in the hospital occurred after the implementation of the following infection control measures: closing the emergency room, discontinuing admission to the CCC, isolating patients with MDRAB colonization or infection to single room status, and conducting environmental cleaning. No MDRAB cases were detected between March 23 and April 20, 2012.

Antimicrobial consumption assessment as a part of infection control surveillance exemplified by bloodstream infection treatment in NICUs

A carbapenem-resistant Acinetobacter baumannii outbreak in the COVID intensive care unit of a community hospital was contained using multidrug resistant organism guidelines. The purpose of this study is to report on an outbreak investigation and containment strategy that was used, and to discuss prevention strategy.A multidisciplinary approach contained the spread of infection. Strategies implemented included consultation with experts, screening, and reversal of personal protective equipment conservation. Ensuring infection control best practices are maintained remain important efforts to reduce the spread of multidrug resistant organisms.Five patients with carbapenem-resistant Acinetobacter baumannii were identified from routine clinical cultures within one week and one patient was identified from active surveillance cultures.Personal protective equipment conservation, strategies to prevent health care personnel exposure, and patient surge staffing protocols may have increased the likelihood of multidrug resistant organism transmission. Environmental and behavioral infection control regulations with effective administrative guidance, active surveillance cultures, and antimicrobial stewardship are critical to prevent future outbreaks.After outbreak containment strategies were implemented, no additional patients were identified with carbapenem-resistant Acinetobacter baumannii. Conventional infection prevention and control strategies were re-instituted. A multidisciplinary approach with continued focus on hand hygiene, environmental cleaning, and correct use of personal protective equipment needs to be put in place to successfully contain and prevent the spread of carbapenem resistant infections.

The impact of inadequate disinfection on outbreak of carbapenem-resistant Acinetobacter baumannii in a medical intensive care unit

Purpose: This study was conducted to investigation of an outbreak caused by carbapenem-resistant A. baumannii (CRAB) in a medical intensive care unit (ICU) in a regional hospital. Methods: In response to carbapenem-resistant A. baumannii (CRAB) outbreak from October 2012 to February 2013, we developed several infection control measures including extensively review process of environmental cleaning and disinfection, and using molecular methods to identify each clinical and environmental CRAB isolate. Results: During this period of five months, 22 patients had CRAB colonization and 18 patients had CRAB infections. In-hospital mortality was significantly higher among patients with infection than colonization (44.4% vs 9.1%, p Z 0.028). Additionally, nine environmental specimens, including five specimens collected after terminal disinfection, were positive for CRAB. Nine of 12 environmental isolates and 31 of 36 available clinical isolates belong to one unique pulsotype, which was confirmed by molecular methods. We found the concentration of disinfectant sodium hypochlorite was inadequate, which was only 0.08%. After correction for environmental cleansing and aforementioned surveillance study, there was no more CRAB on the control panel surfaces of the medical equipment, and patients in the ICU. Additionally, in vitro study of CRAB against different concentration of sodium hypochlorite showed that 0.5% sodium hypochlorite eradicates CRAB after 30 seconds of inoculation, but 0.08% sodium hypochlorite can only reduce the bacterial load. Conclusions: This study highlights the importance of preparation of disinfectant and adequate environmental disinfection in the control of CRAB outbreak in the ICU.

Management and control of a carbapenem-resistant Acinetobacter baumannii outbreak in an intensive care unit

ObjectiveWe had for aim to describe the identification and management of a 14-clonal carbapenem-resistant Acinetobacter baumannii (CRAB) outbreak, following admission of a known CRAB-infected patient in an ICU. MethodsWe reviewed the carriers’ files and outbreak management procedures. ResultsThe index patient was admitted with strict isolation precautions. The outbreak started 2 months after his discharge. It persisted despite reinforcement of strict isolation precautions, staff and patient cohorting, and extensive environmental decontamination including 2 rounds of routine terminal cleaning and disinfection or 1 round of cleaning and disinfection followed by hydrogen peroxide treatment. A second epidemic peak, after 4 weeks without any case, led to another wide environmental sampling and decontamination rounds. The source of the CRAB outbreak was suspected to be the blood pressure cuffs Velcro. Switching to cuffs submersible in a disinfectant stopped the outbreak. ConclusionsCRAB outbreaks are difficult to manage and sources of persistent colonization can be unexpected.

Laboratory to Clinical Investigation of Carbapenem Resistant Acinetobacter baumannii Outbreak in a General Hospital

Background:The number of reported cases, infected with carbepenem resistant Acinetobacter baumannii (CRAb) and multi-drug resistant (MDR) Acinetobacter species had gradually increased in most PLA general hospital wards from April to June in 2007.Objectives:We have described the investigation of an outbreak of CRAb and MDR Acinetobacter in PLA general hospital, Beijing. The prospective and retrospective findings were identified and analyzed to study the infection causes.Materials and Methods:A. baumannii samples were collected from the patients and environment in each hospital unit. The onset times were recorded according to their case information. All samples were characterized by genotype and compared using pulsed-field gel electrophoresis (PFGE). The microorganism susceptibility was tested using the in vitro minimal inhibitory concentration (MIC) breakpoints method.Results:A total of 69 A. baumannii strains were successfully isolated from 53 patients. About 89.1% of them were resistant to ampicillin and 89.2% to cefotaxime and 75.4% to all standard antibiotics. PFGE analysis revealed that nine of the isolates had unique clones and the epidemic clone types were A, B and C.Conclusions:The A. baumannii outbreak, was caused by MDR A. baumannii. The strains had widely spread among 12 departments especially in surgical intensive care unit (SICU), emergency intensive care unit (EICU) and the department of respiratory disease. The outbreak was more likely caused by the A. baumannii infected or carrier patients and EICU was its origin.

Control of a Multi-Drug-Resistant Acinetobacter baumannii Outbreak after Orthopedics Department Relocation.

Acinetobacter baumannii clinical isolates have the ability to survive in the hospital niche for prolonged time periods and to develop resistance against multiple antimicrobial agents. Therefore, A. baumannii has emerged as an important cause of nosocomial outbreaks worldwide, especially in critical-care environments such as intensive care units. In the present communication, we report a multi-drug-resistant A. baumannii outbreak that occurred in an orthopedics department in Greece after the admission of a patient previously hospitalized in the intensive care unit of a Greek tertiary care hospital. Despite the implementation of infection control measures, 29 patients were infected, significantly raising their hospitalization periods and treatment costs. Interestingly, the outbreak was put under control after the department’s previously programmed relocation.

A DNA damage‐inducible response in Acinetobacter baumannii

Acinetobacter baumannii favors chromosomal insertions and rearrangements, lending to its ability to gain antibiotic resistance and succeed as a pathogen. This tendency toward genomic plasticity contradicts efforts of other organisms to preserve their genomes. In turn, it was thought that A. baumannii was missing a DNA damage‐inducible response, which would play a role in maintenance of chromosomal integrity. We sought to characterize such a response in A. baumannii, using fluorescent reporter strains to examine gene induction. We found A. baumannii not only to possess a DNA damage‐inducible system, but genes regulated under this system are induced under bistable promoters. This bistable induction of genes after DNA damage is not seen in other organisms such as Escherichia coli and could allow A. baumannii to take risks, allowing heightened recombination and mutagenesis in a portion of the population, without risking the whole cell line. The control of A. baumannii outbreaks has become a serious problem in hospitals, as multidrug resistance rises. Further insight into the workings of this bistable system will be critical in the growing search for therapies against this increasingly adaptive bacterium.

Multidrug-resistant Acinetobacter baumannii outbreak: an investigation of the possible routes of transmission

ObjectivesTo establish the possible sources and routes of transmission of a multidrug-resistant Acinetobacter baumannii outbreak involving 22 patients. Study designDescriptive, retrospective study. MethodsAn environmental investigation was undertaken, monitoring surfaces, air and water. Reconstruction of the spread of the infection took several factors into account such as intrahospital movements of patients and healthcare personnel, hospitalization of patients in the same ward and in chronologically compatible periods, and length of stay. A. baumannii clinical samples were typed using the Multilocus Sequence Typing scheme. ResultsThe outbreak originated from a patient admitted to the sub-intensive care unit, and the infection subsequently spread to other wards. The allelic profile proved to be the same for all the clinical isolates. Environmental monitoring yielded negative results for A. baumannii. ConclusionsThe results suggest that this epidemic spread through cross-transmission involving healthcare workers.