Carbapenem-resistant Acinetobacter Baumannii Acquisition Research Articles

Respiratory microbiome and clinical course of carbapenem-resistant Acinetobacter baumannii pneumonia in critically Ill patients.

Carbapenem-resistant Acinetobacter baumannii (CRAB) pneumonia has been a serious problem in the intensive care unit (ICU). However, defined characteristics of respiratory microbiome in CRAB pneumonia are lacking nowadays. This study aimed to analyze respiratory microbiome of CRAB pneumonia compared to non-CRAB pneumonia and reveal the clinical significance of respiratory microbiome data in these patients. Patients diagnosed with severe pneumonia with mechanical ventilation were enrolled in the ICU of a tertiary care hospital. Respiratory specimens were collected on days 1, 4, 7, and 14 in each participant via tracheal aspiration. Clinical data and outcomes of each enrolled patient were collected via electronic medical records. Microbiome analysis was conducted with collected respiratory specimens undergone by next-generation sequencing of microbial 16S ribosomal DNA. Six CRAB pneumonia, 4 non-CRAB pneumonia and 5 healthy controls were enrolled. In CRAB pneumonia, CRAB was detected in 3 patients by sputum culture at day 1, while it was negative at day 1 and detected later in the others by follow-up sputum culture. Beta diversity plot analysis showed differences between each group. Shannon index was decreased markedly at day 4 in CRAB pneumonia compared to the others. Among CRAB pneumonia cases, 3 respiratory specimens were culture-negative, but positive by microbiome analysis. Lower respiratory microbiome in CRAB pneumonia had distinct characteristics and early loss of diversity compared to non-CRAB pneumonia, which might be related to poor clinical course. Moreover, CRAB acquisition and colonization would be predicted by preemptive microbiome analysis, which will contribute to effective infection control in the ICU.

Risk factors for transmission of carbapenem-resistant Acinetobacter baumannii in outbreak situations: results of a case-control study

BackgroundAn increase in patients with multidrug-resistant organisms and associated outbreaks during the COVID-19 pandemic have been reported in various settings, including low-endemic settings. Here, we report three distinct carbapenem-resistant Acinetobacter baumannii (CRAB) outbreaks in five intensive care units of a university hospital in Berlin, Germany during the COVID-19 pandemic.MethodsA case-control study was conducted with the objective of identifying risk factors for CRAB acquisition in outbreak situations. Data utilized for the case-control study came from the investigation of three separate CRAB outbreaks during the COVID-19 pandemic (August 2020– March 2021). Cases were defined as outbreak patients with hospital-acquired CRAB. Controls did not have any CRAB positive microbiological findings and were hospitalized at the same ward and for a similar duration as the respective case. Control patients were matched retrospectively in a 2:1 ratio. Parameters routinely collected in the context of outbreak management and data obtained retrospectively specifically for the case-control study were included in the analysis. To analyze risk factors for CRAB acquisition, univariable and multivariable analyses to calculate odds ratios (OR) and 95% confidence intervals (CI) were performed using a conditional logistic regression model.ResultsThe outbreaks contained 26 cases with hospital-acquired CRAB in five different intensive care units. Two exposures were identified to be independent risk factors for nosocomial CRAB acquisition by the multivariable regression analysis: Sharing a patient room with a CRAB patient before availability of the microbiological result was associated with a more than tenfold increase in the risk of nosocomial CRAB acquisition (OR: 10.7, CI: 2.3–50.9), while undergoing bronchoscopy increased the risk more than six times (OR: 6.9, CI: 1.3–38.1).ConclusionsThe risk factors identified, sharing a patient room with a CRAB patient and undergoing bronchoscopy, could point to an underperformance of basic infection control measure, particularly hand hygiene compliance and handling of medical devices. Both findings reinforce the need for continued promotion of infection control measures. Given that the outbreaks occurred in the first year of the COVID-19 pandemic, our study serves as a reminder that a heightened focus on airborne precautions should not lead to a neglect of other transmission-based precautions.

Reduction in the acquisition rate of carbapenem-resistant Acinetobacter baumannii (CRAB) after room privatization in an intensive care unit

Acinetobacter baumannii is one of the major pathogens responsible for healthcare-associated infections, especially in intensive care units (ICUs). To evaluate the effect of room privatization in an ICU on the acquisition of carbapenem-resistant A.baumannii (CRAB). Between March and August 2017, a medical ICU was renovated from a multi-bed bay room to single rooms. Acquisition of CRAB was compared between patients admitted to the ICU over 18 months pre-renovation (September 2015 to February 2017) and post-renovation (September 2017 to February 2019). A Cox proportional hazard model was used with adjustment for demographics and comorbidities. Of the 901 patients, who contributed 8276 patient-days, 95 (10.5%) acquired CRAB during their ICU stay. The CRAB acquisition rate was significantly higher during the pre-renovation period (1.87 per 100 patient-days) than during the post-renovation period (0.39 per 100 patient-days) (P<0.001). In the multi-variable Cox regression model, CRAB acquisition was significantly associated with the presence of a feeding tube (adjusted hazard ratio (aHR), 6.08; 95% confidence interval (CI), 2.46-15.06; P<0.001), continuous renal replacement therapy (aHR, 1.66; 95% CI, 1.09-2.53; P=0.019) and admission after renovation of the ICU to single rooms (aHR, 0.23; 95% CI, 0.12-0.41; P<0.001). Renovation of ICUs to single rooms is an efficient strategy to prevent transmission of multi-drug-resistant organisms and hospital-acquired infections.

Does enhanced environmental cleaning reduce carbapenem-resistant Acinetobacter baumannii colonization in the intensive care unit?

To evaluate the impact of enhanced environmental cleaning (two times per day) compared with conventional cleaning on the acquisition of carbapenem-resistant Acinetobacter baumannii (CRAB) in a highly endemic intensive care unit (ICU). The intervention consisted of alternating environmental cleaning and conventional cleaning every 3 months during the study period from July 2018 to June 2019. CRAB acquisition was assessed using incidence and prevalence rates, and colonization pressure. The incidence rates of CRAB with and without enhanced cleaning were 16.3 and 13.9 cases per 1000 population, respectively; and the prevalence rates were 66.9 and 61.7 cases per 1000 population, respectively. Colonization pressure was 53.3% with enhanced cleaning and 51.3% without enhanced cleaning. No association was found between enhanced environmental cleaning and the incidence (P=0.156), prevalence (P=0.888) and colonization pressure (P=0.825) of CRAB acquisition. The ventilator utilization ratio increased the colonization pressure of CRAB acquisition (P=0.010, β coefficient=0.37). The proportion of new nurses with <3 years of clinical practice experience was positively correlated with the incidence and prevalence of CRAB acquisition. Enhanced environmental cleaning alone failed to reduce CRAB acquisition in a highly endemic ICU. The ventilator utilization ratio may be of more importance than environmental cleaning. Inexperienced nurses may need to be monitored regarding infection control activities in addition to hand hygiene adherence.

Adaptations of carbapenem resistant Acinetobacter baumannii (CRAB) in the hospital environment causing sustained outbreak

Introduction. Carbapenem resistance in Acinetobacter baumannii (A. baumannii) is an emerging global threat.Gap statement. The adaptation strategies of A. baumannii for this emergence as a nosocomial pathogen has been less studied.Aim. This prospective study analysed a sustained outbreak of carbapenem resistant Acinetobacter baumannii (CRAB) in the intensive care unit (ICU) with reference to antimicrobial resistance and virulence in the colonizing and pathogenic isolates under carbapenem stress.Results. The CRAB isolates from initial and sustained outbreak were found harbouring multiple carbapenemase genes. These genes included bla OXA-23 ,bla IMP, bla VIM and bla NDM. From NICU environment three phenotypically carbapenem susceptible isolates were found carrying bla OXA-23, bla IMP, bla VIM genes. Prior imipenem therapy was one of the risk factors (P=0.0016). The outbreak was polyclonal. Under imipenem stress, outbreak isolates showed no loss of carbapenemase genes against stress free conditions (23.7±1.33 days). Biofilm formation increased with imipenem concentration, with outbreak isolates producing highest biomass. While the pathogens showed a slow growth rate on imipenem exposure, the colonisers grew rapidly (P <0.0001).Methods. Sustained outbreak of CRAB was identified in the ICU (July 2015 to December 2017). Risk factors for acquisition of CRAB was studied. A. baumannii isolates were also collected from the environments of ICU and neonatal ICU (NICU) and blood cultures of septic neonates. Isolates were characterized based on antimicrobial susceptibility, genetic profile, integrons carriage and clonality. Biofilm formation and growth kinetics were studied under varying carbapenem stress.Conclusion. Intense carbapenem exposure in the ICU facilitates persistence of CRAB by several adaptations causing sustained outbreaks.

The role of the computerized tomography scanner in the cross-transmission of carbapenem-resistant Acinetobacter baumannii between hospitalized patients

ObjectiveTo assess the role of the computerized tomography (CT) scanner in cross-transmission of carbapenem-resistant Acinetobacter baumannii between hospitalized patients undergoing CT scan. MethodsA single-centre retrospective observational analysis of inpatients undergoing CT scans. Patient-unique CT scans were defined as ‘index cases’ (patients undergoing CT scan with carbapenem-resistant Acinetobacter baumannii (CRAB) colonization documented during the previous 60 days), ‘incident cases’ (patients found colonized with CRAB within 14 days following CT scan), and ‘negative cases’ (negative for CRAB before and after CT scan). CRAB acquisition was analysed by time interval between CT scan and CT scan of the prior index-case patient. ResultsAmongst 73 047 CT scans performed over 5 years, 4834 scans were performed within 12 hours of an index case. CRAB acquisition was detected in 20 patients (incident cases), including 16/2725 (5.8/1000 scans) who underwent CT scan within 6 hours of an index-case CT scan and 4/2109 (1.9/1000 scans) who had their CT scan 7–12 hours after the CT scan of an index-case patient (p 0.033, risk ratio 3.1, 95%CI 1.03–9.25). Patient characteristics for the two time periods were similar. While not the only significant predictor of CRAB acquisition (others included age and length of hospital stay prior to the CT scan), the time elapsed from an index case remained a significant predictor for CRAB acquisition on multivariate analysis (OR 0.84, 95%CI 0.74–0.95, p 0.007). ConclusionsPerforming a CT scan within 6 hours of a CT scan performed in a CRAB-positive patient was an independent predictor of CRAB acquisition, approximately tripling the risk. This probably reflects poor infection control practice in the CT suite.

813. The Reduction of the acquisition rate of carbapenem resistant Acinetobacter baumannii after room privatization in the intensive care unit

Background Acinetobacter baumannii is one of the major pathogens of hospital-acquired infection recently and hospital outbreaks have been reported worldwide. On September 2017, New intensive care unit(ICU) with only single rooms, remodeling from old ICU with multibed bay rooms, was opened in an acute-care tertiary hospital in Seoul, Korea. We investigated the effect of room privatization in the ICU on the acquisition of carbapenem-resistant Acinetobacter baumannii(CRAB).MethodsWe retrospectively reviewed medical records of patients who admitted to the medical ICU in a tertiary care university-affiliated 1,800-bed hospital from 1 January 2015 to 1 January 2019. Patients admitted to the medical ICU before the remodeling of the ICU were designated as the control group, and those who admitted to the medical ICU after the remodeling were designated as the intervention group. Then we compared the acquisition rate of CRAB between the control and intervention groups. Patients colonized with CRAB or patients with CRAB identified in screening tests were excluded from the study population. The multivariable Cox regression model was performed using variables with p-values of less than 0.1 in the univariate analysis.ResultsA total of 1,105 cases admitted to the ICU during the study period were analyzed. CRAB was isolated from 110 cases in the control group(n=687), and 16 cases in the intervention group(n=418). In univariate analysis, room privatization, prior exposure to antibiotics (carbapenem, vancomycin, fluoroquinolone), mechanical ventilation, central venous catheter, tracheostomy, the presence of feeding tube(Levin tube or percutaneous gastrostomy) and the length of ICU stay were significant risk factors for the acquisition of CRAB (p< 0.05). In the multivariable Cox regression model, the presence of feeding tube(Hazard ratio(HR) 4.815, 95% Confidence interval(CI) 1.94-11.96, p=0.001) and room privatization(HR 0.024, 95% CI 0.127-0.396, p=0.000) were independent risk factors.Table 1. Univariate analysis of Carbapenem-resistant Acinetobacter baumannii Table 2. Multivariable Cox regression model of the acquisition of Carbapenem-resistant Acinetobacter baumannii ConclusionIn the present study, room privatization of the ICU was correlated with the reduction of CRAB acquisition independently. Remodeling of the ICU to the single room would be an efficient strategy for preventing the spreading of multidrug-resistant organisms and hospital-acquired infection.Disclosures All Authors: No reported disclosures

Surgical site infection after liver transplantation in the era of multidrug-resistant bacteria: what new risks should be considered?

Surgical site infection (SSI) is a frequent infection site after liver transplantation (LT), and multidrug-resistant bacteria are common agents of those infections. This study aimed to analyze risk factors for SSI, including SSI caused by a multidrug-resistant microorganism (MDRO) after LT. We performed a cohort study of patients who underwent an LT from 2010 to 2018. The outcomes were SSI and SSI caused by MDRO. We analyzed features related to surgical procedure, patients' characteristics, and post-LT intercurrence. Surveillance for carbapenem-resistant Enterobacteriaceae (CRE), vancomycin-resistant Enterococcus (VRE), and carbapenem-resistant Acinetobacter baumannii (CRAB) was performed through rectal swab at the LT admission and weekly until hospital discharge during all study periods. SSI was identified in 30.1% (229/762) of LTs. We observed a decline in the SSI rate from 37.5% in 2014 to 16.7% in 2018 (P 0.02). SSI caused by MDRO occurred in 109 (14.3%) patients. Klebsiella pneumoniae was the most common agent of both SSI and SSI caused by MDRO. The pre-LT colonization was 98 (12.9%) by CRE, 73 (9.6%) by VRE, and 28 (3.7%) by CRAB. Risk factors for SSI caused by MDRO identified were dialysis after LT (P 0.01), CRAB acquisition before LT (0.03), and CRE acquisition before LT (P 0.004); use of adjusted prophylaxis by MDRO risk was the only protective factor identified (P 0.01). MDROs were frequent agents of SSI after LT, and the carbapenem-resistant Gram-negative colonization before LT increased the risk of SSI by these agents.

Epidemiology of carbapenem-resistant Gram-negative infections globally.

The spread of carbapenem-resistant Gram-negative bacteria (GNB) with changes in institutional epidemiology continues to evolve worldwide. The purpose of this review is to evaluate new data with regard to the epidemiology, mechanisms of resistance and the impact of carbapenem resistance on mortality. The rapid expansion of acquired carbapenem resistance is increasingly propagated by mobile genetic elements such as epidemic plasmids that transfer carbapenemase genes within and between GNB. The risk of acquisition of carbapenem-resistant Acinetobacter baumannii increases four-fold with carbapenem exposure and new meta-analyses have confirmed excess mortality associated with carbapenem-resistant Pseudomonas aeruginosa. Carbapenemase-producing Klebsiella pneumoniae, the most commonly encountered carbapenemase-producing Enterobacterales (CPE) and a major cause of high-mortality hospital-related infections, represents the most rapidly growing global threat. Carbapenem use in patients colonized with such genotypes, leads to an increase in CPE abundance in the gastrointestinal tract, which in turn increases the risk of blood-stream infections four-fold. High-resistance rates in carbapenem-resistant GNB in many countries will inevitably complicate treatment of serious infections in vulnerable patient groups and should accelerate global attempts to overcome the impediments we face with regard to effective antimicrobial stewardship and infection prevention and control programs.

515. Acquisition of Antibiotic-Resistant Gram-Negative Bacteria in the Benefits of Universal Glove and Gown (BUGG) Cluster Randomized Trial

BackgroundThe Benefits of Universal Gloves and Gowns (BUGG) randomized trial found a decrease in MRSA acquisition, no effect on VRE acquisition and no increase in adverse events with the intervention of wearing gloves and gowns for all patient contact in the intensive care unit (ICU). The objective of the study was to assess whether wearing gloves and gowns for all patient contact in the ICU decreases the acquisition of antibiotic-resistant Gram-negative bacteria.Methods Design: Secondary study of the BUGG cluster-randomized trial. Participants: 20 medical and surgical ICUs in 20 US hospitals. Intervention: Healthcare workers were required to wear gloves and gowns when entering any patient room compared with standard care. Main outcomes and measures: The primary composite outcome was acquisition of any antibiotic-resistant Gram-negative bacteria based on surveillance cultures collected on admission and discharge. Secondary outcomes were acquisition of carbapenem-resistant Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacteriaceae, or ESBL-producing Enterobacteriaceae.ResultsFor the primary outcome, the intervention had a RR of 0.90 (95% CI 0.71 to 1.12, P = 0.34). Effects on the secondary outcomes were: carbapenem-resistant Enterobacteriaceae [RR 0.86 (95% CI, 0.60 to 1.24), P = 0.43], carbapenem-resistant Acinetobacter [RR 0.81 (95% CI, 0.52 to 1.27) P = 0.36], carbapenem-resistant Pseudomonas [RR 0.88 (95% CI, 0.55 to 1.42) P = 0.62], ESBL producing bacteria [RR 0.94, (95% CI, 0.71 to 1.24) P = 0.67].ConclusionThe association of universal glove and gown use in the ICU with acquisition of antibiotic-resistant Gram-negative bacteria was inconclusive. The observed rate ratios for all five outcomes suggest that the intervention was protective, however, none were statistically significant. The study was likely underpowered to detect statistical significance for the effect sizes found. Individual hospitals should consider implementing the intervention based on the importance of these organisms at their hospital, effect sizes, confidence intervals, and cost. Disclosures All authors: No reported disclosures.

Rapid screening and early precautions for carbapenem-resistant Acinetobacter baumannii carriers decreased nosocomial transmission in hospital settings: a quasi-experimental study

BackgroundActive surveillance has the potential to prevent nosocomial transmission of carbapenem-resistant Acinetobacter baumannii (CRAB). We assessed whether rapid diagnosis using clinical specimen-direct loop-mediated isothermal amplification (LAMP), a rapid molecular diagnostic assay, and subsequent intervention, could reduce CRAB nosocomial transmission in intensive care units (ICUs).MethodsA before and after (quasi-experimental) study was conducted in two ICUs at the Mahidol University Faculty of Medicine Ramathibodi Hospital with 3 months of observational period followed by 9 months of interventional period. All patients were screened for CRAB using both the culture and LAMP method from rectal swab and/or bronchial aspirates (intubated patients only) upon admission, weekly thereafter, and upon discharge. During the pre-intervention period, we performed contact precautions based on culture results. In contrast, during the intervention period, we initiated contact precautions within a few hours after sample collection on the basis of LAMP results.ResultsA total of 1335 patients were admitted to the ICUs, of which 866 patients (pre-intervention period: 187; intervention period: 679) were eligible for this study. Incidence rate of CRAB infection decreased to 20.9 per 1000 patient-days in the intervention period from 35.2 in the pre-intervention period (P < 0.02). The calculated hazard ratio of CRAB transmission was 0.65 (95% confidence interval [CI], 0.44–0.97). Risk factors for CRAB acquisition included exposure to carbapenem (hazard ratio, 2.54 [95% CI: 1.61–5.57]).ConclusionsLAMP screening for CRAB upon ICU admission proved feasible for routine clinical practice. Rapid screening using LAMP followed by early intervention may reduce CRAB transmission rates in ICUs when compared to conventional intervention.

NDM-1- and OXA-23-producing Acinetobacter baumannii isolated from intensive care unit patients in Tunisia

Gastrointestinal colonisation by carbapenem-resistant Acinetobacter baumannii (CRAB) is a critical step before nosocomial infection. This study evaluated CRAB intestinal carriage in patients admitted to a Tunisian ICU and determined the antimicrobial resistance mechanisms involved. From December 2014 to February 2015, all 63 patients admitted to the ICU were screened for rectal CRAB colonisation upon admission and once weekly thereafter. ICU patients who acquired a CRAB nosocomial infection were also included. β-Lactamases and associated resistance genes were screened by PCR sequencing, and molecular typing was performed by PFGE and MLST. The CRAB faecal carriage rate at admission was 4.8% (3/63). The CRAB acquisition rate during ICU stay was analysed in 39 of the remaining 60 patients and the rate of acquired CRAB faecal carriage was 15.4% (6/39); 4 patients also showed an ICU-acquired CRAB infection (one patient was a faecal carrier and suffered infection). Overall, 13 CRAB isolates were collected from 12 patients, of which 11 isolates showed resistance to all antibiotics tested except colistin. blaOXA-23 and blaNDM-1 were detected in 11 and 2 isolates, respectively. All OXA-23-producing strains carried armA, tetB, sul1 and catB, and some of them carried aph(3')-VIa, blaTEM-1, aph(3')-Ia and ant(2'')-Ia. The blaNDM-1-positive isolates harboured aph(3')-VIa and catB. Three PFGE patterns and two STs were identified [ST195 (n = 11), ST1089 (n = 2, NDM-1-positive)]. Whether imported or acquired during ICU stay, CRAB colonisation is a major risk factor for the occurrence of serious nosocomial infection. Systematic screening of faecal carriage is mandatory to prevent their spread.

Management of carbapenem-resistant Acinetobacter baumannii epidemic in an intensive care unit using multifaceted intervention strategy.

Background/AimsWe evaluated the effects of a multifaceted intervention for controlling a carbapenem-resistant Acinetobacter baumannii (CRAB) epidemic in an intensive care unit (ICU) with no restrictions on carbapenem use.MethodsThis study was conducted in a medical ICU between April 2012 and June 2016. The baseline infection control programs included surveillance cultures, contact precautions, and environmental cleaning. However, increases in the detection of CRAB isolates beginning in May 2013 led to the implementation of a new protocol, consisting of universal glove and gown use with daily chlorhexidine bathing for all patients in combination with baseline programs. The efficacy of the intervention was subjected to interrupted time series (ITS) analysis.ResultsThe multifaceted intervention led to a decrease in the incidence of CRAB from 17.65 to 0.89 cases per 1,000 patient-days, during the study period (p < 0.001). ITS analysis revealed a significant change in the trend of CRAB incidence (–0.413, p < 0.001). Over this same period, mean monthly use of carbapenems increased from 143.54 ± 95.73 to 204.95 ± 78.43 doses per 1,000 patient-days (p = 0.018).ConclusionsOur multifaceted intervention reduced the incidence of CRAB acquisition in an ICU where carbapenem use was not restricted.

Active surveillance for carbapenem-resistant Acinetobacter baumannii in a medical intensive care unit: Can it predict and reduce subsequent infections and the use of colistin?

Infection caused by carbapenem-resistant Acinetobacter baumannii (CRAB) has become a major problem in intensive care units (ICUs), with high incidence and mortality. This prospective study investigated the diagnostic value and influence of active surveillance, followed by isolation and enhanced contact precaution (IECP), on the subsequent CRAB infection and colistin use. The study prospectively enrolled 1,115 patients who were admitted to the medical ICU of Chonnam National University Hwasun Hospital between April 2011 and November 2014. Active surveillance cultures were obtained from the throat or trachea, skin, and urine. IECP was performed beginning April 2013. Active surveillance detected CRAB in 168 (15%) patients and CRAB infection developed in 70 (6%) patients. Endotracheal tube was independently associated with both CRAB colonization and infection, whereas IECP was inversely associated with both CRAB colonization and infection in multivariate analysis (all P values <.001). The sensitivity, specificity, and positive and negative predictive values of active surveillance for subsequent CRAB infection were 84%, 90%, 47%, and 98%, respectively. The rate of CRAB acquisition, CRAB infection, and the use of colistin were significantly lower during the IECP period compared with the control period (6.5 vs 34.1, 2.6 vs 14.7, and 19.9 vs 65.5 per 1,000 patient-days, respectively; all P <.001). Active surveillance has good specificity and negative predictive value for subsequent CRAB infection. Active surveillance followed by IECP was inversely associated with the acquisition of CRAB and subsequent CRAB infection, and was associated with a reduction in colistin use in ICU patients.

Carbapenem-resistant Acinetobacter baumannii (CRAB) Recovered from Burn Patients.

Emergence of carbapenem-resistant Acinetobacter baumannii (CRAB) and their prolonged presence in burn units increases the risk of acquisition of CRAB.Methods. From November 2012 to September 2013, 1474 burn patients were screened for CRAB isolates through testing susceptibility to imipenem and its comparators meropenem, and doripenem. Furthermore, the in vitro activity of other antibiotics against CRAB was investigated. Results. Three patients were infected with carbapenem-susceptible A. baumannii (CSAB) and 168 were infected with CRAB. Approximately one-fifth (n=32) of CRAB isolates were obtained from patients hospitalized in Burn Intensive Care Unit (BICU). Most of CRABs were isolated from wound. The mean length of stay (LOS) in hospital prior to A. baumannii isolation was significantly higher for CRAB compared to CSAB cases (P=0.04). Amongst the independent variables, percentage of total burn surface area (TBSA) significantly increased the mortality rate using multivariate logistic regression (P=0.001, OR= 16.5; 95% CI: 4.72-57.7). The majority of tested isolates were resistant to imipenem (94.8%), and to its comparators, doripenem (97.7%), and meropenem (97.7%). The susceptibility of CRAB isolates was less than 10% to all tested antibiotics except for colistin (100%), doxycycline (61.9%), gentamicin (18.5%), and tigecycline (11.9%).Conclusion. Resistance to carbapenem reduces the number of effective antibiotics. The coordinated and intensive efforts of healthcare personnel are required to meet the challenge of dissemination of CRAB.

Carbapenem-resistant Acinetobacter baumannii acquired before liver transplantation: Impact on recipient outcomes.

Infection with carbapenem-resistant Acinetobacter baumannii (CRAB) after liver transplantation (LT) is associated with high mortality. This study aimed to identify risk factors for post-LT CRAB infection, as well as to evaluate the impact of pre-LT CRAB acquisition on the incidence of post-LT CRAB infection. This was a prospective cohort study of all patients undergoing LT at our facility between October 2009 and October 2011. Surveillance cultures (SCs) were collected immediately before LT and weekly thereafter, until discharge. We analyzed 196 patients who were submitted to 222 LTs. CRAB was identified in 105 (53.6%); 24 (22.9%) of these patients were found to have acquired CRAB before LT, and 85 (81.0%) tested positive on SCs. Post-LT CRAB infection occurred in 56 (28.6%), the most common site being the surgical wound. Multivariate analysis showed that the risk factors for developing CRAB infection were prolonged cold ischemia, post-LT dialysis, LT due to fulminant hepatitis, and pre-LT CRAB acquisition with pre-LT CRAB acquisition showing a considerable trend toward significance (P = 0.06). Among the recipients with CRAB infection, 60-day mortality was 46.4%, significantly higher than among those without (P < 0.001). Mortality risk factors were post-LT infection with multidrug-resistant bacteria, LT performed because of fulminant hepatitis, retransplantation, prolonged cold ischemia, longer LT surgical time, and pre-LT CRAB acquisition, the last showing a trend toward significance (P = 0.08). In conclusion, pre-LT CRAB acquisition appears to increase the risk of post-LT CRAB infection, which has a negative impact on recipient survival. Liver Transplantation 22 615-626 2016 AASLD.

Effect of daily chlorhexidine bathing on acquisition of carbapenem-resistant Acinetobacter baumannii (CRAB) in the medical intensive care unit with CRAB endemicity

There is insufficient evidence for daily chlorhexidine bathing to reduce nosocomial spread of carbapenem-resistant Acinetobacter baumannii (CRAB) in endemic situations. An interrupted time series study was performed to evaluate the effect of daily chlorhexidine bathing on the acquisition of CRAB in a medical intensive care unit (ICU) with CRAB endemicity. There was a 14-month control period and 12-month chlorhexidine bathing period. Segmented Poisson regression analysis was performed to assess the impact of chlorhexidine bathing on the level and trend of the series of prevalence rates and incidence density. Also, chlorhexidine susceptibility testing was performed on CRAB isolates collected during the chlorhexidine bathing period. There was a 51.8% reduction of CRAB acquisition rates after an introduction of daily chlorhexidine bathing (44.0 vs 21.2 cases/1,000 at-risk patient days, P<.001). There was a significant reduction in the level (-0.604; 95% CI,-0.904to-0.305; P<.001) of incidence density of CRAB, whereas there was no significant change in both level and trend of CRAB prevalence rates. Minimum inhibitory concentration of chlorhexidine against a total of 98 CRAB isolates ranged from 8-64 μg/mL. Daily chlorhexidine bathing significantly reduces the acquisition of CRAB in a medical ICU with CRAB endemicity.

Comparison between bacteremia caused by carbapenem resistant Acinetobacter baumannii and Acinetobacter nosocomialis

BackgroundIt is unknown whether there are differences between bacteremia caused by carbapenem resistant Acinetobacter baumannii (CRAB) and carbapenem resistant Acinetobacter nosocomialis (CRAN). This study aims to investigate the differences, especially in clinical outcomes, between patients with bacteremia caused by CRAB or CRAN.MethodsThis is a 9-year retrospective study comparing the clinical manifestations, antimicrobial susceptibilities, and clinical outcomes of 71 patients with CRAB bacteremia and 64 patients with CRAN bacteremia.ResultsPatients with CRAB were more likely to have hematologic malignancies and presented with more shock episodes than those with CRAN. CRAB isolates were more resistant to various classes of antimicrobials except colistin, and therefore the patients with CRAB bacteremia were more likely to receive inappropriate antimicrobial therapies. The 14-day mortality was significantly higher in patients with CRAB (40.8% vs. 14.1%; p = 0.001), and in this study, acquisition of CRAB was identified as an independent risk factor for mortality (odds ratio = 4.003; 95% confidence interval = 1.566-10.231; p = 0.004).ConclusionsCRAB and CRAN bacteremia are different in clinical characteristics, antimicrobial susceptibilities, and mortality rates. Genomic species identification should be performed in the study of carbapenem resistant Acinetobacters to better delineate the role of different species.

Risk factors and clinical outcomes of patients with carbapenem-resistant Acinetobacter baumannii bacteremia

It is still controversial whether carbapenem-resistant Acinetobacter baumannii (CRAB) is an independent risk factor for mortality. This study aimed to determine the risk factors and outcomes of patients with CRAB bacteremia, compared to those with carbapenem-susceptible A. baumannii (CSAB) bacteremia. This retrospective cohort study was conducted in Taipei Veterans General Hospital, Taiwan. Patients with bacteremia due to A. baumannii during June 2002 and December 2007 were included. A total of 62 patients with CRAB and 164 with CSAB bacteremia were included. Among these patients, the independent risk factors for acquiring CRAB bacteremia were hematological malignancy [odds ratio (OR): 4.04; 95% confidence interval (CI): 1.29-12.70; p=0.017], previous use of cefepime (OR: 2.60; 95% CI 1.11-6.08; p=0.028) and use of totalparenteral nutrition (OR: 3.06; 95% CI 1.12-8.39; p=0.029). The patients with CRAB bacteremia had higher mortality rate than those with CSAB bacteremia. However, multivariate analysis showed that among patients with A. baumannii bacteremia, acquisition of CRAB by itself was not an independent risk factor for 14-day mortality. Instead, the independent factors predicting14-day mortality were Acute Physiology and Chronic Health Evaluation (APACHE) score>20 (OR: 6.33; 95% CI: 2.32-17.26; p<0.001), shock (OR: 2.68; 95% CI: 1.11-6.23; p=0.025) and inappropriate antimicrobial therapy (OR: 2.14; 95% CI: 1.01-4.53; p=0.046). Risk factors for CRAB bacteremia were hematological malignancies, previous use of cefepime and use of total parenteral nutrition. Acquisition of CRAB itself is not a poor prognostic factor for the patients with A. baumannii bacteremia.

Carbapenem-resistant Acinetobacter baumannii in intensive care unit patients: risk factors for acquisition, infection and their consequences

A retrospective case-control study was performed to assess risk factors and the clinical and economic consequences associated with acquisition of carbapenem-resistant Acinetobacter baumannii (CR-AB) in an intensive care unit (ICU) over a 24-month period. CR-AB was acquired by 64 of 1431 ICU admissions; each was matched with two controls. Risk factors associated with CR-AB acquisition included ICU-wide variables, such as 'colonization pressure' (the prevalence of ICU colonized patients) and ICU antibiotic use over the preceding three months, as well as patient-related variables. Among colonized patients, risk factors for CR-AB infection included transfusion and 'colonization density' (the proportion of body sites colonized with CR-AB). CR-AB infection was independently associated with increased hospital mortality [mortality difference: 20%; 95% confidence interval (CI): 1-40%], prolonged ICU stay (median length of stay difference: 15 days; 95% CI: 9-21 days) and prolonged hospital stay (30 days, 11-38 days) compared with matched controls.