Carbapenem-resistant Acinetobacter Baumannii Colonization Research Articles

Risk factors for infection after carbapenem-resistant Acinetobacter baumannii colonization.

Predicting infection risk in carbapenem-resistant Acinetobacter baumannii (CRAB) colonized patients may help in improving timely appropriate antibiotic therapy. This study aims to explore risk factors for developing infections in hospitalized patients with previous CRAB colonization. We performed an observational retrospective cohort study at ASST Sette Laghi-Varese Hospital between January 2020 and December 2022. All consecutive adult (> 18 years old) hospitalized patients with documented colonization by CRAB at any anatomical site or with CRAB infections preceded by CRAB colonization were included. Univariate and multivariate analyses were performed to investigate infection risk factors. Overall, 144 patients were included in the study: 104 colonized only and 40 infected patients. Colonization and infection rates significantly changed over the years (2020-2022, p < 0.001). The incidence of infections in CRAB carriers was 27.8% (40/144). Median time from colonization to infection was 4 days (IQR 1-8.5). Overall, inhospital mortality was 32.7% and 55.0% in colonized only and infected patients, respectively. At the multivariable logistic regression cardiovascular disease (OR 5.83, 95% CI 1.12-30.43, p = 0.037), COVID-19 (OR 3.72, 95% CI 1.16-11.91, p = 0.027) and intensive care unit (ICU) admission (OR 8.83, 95% CI 2.94-26.51, p < 0.001) were risk factors independently associated with cardiovascular disease CRAB infection after colonization. We observed an increased infection risk in patients colonized with CRAB with cardiovascular disease, COVID-19 and admitted in ICU setting. Additional evidence is needed to identify predictors of infection in colonized patients.

Air dispersal of multi-drug-resistant organisms including meticillin-resistant Staphylococcus aureus, carbapenem-resistant Acinetobacter baumannii and carbapenemase-producing Enterobacterales in general wards: surveillance culture of air grilles

The environmental surveillance of air grilles in clinical areas has not been systematically analysed. Samples were collected from frequently touched items (N= 529), air supply (N= 295) and exhaust (N= 184) grilles in six medical and 11 surgical wards for the cultures of multi-drug-resistant organisms (MDROs): meticillin-resistant Staphylococcus aureus (MRSA), carbapenem-resistant Acinetobacter baumannii (CRAB) and carbapenemase-producing Enterobacterales (CPE), and isolates were selected for whole-genome sequencing (WGS). The contamination rates were correlated with the colonization pressures of the respective MDROs. From 3rd October to 21st November 2023, 9.8% (99/1008) of the samples tested positive, with MRSA (24.2%, 24/99), CRAB (59.6%, 59/99) and CPE (2.0%, 2/99), being the only detected MDROs. The contamination rate in air exhaust grilles (26.6%, 49/184) was significantly higher than in air supply grilles (5.8%, 17/295; P<0.001). The contamination rate of air exhaust grilles with any MDRO in acute medical wards (73.7%, 14/19) was significantly higher than in surgical wards (12.5%, 4/32; P<0.001). However, there was no difference in the contamination rate of air exhaust grilles between those located inside and outside the cohort cubicles for MDROs (27.1%, 13/48 vs 28.8%, 30/104; P=0.823). Nevertheless, the weekly CRAB colonization pressure showed a significant correlation with the overall environmental contamination rate (r= 0.878; 95% confidence interval (CI): 0.136-0.986; P=0.004), as well as with the contamination rate in air supply grilles (r= 0.960; 95% CI: 0.375-0.999; P<0.001) and air exhaust grilles (r= 0.850; 95% CI: 0.401-0.980; P=0.008). WGS demonstrated clonal relatedness of isolates collected from patients and air exhaust grilles. Air grilles may serve as MDRO reservoirs. Cohort nursing in open cubicles may not completely prevent MDRO transmission through air dispersal, prompting the consideration of future hospital design.

Epidemiology of carbapenem-resistant Acinetobacter baumannii colonization in neonatal intensive care units: A systematic review and meta-analysis

BACKGROUND The rising prevalence of carbapenem-resistant Acinetobacter baumannii (CRAB) in neonatal intensive care units (NICUs) represents an escalating challenge in healthcare settings, particularly in managing hospital-acquired infections (HAIs). Studies across various World Health Organization regions have documented a significant incidence of CRAB-related HAIs, with rates as high as 41.7 cases per 1000 patients in ICUs, accounting for 13.6% of all HAIs. These infections pose a doubled mortality risk compared to infections with carbapenem-susceptible Acinetobacter baumannii . A particularly concerning aspect of CRAB colonization is its asymptomatic nature, enabling its transmission through healthcare workers (HCWs) or the NICU environment to vulnerable neonates with developing immune systems. AIM To explore the prevalence of CRAB colonization in NICUs, focusing on neonates, healthcare workers, and the environmental samples, to enhance epidemiological understanding and inform targeted interventions. METHODS We conducted according to PRISMA 2020 checklist guidelines, a comprehensive literature search across multiple databases including MEDLINE (Ovid), EMBASE (Ovid), Global Health (Ovid), Web of Science, and Global Index Medicus. Studies were selected based on predetermined criteria, primarily involving neonates, HCWs, and environmental swabs, using culture or molecular methods to detect CRAB colonization. We excluded studies that did not specifically focus on NICUs, were duplicates, or lacked necessary data. The study selection and quality assessment were conducted independently by two reviewers. Data extraction involved collecting comprehensive details about each study. Our statistical analysis used a random-effects model to calculate the pooled prevalence and confidence intervals, stratifying results by regional location. We assessed study heterogeneity using Cochran's Q statistic and I ² statistic, with regression tests employed to evaluate potential publication bias. RESULTS We analyzed 737 records from five databases, ultimately including 13 studies from ten countries. For neonates, the pooled prevalence was 4.8% (95%CI: 1.1% to 10.5%) with the highest rates observed in South-East Asia (10.5%; 95%CI: 2.4% to 23.3%). Among HCWs, a single Indian study reported a 3.3% prevalence. Environmental samples showed a prevalence of 2.3% (95%CI: 0% to 9.3%), with the highest rates in South-East Asia (10%; 95%CI: 4.2% to 17.7%). Significant heterogeneity was found across studies, and no publication bias was detected. CONCLUSION This systematic review highlights a significant prevalence of CRAB colonization in neonates across various regions, particularly in South-East Asia, contrasting with lower rates in high-income countries. The study reveals a gap in research on HCWs colonization, with only a single study from India reporting moderate prevalence. Environmental samples indicate moderate levels of CRAB contamination, again higher in South-East Asia. These findings underscore the need for more extensive and focused research on CRAB colonization in NICUs, including exploring the roles of HCWs and the environment in transmission, understanding antimicrobial resistance patterns, and developing effective prevention measures.

Risk factors for carbapenem-resistant Acinetobacter baumannii (CRAB) bloodstream infections and related mortality in critically ill patients with CRAB colonization.

Among MDR bacteria, carbapenem-resistant Acinetobacter baumannii (CRAB) is a major concern due to the limited therapeutic options. During the COVID-19 pandemic, a worrying increase in the spread of CRAB infections was reported. The study assessed the risk factors for CRAB bloodstream infection (BSI) in patients admitted to the ICU with CRAB colonization, and the related mortality risk factors. We conducted a single-centre, observational, prospective study; all consecutive patients with CRAB colonization admitted to the ICU of a tertiary hospital in Rome from January 2021 to September 2022 were included in the study. Univariate and multivariate analyses were performed to investigate BSI and mortality risk factors. Overall, 129 patients were included in the study; 57 (44%) out of these developed BSI. In our study population, at the multivariable analysis the Charlson comorbidity index (CCI) (P = 0.026), COVID-19 (P < 0.001), multisite colonization (P = 0.016) and the need for mechanical ventilation (P = 0.024) were risk factors independently associated with BSI development. Furthermore, age (P = 0.026), CCI (P < 0.001), septic shock (P = 0.001) and Pitt score (P < 0.001) were independently associated with mortality in the BSI patients. Instead, early appropriate therapy (P = 0.002) and clinical improvement within 72 h (P = 0.011) were shown to be protective factors. In critically ill patients colonized by CRAB, higher CCI, multisite colonization and the need for mechanical ventilation were identified as risk factors for BSI onset. These predictors could be useful to identify patients at highest risk of BSI.

Assessment of carbapenem-resistant Acinetobacter baumannii–colonized patients: Which specimens produce the highest yield?

Background: Carbapenem-resistant Acinetobacter (CRA) bacteria are an urgent public health threat. Accurate and timely testing of CRA is important for proper infection control practices to minimize spread. In 2017, the CDC estimated 8,500 CRA cases among hospitalized patients, 700 deaths, and $281 million in attributable healthcare costs. Treatment options are extremely limited for carbapenem-resistant Acinetobacter baumannii (CRAB) infections, making CRAB a unique concern. Colonization screening is a valuable tool for containment but requires sampling of 4 body sites. Identifying a reliable specimen collection site for CRAB is important to inform public health recommendations as screening can cost healthcare facilities valuable time and resources. Methods: Results of all screening specimens of patients with at least 1 site positive for CRAB on a unique collection date were extracted from the Southeast Regional data of Antimicrobial Resistance Lab Network (SEARLN) data. Non-CRAB screening and screenings that did not yield at least 1 positive result on a single collection date were excluded. We also limited our data to include only the following screening sites, which have been validated by the Tennessee Department of Health’s State Public Health Laboratory: axilla and groin, rectal, sputum, and wound. For each specimen source, we calculated the percentage of positive specimen among CRAB-colonized patients. Data were extracted and analyzed using SAS version 9.4 software. Results: The SEARLN data contained 594 CRAB screening specimens collected over 4 years, 2018 through 2021, and 486 of those specimens yielded CRAB. For CRAB-colonized patients screened in this study, wound specimens had the highest positivity rate at 93.4% (95% CI, 89.9%–96.9%) of samples culturing CRAB. Sputum followed at 87.7%, then axilla and groin at 77.6% and rectal at 59.7%. Conclusions: Wound specimens produced the highest proportion of positive cultures among CRAB-positive patients, making them the sample type with the highest prevalence in our study. For healthcare facilities with limited time and resources seeking to optimize their CRAB screening process, wound specimens may be the most reliable single site for detecting CRAB colonization in patients with an open wound. When a wound is not present, sputum may be a good alternative single-source collection site. More research should be conducted before CRAB screening recommendations are updated.Disclosures: None

Carbapenem-resistant Acinetobacter baumannii: A challenge in the intensive care unit.

Carbapenem-resistant Acinetobacter baumannii (CRAB) has become one of the leading causes of healthcare-associated infections globally, particularly in intensive care units (ICUs). Cross-transmission of microorganisms between patients and the hospital environment may play a crucial role in ICU-acquired CRAB colonization and infection. The control and treatment of CRAB infection in ICUs have been recognized as a global challenge because of its multiple-drug resistance. The main concern is that CRAB infections can be disastrous for ICU patients if currently existing limited therapeutic alternatives fail in the future. Therefore, the colonization, infection, transmission, and resistance mechanisms of CRAB in ICUs need to be systematically studied. To provide a basis for prevention and control countermeasures for CRAB infection in ICUs, we present an overview of research on CRAB in ICUs, summarize clinical infections and environmental reservoirs, discuss the drug resistance mechanism and homology of CRAB in ICUs, and evaluate contemporary treatment and control strategies.

Gastrointestinal Colonization of Carbapenem-Resistant Acinetobacter baumannii: What Is the Implication for Infection Control?

The epidemiology of patients with gastrointestinal colonization of carbapenem-resistant Acinetobacter baumannii (CRAB) has not been systematically analyzed. We aimed to analyze the incidence, risk factors, and clinical outcomes of patients with newly identified gastrointestinal colonization of CRAB in a healthcare region in Hong Kong, where a multi-pronged screening strategy for gastrointestinal colonization of CRAB, together with other multidrug-resistant organisms (MDROs), was conducted by collecting fecal specimens (rectal swab or stool) upon admission and during hospitalization. From 1 October 2015 to 31 December 2019, a total of 161,339 fecal specimens from 63,588 patients, 61,856 (97.3%) of whom were hospitalized patients, and 54,525 (88.1%) were screened upon admission, with 1309 positive for CRAB (2.4% prevalence). Among patients positive for CRAB in fecal specimens, 698 (53.3%) had newly detected gastrointestinal colonization of CRAB, giving an incidence of 10.03 per 10,000 patient admissions and constituting 2646 CRAB colonization days in the general wards. Excluding the 164 patients with co-colonization of other MDROs, 534 patients had gastrointestinal colonization with only CRAB, and 12.5% (67/534) developed symptomatic CRAB infections at a median of 61 days (range: 2 to 671 days), during prospective follow-up for 2 years. Compared with age- and sex-matched controls, patients being referred from residential care homes for the elderly, the presence of indwelling devices, use of beta-lactam/beta-lactamase inhibitors, carbapenems, and proton pump inhibitors in the preceding 6 months, and history of hospitalization in the past 6 months were significantly associated with gastrointestinal colonization with CRAB, as shown by multivariable analysis. Log-rank test showed that cases had significantly shorter survival duration than controls (p < 0.001). The adjusted hazard ratio of gastrointestinal colonization of CRAB was 1.8 (95% CI: 1.5–2.2; p < 0.001), as shown by Cox regression analysis. Whole-genome sequencing of eight patients with CRAB isolates in their blood cultures and rectal swabs during the same episode of hospitalization revealed ST-195 as the predominant type, as shown by multilocus sequencing type. Gastrointestinal colonization of CRAB poses a considerable challenge for infection prevention and control.

The Burden of Carbapenem-Resistant Acinetobacter baumannii in ICU COVID-19 Patients: A Regional Experience.

Since the beginning of the COVID-19 pandemic, the impact of superinfections in intensive care units (ICUs) has progressively increased, especially carbapenem-resistant Acinetobacter baumannii (CR-Ab). This observational, multicenter, retrospective study was designed to investigate the characteristics of COVID-19 ICU patients developing CR-Ab colonization/infection during an ICU stay and evaluate mortality risk factors in a regional ICU network. A total of 913 COVID-19 patients were admitted to the participating ICUs; 19% became positive for CR-Ab, either colonization or infection (n = 176). The ICU mortality rate in CR-Ab patients was 64.7%. On average, patients developed colonization or infection within 10 ± 8.4 days from ICU admission. Scores of SAPS II and SOFA were significantly higher in the deceased patients (43.8 ± 13.5, p = 0.006 and 9.5 ± 3.6, p < 0.001, respectively). The mortality rate was significantly higher in patients with extracorporeal membrane oxygenation (12; 7%, p = 0.03), septic shock (61; 35%, p < 0.001), and in elders (66 ± 10, p < 0.001). Among the 176 patients, 129 (73%) had invasive infection with CR-Ab: 105 (60.7%) Ventilator-Associated Pneumonia (VAP), and 46 (26.6%) Bloodstream Infections (BSIs). In 22 cases (6.5%), VAP was associated with concomitant BSI. Colonization was reported in 165 patients (93.7%). Mortality was significantly higher in patients with VAP (p = 0.009). Colonized patients who did not develop invasive infections had a higher survival rate (p < 0.001). Being colonized by CR-Ab was associated with a higher risk of developing invasive infections (p < 0.001). In a multivariate analysis, risk factors significantly associated with mortality were age (OR = 1.070; 95% CI (1.028–1.115) p = 0.001) and CR-Ab colonization (OR = 5.463 IC95% 1.572–18.988, p = 0.008). Constant infection-control measures are necessary to stop the spread of A. baumannii in the hospital environment, especially at this time of the SARS-CoV-2 pandemic, with active surveillance cultures and the efficient performance of a multidisciplinary team.

Risk factors for nosocomial rectal colonization with carbapenem-resistant Acinetobacter baumannii in hospital: a matched case\u2013control study

BackgroundDuring the last decade carbapenem-resistant Acinetobacter baumannii (CRAB) became hyper-endemic in hospitals due to difficult to control spreading. Our aim is to identify risk factors for nosocomial rectal CRAB colonization in an endemic hospital.MethodsA retrospective matched case–control study (ratio 1:2) with a prospective inclusion of cases and concurrent selection of controls was conducted from January 2017 to December 2018 in a tertiary-care hospital. Universal active surveillance for CRAB was implemented. Univariate and multivariate logistic regression was carried out using a stepwise selection method to compare prognostic factors between cases and controls. A sub-analysis was carried out according to the type of department.ResultsForty-five cases with nosocomial rectal CRAB colonization and 90 controls were included. One hundred and two (75%) patients were hospitalized in medical departments. At multivariable analysis significant risk factors associated with CRAB colonization were: use of permanent devices (OR 10.15, 95% CI 2.27–45.39; P = 0.002), mechanical ventilation (OR 40.01, 95% CI 4.05–395.1; P = 0.002), urinary catheters (OR 4.9, 95% CI 1.52–16.19; P = 0.008), McCabe score (OR 5.45, 95% CI 1.87–15.89; P = 0.002), length of stay (OR 1.03, 95% CI 1.01–1.05; P = 0.002), carbapenem use (OR 5.39, 95% CI 1.14–25.44; P = 0.033). The sub-analysis showed that patients admitted to different departments had different risk factors. In geriatric department a fatal disease and a longer hospital stay represented significant risk factors both in univariate and multivariate analysis, while in internal medicine department the use of permanent devices, current antibiotic therapy and antibiotic polytherapy represented significant risk factors for CRAB at the univariate analysis, also confirmed in multivariate analysis.ConclusionsOur data suggest that active surveillance for rectal CRAB colonization should be addressed to patients with an unfavourable prognosis, longer hospitalizations and carriers of multiple devices. To counter CRAB spreading in endemic settings, clinicians must limit the use of carbapenems, and reinforce interventions aimed at proper use of devices.

Intervention to reduce carbapenem-resistant Acinetobacter baumannii in a neonatal intensive care unit.

To investigate the effects of environmental cleaning and the installation of heat and moisture exchangers (HMEs) to reduce neonatal carbapenem-resistant Acinetobacter baumannii (CRAB) sepsis and colonization as well as antimicrobial use. We conducted a 7-year, quasi-experimental study. All neonates admitted to a neonatal intensive care unit (NICU). We compared the trends for CRAB sepsis and colonization before (period 1, 2011-2013) and after (period 3, 2015-2017) a 12-month intervention period in 2014 (period 2) to incorporate a combination of HME use and sodium hypochlorite cleaning (5,000 ppm in the NICU and 500 ppm in the neonatal environment) using interrupted time series analysis with segmented regression. During the 7-year study period, 3,367 neonates were admitted to the NICU; the prevalence rates of CRAB sepsis and endotracheal CRAB colonization were 0.5 per 1,000 patient days, and 19.4 per 1,000 ventilator days. A comparison of period 1 to period 3 showed significant decreases in the percentages of both CRAB of A. baumannii sepsis (100% versus 11%) and endotracheal colonization (76% vs 52%) following the introduction of disposable HMEs and sodium hypochlorite cleaning (both P < .001). In period 3, compared with period 1, segmented regression analysis showed significant reductions in endotracheal CRAB colonization per 1,000 ventilator days (ie, change in level) and both carbapenem and colistin use (changes in both level and slope) (P < .001). Interventions featuring environmental cleaning and use of HMEs led to a sustainable reduction of CRAB colonization coupled with a reduction in broad-spectrum antimicrobial use in the NICU.

Surveillance culture for multidrug-resistant gram-negative bacteria: Performance in liver transplant recipients.

The prevalence of infection with multidrug-resistant gram-negative bacteria (MDR-GNB) after solid-organ transplantation is increasing. Surveillance culture (SC) seems to be an important tool for MDR-GNB control. The goal of this study was to analyze the performance of SC for MDR-GNB among liver transplant (LT) recipients. This was a prospective cohort study involving patients who underwent LT between November 2009 and November 2011. We screened patients for extended spectrum β-lactamase-producing Escherichia coli, extended spectrum β-lactamase-producing Klebsiella pneumoniae, and carbapenem-resistant Enterobacteriaceae, carbapenem-resistant Pseudomonas aeruginosa (CRPA), and carbapenem-resistant Acinetobacter baumannii (CRAB). We collected SC samples immediately before LT and weekly thereafter, until hospital discharge. Samples were collected from the inguinal-rectal area, axilla, and throat. The performance of SC was evaluated through analysis of its sensitivity, negative predictive value, and accuracy. During the study period, 181 patients were evaluated and 4,110 SC samples were collected. The GNB most often identified was CRAB, in 45.9% of patients, followed by CRKP in 40.3%. For all microorganisms, the positivity rate was highest among the inguinal-rectal samples. If only samples collected from this area were considered, the SC would fail to identify 34.9% of the cases of CRAB colonization. The sensitivity of SC for CRKP was 92.5%. The performance of SC was poorest for CRAB (sensitivity, 80.6%). Our data indicate that SC is a sensitive tool to identify LT recipients colonized by MDR-GNB.

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.