Active screening cultures to reduce infections caused by carbapenem-resistant Acinetobacter baumannii: a systematic review and meta-analysis

Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) has emerged as a significant healthcare-associated infection carrying substantial mortality. We aimed to assess the clinical impact of active screening cultures for CRAB. Methods: A systematic review and meta-analysis, aiming to answer two questions: 1. Does screening vs no screening improve clinical outcomes? 2. Does positive screening ("CRAB carrier") predict CRAB infections? We searched MEDLINE, Cochrane library, Web of Science, and conferences, until January 2024, comparative studies reporting clinical outcomes (mortality, invasive CRAB infections). Results: Of 5,407 screened publications, 9 studies (10,865 individuals) were included for study question #2. Invasive CRAB infection rate was significantly higher among CRAB carriers (odds ratio [OR] 11.14, 95% confidence interval [CI] 4.95-25.05, with substantial heterogeneity stemming from size rather than direction of the effect). Negative predictive value (NPV) of non-carriage for invasive infection was 97%. CRAB bloodstream infections rate was significantly higher among carriers (OR 16.23, 95% CI 2.9-110.08). No significant difference was demonstrated between the two groups CRAB ventilator-associated pneumonia, length of stay, and mortality. Only one study reported outcomes for the screening vs no screening (study question #1). Conclusions: Data to support active CRAB screening are scarce regarding its clinical benefit for patients. Positively screened patients are at significantly higher risk for invasive CRAB infections, with high NPV for non-carriage. This did not translate to reduced mortality.