Effectiveness of Colistin in carbapenem resistant Acinetobacter baumannii – A systematic review

Treatment of carbapenem-resistant Acinetobacter baumannii (CRAb) infections has become a significant challenge for physicians due to its resistance to common antibiotics. Colistin, previously banned, has been reintroduced despite debates about its effectiveness and safety. We aimed to synthesize evidence on the effectiveness of Colistin in the CRAb infection management, based on current literature. We conducted a comprehensive search to identify relevant studies on the effectiveness of Colistin in treating CRAb infection in major databases such as Medline through PubMed, Embase, Web of Science, The Cochrane Library, and Scopus. We did not limit the search by age of participants, sex, region, or year of publication, but we only included randomized controlled trials (RCTs), quasi-experimental studies, cohort studies, case-control studies, and cross-sectional studies published in English, which had at least one comparison control group. Two independent authors screened articles, extracted data, and assessed the risk of bias in selected articles using the RoBANS tool. Our search retrieved 7907 articles, of which five were included after the sequential screening. All five studies were retrospective case-control studies from five different countries, with a total of 776 participants. Two studies showed a lower mortality rate in the intervention (Colistin) group as the primary outcome, whereas two studies showed the opposite mortality trend. One study reported a higher rate of infection remission in the intervention group, but the result was not statistically significant. Our systematic review could not find any robust evidence to support the effectiveness of Colistin over commonly used antibiotics. Due to the large discrepancy among the primary outcomes of the included studies, we recommend further randomized controlled trials with a larger number of participants to determine the suitability of Colistin for treating CRAb infections.