Molecular epidemiology of carbapenemase encoding genes in A. baumannii-calcoaceticus complex infections in children: a systematic review

Background Acinetobacter baumannii-calcoaeticus complex is the leader pathogen for the World Health Organization's list due to the escalating prevalence of multidrug-resistant strains. Insights into the molecular characterization of carbapenemase genes in A. baumannii-calcoaceticus complex infections among children are scarce. To address this gap, we conducted a systematic review to describe the molecular epidemiology of the carbapenemase genes in A. baumannii-calcoaceticus complex infections in the pediatric population.Methods Adhering to the PRISMA 2020 guidelines for reporting systematic reviews, we conducted a review of in chore bibliographic databases published in English and Spanish, between January 2020 and December 2022. All studies conducted in patients <= 6 years with molecular characterization of carbapenemase-encoding genes in A. baumannii-calcoaceticus infections were included.Results In total, 1129 cases were reviewed, with an overall carbapenem-resistance rate of 60.3%. A. baumannii-calcoaceticus was isolated from blood cultures in 66.6% of cases. Regionally, the Eastern Mediterranean exhibited the highest prevalence of carbapenem resistance (88.3%). Regarding the carbapenemase genes, blaKPC displayed an overall prevalence of 1.2%, while class B blaNDM had a prevalence of 10.9%. Class D blaOXA-23-like reported a prevalence of 64%, blaOXA-48 and blaOXA-40 had a prevalence of 33% and 18.1%, respectively. Notably, the Americas region showed a prevalence of blaOXA-23-like at 91.6%.Conclusion Our work highlights the high prevalence of carbapenem-resistant A. baumannii-calcoaceticus and class D carbapenemase genes in children. Of note the distribution of different carbapenemase genes reveals considerable variations across WHO regions. To enhance epidemiological understanding, further extensive studies in children are imperative.