Analysis of clinical characteristics and whole-genome sequencing of carbapenem-resistant Acinetobacter baumannii isolates from pediatric patients in Guangxi, China

Carbapenem-resistant Acinetobacter baumannii (CRAB) is an urgent global threat and has been designated as a priority pathogen. We conducted a retrospective study of pediatric patients with CRAB infection at a Maternal and Child Health Hospital in Guangxi, China, from January 2019 to December 2024. The bacterial isolates were then subjected to antimicrobial susceptibility testing (AST) and whole-genome sequencing (WGS). A total of 132 pediatric patients with CRAB infections were included in this study (83 with positive outcomes and 49 with negative outcomes). AST revealed that all CRAB isolates were multidrug-resistant (MDR). Polymyxin B (99.2% susceptible), minocycline (68.9%), and cefoperazone-sulbactam (65.2%) demonstrated the highest susceptibility rates among the antibiotics tested. WGS revealed that the most prevalent strain was ST2Pasteur/ST208Oxford - KL2(65.9%), harboring the OXA-23 carbapenemase. Furthermore, the genetically distinct ST1208Oxford-KL24 (22.0%), characterized by NDM-1 carriage, is the second most common sequence type and an emerging cause of pediatric hospital infections. A diverse array of antimicrobial resistance (AMR) genes, plasmid replicons, and virulence genes was detected across the isolates. Notably, the overall genetic profile of ST1208Oxford was similar to that of ST150Pasteur/ST718Oxford, but distinct from that of ST2Pasteur. Multivariable logistic regression identified prior hospitalizations (OR = 3.236; P = 0.015), presence of a central venous catheter (CVC) (OR = 2.683; P = 0.028), and decreased platelet count (OR = 0.996; P = 0.005) as independent risk factors for negative outcomes in pediatric patients with CRAB infections. This study details the clinical and molecular features of CRAB infections in pediatric patients in Guangxi, China. Pediatric infection control should be highly alert to the emergence of ST1208Oxford CRAB, which produces the NDM-1 carbapenemase.