Phenotypic, PCR, and whole-genome sequencing characterization of carbapenem-resistant Acinetobacter baumannii in Makkah and Riyadh, Saudi Arabia: AST discordance and local genomic micro-clusters

BackgroundCarbapenem-resistant Acinetobacter baumannii (CRAB) is a World Health Organization (WHO) critical-priority pathogen, yet hospitals need practical workflows that link rapid rule-in testing, definitive minimum inhibitory concentration (MIC) confirmation, and actionable genomic thresholds for outbreak response. Integrated phenotype–polymerase chain reaction (PCR)–whole-genome sequencing (WGS) characterization studies with decision-ready performance metrics remain limited for settings in S