Antimicrobial resistance in Gram-negative bacteria has become a critical global health concern. The most alarming pathogens include Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae, which are major drivers of increasing resistance worldwide. Gram-negative bacteria, characterized by an outer membrane containing lipopolysaccharides, also include opportunistic pathogens such as Escherichia coli, which can cause severe infections in vulnerable patients. Infections caused by resistant organisms are associated with prolonged hospitalization, higher mortality rates, and substantial healthcare costs.

Traditional susceptibility testing remains valuable for guiding therapy; however, these methods are slow and limited, as they do not provide insight into the molecular mechanisms of resistance. Molecular approaches address this gap by enabling the detection of resistance determinants, tracking bacterial evolution, and informing the development of targeted interventions.

Multidrug-resistant (MDR) Gram-negative bacteria, particularlyA. baumannii,P. aeruginosa,K. pneumoniae, andE. coli, are highly prevalent; however, their molecular epidemiology remains insufficiently explored. This project aims to investigate clinical isolates, including theA. baumanniicomplex, P. aeruginosa,K. pneumoniaespecies,E. coli, and Serratia marcescens, in order to determine their susceptibility patterns, resistance mechanisms, and epidemiological characteristics. The outcomes of this study will provide critical insights to inform infection control strategies and help mitigate the clinical and economic burden of drug-resistant Gram-negative bacteria in Saudi Arabia.