Introduction: Antimicrobial resistance is a critical concern, especially in immunocompromised cancer patients, where multidrug-resistant (MDR) and extensively drug-resistant (XDR) infections limit treatment options. This study investigates the resistance profiles of Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli isolated from cancer patients at a tertiary hospital.
Methods: Clinical isolates from urine, blood, and sputum samples were collected from a tertiary hospital in Abu Dhabi. Antibiotic susceptibility testing was conducted using the disc diffusion method according to CLSI guidelines. Isolates were classified as CRE, MDR, or XDR based on resistance profiles. Genomic DNA was extracted using the Promega Kit, and whole-genome sequencing was performed on the Illumina platform. Resistance genes were identified using ResFinder, and plasmid incompatibility types were determined with PlasmidFinder. The genetic context of resistance genes, including IS elements and transposons, was assessed using ISfinder. Data analysis focused on resistance profiles, plasmid types, and potential clonal transmission.
Results: A total of six P. aeruginosa, three K. pneumoniae, three E. coli, and additional isolates of Aeromonas dhakensis, Salmonella enterica, and Stenotrophomonas maltophilia were analyzed. P. aeruginosa isolates exhibited widespread resistance, including blaNDM-1 (carbapenem resistance), aph(3')-IIb (aminoglycoside resistance), and tet(A) (tetracycline resistance). K. pneumoniae isolates carried blaOXA-181 and blaCTX-M-15. E. coli strains harbored blaNDM-5 and blaCTX-M-15, along with aminoglycoside and fluoroquinolone resistance genes, with blaNDM-5 located on plasmids (MGEs) together with other resistance genes, facilitating their spread. Additional isolates included Aeromonas dhakensis from a leukemia patient, Salmonella enterica with IncFIB/IncFII plasmids from a breast cancer patient, and MDR Stenotrophomonas maltophilia from a cervical cancer patient.
Conclusion: This study highlights the prevalence of MDR and XDR pathogens in cancer patients and the significance of plasmid-mediated gene transfer in resistance. Improved infection control and novel therapeutic strategies are critical to addressing these complex resistance mechanisms.