Abstract
Background/Objectives: The World Health Organization has recognized Pseudomonas aeruginosa as a multidrug-resistant bacterium that presents public health concerns. This study aimed to evaluate the prevalence of MDR P. aeruginosa isolates along with their susceptibility profiles and determine the genetic basis of resistance. Methods: A total of 100 P. aeruginosa isolates were cultured on MacConkey agar with various specimens from patients admitted to ICUs and wards. Species identification was performed for each isolate using the VITEK(®) 2 system. Each isolate was tested for susceptibility to specific antibiotics by the broth microdilution method. The resistance genes were detected by molecular methods, i.e., PCR and Sangar sequencing. Results: Among the 100 P. aeruginosa isolates tested phenotypically, 33 MDR P. aeruginosa isolates were detected. The aminoglycoside group of antibiotics showed the least resistance against P. aeruginosa, with increasing resistance to carbapenems and ciprofloxacin. The most prevalent detected genes responsible for resistance were blaVEB, blaVIM, aac (6')-Ib, and qnr S. DNA sequencing results for the MDR isolates showed that 14 isolates had Thr-83> Ile mutation in gyrA, and 12 isolates had Ser-87>Leu mutation in parC genes. Conclusions: We conclude that the low rates of resistance to certain antibiotics, such as amikacin and piperacillin-tazobactam, seem encouraging to be effective for the treatment of Pseudomonas infections. Furthermore, the prominent mechanisms of resistance to fluoroquinolones in clinical strains of P. aeruginosa include mutations in gyrA and parC genes. These findings highlight the necessity of molecular diagnostics in guiding therapy and the potential need for broader surveillance.