Antimicrobial Resistance Patterns and Phenotypic Profiles of Pseudomonas aeruginosa Is­­­olated from Clinical Samples

Open Access

Abstract

Background: Pseudomonas aeruginosa is a significant concern among hospital-acquired pathogens, due to the growing resistance to antibiotics, particularly colistin and carbapenems. The goal of this study was to determine the resistances and phenotypes of P. aeruginosa strains obtained from clinical samples. Methods & Materials: This cross-sectional study, conducted at the Department of Microbiology, Dhaka Medical College in 2019, analyzed 350 clinical samples using standard microbiological and molecular techniques to identify Pseudomonas aeruginosa and assess antimicrobial resistance. Susceptibility testing was performed via disc diffusion and MIC methods, with PCR used to detect resistance genes. In vivo efficacy of various antibiotic regimens was evaluated in mice models. Data were analyzed using SPSS version 26. Results: Among 236 bacterial isolates, P. aeruginosa was found to constitute 26.69% (n=63), mostly from wound swabs (66.67%). High levels of resistance were found to ceftriaxone (82.54%), ceftazidime (74.60%), and amikacin (74.60%). The incidence of multi-drug resistance was found to be 61.90%, of which 19.05% had extensive drug resistance, while 6.35% had pan-resistance. The overall colistin resistance was found to be 19.05%, while the detection of both pmrC and phoP genes was found to occur in 50% of colistin-resistant strains. Carbapenemase was detected in 85.71% of imipenem-resistant strains. Conclusion: High levels of multidrug, extensive, and pan-resistance in P. aeruginosa isolates were alarming. The colistin-imipenem combination appeared to possess encouraging effectiveness against resistant isolates, justifying assessment for therapeutic use.