Prevalence and Antimicrobial Susceptibility Pattern of Multidrug-Resistant Pseudomonas spp. Isolated from Pus and Wound Swabs in a Tertiary Care Hospital

Background: Pseudomonas aeruginosa is a major opportunistic pathogen commonly associated with wound and soft-tissue infections, particularly among hospitalized and immunocompromised individuals. The growing prevalence of multidrug-resistant (MDR) strains has increased the complexity of treatment and negatively affected patient outcomes. Objective: This study aimed to determine the incidence of MDR Pseudomonas infections from pus and wound swab samples, analyse demographic patterns, and examine antimicrobial susceptibility profiles, including the efficacy of second- and third-line agents such as colistin. Methods: A prospective observational study was carried out in a tertiary care hospital, evaluating 1132 pus and wound swab samples. Standard microbiological techniques—including Gram staining, culture, biochemical identification, and antimicrobial susceptibility testing following CLSI guidelines—were employed. MDR was defined as resistance to at least one drug in three or more antimicrobial categories. Results: Among the 1132 samples, Pseudomonas spp. were isolated in 103 cases (9.1%). Of these, 85 isolates were identified as P. aeruginosa and 18 as non-aeruginosa Pseudomonas species. MDR strains were found in 32 of 85 P. aeruginosa isolates (37.6%) and 8 of 18 non-aeruginosa isolates (44.4%). High resistance levels were seen against piperacillin–tazobactam, cefoperazone–sulbactam, and carbapenems. All MDR isolates tested were fully susceptible to colistin. Conclusion: The study reveals a considerable prevalence of MDR Pseudomonas infections, underscoring the importance of robust antimicrobial stewardship, stringent infection control measures, and ongoing surveillance. Colistin continues to be a reliable last-line therapeutic option. Key words: Pseudomonas aeruginosa, MDR, wound infection, antimicrobial resistance, Colistin.