EVALUATION OF ANTIBIOTIC RESISTANCE PATTERNS OF PSEUDOMONAS AERUGINOSA ACROSS DIFFERENT INFECTIONS AND HOSPITAL SETTINGS IN DERA GHAZI KHAN

Abstract

Background: Antimicrobial resistance in Pseudomonas aeruginosa is an important challenge in the management of healthcare-associated and community-associated infections. Local surveillance of resistance patterns is essential for guiding antimicrobial therapy and stewardship.

Objective: To determine the antibiotic susceptibility and resistance profiles of Pseudomonas aeruginosa isolated from various clinical samples and to compare antibiotic resistance patterns between hospital-acquired (ICU and non-ICU) and community-acquired infections.

Methods: A cross-sectional descriptive study was conducted at Allama Iqbal Teaching Hospital, Dera Ghazi Khan. A total of 156 non-duplicate P. aeruginosa isolates recovered from clinical specimens were included. Isolates were obtained from outpatient, non-ICU inpatient, and ICU settings and were identified using conventional microbiological and biochemical methods. Antimicrobial susceptibility testing was performed by the Kirby-Bauer disk diffusion method according to applicable CLSI criteria. Susceptibility patterns were assessed for 13 antibiotics, and resistance was compared according to specimen type, infection acquisition, and healthcare setting. Statistical analysis was performed using IBM SPSS Statistics version 26.0, with p<0.05 considered statistically significant.

Results: Among 156 isolates, urinary tract specimens were the most frequent source (52, 33.3%), followed by wound/burn (43, 27.6%) and bloodstream infections (31, 19.9%). The highest resistance rates were observed for imipenem (75.0%), ciprofloxacin (71.2%), levofloxacin (70.5%), and meropenem (66.7%). Resistance to piperacillin, amikacin, ceftazidime, cefepime, aztreonam, and tobramycin was 57.7%, 57.1%, 53.8%, 51.9%, 51.9%, and 49.4%, respectively. Colistin showed the highest susceptibility, with 122 (78.2%) isolates susceptible and 9 (5.8%) resistant. MDR was detected in 155 (99.4%) isolates. Resistance was generally higher among ICU isolates for several antibiotics; however, differences according to hospital setting were not statistically significant (p>0.05). Similarly, differences between hospital-acquired and community-acquired isolates were not statistically significant for any tested antibiotic (p>0.05).

Conclusion: P. aeruginosa isolates in this study demonstrated a very high burden of antimicrobial resistance and MDR, with particularly high resistance to carbapenems and fluoroquinolones. Colistin retained the greatest in-vitro activity, although resistant isolates were identified. The findings support routine culture-based susceptibility testing, antimicrobial stewardship, infection-prevention measures, and continued local surveillance of P. aeruginosa resistance patterns.