Introduction: Non-fermenting Gram-negative bacilli (NFGNB), particularly the
Acinetobacter baumannii complex (ABC) and Pseudomonas aeruginosa, are common causes of infections in both hospitalized patients and outpatients, posing significant clinical and therapeutic challenges. The primary objective of this study was to conduct a comprehensive analysis of NFGNB, specifically ABC and P. aeruginosa, isolated from pus specimens obtained from both hospitalized patients and outpatients. Methods: This study investigated the antibiotic resistance patterns of NFGNB, focusing on ABC and P. aeruginosa, isolated from pus samples collected from both hospitalized patients and outpatients. The isolates were tested for multidrug resistance (MDR) and extensive drug resistance (XDR) using standardized microbiological protocols. The data were analyzed using descriptive statistics to summarize the findings. Results: Out of ۱۲۳۴ pus samples received, ۱۱۷ (۹.۵%) NFGNB were isolated, accounting for ۳۰% of the total Gram-negative bacilli (GNB) isolates. The majority of NFGNB (۸۲.۹%, n = ۹۷/۱۱۷) were isolated from inpatients, with surgical site infections being the most common clinical condition (۳۳.۳%, n = ۳۹/۱۱۷). Among the NFGNB isolates, P. aeruginosa was the predominant species (۷۶.۹%, n = ۹۰/۱۱۷), followed by A. baumannii (۲۲.۲%, n = ۲۶/۱۱۷). Antimicrobial susceptibility testing revealed that ۳۷.۷% (n = ۳۴/۹۰) of P. aeruginosa isolates were MDR and ۱۳% (n = ۱۲/۹۰) were XDR, while ۶۵% (n = ۱۷/۲۶) of A. baumannii isolates were MDR and ۲۶.۹% (n = ۷/۲۶) were XDR. Conclusion: This study highlights the emergence of NFGNB as significant nosocomial pathogens, exhibiting a high degree of resistance to commonly used antibiotics. The findings underscore the urgent need to enhance and strictly implement effective antibiotic stewardship policies, including the development of new antibiotic regimens and antimicrobial resistance surveillance programs, to combat the growing resistance of nosocomial pathogens and ultimately improve patient outcomes.