Surgical site infections (SSIs) are among the most common healthcare-associated infections and contribute substantially to postoperative morbidity, prolonged hospitalization, and increased healthcare costs. Data on SSI epidemiology, microbiological profiles, and antimicrobial resistance patterns remain limited in many low- and middle-income countries, including Pakistan. This study aimed to determine the incidence of surgical site infections and characterize the associated microbiological spectrum and antimicrobial resistance patterns using surveillance data from a tertiary care hospital in Karachi, Pakistan. This single-center retrospective cohort study was conducted at Aga Khan University Hospital, Karachi. Surgical procedures performed between January 2020 and December 2023 were identified from the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database. Surgical site infections were defined according to standardized ACS NSQIP criteria. SSI incidence was calculated across nine surgical specialties including colorectal, neurosurgery, otolaryngology, orthopedic, cardiac, vascular, plastic, gynecologic, and general surgery. Microbiological and antimicrobial susceptibility data for culture-positive SSI cases were extracted from electronic medical records. Descriptive analyses were used to summarize pathogen distribution and antimicrobial resistance patterns. A total of 37,768 surgical procedures were analyzed, among which 557 SSIs were identified, corresponding to an overall incidence of 1.5% (95% CI: 1.36–1.61). Higher SSI occurrence was observed in colorectal surgery (6%), neurosurgery (3.1%), and otolaryngology procedures (2.7%), whereas lower rates were seen in vascular (0.1%), cardiac (0.4%), and orthopedic procedures (0.4%). Wound cultures were obtained in 247 of 557 SSI cases (44.3%), yielding 208 microbial isolates. Gram-negative bacteria predominated (52.9%), followed by Gram-positive cocci (41%) and Candida species (3.8%). The most frequently isolated pathogens included Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Among Gram-negative isolates tested, resistance was highest to amoxicillin–clavulanate (63.0%) and ciprofloxacin (40.8%), whereas lower resistance rates were observed for amikacin (6.5%) and imipenem (12.5%). This study provides current data on the epidemiology and microbiology of surgical site infections in a tertiary care hospital in Pakistan. The predominance of Gram-negative pathogens and the observed antimicrobial resistance patterns highlight the importance of ongoing microbiological surveillance and integration of local antibiogram data to guide empiric antimicrobial therapy, optimize surgical prophylaxis, and strengthen infection prevention strategies. Not applicable.
Ahmed et al. (Tue,) studied this question.