Microbiological Profile and Antimicrobial Resistance Patterns of Surgical Site Infections Following Orthopedic Surgery at Imam Hossein Hospital, Tehran, Iran (2023 - 2025)

Abstract

Background: Surgical site infections (SSIs) remain a major cause of postoperative morbidity in orthopedic surgery. Increasing antimicrobial resistance has made empiric treatment progressively more difficult. Objectives: This study aimed to analyze the microbiological profile and antimicrobial resistance patterns of orthopedic SSIs in a tertiary care hospital in Iran. Methods: This retrospective cross-sectional study included all patients diagnosed with culture-confirmed orthopedic SSIs between 2023 and 2025 at Imam Hossein Hospital. All patients who underwent orthopedic surgery and subsequently developed a culture-confirmed SSI during the study period were eligible for inclusion. Patients with open fractures and those undergoing emergency orthopedic procedures were excluded. Demographic, clinical, and microbiological data were extracted from patient records. Statistical analyses were performed using descriptive statistics and the chi-square or Fisher exact test, as appropriate. A P value < 0.05 was considered statistically significant. Results: A total of 100 bacterial isolates were recovered from 100 patients. The most common pathogen was Klebsiella pneumoniae (25.0%), followed by Staphylococcus aureus (15.0%), Acinetobacter baumannii (14.0%), and Escherichia coli (14.0%). Gram-negative isolates exhibited high resistance to third-generation cephalosporins and ciprofloxacin, whereas linezolid showed excellent activity against all tested Gram-positive organisms. The prevalence of multidrug resistance (MDR) was high, accounting for 73.3% of isolates. Statistically significant associations were observed between A. baumannii and femur infections (P = 0.011) and between S. epidermidis and hip infections (P = 0.008). Conclusions: The high prevalence of antimicrobial resistance and MDR pathogens among orthopedic SSIs underscores the urgent need for continued local surveillance and for the development of evidence-based antimicrobial stewardship strategies to improve clinical outcomes.