Pathogenic characteristics and factors associated with multidrug-resistant bacterial infections after perianal abscess surgery.

OBJECTIVE: This study aims to describe the pathogenic characteristics of multidrug-resistant (MDR) bacterial infections after perianal abscess surgery and explore its associated factors. METHODS: This retrospective study included 246 adult patients who underwent perianal abscess surgery at our hospital between June 2022 and June 2025. All patients underwent postoperative wound secretion bacterial culture and antimicrobial susceptibility testing. The primary endpoint of this study was the detection of MDR strains in culture, rather than the diagnosis of clinical infection based solely on culture results. Based on culture results, patients were categorized into an MDR culture-positive group (n = 78) and a non-MDR culture-positive group (n = 168). Baseline characteristics, disease-related features, treatment-related factors, and clinical outcomes were compared between the two groups. Logistic regression analysis was performed to identify factors associated with MDR culture positivity. RESULTS: Among the 246 patients, 78 (31.71%) were positive for MDR strains. A total of 96 pathogenic isolates were identified, including 62 Gram-negative bacteria (64.58%). The predominant pathogens were Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Multivariable logistic regression analysis showed that a history of diabetes (P < 0.001), prior antimicrobial use (P < 0.001), recurrent abscesses (P = 0.002), and length of hospital stay ≥14 days (P < 0.001) were statistically associated with MDR-positive cultures. However, the length of hospital stay was considered a postoperative process variable and should not be interpreted as a causal factor for MDR culture positivity. Patients in the MDR culture-positive group had longer incision healing times, prolonged antimicrobial use, higher hospitalization costs, and a higher incidence of complications compared with those in the non-MDR culture-positive group; all of these were unadjusted between-group associations. CONCLUSIONS: MDR culture positivity was relatively common among adult patients with perianal abscess undergoing postoperative wound culture and was associated with diabetes mellitus, prior antimicrobial use, and recurrent abscesses. Culture results should be interpreted in conjunction with clinical manifestations of infection. Treatment should be individualized based on pathogen-specific susceptibility results, patient conditions, and local antimicrobial resistance surveillance data. The observed associations should not be interpreted as causal inferences.