Twenty-Two Years of Aeromonas Septicemia: Clinical Characteristics, Antimicrobial Resistance Patterns, and Mortality Predictors in a Tertiary Care Center

ABSTRACT Background Aeromonas species are opportunistic pathogens causing severe bloodstream infections primarily in immunocompromised individuals. Regional epidemiologic and resistance data are scarce. Methods Retrospective chart review of all culture-confirmed Aeromonas septicemia cases (January 2003–September 2025) at a tertiary care center. Clinical and demographic data were extracted from electronic records. Bacterial identification and antimicrobial susceptibility testing (AST) were performed according to CLSI guidelines using VITEK systems. Multidrug resistance (MDR) was defined as non-susceptibility to ≥1 agent across ≥3 antimicrobial classes 24. Univariate and multivariate logistic regression analyses identified mortality predictors, adjusting for age, gender, cancer type, diabetes, neutropenia, and appropriateness of empirical therapy. Results Sixty-six patients (mean age 53.2 years; 53% male) were analyzed. Cancer (51.5%)—predominantly gastrointestinal—and diabetes (43.7%) were primary comorbidities. Fever (58%) and septic shock (18%) were common presentations. High resistance to β-lactams: amoxicillin–clavulanate 25% susceptible, imipenem/meropenem 67%/75%. Aminoglycosides (amikacin 96%) and fluoroquinolones (ciprofloxacin 95%) retained high efficacy. Thirty-day all-cause and sepsis-related mortality were 15% and 12%, respectively. On multivariate analysis, empirical therapy mismatch (adjusted odds ratio aOR 12.4, 95% CI 2.1–73.8, p=0.005) independently predicted sepsis-related mortality. Conclusions Aeromonas septicemia primarily affects immunocompromised patients and shows substantial regional antimicrobial resistance. Empirical therapy selection critically influences outcomes. Rapid organism identification and susceptibility testing are essential for guiding targeted therapy and improving survival.