Clinical Features of Multidrug-Resistant Gram-Negative Bacteremia: A Comparative Study of Cancer and Non-Cancer Patients

Multidrug-resistant Gram-negative bacteremia (MDR-GNB) is a significant health threat associated with increased morbidity and mortality rates. Patients with cancer are particularly vulnerable to MDR-GNB due to immunosuppression and frequent healthcare exposure. The aim of this study was to evaluate risk factors, 30-day mortality, and outcomes in cancer and non-cancer patients. We conducted a retrospective study of adult patients aged 18 years or older with MDR-GNB who were hospitalized at Ochsner LSU Health-Academic Medical Center between January 2018 and July 2022. We collected data about demographics, comorbidities, cancer diagnosis, causative organisms, infection source, antibiotic therapy, and clinical outcomes. A total of 112 patients with MDR-GNB were included, where 31 patients (27.7%) had cancer and 81 patients (72.3%) did not. Cancer patients were more frequently male and white (74.2% vs. 58.0%, <i>p</i> = 0.114 and 45.2% vs. 25.9%, <i>p</i> = 0.031). Diabetes mellitus was more common in non-cancer patients, but it was associated with increased mortality risk in the cancer group (OR = 2.39, 95% CI: 1.125-5.074). Enterobacteriaceae species were the most frequently isolated organisms (83.0%), with no significant difference between groups. The most common source of infection was genitourinary (49.1%). ICU admission was more frequent in non-cancer patients (49.4% vs. 25.8%, <i>p</i> = 0.024). However, cancer patients had a higher ICU admission mortality risk (OR 2.156, 95% CI: 1.058-4.395) and recent hospitalization rates (67.7% vs. 40.7%, <i>p</i> = 0.011), both associated with increased mortality risk. Cancer patients had a significantly higher 30-day mortality rate (39.0% vs. 16.4%, <i>p</i> = 0.017; OR = 3.012, 95% CI: 1.190-7.622) and hospice admissions (22.6% vs. 3.7%, <i>p</i> = 0.002; OR = 7.583, 95% CI: 1.819-31.618). These findings emphasize the urgent need for early microbiological identification, targeted antimicrobial therapy, and improved infection control strategies. Given the rising prevalence of MDR-GNB pathogens, future research is needed for prompt appropriate antibacterial therapy based on risk stratification and enhanced antimicrobial stewardship programs as these are critical for high-risk cancer patients.