Predictors and outcomes of multi-drug-resistant gram-negative bacteremia in patients with cancer: A retrospective cohort study at a tertiary cancer center in Oman

Objectives: This study aimed to delineate the characteristics and outcomes of gram-negative bacteremia (GNB) in oncology patients; analyze the risk factors for multi-drug-resistant (MDR) GNB; and assess its impact on the recurrence of bloodstream infection (BSI), hospital stay, and 30-day mortality. Methods: Data, including demographics, clinical features, common cancers, and microbiologic findings, were collected retrospectively from electronic medical records of patients admitted with solid tumors and BSI episodes between January and December 2022. Fisher's exact tests were used to determine the effect of MDR-GNB on 30- day mortality and BSI recurrence. The Wilcoxon rank-sum test assessed the differences in the length of hospital stay. Logistic regression models identified the risk factors for MDR-GNB. Results: Among 1074 patients, 77 episodes of GNB bacteremia occurred in 59 individuals (47% male, median age 57.4 years). Of these, 37 (48%) were MDR-GNB. Carbapenem resistance was noted in 9.1% of GNB episodes. Previous antibiotic use was significantly associated with MDR-GNB (odds ratio 7.82; 95% confidence interval 2.52-24). MDR-GNB was linked to longer hospital stays (median 23 vs 10.5 days, P = 0.003) and higher recurrence rates than non-MDR-GNB (35.13% vs 5.0%, P < 0.001). However, 30-day mortality did not significantly differ between the groups (35.14% vs 32.5%, P = 0.81). Conclusion: Previous antibiotic use predicted MDR-GNB in patients with solid tumor. MDR-GNB bacteremia increased the length of hospital stay and risk of recurrence compared with non-MDR-GNB bacteremia.