Proposal of a clinical score to stratify the risk of multidrug-resistant gram-negative rods bacteremia in cancer patients

INTRODUCTION: Multidrug-resistant gram-negative rods (MDR GNR) represent a growing threat for patients with cancer. Our objective was to determine the characteristics of and risk factors for MDR GNR bacteremia in patients with cancer and to develop a clinical score to predict MDR GNR bacteremia. MATERIAL AND METHODS: Multicenter prospective study analyzing initial episodes of MDR GNR bacteremia. Risk factors were evaluated using a multiple logistic regression (forward-stepwise selection) analysis including variables with a p < 0.10 in univariate analysis. RESULTS: 394 episodes of GNR bacteremia were included, with 168 (42.6 %) being MDR GNR. Five variables were identified as independent risk factors: recent antibiotic use (OR = 2.8, 95 % CI 1.7–4.6, p = 0.001), recent intensive care unit admission (OR = 2.9, 95 % CI 1.1–7.8, p = 0.027), hospitalization ≥ 7 days prior to the episode of bacteremia (OR = 3.5, 95 % CI 2–6.2, p = 0.005), severe mucositis (OR = 5.3, 95 % CI 1.8–15.6, p = 0.002), and recent or previous colonization/infection with MDR GNR (OR = 2.3, 95 % CI 1.2–4.3, p = 0.028). Using a cut-off value of two points, the score had a sensitivity of 66.07 % (95 % CI 58.4–73.2 %), a specificity of 77.8 % (95 % CI 71.4–82.7 %), a positive predictive value of 68 % (95 % CI 61.9–73.4 %), and a negative predictive value of 75.9 % (95 % CI 71.6–79.7 %). The overall performance of the score was satisfactory (AUROC 0.78; 95 % CI 0.73-0.82). In the cases with one or none of the risk factors identified, the negative likelihood ratio was 0.18 and the post-test probability of having MDR GNR was 11.68 %. CONCLUSIONS: With the growing incidence of MDR GNR as etiologic agents of bacteremia in cancer patients, the development of this score could be a potential tool for clinicians.