Among individuals with acute myelogenous leukemia (AML), carbapenem-nonsusceptible gram-negative bacteremia (GNB) is associated with worse outcomes than bacteremia with carbapenem-susceptible isolates. Several risk factors for carbapenem-nonsusceptible GNB were also identified in this research, which was presented at IDWeek 2019, held from October 2 to October 6, 2019, in Washington, DC.

This retrospective cohort study included 929 individuals who received induction or consolidation chemotherapy for AML at Seoul National University Hospital between January 2000 and December 2015. The study researchers investigated independent risk factors for carbapenem-nonsusceptible GNB and the association between such infection and in-hospital mortality. Researchers also compared clinical outcomes and microbiologic features of carbapenem-susceptible vs carbapenem-nonsusceptible GNB.

In a study cohort of 930 patients, researchers identified 489 cases of GNB: 90.8% of bacteria isolated were carbapenem-susceptible bacteria and 9.2% were carbapenem-nonsusceptible. The most frequent nonsusceptible isolates were Stenotrophomonas maltophilia (n=23), Pseudomonas aeruginosa (n=11), and Acinetobacter baumannii (n=10).

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Several independent risk factors for carbapenem-nonsusceptible GNB were identified, including the use of carbapenem at GNB onset (adjusted odds ratio [aOR] 88.8; 95% CI, 27.5-286.0; P <.001), an interval of ≥20 days between chemotherapy and bacteremia onset (aOR 5.2; 95% CI, 1.8-15.0; P =.002), isolation of a resistant organism within the past year (aOR 28.2; 95% CI, 4.6-171.5; P <.001), and previous hospitalization with bacteremia occurrence (aOR 3.2; 95% CI, 1.1-9.3; P =.037). A significant association was identified between carbapenem-nonsusceptible GNB and in-hospital mortality (aOR 6.6; 95% CI, 3.0-14.8; P <.001).

Clinical outcomes were poorer among patients with carbapenem-nonsusceptible GNB compared with carbapenem-susceptible GNB, leading researchers to recommend that the selection of antibiotic regimens that target carbapenem-nonsusceptible GNB in individuals with AML and the identified risk factors.