Fulminant sepsis caused by Bacillus cereus in patients with hematologic malignancies: analysis of its prognosis and risk factors

Bacillus cereus is a growing concern as a cause of life-threatening infections in patients with hematologic malignancies. However, the risk factors for patients with unfavorable outcomes have not been fully elucidated. At our institution, we observed the growth of B. cereus in blood culture in 68 patients with (23) or without (45) hematologic malignancies treated from September 2002 to November 2009. We defined a case as having sepsis when more than two blood culture sets were positive for B. cereus or only a single set was positive in the absence of other microorganisms in patients who had definite infectious lesions. We determined 12 of 23 patients with hematologic malignancies as having sepsis, as well as 10 of 45 patients without hematologic malignancies (p = 0.012). Of the 12 patients with hematologic malignancies, four patients with acute leukemia died of B. cereus sepsis within a few days. In our cohort, risk factor analysis demonstrated that a neutrophil count of 0/mm