Epidemiologic Investigation of a Cluster of Neuroinvasive Bacillus cereus Infections in 5 Patients With Acute Myelogenous Leukemia

Abstract

Background. Five neuroinvasive Bacillus cereus infections (4 fatal) occurred in hospitalized patients with acute myelogenous leukemia (AML) during a 9-month period, prompting an investigation by infection control and public health officials.Methods. Medical records of case-patients were reviewed and a matched case-control study was performed. Infection control practices were observed. Multiple environmental, food, and medication samples common to AML patients were cultured. Multilocus sequence typing was performed for case and environmental B cereus isolates.Results. All 5 case-patients received chemotherapy and had early-onset neutropenic fevers that resolved with empiric antibiotics. Fever recurred at a median of 17 days (range, 9–20) with headaches and abrupt neurological deterioration. Case-patients had B cereus identified in central nervous system (CNS) samples by (1) polymerase chain reaction or culture or (2) bacilli seen on CNS pathology stains with high-grade B cereus bacteremia. Two case-patients also had colonic ulcers with abundant bacilli on autopsy. No infection control breaches were observed. On case-control analysis, bananas were the only significant exposure shared by all 5 case-patients (odds ratio, 9.3; P = .04). Five environmental or food isolates tested positive for B cereus, including a homogenized banana peel isolate and the shelf of a kitchen cart where bananas were stored. Multilocus sequence typing confirmed that all case and environmental strains were genetically distinct. Multilocus sequence typing-based phylogenetic analysis revealed that the organisms clustered in 2 separate clades.Conclusions. The investigation of this neuroinvasive B cereus cluster did not identify a single point source but was suggestive of a possible dietary exposure. Our experience underscores the potential virulence of B cereus in immunocompromised hosts.

Bacillus cereus bacteraemia: comparison between haematologic and nonhaematologic patients

“…A paediatric study of 12 patients identified corticosteroid and cephalosporin exposure, neutropenia and intrathecal therapy as possible risk factors for CNS complications [7]. Some authors have described an association with intestinal mucositis [7], [8]. None of our patients with CNS complications experienced abdominal symptoms.…”

“…It is widely recognized that haematologic patients have a higher risk for invasive B. cereus infection [5], [6], [7], [8], but few data are available on other risk factors for complications of B. cereus bacteraemia (such as mortality and metastatic infections). The aims of the present study were to compare episodes between haematologic and nonhaematologic patients and to identify possible risk factors that may predispose patients to a complicated course of B. cereus bacteraemia.…”

Bacillus cereus Catheter-Related Infection in Acute Lymphoblastic Leukemia (ALL) Patient: A Case Report and Review of Literature

“…cereus septicaemia is a relatively rare event which accounts for about 2% of all cases of bacteremia or fungemia [5]. The few reports of septicemia due to B. cereus deal with patients with severe neutropenia who were receiving chemotherapy for hematologic malignancies [2,[6][7][8][9][10][11][12][13][14][15]. In these patients the clinical course was generally fulminant and death was rapid.…”

“…This microorganism is widely distributed in the air, water, soil and feces with some species being a part of the normal flora particularly in patients with prolonged hospitalization [1,2]. The most commonly reported systemic infection is bacteremia.…”

Characterization of Ba813 harbouring Bacillus cereus in patients with haematological malignancy and hospital environments at a medical centre in Japan

“…Patients with haematological malignancy are known to be a high-risk group for B. cereus bacteraemia due to neutropenia following the initiation of chemotherapy [2, 3]. In addition, in patients with haematological malignancy, B.…”