Epidemiologic Investigation of a Cluster of Neuroinvasive Bacillus cereus Infections in 5 Patients With Acute Myelogenous Leukemia.
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.
Department of Population Medicine , Harvard Medical School and Harvard Pilgrim Health Care Institute , Boston, Massachusetts ; Infection Control Department.
Chanu
C
Rhee
Department of Population Medicine , Harvard Medical School and Harvard Pilgrim Health Care Institute , Boston, Massachusetts ; Infection Control Department.
Michael
M
Klompas
School of Medicine , Stanford University , California.
Fiona B
FB
Tamburini
School of Medicine , Stanford University , California.
Brayon J
BJ
Fremin
Divisions of Healthcare Quality Promotion ; Epidemic Intelligence Service, Division of Scientific Education and Professional Development , Centers for Disease Control and Prevention , Atlanta, Georgia.
Nora
N
Chea
Divisions of Healthcare Quality Promotion ; Epidemic Intelligence Service, Division of Scientific Education and Professional Development , Centers for Disease Control and Prevention , Atlanta, Georgia.
Lauren
L
Epstein
Divisions of Healthcare Quality Promotion.
Alison Laufer
AL
Halpin
Divisions of Healthcare Quality Promotion.
Alice
A
Guh
Foodborne, Waterborne and Environmental Diseases.
Rachel
R
Gallen
Divisions of Healthcare Quality Promotion ; Epidemic Intelligence Service, Division of Scientific Education and Professional Development , Centers for Disease Control and Prevention , Atlanta, Georgia.
Angela
A
Coulliette
High-Consequence Pathogens and Pathology.
Jay
J
Gee
Infection Control Department.
Candace
C
Hsieh
Broad Institute , Cambridge.
Christopher A
CA
Desjardins
Broad Institute , Cambridge ; Department of Medical Oncology , Dana Farber Cancer Institute , Boston.
Chandra Sekhar
CS
Pedamullu
Department of Medical Oncology , Dana Farber Cancer Institute , Boston.
Daniel J
DJ
DeAngelo
School of Medicine , Stanford University , California.
Veronica E
VE
Manzo
Department of Pathology , Brigham and Women's Hospital , Boston, Massachusetts.
Rebecca Dunn
RD
Folkerth
Department of Pathology , Brigham and Women's Hospital , Boston, Massachusetts.
Danny A
DA
Milner
Department of Pathology , Brigham and Women's Hospital , Boston, Massachusetts.
Nicole
N
Pecora
Division of Epidemiology and Immunization, Massachusetts Department of Public Health, Jamaica Plain.
Matthew
M
Osborne
Boston Inspectional Services Department, Massachusetts.
Diane
D
Chalifoux-Judge
School of Medicine , Stanford University , California.
Ami S
AS
Bhatt
Infection Control Department.
Deborah S
DS
Yokoe
Bacillus cereus; acute myelogenous leukemia; central nervous system infection; infection control investigation