Health Alert
NEWLY IDENTIFIED STRAIN OF BACILLUS CEREUS CAUSES DISEASE SIMILAR TO ANTHRAX

The Delaware Division of Public Health (DPH) is issuing this health advisory to alert health care providers about a newly identified organism, B. cereus bv anthracis,and request reporting of suspected cases.

Summary

A previously unknown strain of Bacillus cereus (B. cereus) causing anthrax-like disease was first isolated in a dead chimpanzee in Côte d'Ivoire in 2001 and subsequently, was isolated from a handful of other mammals in West and Central Africa. The strain has not been found in humans at this time and has only been confirmed in animals. The purpose of this alert is to help in the recognition of potential B. cereus bv anthracis in humans.

Although anthrax is caused by Bacillus anthracis, tests showed that the newly identified strain of B. cereus carried plasmids (genetic material) that were identical to the virulence plasmids found in B. anthracis. This new strain of B. cereus was named Bacillus cereus biovar anthracis (B. cereus bv anthracis).

Background

Currently, B. cereus bv anthracis has only been found in a few animals (wild chimpanzees, gorillas, elephant and goats) in a few countries in West and Central Africa (Côte d’Ivoire, Cameroon, Central African Republic and Democratic Republic of Congo). However, it should be noted that B. cereus bv anthracis has all of the virulence determinants and the biothreat potential to pose a severe threat to public health as does B. anthracis, the causative agent of anthrax. In October 2016, the U.S. Department of Health and Human Services (HHS) added B. cereus bv anthracis to the HHS select agents and toxins list because B. cereus bv anthracis presents the same threat to public health and national security as B. anthracis.

Recommendations/Reporting

General Information

B. cereus bv anthracis isolates share several phenotypic features of both B. anthracis and B. cereus, but differ with regard to motility and their resistance or sensitivity to penicillin. B. cereus is a Gram-positive, rod-shaped, aerobic (facultatively anaerobic), motile, beta hemolytic bacterium commonly found in the soil and in raw, dried, and processed foods, particularly uncooked rice. A few strains of this organism have been known to cause foodborne illness in humans. The heat-stable bacterial spores are known to survive initial boiling of food, especially rice, and can subsequently germinate, multiply, and produce toxins when left unrefrigerated. B. cereus is the cause of “fried rice syndrome,” as the bacteria are classically contracted from fried rice dishes that have been sitting at room temperature for hours. But the typical B. cereus organism should not be confused with B. cereus bv anthracis because B. cereus bv anthracis isolates are non-hemolytic, (like B. anthracis), and motile, like B. cereus.

Diagnosis

Subject matter experts at the Centers for Disease Control and Prevention (CDC), the American Society for Microbiology (ASM), and the Association of Public Health Laboratories (APHL) are working to develop testing algorithms for B. cereus bv anthracis.

Sentinel laboratories should continue using the existing ASM Sentinel Level Clinical Laboratory Guidelines for Suspected Agents of Bioterrorism and Emerging Infectious Diseases, Bacillus anthracis (http://www.asm.org/images/PSAB/LRN/Anthrax316.pdf) to rule out or refer isolates of Bacillus spp. that produce non-hemolytic colonies with a ground glass appearance and are non-motile. Until new guidelines are available, the following recommendations should be considered:

1. Suspect Bacillus spp. isolates that are large Gram-positive rods and weakly or non-hemolytic (at 24 hours or less) should be tested for motility and catalase production. Semi-solid medium is recommended for motility for consistent results.
2. Isolates that are positive for catalase and motility should be investigated further by contacting the patient’s attending physician to determine if the patient has an anthrax-like illness or if the patient has a clinical infection compatible with this organism.
3. If the isolate is deemed significant, the local LRN reference laboratory (such as the Delaware Public Health Laboratory) should be contacted and the isolate forwarded for further testing. If the sentinel laboratory is unable or unwilling to contact the patient’s physician, notify the local LRN reference laboratory and provide the physician’s contact information and laboratory testing results.

Clinicians

Until new guidelines are available, the following recommendations should be considered:

Ordering Testing

B. cereus is commonly isolated in the laboratory and is typically considered to be non-pathogenic, but B. cereus bv anthracis is different. To reduce the burden of unnecessary rule-out testing of all B. cereus isolates and to ensure that B. cereus bv anthracis infection is properly identified when present, clinicians are asked to do the following:

1. Notify the laboratory when you order testing on a patient who presents with anthrax-like symptoms.
2. Include a patient travel history with the laboratory test requisition form.
3. Elicit a history of consumption of dead wildlife
4. Report suspect cases to the Division of Public Health. See below for contact information.
5. If you have questions about testing, contact the Delaware Public Health Laboratory at 302-223-1520

Reporting

Report all cases of suspected B. cereus bv anthracis infection to the DPH Office of Infectious Disease Epidemiology via phone at 302-744-4990, 24 hours a day at 1-888-295-5156, by fax at 302-223-1540, or by email at reportdisease@delaware.gov.

Additional Information

1. Federal Register, Wednesday, September 14, 2016, 81:63138-63143. Also available at: https://www.federalregister.gov/documents/2016/09/14/2016-22049/possession-use-and-transfer-of-select-agents-and-toxins-addition-of-bacillus-cereus-biovar-anthracis
2. American Society For Microbiology Statements and Testimony, Monday, February 13, 2017. Also available at  https://www.asm.org/index.php/statements-and-testimony/item/5900-b-cereus-biovar-anthracis
3. Antonation KS, Grützmacher K, Dupke S, Mabon P, Zimmermann F, Lankester F, et al. (2016) Bacillus cereus Biovar Anthracis Causing Anthrax in Sub-Saharan Africa—Chromosomal Monophyly and Broad Geographic Distribution. PLoS Negl Trop Dis10(9): e0004923. https://doi.org/10.1371/journal.pntd.0004923
4. Hoffmann, Constanze; Zimmermann, Fee; Biek, Roman; Kuehl, Hjalmar; Nowak, Kathrin; Mundry, Roger; Agbor, Anthony; Angedakin, Samuel; Arandjelovic, Mimi (2017-08-03). "Persistent anthrax as a major driver of wildlife mortality in a tropical rainforest". Nature. 548 (7665): 82–86. ISSN 0028-0836. doi:10.1038/nature23309.
5. Christopher A. Sanford; Elaine C. Jong (5 August 2008). The Travel and Tropical Medicine Manual. Elsevier Health Sciences. pp. 469–. ISBN 1-4377-1069-7.

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