Notes from the Field: Fatal Anthrax Pneumonia in Welders and Other Metalworkers Caused by Bacillus cereus Group Bacteria Containing Anthrax Toxin Genes — U.S. Gulf Coast States, 1994–2020
Weekly / October 15, 2021 / 70(41);1453–1454
Patrick Dawson, PhD1,2,*; Caroline A. Schrodt, MD1,2,*; Karl Feldmann, MS3; Rita M. Traxler, PhD1; Jay E. Gee, PhD1; Cari B. Kolton, MS1; Chung K. Marston1; Christopher A. Gulvik, PhD1; James M. Antonini, PhD3; María E. Negrón, DVM, PhD1; John R. McQuiston, PhD1; Kate Hendricks, MD1; Zachary Weiner, PhD1; Gary A. Balsamo, DVM4; Theresa Sokol, MPH4; Paul Byers, MD5; Kathryn Taylor, MD5; Saad Zaheer, MD6; Stephen Long, MD7; Briana O’Sullivan, MPH8; Marie A. de Perio, MD3; Alex R. Hoffmaster, PhD1; Johanna S. Salzer, DVM, PhD1; William A. Bower, MD1 (View author affiliations)View suggested citation
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In 2020, CDC confirmed two cases of pneumonia (one fatal) in welders caused by rare Bacillus cereus group bacteria containing anthrax toxin genes typically associated with Bacillus anthracis. B. cereus group bacteria are gram-positive facultative anaerobes, often toxin-producing, that are ubiquitous in the environment and reside naturally in soil and dust (1). B. cereus can also be found in food, and although infection typically causes illnesses characterized by diarrhea or vomiting, B. cereus can have other clinical manifestations (e.g., pulmonary, ocular, or cutaneous). Among seven persons in the United States reported to be infected with B. cereus group bacteria containing anthrax toxin genes resulting in pneumonia since 1994, five patients died and two had critical illness with prolonged hospitalization and recovery (2–5). All persons with pneumonia were welders or other metalworkers who had worked in Louisiana or Texas (Table). In addition to the seven pneumonia cases, a cutaneous infection with B. cereus group bacteria containing anthrax toxin genes has been reported in a patient with an anthrax eschar in Florida.†
Understanding the extent to which Bacillus species other than B. anthracis carry anthrax toxin genes and whether their geographic range extends beyond the U.S. Gulf Coast states is limited. Furthermore, little is known about why these highly fatal pneumonia cases have only been detected among welders and other metalworkers. Long-term exposure to welding and metalworking fumes is associated with various forms of lung injury that can cause changes in lung function and increase susceptibility to pulmonary infections, including fatal pneumonia.§ An investigation by CDC at one patient’s worksite in Louisiana (patient F) identified a bacterial isolate in a soil sample that genetically matched a clinical isolate from the patient. However, it is unclear why only one person at each worksite became ill and what environmental or host risk factors might have facilitated the exposure and infection.
Several actions can decrease risk for lung injury or infection, including anthrax pneumonia caused by B. cereus group bacteria, among welders and other metalworkers. Because of the association between welding or metalworking and pulmonary infections or injury, it is important that employers educate workers regarding hazards associated with welding and measures they can take to minimize potential exposures. Welding and metalworking employers, trade associations, and unions might consider targeted outreach to increase workers’ awareness about pulmonary infections, including anthrax, especially those workers in the U.S. Gulf Coast states. In addition, employers should conduct a hazard assessment at worksites and consider the use of National Institute for Occupational Safety and Health–approved respirators as part of a written respiratory protection program.¶,**
Clinicians should consider B. cereus group bacteria in the differential diagnosis when treating welders and other metalworkers with severe, rapidly progressive pneumonia or other anthrax-like disease.†† B. cereus group bacteria identified on culture are not always contaminants; when B. cereus with anthrax toxin is suspected, laboratorians and clinicians should pursue additional testing through their state Laboratory Response Network laboratory.§§ Regional health departments and the Laboratory Response Network serve pivotal roles in pathogen detection and procuring anthrax antitoxin for confirmed cases.
Corresponding author: William A. Bower, firstname.lastname@example.org, 404-639-0376.
1Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, CDC; 2Epidemic Intelligence Service, CDC; 3National Institute for Occupational Safety and Health, CDC; 4Louisiana Department of Health; 5Mississippi State Department of Health; 6Harris County Public Health, Houston, Texas; 7Houston Health Department, Houston, Texas; 8Texas Department of State Health Services, Austin, Texas.
All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.
* These authors contributed equally to this report.
¶ Occupational Safety and Health Administration. 29 CFR Sect. 1910.134. https://www.osha.gov/enforcement/directives/cpl-02-02-054external icon
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- Pena-Gonzalez A, Marston CK, Rodriguez-R LM, et al. Draft genome sequence of Bacillus cereus LA2007, a human-pathogenic isolate harboring anthrax-like plasmids. Genome Announc 2017;5:e00181–17. https://doi.org/10.1128/genomeA.00181-17external icon PMID:28428293external icon
Suggested citation for this article: Dawson P, Schrodt CA, Feldmann K, et al. Notes from the Field: Fatal Anthrax Pneumonia in Welders and Other Metalworkers Caused by Bacillus cereus Group Bacteria Containing Anthrax Toxin Genes — U.S. Gulf Coast States, 1994–2020. MMWR Morb Mortal Wkly Rep 2021;70:1453–1454. DOI: http://dx.doi.org/10.15585/mmwr.mm7041a4external icon.
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