Cross-Contamination of Clinical Specimens with Bacillus anthracis During a Laboratory Proficiency Test - Idaho, 2006

On July 18, 2006, the Utah Department of Health notified epidemiologists at the Idaho Department of Health and Welfare that Bacillus anthracis, the causative agent for anthrax, has been isolated from a patient. On the same day, the Idaho epidemiologists were notified by the Idaho Bureau of Laboratories of a specimen from a second patient received for anthrax testing. Investigations that were conducted revealed that, neither patient had signs or symptoms consistent with B. anthracis infection and that the two specimens had become cross-contaminated with B. anthracis during laboratory proficiency testing. Details of the case are presented. A CDC editorial note is also included.