Bacillus cereus isolates causing an outbreak in the neonatal intensive care unit were investigated using whole-genome sequencing. The outbreak coincided with construction work performed adjacent to the neonatal intensive care unit and ceased after strict sealing of the construction area. We found the outbreak to be polyclonal, however, the clonality did not correlate with the virulence in vivo. Genotypically similar isolates were associated with both lethal/severe infection and colonization/environmental contamination. Environmental bacterial load may be a major determinant of infection, especially in high-risk patients. Clinicians should be alert to unusual increase in B. cereus isolations from clinical cultures to facilitate early recognition and investigations of Bacillus outbreaks and pseudo-outbreaks. The integration of genomics into the classical infectious disease work can augment our understanding of pathogen transmission and virulence, and can rapidly assist our response to unusual disease trends.
From the *Infectious Diseases, Shaare-Zedek Medical Center
†Faculty of Medicine, Hebrew University
‡The microbiology laboratory, Shaare-Zedek Medical Center
§Medical Genetics Institute - Shaare Zedek Medical Center, Jerusalem, Israel.
Accepted for publication June 30, 2019.
Supported by Mirsky foundation grant from the Sharre-Zedek Medical Center.
The authors have no conflicts of interest to disclose.
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Address for correspondence: Maskit Bar-Meir, MD, MSc, Shaare-Zedek Medical Center, Byte St., Jerusalem, Israel 91031. E-mail: email@example.com.