Objective: Members of the genus Bacillus are Gram-positive bacilli, ubiquitous in the environment. When isolated in clinical practice, it is frequently considered as due to environmental contamination. Bacillus cereus is the most frequent species isolated in clinical practice, nevertheless other Bacillus spp. are sometimes isolated. Bacillus bacteremia is uncommon, the affected patients are severely ill and frequently immunocompromised with hematological malignancies.
Study design: Two cases of bloodstream infection due to Bacillus species rarely described before are described, one due to Bacillus macerans and the other to Bacillus pumilus. Both patients presented with severe bacteremia and were immunodepressed after recent chemotherapy. They died a few days after admission to our ICU.
Conclusion: The initial report of Bacillus spp. isolated in blood culture in oncohematological patients indicates a potentially severe infection.