Central line infections in a haematology-oncology patient associated with Bacillus containing cleaning spray.

Haemato-oncological patients are susceptible to infections due to aplasia. We describe an adolescent with a history of a relapse precursor B-cell acute lymphoblastic leukaemia, who experienced a second leukaemia after CAR-T-cell therapy with a lineage switch to acute myeloid leukaemia. He experienced events of central-line associated bloodstream infections with Bacillus species, requiring long-term broad spectrum antibiotics, central venous line replacements and removal of a port catheter. We identified a commercially available 'synbiotic spray', containing Bacillus strains as the likely source of contamination. We advocate for public health warnings regarding using household probiotic cleaning products in environments with immunocompromized individuals.