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

Haemato-oncological patients are susceptible to infections due to aplasia. This article describes 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 spp., requiring long-term broad-spectrum antibiotics, central venous line replacements and removal of a port catheter. A commercially available 'synbiotic spray' containing Bacillus strains was identified as the likely source of contamination. We advocate for public health warnings regarding the use of household probiotic cleaning products in environments with immunocompromised individuals.