Non-anthrax Bacillus species are usually considered to be contaminants if found in clinical specimens. Only a few patients with systemic infections due to Bacillus cereus are reported. We present the case of a 18-month old boy with a primitive neuroectodermal tumor (PNET) in the brainstem and obstructive hydrocephalus that required an outlying and subsequently a ventriculoperitoneal drain. Following contamination at the site of entry of the external drain, shunt infection and meningitis with Bacillus cereus developed. Antibiotic treatment with vancomycin failed to eliminate the bacterium from the cerebrospinal fluid, so the shunt system had to be removed. Explantation of the shunt and addition of fosfomycin to the antibiotic regimen resulted in a complete cure of the infection.