xylophilus (bacterium) xylophilus (bacterium) xylophilus is a species of bacteria, which causes plant disease. it is available from the ncppb in the united kingdom for legitimate researchers and plant disease diagnosticians working in premises licensed to hold it. xylophilus scientific classification domain: bacteria phylum: pseudomonadota class: betaproteobacteria order: burkholderiales family: comamonadaceae genus: xylophiluswillems et al. 1987 type species xylophilus ampelinus type strain ncppb 2217 species x. ampelinus the genus xylophilus currently comprises only the species x. ampelinus, which affects grapevines.