'bacterize' originates from New Latin/Modern scientific Latin, specifically the word 'bacterium', ultimately from Greek 'bakterion' meaning 'small staff' (a diminutive of 'bakteria' meaning 'stick, rod'), combined with the English verb-forming suffix '-ize'.

'bacterion' (Greek) became New Latin 'bacterium' in scientific usage in the 19th century; the verb 'bacterize' was formed in English in the mid-19th century (around the rise of bacteriology) by adding '-ize' to 'bacterium', and from this the participial form 'bacterizing' developed.

Initially related to the noun 'bacterium' (a bacterial organism), the verbal form came to mean 'to introduce or be affected by bacteria'—a shift from a noun-based label to an action of causing bacterial presence or infection; the core sense of 'involving bacteria' has been retained but applied as an action.