ubiquitous one-celled organisms, spherical, spiral, or rod-shaped and appearing singly or in chains, comprising the Schizomycota, a phylum of the kingdom Monera (in some classification systems the plant class Schizomycetes), various species of which are involved in fermentation, putrefaction, infectious diseases, or nitrogen fixation.

noun

bacilli , germs , microbes , organisms , pathogens , aerobe , anaerobe , antibiotic , antiseptic , bacillus , bacterium , bug , cocci , coccus , culture , germ , microbe , nidus , organism , spirillum , spirochete , staphylococcus , streptococcus , virus , zooglea