GNU Collaborative International Dictionary of English

Found one definition

1.       
    Microbe (?), ‖Microbion (?),  n. [NL. microbion, fr. Gr.  little +  life.] (Biol.) A microscopic organism; a microorganism; -- particularly applied to bacteria and especially to pathogenic forms; as, “the microbe of fowl cholera”.
   
   [1913 Webster]