anaerobe

anaerobe
    n 1: an organism (especially a bacterium) that does not require
         air or free oxygen to live
    

37 Moby Thesaurus words for "anaerobe":
      adenovirus, aerobe, aerobic bacteria, amoeba, anaerobic bacteria,
      bacillus, bacteria, bacterium, bug, coccus,
      disease-producing microorganism, echovirus, enterovirus,
      filterable virus, fungus, germ, gram-negative bacteria,
      gram-positive bacteria, microbe, microorganism, mold,
      nonfilterable virus, pathogen, picornavirus, protozoa, protozoon,
      reovirus, rhinovirus, rickettsia, spirillum, spirochete, spore,
      staphylococcus, streptococcus, trypanosome, vibrio, virus