n 1  cap  :  a genus of gram-negative motile bacteria that do not ferment carbohydrates and are aerobes or facultative anaerobes, commonly occur in water and soil, and include some (as A. faecalis) that are found in the intestines of vertebrates including humans and are usu. harmless but have been associated with opportunistic infections  2  pl  alcaligenes  :  an organism of the genus Alcaligenes .
 
 
 
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