Carbon substrate utilization studies of some cultures of Alcaligenes denitrificans, Alcaligenes faecalis, and Alcaligenes odorans isolated from clinical specimens.

One hundred and sixty-two cultures of Alcaligenes species (A. denitrificans, A. faecalis, and A. odorans) of clinical origin were characterized by routine diagnostic and carbon substrate utilization techniques. The microorganisms were tested for their ability to utilize a total of 188 substrates. Substrate utilization was assayed by (i) growth stimulation and (ii) substrate alkalinization. The A. denitrificans and A. odorans cultures had unique substrate utilization profiles for each species. The A. faecalis isolates were redefined by colonial morphology into two biotypes: (i) biotype I, morphologically and biochemically similar to the A. denitrificans cultures and (ii) biotype II, morphologically similar to the A. odorans cultures.