Additional tests to differentiate Arcanobacterium haemolyticum and Actinomyces pyogenes.

ABSTRACT

A commercially available biochemical test panel, commercially available diagnostic tablets and gas-liquid chromatography (GLC) of cellular fatty acids were used to find out whether Arcanobacterium haemolyticum and Actinomyces pyogenes could be further differentiated from each other. Xylitol and alpha-methyl-D-glucoside fermentation, Voges-Proskauer reaction and tributyrate hydrolysis were found to be useful additional tests which differentiated Arc. haemolyticum and A. pyogenes. GLC analysis revealed major differences in the cellular 160, 182(9,12) and 181(9) fatty acid composition of the two species. Especially the Voges-Proskauer test available as diagnostic tablets can be easily performed in clinical microbiology laboratories, in addition to the tests now used to differentiate Arc. haemolyticum from A. pyogenes.