Enzymatic characterization of some oral and nonoral gram-negative bacteria with the API ZYM system

Abstract

The API ZYN system, containing 19 chromogenic substrates, was utilized semiquantitatively to detect extracellular acid and alkaline phosphatases, aminopeptidases, proteases, esterase-lipase, phosphoamidase, and glycosidases in 128 oral (human) and nonoral isolates of black-pigmented Bacteroides, Actinobacillus, Haemophilus aphrophilus, Capnocytophaga, Fusobacterium nucleatum, Wolinella recta and Veillonella parvula. In the black-pigmented Bacteroides group of organisms, a strong trypsin reaction was present in Bacteroides gingivalis (oral species) but not in B. asaccharolyticus (nonoral species). B. melaninogenicus spp. melaninogenicus, in contrast to B. melaninogenicus spp. intermedius, exhibited strong N-acetyl-.beta.-glucosaminidase activity. H. aphrophilus produced .beta.-galactosidase and .alpha.-glucosidase, but the closely related Actinobacillus actinomycetemcomitans did not. Capnocytophaga was distinct with respect to strong aminopeptidase reactions. Thus, a wide range of enzymes which have the potential of causing tissue injury and inflammation evidently can be elaborated from major oral gram-negative spp. The API ZYM system appears to be a valuable adjunct to traditional biochemical testing in identifying oral gram-negative spp.