title: Value of the O-nitrophenyl-beta-D-galactopyranoside test to differentiate among the aerobic actinomycetes.
abstract: A comparative study to determine beta-D-galactosidase activity among 171 strains of aerobic actinomycetes (including mycobacteria and rhodococci) was performed by using two growth media and four O-nitrophenyl-beta-D-galactopyranoside (ONPG) substrates. The ONPG test was found to be a valuable screening test to differentiate between the ONPG-positive Nocardia spp. and the rapidly growing ONPG-negative mycobacteria and rhodococci. However, ONPG results varied significantly depending on the growth medium and test substrate used.
authors.affiliation: Microbial Diseases Laboratory, California Department of Health Services, Berkeley 94704.
authors.forename: M
authors.initials: M
authors.lastname: Flores
authors.forename: E G
authors.initials: EG
authors.lastname: Ford
authors.forename: J M
authors.initials: JM
authors.lastname: Janda
mesh_terms: D000192:Actinomycetales / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D000332:Aerobiosis; D001431:Bacteriological Techniques; D003470:Culture Media; D005069:Evaluation Studies as Topic; D006801:Humans; D009598:Nitrophenylgalactosides / Q000378:metabolism*; D013045:Species Specificity; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D003470:Culture Media; C055012:2-nitrophenylgalactoside; D009598:Nitrophenylgalactosides; D001616:beta-Galactosidase