Identification of mycobacteria by specific precipitation of catalase with absorbed sera

Cross-absorbed antisera have been prepared against catalase from reference strains of Mycobacterium asiaticum, Mycobacterium gordonae, Mycobacterium scrofulaceum, Mycobacterium simiae, and Mycobacterium szulgai. A total of 61 strains of mycobacteria were grown in small volumes of liquid medium and disrupted in sealed tubes in a cup horn sonicator, and the extracts were tested by a seroprecipitation technique against each of the reference antibody preparations. All 35 strains that belonged to one of the reference species reacted with the corresponding antibody, and none of the 61 extracts gave a significant cross-reaction with the absorbed antibody to a species to which it did not belong. This method appears to provide a rapid and accurate means of identifying mycobacterial cultures in the diagnostic laboratory.