Clinical and epidemiological importance of typing of Mycobacterium avium complex isolates.

The results of the application of a range of typing procedures to the identification and classification of 6,264 cultures of nontuberculous mycobacteria from human sources and the environment are reported. Seroagglutination, an enzyme-linked immunosorbent assay applied to whole bacteria or the glycolipid typing antigens and based on serovar-specific polyclonal or monoclonal antibodies, thin-layer chromatography of these antigens, and gas chromatography of their specific sugar determinants were used to arrive at identifications. As a result of this comprehensive approach, 4,452 (71%) of all cultures and 88% of those of samples from patients with AIDS proved to be typeable. The rank order of frequency of occurrence of individual organisms within the entire group of isolates was Mycobacterium avium complex serovar 4 greater than serovar 8 greater than serovar 1 greater than serovar 9 greater than serovar 6 greater than serovar 14 greater than serovar 2 greater than M. fortuitum greater than M. kansasii greater than M. xenopi greater than an apparent mixture of serovar 4 and M. xenopi greater than a mixture of serovar 4 and serovar 8. These results were similar but not identical to the pattern observed for isolates obtained from patients with AIDS; the order was M. avium complex serovar 4 greater than serovar 8 greater than serovar 1 greater than a mixture of serovar 4 and M. xenopi, a mixture of serovar 4 and serovar 8 greater than serovar 9 greater than serovar 2 greater than serovar 6. Serotyping was also used to demonstrate the possible clinical significance of nontuberculous mycobacteria recovered from different body sites. Other information on the distribution of M. avium serovars in patients from different geographical environments is provided.