Strain variation in Mycobacterium avium: Polymorphism of IS1110-related sequences

Abstract

Objectives: To determine the occurrence and distribution of IS1110 in a sample of clinical isolates; to investigate the polymorphism detected with IS1110-derived probes, and the stability of such patterns; and to evaluate IS1110-based probes, in comparison with other methods, for differentiation of Mycobacterium avium isolates. Design: Fifty M. avium complex strains used for evaluation of the IS1110 probe originated from the Memorial Sloan-Kettering Cancer Center, New York. Results: IS1110 hybridizes to a highly polymorphic element in most M, avium strains. Most banding patterns were found to be unique, but four groups of identical strains were identified. One group, from non-AIDS subjects, was associated with colonization rather than dissemination or invasion Combining pMB22 and IS1110 typing yielded higher discrimination than either probe alone. Comparison of IS1110 and pMB22 polymorphisms with multilocus enzyme electrophoresis indicated that the three methods were essentially independent. Conclusions: IS1110 provides a convenient method for differentiating M, avium isolates for epidemiologic purposes.