Occurrence of the IS900 gene in Mycobacterium avium complex derived from HIV patients

The occurrence of the insertion sequence IS900 in Mycobacterium avium subsp . avium strains isolated from HIV infected patients has been investigated. In this study, genomic DNA from 62 mycobacterial isolates [31 strains of M. avium complex (MAC) consisting of 26 M. avium subsp. avium HIV-isolates an d five non-HIV isolates and 31 additional Mycobacterium species] were analy sed by an IS900-based polymerase chain reaction (PCR) assay and Southern hy bridization using a non-radioactive-labelled 251 bp DNA fragment located at the 5'-region of the IS900 sequence. As expected, none of the 28 Mycobacte rium species contained the IS900 in their genomic DNA. Of the 26 M, avium s ubsp. avium HIV-isolates, 15 (57.6%) were strongly positive for the IS900 o r IS900 related sequence. The five pulmonary non-HIV MAC isolates were nega tive for the IS900. As expected, the three strains of M. avium subsp. parat uberculosis were positive. This PCR guided study suggest that the IS900 gen e is very common in clinical strains of M. avium subsp. avium especially th ose isolated from HIV patients. Ultimately the IS900 PCR-based assay may pr ovide a useful tool for diagnostic and epidemiological studies related to M AC infections in HIV patients. (C) 1999 Academic Press.