PCR comparison of Mycobacterium avium isolates obtained from patients and foods

Mycobacterium avium is a cause of disseminated disease in AIDS patients. A need for a better understanding of possible sources and routes of transmiss ion of this organism has arisen. This study utilized a PCR typing method de signed to amplify DNA segments located between the insertion sequences ISI2 45 and IS1311 to compare levels of relatedness of M. avium isolates found i n patients and foods. Twenty-five of 121 food samples yielded 29 mycobacter ial isolates, of which 12 were M. avium. Twelve food and 103 clinical M. av ium isolates were tested. A clinical isolate was found to be identical to a food isolate, and close relationships were found between two patient isola tes and two food isolates. Relatedness between food isolates and patient is olates suggests the possibility that food is a potential source of M. avian infection. This study demonstrates a rapid, inexpensive method for typing M. avium, possibly replacing pulsed-field gel electrophoresis.