Affiliation:
1. Departments of Pathology,1
2. Anatomy,2 and
3. Microbiology and Immunology,3 University of Arkansas for Medical Sciences, and J. L. McClellan Memorial Veterans Hospital, Little Rock, Arkansas
Abstract
ABSTRACT
Organisms in the
Mycobacterium avium
complex (MAC;
M. avium
,
M. intracellulare
, and “nonspecific or X” MAC) are emerging pathogens among individual organisms of which significant genetic variability is displayed. The objective of the present study was to evaluate various molecular methods for the rapid and definitive identification of MAC species. Isolates were obtained from both human immunodeficiency virus (HIV)-positive patients and HIV-negative patients with and without known predisposing conditions. The isolates were initially hybridized with nucleic acid probes complementary to the rRNA of the respective mycobacterial species (AccuProbe Culture Confirmation kits for
M. avium
,
M. intracellulare
, and MAC species; Gen-Probe). Isolates were also examined by PCR and in some cases by Southern blot hybridization for the insertion element IS
1245
. Two other techniques included a PCR assay that amplifies the
mig
gene, a putative virulence factor for MAC, and
hsp65
gene amplification and sequencing. This study led to the following observations. Eighty-five percent of the isolates from HIV-positive patients were
M. avium
and 86% of the isolates from HIV-negative patients were
M. intracellulare
. Fifteen of the
M. avium
isolates did not contain IS
1245
and 7% of the
M. intracellulare
isolates were found to carry IS
1245
. All of the
M. avium
strains were
mig
positive, and all of the
M. intracellulare
strains were
mig
negative.
Publisher
American Society for Microbiology
Cited by
51 articles.
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