Appl. Environ. Microbiol. doi:10.1128/AEM.01480-07
Copyright (c) 2007, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.
Species of environmental mycobacteria vary in their ability to grow in human, mouse, and carp macrophages, and differ regarding the presence of mycobacterial virulence genes observed by DNA microarray hybridization
Melanie J. Harriff,
Martin Wu,
Michael L. Kent,
and
Luiz E. Bermudez*
Department of Biomedical Sciences, College of Veterinary Medicine, 105 Magruder, Oregon State University, Corvallis, OR 97331; Molecular and Cellular Biology Program, Center for Gene Research and Biotechnology, 3021 Agricultural and Life Sciences, Oregon State University, Corvallis, OR 97331
* To whom correspondence should be addressed. Email:
luiz.bermudez{at}oregonstate.edu.
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Abstract |
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There are many species of environmental mycobacteria (EM) that infect animals important to the economy and research that also have zoonotic potential. The genomes of very few of these species have been sequenced, and little is known about the molecular mechanisms by which most of these opportunistic pathogens cause disease. In this study, 18 isolates of environmental mycobacteria isolated from fish and humans (including strains of Mycobacterium avium, Mycobacterium peregrinum, Mycobacterium chelonae, and Mycobacterium salmoniphilum) were examined for their ability to grow in macrophage lines from humans, mice, and carp. Genomic DNA from 14 of these isolates was then hybridized against DNA from a reference M. avium strain on a custom microarray containing virulence genes of mycobacteria, and a selection of representative genes from metabolic pathways. The strains of EM had different abilities to grow within the three types of cell lines that grouped largely according to the host from which they were isolated. Genes identified as being putatively absent in some of the strains included those with response regulatory function, cell wall composition, and fatty acid metabolism, as well as a recently identified pathogenicity island important to macrophage uptake. Further understanding of the role these genes play in host specificity and pathogenicity will be important to gain insight into the zoonotic potential of certain environmental mycobacteria, as well their mechanisms of virulence.