Mycobacterium avium grown in Acanthamoeba castellanii is protected from the effects of antimicrobials.

TitleMycobacterium avium grown in Acanthamoeba castellanii is protected from the effects of antimicrobials.
Publication TypeJournal Article
Year of Publication2000
AuthorsMiltner EC, Bermudez LE
JournalAntimicrobial agents and chemotherapy
Volume44
Issue7
Pagination1990-4
Date Published2000 Jul
ISSN0066-4804
KeywordsAcanthamoeba, Animals, Anti-Bacterial Agents, Azithromycin, Clarithromycin, HT29 Cells, Humans, Mice, Microbial Sensitivity Tests, Mycobacterium avium, Rifabutin, U937 Cells
Abstract

Mycobacterium avium is a common cause of systemic bacterial infection in patients with AIDS. Infection with M. avium has been linked to bacterial colonization of domestic water supplies and commonly occurs through the gastrointestinal tract. Acanthamoeba castellanii, a waterborne protozoan, may serve as an environmental host for M. avium. It has been shown that growth of M. avium in amoebae enhances invasion and intracellular replication of the bacteria in human macrophages and intestinal epithelial cell line HT-29 as well as in mice. We determined that growth of M. avium within A. castellanii influenced susceptibility to rifabutin, azithromycin, and clarithromycin. No significant activity against M. avium was seen with rifabutin, azithromycin, and clarithromycin when used to treat monolayers on both day 1 and day 4 after infection. When tested in a macrophage-like cell line (U937), all compounds showed significant anti-M. avium activity. Growth of M. avium in amoebae appears to reduce the effectiveness of the antimicrobials. These findings may have significant implications for prophylaxis of M. avium infection in AIDS.

Alternate JournalAntimicrob. Agents Chemother.