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

• Published in: Antimicrobial agents and chemotherapy Vol. 44; no. 7; pp. 1990 - 1994
• Main Authors: MILTNER, E. C, BERMUDEZ, L. E
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01.07.2000
• Series: Note
• Subjects: Acanthamoeba - drug effects; Acanthamoeba - microbiology; Acanthamoeba - physiology; Acanthamoeba castellanii; AIDS/HIV; Animals; Anti-Bacterial Agents - pharmacology; Antibacterial agents; Antibiotics. Antiinfectious agents. Antiparasitic agents; Azithromycin - pharmacology; Bacteriology; Biological and medical sciences; Clarithromycin - pharmacology; Experimental Therapeutics; Fundamental and applied biological sciences. Psychology; HT29 Cells - drug effects; HT29 Cells - microbiology; Humans; Medical sciences; Mice; Microbial Sensitivity Tests; Microbiology; Mycobacterium avium; Mycobacterium avium - drug effects; Mycobacterium avium - growth & development; Mycobacterium avium - physiology; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Pharmacology. Drug treatments; Rifabutin - pharmacology; U937 Cells - drug effects; U937 Cells - microbiology; Clarithromycin; Lobosea; Azithromycin; Bacteria; Mechanism of action; Heterolobosea; Immunopathology; Protozoa; Mycobacterium avium; AIDS; Host; Acanthamoeba castellanii; Immune deficiency; In vitro; Macrolide; Biological activity; Infection; Rifabutin; Resistance; Sensitivity resistance; Mycobacteriales; Viral disease; Mycobacteriaceae; Actinomycetes; Antibacterial agent; Amoeba
• ISSN: 0066-4804; 1098-6596
• DOI: 10.1128/AAC.44.7.1990-1994.2000

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.