title: Characterization of biofilm formation by clinical isolates of Mycobacterium avium.
abstract: Mycobacterium avium is an environmental organism encountered in natural and urban water sources as well as soil. M. avium biofilm has recently been identified on sauna walls and in city water pipes and might have a role in the survival of virulent strains in the environment and in the host. To characterize the M. avium biofilm, an in vitro model was adapted wherein biofilm develops on a PVC surface. Biofilm was detected by staining with crystal violet and visualization by optical microscopy and quantified by A(570). M. avium strains MAC 101, MAC 100, MAC 104, MAC 109, MAC A5 and MAC 5501 (all isolated from the blood of AIDS patients) were used in the assays. Biofilm formation was dependent on the presence of Ca(2+), Mg(2+) or Zn(2+) ions in the water, with the maximal effect seen at a concentration of 1 micro M. The presence of 2 % glucose and peptone as sources of carbon increased the formation of biofilm, while this was partially inhibited by humic acid. Since sliding motility has been associated with the amount of glycopeptidolipid (GPL), TLC was used to determine the presence of GPL. The supernatant of a biofilm-forming culture induced formation of a stable biofilm and amikacin blocked the establishment of biofilm by M. avium strains at subinhibitory concentrations. Bacteria in the biofilm were more resistant to chlorine as well as to exposure to potassium monopersulfate and chloroheximide acetate than were planktonic bacteria. Identification of M. avium genes involved in biofilm formation and further studies of the effect of antimicrobials on the establishment of biofilm may identify approaches for inhibiting M. avium biofilm formation and colonization.
authors.affiliation: Laboratory of Bacterial Pathogenesis, Kuzell Institute1 and Liposome Research Laboratory2, California Pacific Medical Center Research Institute, San Francisco, CA, USA 3Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 106 Dryden Hall, Corvallis, OR 97331-4804, USA 4Department of Microbiology, College of Sciences, Oregon State University, Corvallis, OR, USA.
authors.forename: George
authors.initials: G
authors.lastname: Carter
authors.affiliation: Laboratory of Bacterial Pathogenesis, Kuzell Institute1 and Liposome Research Laboratory2, California Pacific Medical Center Research Institute, San Francisco, CA, USA 3Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 106 Dryden Hall, Corvallis, OR 97331-4804, USA 4Department of Microbiology, College of Sciences, Oregon State University, Corvallis, OR, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Wu
authors.affiliation: Laboratory of Bacterial Pathogenesis, Kuzell Institute1 and Liposome Research Laboratory2, California Pacific Medical Center Research Institute, San Francisco, CA, USA 3Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 106 Dryden Hall, Corvallis, OR 97331-4804, USA 4Department of Microbiology, College of Sciences, Oregon State University, Corvallis, OR, USA.
authors.forename: Daryl C
authors.initials: DC
authors.lastname: Drummond
authors.affiliation: Laboratory of Bacterial Pathogenesis, Kuzell Institute1 and Liposome Research Laboratory2, California Pacific Medical Center Research Institute, San Francisco, CA, USA 3Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 106 Dryden Hall, Corvallis, OR 97331-4804, USA 4Department of Microbiology, College of Sciences, Oregon State University, Corvallis, OR, USA.
authors.forename: Luiz E
authors.initials: LE
authors.lastname: Bermudez
mesh_terms: D017088:AIDS-Related Opportunistic Infections / Q000382:microbiology; D018441:Biofilms / Q000254:growth & development*; D002244:Carbon / Q000378:metabolism; D002413:Cations, Divalent / Q000494:pharmacology; D017606:Chlorine Compounds / Q000494:pharmacology; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004202:Disinfectants / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D006001:Glycoconjugates / Q000032:analysis; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D015269:Mycobacterium avium Complex / Q000737:chemistry / Q000187:drug effects / Q000254:growth & development*; D015270:Mycobacterium avium-intracellulare Infection / Q000382:microbiology; D011143:Polyvinyl Chloride
chemical_list: D002413:Cations, Divalent; D017606:Chlorine Compounds; D017077:Culture Media, Conditioned; D004202:Disinfectants; D006001:Glycoconjugates; D002244:Carbon; D011143:Polyvinyl Chloride