title: The ability to form biofilm influences Mycobacterium avium invasion and translocation of bronchial epithelial cells.
abstract: Organisms of the Mycobacterium avium complex (MAC) are widely distributed in the environment, form biofilms in water pipes and potable water tanks, and cause chronic lung infections in patients with chronic obstructive pulmonary disease and cystic fibrosis. Pathological studies in patients with pulmonary MAC infection revealed granulomatous inflammation around bronchi and bronchioles. BEAS-2B human bronchial epithelial cell line was used to study MAC invasion. MAC strain A5 entered polarized BEAS-2B cells with an efficiency of 0.1 +/- 0.03% in 2 h and 11.3 +/- 4.0% in 24 h. In contrast, biofilm-deficient transposon mutants 5G4, 6H9 and 9B5 showed impaired invasion. Bacteria exposed to BEAS-2B cells for 24 h had greater ability to invade BEAS-2B cells compared with bacteria incubated in broth. M. avium had no impact on the monolayer transmembrane resistance. Scanning electron microscopy showed that MAC A5 forms aggregates on the surface of BEAS-2B cell monolayers, and transmission electron microscopy evidenced MAC within vacuoles in BEAS-2B cells. Cells infected with the 5G4 mutant, however, showed significantly fewer bacteria and no aggregates on the cell surface. Mutants had impaired ability to cause infection in mice, as well. The ability to form biofilm appeared to be associated with the invasiveness of MAC A5.
authors.affiliation: Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Yamazaki
authors.forename: Lia
authors.initials: L
authors.lastname: Danelishvili
authors.forename: Martin
authors.initials: M
authors.lastname: Wu
authors.forename: Eiko
authors.initials: E
authors.lastname: Hidaka
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Katsuyama
authors.forename: Bernadette
authors.initials: B
authors.lastname: Stang
authors.forename: Mary
authors.initials: M
authors.lastname: Petrofsky
authors.forename: Robert
authors.initials: R
authors.lastname: Bildfell
authors.forename: Luiz E
authors.initials: LE
authors.lastname: Bermudez
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion; D018441:Biofilms; D001980:Bronchi / Q000382:microbiology / Q000473:pathology; D002460:Cell Line; D004251:DNA Transposable Elements; D004847:Epithelial Cells / Q000382:microbiology* / Q000502:physiology / Q000648:ultrastructure; D006801:Humans; D019012:Integrin beta1 / Q000502:physiology; D051379:Mice; D008854:Microscopy, Electron; D009154:Mutation; D015269:Mycobacterium avium Complex / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D015270:Mycobacterium avium-intracellulare Infection / Q000382:microbiology*; D020545:Respiratory Mucosa / Q000382:microbiology* / Q000473:pathology
chemical_list: D004251:DNA Transposable Elements; D019012:Integrin beta1