Planktonic Replication Is Essential for Biofilm Formation byLegionella pneumophilain a Complex Medium under Static and Dynamic Flow Conditions

• DOI: 10.1128/aem.72.4.2885-2895.2006
• Publication Date: 2006-04-06T13:43:49Z
• Authors: Jörg Mampel; Thomas Spirig; Stefan S. Weber; Janus A. J. Haage...; Søren Molin; Hubert Hilbi
• Keywords: Crystal violet; Legionella; Axenic

ABSTRACT Legionella pneumophila persists for a long time in aquatic habitats, where the bacteria associate with biofilms and replicate within protozoan predators. While L. serves as paradigm intracellular growth protozoa, it is less clear whether form or absence of protozoa. In this study, we analyzed surface adherence biofilm formation by rich medium that supported axenic replication. Biofilm virulent strain JR32 clinical environmental isolates was confocal microscopy crystal violet staining. Strain formed on glass surfaces upright polystyrene wells, well pins “inverse” microtiter plates, indicating not simply due to sedimentation bacteria. an fliA mutant lacking alternative sigma factor σ 28 reduced, which demonstrated bacterial factors are required. Accumulation biomass coincided increase optical density at 600 nm ceased when reached stationary phase. neither grew nor inverse system if exchanged twice day. However, after addition Acanthamoeba castellanii , proliferated adhered surfaces. Sessile (surface-attached) planktonic (free-swimming) expressed β-galactosidase activity similar extents, therefore, observed lack proliferation surface-attached impaired protein synthesis metabolic activity. Cocultivation green fluorescent (GFP)- DsRed-labeled led randomly interspersed cells substratum aggregates, no sizeable patches clonally growing were observed. Our findings indicate rather than sessile agreement conclusion, GFP-labeled initially continuous-flow chamber but detached over time; detachment correlated flow rate, there accumulation biomass. Under these conditions, persisted Empedobacter breve Microbacterium sp. Klebsiella pneumoniae other bacteria, suggesting specific interactions between modulate adherence.