AIMS: Colony morphology variants of fish pathogenic Flavobacterium columnare were studied to clarify the role of colony morphology change in the virulence of the bacterium. Typical rhizoid colony (Rz) variants are virulent and moderately adherent, nonrhizoid rough (R) colony variants are nonvirulent and highly adherent, and soft colony (S) variants are nonvirulent and poorly adherent. METHODS AND RESULTS: Chondroitin AC lyase activity, adhesion to polystyrene at different temperatures and after modification of bacterial surface, and lipopolysaccharide (LPS) profiles of the variants were studied. The chondroitinase activity was significantly higher in the virulent, rhizoid variants than in the rough variants of the same strain. Temperature significantly increased the adhesion of rhizoid variants up to 20°C. Modification of bacterial surface suggested that adhesion molecules contain both carbohydrates and proteins. LPS did not differ between the variants of the same strain. CONCLUSIONS: The results suggest that in Fl. columnare both rhizoid colony morphology and high chondroitinase activity are needed for virulence and that temperature may promote the adhesion of the virulent variants to surfaces at fish farms. SIGNIFICANCE AND IMPACT OF THE STUDY: New information is produced on the virulence mechanisms of Fl. columnare and the reasons behind the survival of the bacterium at fish farms.
AIMS: Colony morphology variants of fish pathogenic Flavobacterium columnare were studied to clarify the role of colony morphology change in the virulence of the bacterium. Typical rhizoid colony (Rz) variants are virulent and moderately adherent, nonrhizoid rough (R) colony variants are nonvirulent and highly adherent, and soft colony (S) variants are nonvirulent and poorly adherent. METHODS AND RESULTS: Chondroitin AC lyase activity, adhesion to polystyrene at different temperatures and after modification of bacterial surface, and lipopolysaccharide (LPS) profiles of the variants were studied. The chondroitinase activity was significantly higher in the virulent, rhizoid variants than in the rough variants of the same strain. Temperature significantly increased the adhesion of rhizoid variants up to 20°C. Modification of bacterial surface suggested that adhesion molecules contain both carbohydrates and proteins. LPS did not differ between the variants of the same strain. CONCLUSIONS: The results suggest that in Fl. columnare both rhizoid colony morphology and high chondroitinase activity are needed for virulence and that temperature may promote the adhesion of the virulent variants to surfaces at fish farms. SIGNIFICANCE AND IMPACT OF THE STUDY: New information is produced on the virulence mechanisms of Fl. columnare and the reasons behind the survival of the bacterium at fish farms.
Authors: Nan Li; Yongtao Zhu; Benjamin R LaFrentz; Jason P Evenhuis; David W Hunnicutt; Rachel A Conrad; Paul Barbier; Connor W Gullstrand; Jack E Roets; Jonathan L Powers; Surashree S Kulkarni; Devon H Erbes; Julio C García; Pin Nie; Mark J McBride Journal: Appl Environ Microbiol Date: 2017-11-16 Impact factor: 4.792
Authors: Nicole C Thunes; Rachel A Conrad; Haitham H Mohammed; Yongtao Zhu; Paul Barbier; Jason P Evenhuis; David Perez-Pascual; Jean-Marc Ghigo; Ryan S Lipscomb; John R Schneider; Nan Li; Devon H Erbes; Clayton Birkett; Benjamin R LaFrentz; Timothy J Welch; Mark J McBride Journal: Appl Environ Microbiol Date: 2021-11-24 Impact factor: 5.005
Authors: Annelies Maria Declercq; Johan Aerts; Bart Ampe; Freddy Haesebrouck; Sarah De Saeger; Annemie Decostere Journal: Vet Res Date: 2016-08-17 Impact factor: 3.683
Authors: Annelies Maria Declercq; Freddy Haesebrouck; Wim Van den Broeck; Peter Bossier; Annemie Decostere Journal: Vet Res Date: 2013-04-24 Impact factor: 3.683