Effect of physiochemical factors on autoaggregation and adhesion of Flavobacterium johnsoniae-like isolates

Abstract

Flavobacterium johnsoniae-like isolates are able to form biofilms and have been associated with disease outbreaks in fish. Surface colonization requires microbial adhesion strategies that are mediated by specific surface-associated molecules. Blocking or inhibiting these molecules would facilitate the identification of adhesins involved in surface adherence and development of appropriate anti-adhesion strategies for F. johnsoniae-like isolates. Autoaggregation and adhesion assays were performed using F. johnsoniae-like isolates and Flavobacterium spp. type strains to determine the anti-adhesion effect of heat, proteinase K, glucose, galactose, mannose, and sodium metaperiodate. Majority of the isolates (~85%) displayed decreased autoaggregation following heat treatment, while ~80% and 100% of isolates demonstrated increased autoaggegation following proteinase K and sodium metaperiodate treatments. Although carbohydrate treatments increased autoaggregation indices, they were not significant. Heat, proteinase K, sodium metaperiodate (SMP), glucose and galactose treatments significantly decreased adhesion of flavobacterial isolates to microtitre plates under static conditions, but not under dynamic conditions. Autoaggregation and surface adhesion by F. johnsoniae-like isolates appears to be mediated by chemically diverse groups of adhesins and receptors, given the diverse responses observed following treatment of cells. Glycoprotein molecules form part of the complement involved in mediating successful attachment of Flavobacterium spp. isolates to surfaces. To prevent attachment and recurring infections by F. johnsoniae-like isolates, understanding the type of adhesin-receptor interactions in adhesion is critical. This will allow the development of strategies to disrupt initial attachment and prevent biofilm formation by Flavobacterium spp.