Acinetobacter calcoaceticus plays a bridging function in drinking water biofilms

• Autor(a) principal: Simões, Lúcia C.
• Data de Publicação: 2008
• Outros Autores: Simões, M., Vieira, M. J.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/1822/9127
• topic: Autochthonous microflora; Bridging bacteria; Coaggregation; Drinking water; Multispecies biofilm

Intergeneric coaggregation of six drinking water autochthonous heterotrophic bacteria isolated from a model laboratory system were tested for their ability to coaggregate by a visual assay and by two microscopic techniques (epifluorescence and scanning electron microscopies). One isolate, identified as Acinetobacter calcoacticus, was found not only to autoaggregate, but also to coaggregate with four of the five other isolates (Burkholderia cepacia, Methylobacterium sp., Mycobacterium mucogenicum, Sphingomonas capsulata and Staphylococcus sp.) to different degrees as assessed by the visual assay, highlighting a possible bridging function in a biofilm consortium. In its absence, no coaggregation was found. Microscopic observations revealed a higher degree of interaction for all the aggregates than did the visual assay. Heat and protease reversed autoaggregation and coaggregation, suggesting that interactions were lectin-saccharide mediated. The increase/decrease in the level of extracellular proteins and polysaccharides produced during intergeneric bacteria association was not correlated with coaggregation occurrence, but probably with coaggregation strength. The bridging function of A. calcoaceticus was evidenced by multispecies biofilm studies through a strain exclusion process.