Study of the initial phase of biofilm formation using a biofomic approach

Aims: The purpose of this work was to study the initial steps of formation of a biofilm using the BioFilm Ring Test (R) and the Crystal violet staining technique. Methods and results: Eight strains of Pseudomonas aeruginosa were studied. The two methods revealed that four strains formed a rapid biofilm. The biofilm formed by these strains was detected after only 45 min with the BioFilm Ring Test (R) and after 6 h with the Crystal violet method. The enumeration of bacteria of the PA01 strain confirmed that, after 30 min, a significant amount of bacteria had attached on the bottom of the culture wells. After 48 h the Crystal violet method detected a biofilm with all strains. The four strains which rapidly formed a biofilm did not differ from the slow-forming strains by their mucoid character or their swarming motility or their synthesis of rhamnose. They showed higher swimming mobility. Conclusions: Our results show that the BioFilm Ring Test (R) is a method specially suited for the study of the initial phase of the formation of a biofilm. Significance and impact of study: The BioFilm Ring Test (R) is an easy and rapid alternative to the Crystal violet staining and the enumeration methods. (C) 2010 Elsevier B.V. All rights reserved.