Adhesion and biofilm formation of non-Candida albicans Candida species on silicone in the presence of urine

Background: An imbalance of intestinal microflora or association of specific pathogens with the intestinal mucosa may contribute to the development of gastrointestinal diseases such as Inflammatory Bowel Disease.Studies of intestinal microflora have generally focused on the characterization of microorganisms in free-swimming form.Recently, studies have demonstrated that microbes grow as biofilms on the gastrointestinal mucosa.The study of biofilms is therefore an important step in understanding the complex nature of the intestinal microflora.This study aimed to characterize the community structure of biofilms formed by mucosal bacteria isolated from the human colon.Methods: Mucosal biopsies of the colon were obtained from healthy patients undergoing screening colonoscopy.Homogenates of the biopsies were used to seed anaerobic biofilms in the Calgary Biofilm Device.Biofilm growth was assessed by viable cell counting and confocal scanning laser microscopy (CSLM), and biofilm community structure was assessed using polymerase chain reaction (PCR), quantitative PCR, and terminal restriction fragment length polymorphism (T-RFLP).Results: The anaerobic biofilms developed quickly and continued to increase in size over a period of up to five days.CSLM imaging of the biofilms demonstrated dense, three-dimensional structures, with biofilms reaching a thickness of between 20 and 80 µm after five days of growth.The biofilm communities showed great diversity, with PCR analysis detecting bacteria from the Bacteroides-Prevotella group, Clostridium coccoides group, Enterobacteriaceae, and the following genera: Bacteroides, Clostridium, Desulfovibrio, Eubacterium, Faecalibacterium, Lactobacillus and Ruminococcus.Community composition, as measured by quantitative PCR, shifted during the growth period.Conclusion: Complex biofilm communities were formed using mucosal bacteria from the human colon.These biofilm communities serve as a "representative microflora", which will be useful in further characterization of host-microbe interactions in the gastrointestinal tract.