Growing and analyzing biofilms in fermenters.

One of the most daunting challenges of biofilm research is comparing experimental results produced by multiple laboratories, each of which uses different techniques to generate, analyze, and interpret biofilm data. The heterogeneity inherent to biofilm communities contributes to the difficulty in obtaining reproducible results between experiments within a single laboratory, but the problem is compounded further by a lack of standardization in techniques. A number of biofilm culture methods are presented in this unit to provide a set of standards for biofilm study. Each model system differs in growth conditions, applied variables, and experimental output, all of which must be carefully considered when designing an experiment and, most critically, during data interpretation. In this unit, two methods of biofilm culture that are known to reliably provide reproducible, statistically clean results in determining the viability and antimicrobial susceptibility of biofilm communities are described. The spinning disc model provides multiple biofilm samples from the same biofilm reactor, significantly reducing data variability. The tube biofilm method, in addition to providing this benefit, can be used for expression analysis, and thus can yield informative data on both macro- and micro-scales. These methods also utilize continuous culture, or chemostat, conditions to maintain a quasi-steady state.