Effect of CSLM imaging rate on biofilms of P. aeruginosa and S. aureus

Du, Reginald
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Biofilms are sessile communities of bacteria that can be found in an wide range of environments. Their inhabitants are phenotypically distinct from plank- tonic bacteria and are capable of forming complex, three-dimensional structures. Biofilms are studied using confocal scanning laser microscopy, or CSLM. This technique uses lasers and Novel Fluorescent Proteins (NFPs) to measure growth and structure formation of single- and multi-species biofilms in situ in three dimensions. We investigate the effects of slow and fast rates of image acquisition on mono- and co-cultures of biofilm forming bacteria: Pseudomonas aeruginosa and Staphylococcus aureus. After calculating growth rates and lag times, we find that fast scanning rates reduce the growth rate of P. aeruginosa in co-culture. Additionally, co-culture speeds up P. aeruginosa growth relative to monoculture when imaged at a slow rate, and fast scanning reverts co-culture growth to monoculture-like behavior. Additionally, a significant lag time is observed for P. aeruginosa grown in co-culture. The observed influence of confocal imaging rate on population dynamics should be considered in future studies to ensure accurate measurement of bacterial phenomena.