Determining the dispersion time in biofilm using physical and molecular approaches.

Despite being an innocuous commensal of human skin and mucous membranes, infects surgical wounds and causes infections through biofilm formation. This study evaluates, in a time-dependent experiment, the self-dispersion of CIP 444 biofilm when formed on borosilicate glass (hydrophilic) and polystyrene (hydrophobic) surfaces, using physical and molecular approaches. During a seven-day period of incubation, absorbance measurement revealed a drop in biofilm optical density on both studied surfaces on day 4 (0.043-0.035 nm/cm, polystyrene), (0.06-0.053 nm/cm, borosilicate glass). Absorbance results were correlated with crystal violet staining that showed a clear detachment from day 4. The blue color increases again on day 7, with an increase in biofilm optical density indicating the regeneration of the biofilm. Changes in gene expression in the biofilm were assessed using a real-time reverse transcription-polymerase chain reaction. High expression of genes was detected on days 4 and 5, confirming our supposition of dispersion in this period, autolysin genes like and were upregulated from day 3 until day 6 and the genes responsible for slime production and biofilm accumulation were upregulated on days 4, 5, and 6 () and on days 5, 6 and 7 (), indicating a dual process taking place. These findings suggest that CIP 444 biofilms disperse at day 4 and reform at day 7. Over the course of the seven-day investigation, 2 results showed that some genes in the biofilm were dramatically enhanced while others were significantly decreased as compared to planktonic ones.