Determining the dispersion time in Staphylococcus epidermidis biofilm using physical and molecular approaches
Suzanne Jonblat,
Falah As-sadi,
Andre El Khoury,
Neressa Badr,
Mireille Kallassy,
Ali Chokr
Affiliations
Suzanne Jonblat
Research Laboratory of Microbiology (RLM), Department of Life and Earth Sciences, Faculty of Sciences I, Lebanese University, Hadat Campus, Beirut, Lebanon; Functional Genomic and Proteomic Laboratory, Faculté des Sciences, Université Saint-Joseph de Beyrouth, Campus des Sciences et Technologies, Mar Roukos, Matn, Lebanon; Centre d'Analyses et de Recherche (CAR), Unité de Recherche Technologies et Valorisation Agro-Alimentaire (UR-TVA), Faculté des Sciences, Université Saint-Joseph de Beyrouth, Campus des Sciences et Technologies, Mar Roukos, Matn, Lebanon; Platform of Research and Analysis in Environmental Sciences (PRASE), Doctoral School of Sciences and Technologies, Lebanese University, Hadat Campus, Beirut, Lebanon
Falah As-sadi
Research Laboratory of Microbiology (RLM), Department of Life and Earth Sciences, Faculty of Sciences I, Lebanese University, Hadat Campus, Beirut, Lebanon; Department of Plant Production, Faculty of Agriculture and Veterinary Medicine, Lebanese University, Beirut, 999095, Lebanon
Andre El Khoury
Centre d'Analyses et de Recherche (CAR), Unité de Recherche Technologies et Valorisation Agro-Alimentaire (UR-TVA), Faculté des Sciences, Université Saint-Joseph de Beyrouth, Campus des Sciences et Technologies, Mar Roukos, Matn, Lebanon
Neressa Badr
Research Laboratory of Microbiology (RLM), Department of Life and Earth Sciences, Faculty of Sciences I, Lebanese University, Hadat Campus, Beirut, Lebanon
Mireille Kallassy
Functional Genomic and Proteomic Laboratory, Faculté des Sciences, Université Saint-Joseph de Beyrouth, Campus des Sciences et Technologies, Mar Roukos, Matn, Lebanon
Ali Chokr
Research Laboratory of Microbiology (RLM), Department of Life and Earth Sciences, Faculty of Sciences I, Lebanese University, Hadat Campus, Beirut, Lebanon; Platform of Research and Analysis in Environmental Sciences (PRASE), Doctoral School of Sciences and Technologies, Lebanese University, Hadat Campus, Beirut, Lebanon; Corresponding author. Research Laboratory of Microbiology (RLM), Department of Life and Earth Sciences, Faculty of Sciences I, Lebanese University, Hadat Campus, Beirut, Lebanon.
Despite being an innocuous commensal of human skin and mucous membranes, Staphylococcus epidermidis, infects surgical wounds and causes infections through biofilm formation. This study evaluates, in a time-dependent experiment, the self-dispersion of S. epidermidis 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/cm2, polystyrene), (0.06–0.053 nm/cm2, 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 S. epidermidis biofilm were assessed using a real-time reverse transcription-polymerase chain reaction. High expression of agr genes was detected on days 4 and 5, confirming our supposition of dispersion in this period, autolysin genes like atlE1 and aae 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 (ica ADBC) and on days 5, 6 and 7 (aap), indicating a dual process taking place. These findings suggest that S. epidermidis CIP 444 biofilms disperse at day 4 and reform at day 7. Over the course of the seven-day investigation, 2-ΔΔCt results showed that some genes in the biofilm were dramatically enhanced while others were significantly decreased as compared to planktonic ones.
