title: Acoustic vibration can enhance bacterial biofilm formation.
abstract: This paper explores the use of low-frequency-low-amplitude acoustic vibration on biofilm formation. Biofilm development is thought to be governed by a diverse range of environmental signals and much effort has gone into researching the effects of environmental factors including; nutrient availability, pH and temperature on the growth of biofilms. Many biofilm-forming organisms have evolved to thrive in mechanically challenging environments, for example soil yet, the effects of the physical environment on biofilm formation has been largely ignored. Exposure of Pseudomonas aeruginosa to vibration at 100, 800 and 1600 Hz for 48 h, resulted in a significant increase in biofilm formation compared with the control, with the greatest growth seen at 800 Hz vibration. The results also show that this increase in biofilm formation is accompanied with an increase in P. aeruginosa cell number. Acoustic vibration was also found to regulate the spatial distribution of biofilm formation in a frequency-dependent manner. Exposure of Staphylococcus aureus to acoustic vibration also resulted in enhanced biofilm formation with the greatest level of biofilm being formed following 48 h exposure at 1600 Hz. These results show that acoustic vibration can be used to control biofilm formation and therefore presents a novel and potentially cost effective means to manipulate the development and yield of biofilms in a range of important industrial and medical processes.
authors.affiliation: General Engineering Research Institute, Liverpool John Moores University, Liverpool L33AF, UK; School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool L33AF, UK. Electronic address: m.f.murphy@ljmu.ac.uk.
authors.forename: Mark F
authors.initials: MF
authors.lastname: Murphy
authors.affiliation: School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool L33AF, UK. Electronic address: Thomas.Edwards@lstmed.ac.uk.
authors.forename: Thomas
authors.initials: T
authors.lastname: Edwards
authors.affiliation: School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool L33AF, UK. Electronic address: G.Hobbs@ljmu.ac.uk.
authors.forename: Glyn
authors.initials: G
authors.lastname: Hobbs
authors.affiliation: School of Clinical Dentistry, University of Sheffield, Sheffield S102TA, UK. Electronic address: J.Shepherd@sheffield.ac.uk.
authors.forename: Joanna
authors.initials: J
authors.lastname: Shepherd
authors.affiliation: General Engineering Research Institute, Liverpool John Moores University, Liverpool L33AF, UK. Electronic address: F.Bezombes@ljmu.ac.uk.
authors.forename: Frederic
authors.initials: F
authors.lastname: Bezombes
mesh_terms: D058491:Bacterial Load / Q000528:radiation effects; D018441:Biofilms / Q000528:radiation effects*; D008828:Microbiological Techniques; D011550:Pseudomonas aeruginosa / Q000254:growth & development / Q000528:radiation effects*; D013016:Sound; D013211:Staphylococcus aureus / Q000254:growth & development / Q000528:radiation effects*; D014732:Vibration
keywords: Acoustic vibration; Enhanced biofilm formation; Increased cell number; Pseudomonas aeruginosa; Staphylococcus aureus