Olsson Adam, UMC Groningen, The Netherlands

Listening to bacterial adhesion

A. Olsson, P.K. Sharma, H.C. van der Mei and H.J. Busscher
Department of BioMedical Engineering, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, Netherlands, e-mail a.l.j.olsson@med.umcg.nl

The scientists involved in the study of microbial adhesion has a long tradition of using newly available techniques to increase the knowledge about the complex mechanisms controlling initial attachment, bond maturation and later biofilm formation. One such technique added recently to the repertoire is Quartz Crystal Microbalance with Dissipation (QCM-D) due to its unique nondestructive ability to measure interactions at the bacteria-substrate interface real time without interfering the adhesion process. Voltage across a gold plated AT-cut quartz crystal sets it into lateral resonant vibrations at a frequency f which changes as molecules interact with the sensor surface. Further the QCM-D has additional capability to measure the dissipative nature of the attached mass. In this study we have used a model system consisting of a series of S. salivarus strains with well characterized surface properties. Consequent deduction of different antigen has provided a group of mutants with well defined fibril compositions and length, ranging from the “hairy” fully fimbriated wildtype (HB) to the “bald” non fimbriated HBC12 mutant. Possessing the same physico-chemical characteristics, the QCM-D signal can be affiliated to fibril composition. The results reveal a relation between obtained frequencies and fibril lengths, thus giving information about the distance between substrate and attached cell.