RESUMEN
An Escherichia coli K-12 biofilm was grown at a dilution rate of 0.028 h(-1) for 48 h in a glucose-limited chemostat coupled to a modified Robbins' device to determine its susceptibility to infection by bacteriophage T4. Bacteriophage T4 at a multiplicity of infection (MOI) of 10 caused a log reduction in biofilm density (expressed as colony forming units (CFU) per cm2) at 90 min postinfection. After 6 h, a net decrease and equilibrium in viral titer was seen. When biofilms were exposed to T4 phage at a MOI of 100, viral titer doubled after 90 min. After 6 h, viral titers (expressed as plaque forming units (PFU) per cm2) stabilized at levels approximately one order of magnitude higher than seen at a MOI of 10. Scanning confocal laser microscopy images also indicated disruption of biofilm morphology following T4 infection with the effects being more pronounced at a MOI of 100 than at a MOI of 10. These results imply that biofilms under carbon limitation can act as natural reservoirs for bacteriophage and that bacteriophage can have some influence on biofilm morphology.
Asunto(s)
Bacteriófago T4/crecimiento & desarrollo , Bacteriófago T4/patogenicidad , Biopelículas/crecimiento & desarrollo , Escherichia coli/crecimiento & desarrollo , Glucosa/metabolismo , Recuento de Colonia Microbiana , Medios de Cultivo , Escherichia coli/virologíaRESUMEN
Phenotypic characterization will be a pivotal aspect of future research in understanding the biofilm mode of growth. We hope that the concepts and techniques presented in this chapter will benefit other investigators in this field. Although initial studies will necessarily involve monocultures, eventually mixed culture work will have to be performed to understand biofilm growth in the natural environment. As the study of biofilm-phage interactions is new, there is considerable fundamental work that needs to be addressed. Here, we anticipate that some phage are better adapted to growth in biofilms, some are adept in growing in mixed culture biofilms, and others are better adapted to infecting planktonic organisms. Whereas biofilms are now widely accepted as a fundamental aspect of microbial growth in nature, the field of phage ecology is quite new and an exciting challenge for the future.