[43] In vitro and in Vivo models of bacterial biofilms

This chapter focuses on several methods that have been developed in the laboratory to form bacterial biofilm models in vitro and in vivo, as well as several methods developed to investigate the nature of biofilm bacteria. Ideal properties sought in an in vitro bacterial biofilm model are uniform film formation, uniform reproducibility, and the ability to be investigated quantitatively. However, the ability to mimic a highly complicated in vivo condition is desirable in an in vitro model. There have been relatively few reports on in vivo models of biofilm growth. One of the most difficult challenges to overcome is to devise a durable infection model. Generally, it takes several days for infected bacteria to form biofilms in an infected tissue or organ, and it takes several days longer to investigate the therapeutic effect of a drug after the biofilm mode of growth of the infected bacteria has been established. Ideally, the infection should continue in a stable condition for more than 7–10 days. Respiratory tract infections, urinary tract infections, infective endocarditis, foreign body infections, and so forth are typical infectious diseases in which the biofilm mode of bacterial growth is sometimes characteristic. Therefore, these diseases should be taken into account in making a useful in vivo experimental biofilm infection model.