Factors that Affect Detachment of Bacteria from Biofilm - Research Proposal Example

Biofilms have been shown to be more than 500 times more resistant than free bacteria to antibacterial agents (Costerton et al., 1995).  Because of their high level of resistance and stability, they are able to provide effective reservoirs for pathogens, as well as survival advantages and potential increases in their virulence.  Biofilms have been linked to some human diseases and chronic infections, including kidney stones and cystic fibrosis infections of the lungs (Parsek and Singh, 2003). More than 99% of all bacteria that is present in the world exist in biofilms (Prakash et al., 2003), as a consequence the presence of biofilms and their role with pathogenic bacteria is an important area of study.

Bacteria within and exteriors of biofilms are different than one another in several ways. As well as increased resistance to antibacterial agents, bacteria within biofilms exist in an environment of cooperatively that has a primitive circulatory system and exhibit a primitive form of homeostasis (Costerton et al., 1995). Bacteria attach to biofilms by approaching closely so that a brief association is formed between the bacterium and either the surface or other bacteria already attached. Rough surfaces increase the formation of biofilms as they are more hydrophobic (Prakash et al., 2003)

A particular area of interest in regard to biofilms is the effect that they have on water quality through their presence in systems of water distribution. Microbes that are present in the water are able to form biofilms along the surface of the pipes. The biofilms are anchored firmly to the support and provide protection for the microbes that are part of them. They are stable, self-contained ecosystems and as a consequence are difficult to remove (Block, 1992). There is a relationship between biofilms and the pathogenic bacteria that is present within the system. Cells in the biofilms are able to detach from the biofilms as a consequence of factors both internal and external. This detachment can serve to seed a new site for biofilms and can contaminate the water supply, resulting in the pathogenic bacteria infecting those using the water supply

The scanning electron microscope (SEM) and the environment scanning electron microscope (ESEM) are both used for observing biofilms however these make it difficult to observe the dynamics involved with attachment and detachment to biofilms.  The most effective techniques for observing biofilms have been the use of scanning confocal laser microscopy (SCLM) and the multi-photon form of SCLM (MP-SCLM). These have shown biofilms do not have a consistent, thick structure, but rather consist of a mosaic of structural elements as well as water channels (Keevil, 2003).

These substances provide an important field of research as they have a significant role in human health, with the potential to contaminate the water supply, and their structure makes them difficult to remove. The determination of what factors induce the detachment of bacteria is important both for applications in removing biofilms, and in understanding the processes that occur within them, and between free bacteria in the system and the bacteria in the biofilm.

I propose the use of bacterial biofilms that occur naturally in the water distribution system as the biofilm system to test. Biofilms will be examined both in the lab and in the natural environment, and exposed to a range of different factors to test what effect these have on the stability of the biofilms and on the number of bacteria that is free in the water. The biofilms will also be examined at the microscopic level using microscopy techniques to determine the manner in which bacteria attach and detach from the biofilm.