Contamination, Infection and Fouling

Contamination refers to the non-intended introduction of infectious microorganisms such as bacteria, yeast, fungi, and protozoans as well as viruses and prions. This also includes contamination by toxins such as endotoxins, exotoxins and any by-products.

Infection refers to an invasion of body tissues by microbes. The outcome of this depends on many factors. If an infection is left unchecked it can develop into disease. Disease sets in when you have a change from a healthy state to ill state from microbes living in the tissue. Many infections are taken care of by the immune system and do not develop into disease.

Fouling refers to an accumulation of unwanted material on a surface that is harmful to its function. Fouling substances may be living organisms or non-living substances of inorganic or organic nature. Fouling in the form of proteins, cells, and bacterial attachment on medical devices alters device performance and can lead to patient infection. Fouling is common on bio-sensors, cardiovascular implants, catheters, contact lenses, and surgical tools.

Fouling is of particular concern to the food industry, medical community, and research facilities. Microbial fouling and antibiotic resistant bacteria are found everywhere. The development of new technologies are always on the horizon that may help prevent fouling of surfaces and inhibit biofilm formation. More recently, Oak Ridge National Laboratory has developed an active composite material that can be directly, or remotely activated to alter physically or chemically a surface to prevent microorganism fouling or at least destabilize its formation. The idea is to apply a stimulus to a material structure altering its nanostructure properties. This in turn has the ability to obstruct bacterial fouling. They believe this would work on catheters, drug delivery devices and shunts. This could also be used on joint replacement materials, prosthetics, and other devices for the long term. This type of technology carries economic significance for reduction in nosocomial infections (hospital-acquired infections) and costs ssociated with mortality rates due to contamination, fouling, and infection. A number of active material technologies are on their way.