The Principles of Medical Device Decontamination

This essentially relates to breach of skin and mucous membranes by the procedure, allowing the microbiota access to deeper tissues and may lead to infection. Only if the decontamination process has failed to remove microorganisms are they capable of direct transmission to exposed tissues and establish infection.

What are microorganisms?

The simplest way to look at this is to understand the micro element of microorganisms. Micro is derived from both New Latin micro- (“small”) and from Ancient Greek μικρός (mikrós, “small”) 5 and therefore means a small organism, which can normally be studied via a micro-scope. Similarly, this chapter on micro-biology is the study of organisms that are of a small biology.

Clinical microbiology also includes organisms that can be seen without the microscope e.g. worms, insect parasites e.g. fleas and lice but these are more complex organisms. Many are smaller or are detected by finding their eggs using the microscope.

All organisms are classified as either Eucaryote or Procaryote 6 , which are defined at the cellular level. A eucaryote is the more complex organism and the essential difference between a eucaryote and procaryote is the presence of the replicating DNA being bound within a nuclear membrane. Eucaryotes range from the very large giant sequoia trees and blue whales to single celled organisms. By contrast procaryotes are always single celled and lack any internal compartmentalisation.

The decontamination scientist is seeking to make a medical device safe, which requires the inactivation or removal of potentially harmful agents capable of initiating disease including infecting microorganisms.

i Not strictly true, there are bacteria that live in extreme conditions (not known to be human pathogens or even opportunistic pathogens), which do have partitions in their structures 7 .

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