fficial definition: "Disinfection--killing of pathogenic agents by chemical or physical means directly applied (1:19)." Finally, Block (1991) notes that there are at least five different elements which should be included in any definition of disinfection. These are that a "disinfectant (1) removes infection, (2) kills, not just inhibits, microorganisms in the vegetative stage, (3) does not necessarily kill spores, (4) is ordinarily a chemical but can be a physical agent, and (5) is used only on inanimate objects, not on the human or animal body (1:19)."
The disinfectants employed in this experiment do not fulfill all of Block's (1991) requirements. All three might be used on the human body. For example, shortly after its discovery in 1834, phenol (also known as carbolic acid) was applied to sewage and garbage as a deodorant. However, somewhat later, the weak acid was also used to treat wounds (2:14-15). Likewise, both oxacillin and cefotetan might be used for therapeutic purposes.
Considerable time and effort has been spent studying the effects of different chemical agents on microorganisms. Regardless though, the precise mechanism of action for many disinfectants remains unknown (6:36-38). Several attack either the bacterial cell wall or the underlying cytoplasmic membrane. Phenol may cause membrane leakage and protein denaturation. These process
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