11. Effects of Chemical Factors on Mivrosorganism- Disinfection, Groups of Disinfectious and antiseptic agent.
Covers the killing of microorganisms by chemical agents, then separates disinfection from antisepsis and explains the mechanisms, contact times and factors that affect activity. It sets out high-, intermediate- and low-level disinfectants with example agents and concentrations, followed by a group-by-group account of alcohols, halogens, aldehydes, phenolics, oxidants, surfactants and biguanides. It closes with a ranking of microbes from most to least resistant to chemical agents.
Topic 11 of 113 in the MU Sofia syllabus for Microbiology (Medicine, Year 3). The free AceMed note covers it in 7 sections, about 657 words (5 min of reading), with 14 flashcards.
In this note
Effects of Chemical Factors on Mivrosorganism- Disinfection, Groups of Disinfectious and antiseptic agent.
Effects of Chemical Factors on Microorganisms: Disinfection and Antiseptic Agents
Disinfection
Groups and Categories of Disinfectants
Antisepsis and Antiseptic Agents
Specific Groups of Disinfectants and Antiseptics Mentioned:
Relative Resistance to Chemical Agents
Effects of Chemical Factors on Microorganisms: Disinfection and Antiseptic Agents
Chemical agents are used to eliminate microorganisms.
They can be used for sterilization, disinfection, or antisepsis.
The killing of microorganisms by chemical agents follows an exponential kinetic. The killing rate varies among bacterial species. The concentration (c) of chemical agents plays a significant role. Temperature also influences effectiveness.
Cleaning to remove visible dirt and organic matter is an essential first step before sanitising, disinfection, or sterilisation, as organic matter can inactivate some agents.
Disinfection
Disinfection is the use of physical or chemical agents to eliminate most, but not all, microorganisms.
Some microorganisms and spores can survive the process. Endospores tend to survive even when vegetative cells are killed.
The purpose is to render an object incapable of spreading infection.
Disinfectants are applied to the surface of non-living objects (tables, floors, utensils, instruments).
They work by destroying the cell wall or interfering with metabolism. Mechanisms include denaturing proteins, forming reactive oxygen species, or disrupting microbial membranes.
All disinfectants require a contact time for at least 30 seconds.
Their activity can be influenced by factors like temperature, concentration, time, range of action (spectrum), and the presence of organic matter.
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