chapter 9 Flashcards
controlling microbes is
controlling our degree of exposure to potentially harmful microbes
4 methods of microbial control used outside of the body are
sterilization, disinfection, decontamination/sanitization, & antisepsis/degermation
sterilization
process that destroys or removes all viable microorganisms (including viruses)
examples of agents (sterilization)
heat, and sterilants
disinfection
is the killing or removal of microorganisms that may cause disease.
examples of agents (disinfection)
bleach, iodine, & heat boiling
decontamination/sanitization
cleansing technique that mechanically removes microorganisms as well as other debris to reduce contamination to safe levels.
examples of agents (decontamination/sanitization)
soaps/detergents & commercial dishwashers
antisepsis/degermation
reduces the number of microbes on the human skin, a form of degermation but on living tissues.
examples of agents (antisepsis/degermation)
alcohol & surgical hand scrubs
chemotherapy
is the use of chemicals to kill or inhibit growth of microbes within host tissue
biocides
are what all agents use to control microbes.
bactericide
a chemical that destroys bacteria (except for those in the endospore stage)
fungicide
a chemical that can kill fungal spores, hyphae, and yeast.
virucide
a chemical that inactivates viruses, especially on living tissues.
sporicide
an agent capable of destroying bacterial endospores
static agents
agents that do not kill but instead inhibit growth!
germicide and microbicide
chemical agents that kill microorganisms.
sepsis
is the growth of microorganisms in the blood and other tissues.
asepsis
is a practice that prevents the entry of infectious agents into a sterile environment (or tissues), preventing infection.
antiseptic techniques
sterile methods that exclude all microbes to antisepsis
antisepsis
are applied directly to exposed body surfaces; wounds, surgical incisions in order to destroy or inhibit pathogens.
bacteristatic
agents that prevent the growth of bacteria on tissues or on objects in the environment.
fungistatic
chemicals that inhibit fungal growth.
critical medical devices
are devices expected to come into contact with sterile tissues
semicritical devices
are devices that come into contact with mucosal membranes
noncritical devices
are devices that do not touch the patient or only expected to touch intact skin– these require disinfection (only)
selective agents
tend to target only a single cellular component and are much more effective against the widest range of microbes.
antimicrobials
have a range of cellular targets, inflicting damage progressively until the cell is no longer able to survive.
agents target the ______ by blocking its synthesis or destroying it.
cell wall
agents target the _________ by disrupting the lipid bilayer, allowing damaging chemicals to enter the cell and important ions to exit the cell.
cytoplasmic membrane
agents target _____________ interrupt the synthesis of proteins via ribosomes.
cellular processes
agents target _________ by denaturing them, breaking protein bonds, protein structure.
proteins
moist heat (boiling water)
DISINFECTION
destroys bacterial cells & viruses.
degrades enzymes, proteins, and nucleic acids.
disrupts cell membranes.
the temperature of moist heat usually ranges from
60-100 degrees celsius
exposure to boiling water for 30 minutes destroys ________ cells, but not ________ spores.
vegetative, bacterial
autoclave
an instrument for sterilizing objects using stem and pressure
pasteurization
a technique using heat in a controlled manner, commonly used on heat sensitive liquids (milk, wine)
dry heat
STERILIZATION
hot or an open flame
dehydrates the cell
dry heat is _____ effective than moist heat.
less
thermal death time (TDT)
is the shortest length of time required to kill all microbes are a specific temperature
thermal death point (TDP)
is the lowest temperature required to kill all microbes in a sample in a given time (usually 10 minutes)
dry heat temperatures are
150-180 degree celsius
radiation
is energy emitted from atomic activities and dispersed at high velocity through matter or space.
UV radiation
lethal form of radiation
has limited uses
cannot penetrate glass, limited for water
gamma radiation and x rays
destroys endospores and vegetative cells.
highly effective alternative for sterilizing materials that are sensitive to heat or chemicals.
filtration
an effective method to remove microbes from air and liquids,
osmotic pressure
adding large amounts of salts or sugars to food to create a hypertonic environment for bacteria
3 levels of antimicrobial properties
high level agents
intermediate level agents
low level agents
high level agents
kill endospores
considered sterilant
intermediate level agents
kill fungal (but NOT bacterial) spores, resistant pathogens and viruses
low level agents
eliminate only vegetative bacteria, vegetative fungi, some viruses
oxidizing agents
ex. HYDROGEN PEROXIDE
kill endospores and all other microbes.
used as an antiseptic
aldehydes
ex. GLUTARALDEHYDE
chemical sterilant that is sporicidal and kills all other microbes.
used to sterilize respiratory equipment; dental instruments.
sterilizing gas
ethylene oxide gas blocks DNA replication and denature enxymes
used to sterilize heat sensitive things; petri dishes, catheters.
phenol/phenolics
used as an disinfectant.
kills some bacteria; viruses and fungi
acts by denaturing proteins and disrupting cell membrane, inactivates enzymes.
advantages of phenol/phenolics
its effective long after its application
disadvantages of phenol/phenolics
its odor and irritation on the skin
alcohols
50-80% concentration–most effective
bactericidal, fungicidal but no sporicidal
95% will cause coagulation of surface/cell wall proteins and prevent passage of alcohol into the cell.
heavy metals (hg, silver, zinc, cu)
used against some bacteria, viruses, fungi.
not a sporicidal agent
