terminology of microbe control
sterilization |
removal or destruction of ALL microbes in or on an object |
sterilant |
sterilizing agent |
aseptic |
an environment or procedure that is free of all pathogenic contaminants |
sepsis |
microbial contamination |
disinfection |
using physical or chemical agents to destroy microbes/viruses on NON LIVING surface |
antisepsis |
reduction of microbes on LIVING tissue |
degerming |
removing microbes by mechanical means (ex. washing hands with soap) |
sanitization |
removing pathogens from objects to meet public health standard |
pateurization |
use of heat to destroy pathogen |
-stasis/-static |
a chemical or physical agent PREVENTS microbial metabolism and growth |
-cide/ cidal |
agents that destroy or permanently inactivate a particular type of microbe |
physical microbe control
heat sterilization |
uses heat at specific time and temp. to denature and destroy cell membranes can be used to pasteurize, sterilize, sanitize and disinfect |
moist heat (boiling) |
kills vegetative bacterial pathogens, fungi, protozoa, and some virus |
dry heat (pressure chamber) |
most effective sterilization is when the steam penetrates the object |
pasteurization |
not sterilization kills pathogens |
refrigeration and freeze |
freeze - ice crystals puncture cell membranes |
filtration (masks) |
passing fluid through a sieve designed to trap particles (prevents airborne contamination by microbes) |
X rays and gamma rays |
kills microbes by creating oxygen radicals, breaking DNA, and ionizing. |
ultraviolet light |
nonionizing, kills microbes by being absorbed by DNA and creating mutations in DNA |
resistance to drugs
cells can acquire resistance 2 ways |
new mutations, acquiring genes on extra DNA |
enzyme |
destroys or deactivates drug |
prevent entry |
changes in structure to slow or stop entry of drug |
alteration |
alter target to the drug to affect binding |
metabolic chemistry |
resistant drugs can alter or abandon sensitive metabolic steps |
resistance pumps |
cell pumps antimicrobial out of cell |
unusual proteins |
resistance to fluoroquinolone drugs |
cross resistance |
resistance to one antimicrobial agent confers resistance to similar drugs |
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microbial death rates
microbial death |
permanent loss of reproduction ability when in perfect environment |
how to know if antimicrobial agent works |
calculate microbial death rate(microbes die at constant rate) |
action of antimicrobial agents
alteration of cell wall and membranes |
in enveloped membranes when membrane is destroyed no way for viral attachments but non enveloped are have more tolerance to this method because of lack of cell wall. |
damage to proteins and nucleic acid |
extreme heat and chemicals are used to denature the DNA and proteins making the microbe inactive |
chemical microbe control
chemical agents |
destroy enveloped viruses, bacteria, fungi, protozoa, by affecting their cell walls and membranes, DNA and proteins |
phenol |
rarely used because irritates skin and smelly |
phenolics |
by product of phenol (less irritation) it is a low level disinfectant |
alcohols |
intermediate level microbe control that is ineffective against spores. |
halogens |
intermediate level effective agains bacteria/fungal cells and spores, some bacterial endospores, protozoan cysts and some viruses |
oxidizing agents |
high level release oxygen radicals (toxic oxygen). used to kill anaerobes in deep puncture wounds |
surfactants (soap) |
"surface active" chemicals |
aldehydes |
broad spectrum disinfectant (kills many microbe types) inactivate nucleic acids and enzymes |
gaseous agents |
cold sterilization for objects that are heat sensitive, penetrate objects readily destroying proteins and DNA |
natural chemicals |
microbial control produced by organisms |
retarding resistance
administer high concentrations of drug |
use antimicrobials in combination |
limit use of antimicrobials to necessary cases |
development of new variations of existing drugs (e.g. second generation, third generation) |
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influences of antimicrobial treatment
1 number of microbes |
2 environment |
3 time of exposure |
4 microbial characteristics |
ideal microbe control
inexpensive fast acting and stable agents |
controls growth of microbes |
harmless to humans animals and objects |
3 things to consider
site to be treated |
degree of susceptibility of microbes involved |
environment conditions |
drugs
chemotherapeutics |
drugs acting against a disease |
antimicrobials |
drugs used to treat infection |
chemotherapy |
the use of drugs to treat disease |
antibiotics |
naturally produced by an organism |
semisynthesis |
antibiotics chemically altered |
synthesis |
completely synthesized in a lab |
spectrum of antibiotic
narrow spectrum of microbial activity |
work against few types of pathogens |
broad spectrum of microbial activity |
drugs work against many different kinds of pathogens . when pathogen is not able to be identified broad spectrum drug will be used |
safety and side effects
toxicity |
allergies |
disruption of normal microbiota |
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