LAB: Microbial Control Flashcards
the removal or destruction of ALL LIVING MICROORGANISMS
Sterilization
The most common method used for killing microbes is
heating
a sterilizing agent is called a __________
liquids and gases can be sterilized by filtration
sterilant
Type of sterilization in which food is subjected only to enough heat to destroy the endospores Clostridium botulinum which can produce a deadly toxin.
commercial sterilization
control directed at destroying harmful microorganisms. USUALLY refers to the destruction of vegetatice pathogens. Make use of chemicals, ultraviolet radiation, boiling water or steam. Most commonly applied to the use of a chemical to treat an inert surface or substance
Disinfection
Destruction of vegetative pathogens on LIVING TISSUE
antisepsis
Removal of microbes from a limited area such as the skin around the injection site
degerming
kills microorganisms
biocide/germicide
inhibit the growth and multiplication of microorganisms
bacteriostasis
decay or putrid
sepsis
the absence of significant contamination
asepsis
factors that influence the effectiveness of antimicrobial treatments
number of microbes
environmental influences
time of exposure
microbial characteristics
actions of microbial control agents include
alteration of membrane permeability
damage to proteins and nucleic acids
How does altering the membrane permeability aid in microbial control?
Damaging the lipids or proteins of the plasma membrane causes cellular contents to leak into the surrounding medium and interferes with the growth of the cell
How does damaging the proteins and nucleic acid of the microbes affect their function?
By damaging these nucleic acids by heat, radiation or chemicals, the cell can no longer replicate nor can it carry out normal metabolic functions.
MODE OF ACTION AND RELIABLY ACTIVE AGAINST:
Bleach
oxidizes proteins, membranes, DNA
vegetative bacteria, fungi , viruses
DISINFECTANT
MODE OF ACTION AND RELIABLY ACTIVE AGAINST:
60-80% alcohol
denatures proteins
damages lipid membranes
vegetative bacteria, fungi, enveloped viruses
Both antiseptic/disinfectant
MODE OF ACTION AND RELIABLY ACTIVE AGAINST:
quaternary ammonium compounds (benzalkonium chloride)
damages lipid membranes
vegetative bacteria (except Pseudomonads), fungi, enveloped viruses
BOTH
MODE OF ACTION AND RELIABLY ACTIVE AGAINST:
Hydrogen peroxide
produces reactive oxygen species that oxidize proteins, membranes, DNA
vegetative bacteria (more effective against anaerobes), fungi and viruses
BOTH
MODE OF ACTION AND RELIABLY ACTIVE AGAINST:
Phenol (thymol)
denatures proteins, damages lipid membranes
veg. bacteria, fungi and enveloped viruses
Active ingredient of : antibacterial hand soap
benzalkonium chloride
Active ingredient of : hand sanitizer
ethyl alcohol
Active ingredient of : Lysol (white)
bleach
Active ingredient of : Lysol
hydrogen peroxide
Active ingredient of : Assured
benzalkonium chloride
Active ingredient of : Seventh generation
thymol
kills microorganisms primarily by coagulating proteins which is caused by breakage of the hydrogen bonds that holds the proteins in their 3d structure. EX. boiling
moist heat sterilization
the preferred method of sterilization. HEAT ABOVE THE TEMP OF BOILING WATER. Method is most effective when the organisms either are contacted by the steam directly or are contained in small volume of aq. liquid. WILL KILL ALL ORGANISMS
autoclave
What method is used to test antibiotic susceptibility
kirby bauer disk diffusion method
Steps on how to perform kirby bauer disk diffusion test
do not touch the plate with the device
4 drops of the four diff types of chemotherepeutic agent concentrated filter paper on the solid agar
MAKE SURE THERE IS EQUAL SEPERATION from one another
Place it right side up
forms around the disk after a standard incubation; the larger the zone the more sensitive the microbe is to the antibiotic. Diameter in mm.
Zone of inhibition
Bacilllus is most & least sensitive to:
vancomycin
tetracycline
Bacitracin
ampicillin
Staphylococcus is most & least sensitive to:
ampicillin
vancomycin
bacitracin
tetracycline (resistant)
E.coli is most & least sensitive to:
ampicilin
tetracyline
RESISTANT TO bacitracin and vancomycin
Pseudomonas is most and least sensitive to:
RESISTANT TO ALL
