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38 Cards in this Set

  • Front
  • Back
Remove all forms of microbial life
destruction of vegetative pathogens; used on inert, non-living surfaces
destruction of vegetative pathogens on living tissue
lower the microbial count on surfaces – restaurants for example
Aseptic Technique
techniques used to prevent contamination
– kills bacteria
inhibits bacterial growth, Completly stops growth unitl removed
Factors effecting Anitmicrobial activity
Microbial Suscepibility
number of microbes
concentration of agent
environmental conditions (blood)
length of exposure
Slow heating to kill potential food-borne pathogens but not alter the taste, e.g., milk
Heat to 63oC for 30 min
High Temp short time pasteurization
70 degrees C for 15 min
Ultra High Temperature Treatment
140 C for 1 second
European milk
How do you test disinfectant, antiseptic and perservative activity?
disk diffusion test
dilution test
15psi 121 c for 15min
Ionizing radiation
<1nm in wavelength
Ionizes water to create hydroxyl radicals or toxic forms of oxygen both of which react with DNA and other organic cellular components
Nonionizing radiation -
1nm in wavelength
UV for example – damages DNA by causing thymine dimers which inhibit DNA replication

260 nm most effective – germicidal lamps used in hospital rooms, operating rooms research labs.
filter sterilization
seful for sterilizing fluids that cannot withstand autoclaving – organic supplements, antibiotics, enzyme solutions

Depends on pore size – 0.22 um for bacteria

0.01um for some viruses and large proteins
Physical methods of Controling microbial growth
Heat-Protien denature
Direct flaming- incineration
Filter-seperate from liquid
Cold-decreases chem reactions
High pressure-changes structure of proteins and Carbs
Dessication-disrupts metabolism
ossmotic pressure-plasmolysis
Radiation-damages DNA
Water removed by vacuum or low temp, best for preserving cultures longterm
What do Phenols and Phenolics target in bacteria?
injure the plasma membrane
Lister first used _______as a disinfectant
What do bisphenols target in bacteria? What is an example of a bisphenol?
Plasma membrane
Example: triclosans – antibacterial soaps
– incorporated into cutting boards and counter tops
– inhibits fatty acid biosynthesis
– may increase antibiotic resistance in bacteria
What do Quaternary Ammonium compounds target?
Quats – modification of four valent ammonium compounds
– action unknown but probably the plasma membrane
Alcohols target what?

Ideal concentration?
denature proteins and / or disrupt membrane
Degerming – before a shot
70% is optimum concentration of ethanol – the 30% water seems to help its penetrating action
Halogen target
iodine and chlorine – seem to interfere with protein function
Heavy metal target
denatures proteins

Silver used in newborns to prevent gonorrheal ophthalmia neonatorum
Aldehyde target
Protein denature
Gassous Chemosterilizer target?

Peroxygen action?
protein denature

Chemical food Preservatives
Orgainic acid

Organic-inhibits metabolism

Nitrites-inhibit iron containing enzymes
Who discovered penicillin?

What do penicillins affect?
Alezander Flemming

Inhibit cell wall
Who founded chemotherapy and with what drug?
Paul Ehrlich- salvarsan for siphalis
What antibiotics work by inhibiting cell wall synthesis?
What antibiotics work by inhibiting protein synthesis?
What antibiotics work by inhibiting neuclic acid replication and trascription?
What antibiotics work by inhibiting synthesis of essential metabolites?
What antibiotics work by injury to plasma membrane?
polymyxin B
How does penicillin inhibit cell wall synthesis?

What is a broad spectrum derivative of penicillin?
prevents cross linking of peptidoglycan

How has penicillin been changes to work better? 3 ways
1. Acid resistance
2. Penicillinase resistance
3. broad spectrum
How does bacteria become resistant to antibiotics?
Acquired by either mutation in the pathogen’s chromosome or by direct transfer of R-factor plasmids.
Sensitive microbes may become resistant to a drug by gaining the ability to:
Inactivate or destroy the antibiotic
Alter their own membranes
Alter the target site
Rapid efflux