MicroBio Chapter 10 Flashcards
A treatment the kills all living cells including viruses and spores from a substance or object
Sterilization
A treatment that reduces the total number of microbes but does not necessarily kill all of them
Disinfection
Reduction of microbial population to levels considered safe by public health standards
Sanitation
A mild disinfectant agent suitable for use on skin surfaces
Antiseptic
Physical methods of destroying microorganisms
H eat
T emperature
D esiccation
O smotic pressure
F filtration
R adiation
Kills microbes by denaturing enzyymes
Heat
Lowest temperature to all bacteria in 10 minutes. Used in purifying water
Thermal Death Point (TDP)
Based on length of time. 90% of bacterial population killed at a given temperature
Decimal Reduction Time (DRT)
Process of preserving heat-sensitive foods. 65 degree Celsius for 30 minutes.
Pasteurization
True or false
In low temperatures, bacteria does not die. They just don’t reproduce.
True
Burning contaminants
Direct flaming
Burns and physically destroys organisms
Incineration
Oxidation at 160 deg C for 2 hours or 170 deg C for 1 hour
Hot air sterilization
The passage of liquid or gas through a filter with pores small enough to retain microbes
Filtration
Filter is made from
Nitrocellulose, acetate
Removing water from microbes
Dessication
Freeze drying is also known as
Lyophilization
Application of high amount of sugar and salt to induce plasmolysis
High osmotic pressure
Use of ionizing and non-ionizing waves to kill bacteria
Radiation
Such as gamma rays and high energy electron beam that can disrupt DNA
Ionizing radiation
An example is UV light, can only penetrate outer surfaces
Non-ionizing radiation
Another name for carbolic acid/lysol. It injures the plasma membrane and denatures proteins. Used by Joseph Lister
Phenols and Phenolics
Can b used alone or in solution buy inactivated with sunlight. It inactivate enzymes and cell components
Halogens
Denatures proteins and dissolve lipids but is not effective against endospores
Alcohol
Includes soap and detergents for skin degerming
Surface Active Agents
Examples re sorbic acid for inhibiting fungus, Nitrate salts to preserve meats and calcium propionate to prevent germination of clostridium
Chemical food preservatives
Examples are silver and mercury for germicidal, copper sulfate for algicide and zinc oxide as antifungal
Heavy Metals
They are antimicrobial compounds which inactivate proteins. Formaldehyde is an example
Aldehydes
Chemicals produced by microorganisms that inhibit growth or kills other microorganisms
Antibiotics
Chemical substances from biological source or produced by chemical synthesis that kills micoorganisms
Antimicrobial agents
Antibiotic from mainly fungal sources
Natural
antibiotic that is chemically-altered natural compounds
Semi-synthetic
Antibiotic that is chemically designed in the lab
Synthetic
An ideal antibacterial agent is
Has selective target
Bactericidal
HIgh therapeutic index ratio of toxic level to therapeutic level)
Inhibitors of cell wall syntheis
Beta-lactams (dirupts NAM-NAG cross linking)
Glycopeptide (effective against gram-positive bacteria
How bacteria resist antibiotics
1.Restrict access of the antibiotic
2.Get rid of the antibiotic or antifungal
3. Change or destroy the antibiotic
4.Change the targets of the antibiotic or antifungal
5. Bypass the effects of the antibiotic
Inhibitors of NA synthesis
Quinolones (targets topoisomerases)
Inhibits membrane function
Polymyxin (membrane phospholipid), Antimetabolites
Inhibitors of Protein syntheis
Aminoglycosides (bactericidal)
Tetracycline (active against mycoplasmas)
Macrolides (active against h.pylori)
Chloramphenicol (active against rickettsiae
They interfere with ribosomes
Inhibitors of protein synthesis