infection control

*Inhibits enzyme activity
*Drying of microorganism from a frozen state
*Drying takes place under a high vacuum which removes water
*Organisms can remain viable in this state for many years
*Used to preserve microogranisms

*Affects microbe's nucleic acids impairing microbial functions
*denatures proteins
*Used in biological hoods and surgical fields in healthcare
*Microwave ovens can kill microorganisms however, endospore contain little water and are therefore not destroyed my microwave cooking

*Mechanically removes organisms
*Requires filters with very small pores
*Highly-efficiency particulate air (HEPA) filters are used in healthcare ventilation systems to trap organisms
*Filters are then disinfected prior to disposal

Action against microbe but not harmful to host (patient)

range of effectiveness

contradictions of use

effect on microbes

Microbes resist effects of antimicrobial agent

Level at which the antimicrobial agent will cause host damage
*Liver and kidney involvement

Level at which the antimicrobial agent eliminates the patogenic organism if the level is maintained over a period of time

The maximum tolerable dose per body weight that will eradicate infection

-Antibiotics that attack a large range of microbial agents
-May attack gram positive or gram negative organisms
-Can be ordered after gram stain result of a specimen

-Attack a much smaller group of microbial species
-Ordered after susceptibility testing indicates the drug of choice for the pathogen
-Limits drug resistancy because fewer organisms are eliminated

*Penicillin
*Ampicillin
*Amoxicillin
*cephalosporins

*polymyxin

*Gentamicin
*Tobramycin
*Tetracycline
*erthyromycin

*rifampin

*Sulfa agents
*Isoniazid (INH)

-Can adversely affect liver, kidney, central nervous system, hearing, balance, bone marrow, and the gastrointestinal tract

-Mild->rash, swelling, itching
-Life threatening->anaphylactic shock

-Pathogens and normal flora are destroyed by antimicrobial therapy
-can give rise to a secondary infection often referred to as a "superinfection"

microbes migrate out of the reach of the antimicrobials and are not eradicated

some microbes can modify their structure which can inhibit the attachment of the antimicrobial agent to the microbe and therefore impair its action against the microbe

genetic information code for endospores or capsules can inhibit the action of antimicrobials

transfer of resistant genes from one organism to another

*Do not over use Antibiotics
*use Narrow Spectrum Antibiotics
*Be compliant and take the antibiotics for the complete duration of the prescription

Purpose is to determine the appropriate antibiotic that will eradicate an infection
-disk diffusion
-tube dilution

*Based on a theory that a specific amount of drug will diffuse on a culture media that has been inoculated with a blanket of microbial growth and that zones of inhibition around the drugs will determine the effectiveness of the drug to treat the microbial agent
*Qualitative measurement
-The validity of the procedure lies with standardizations that must be followed precisely to achieve accurate results

-Agar used is Mueller-Hinton (enrichment media)
-Increased volume of agar causes decrease diffusion rate of drugs resulting in smaller zones of inhibition
-Decrease volume of agar causes increased diffusion rate of drugs resulting in larger zones of inhibition

-increased concentratioon of the organism results in overgrowth of the organism and smaller zones of inhibition

-Disks are impregnated with specific concentrations of a drug which correlate with established zones of inhibition used for the reporting system of this method

Overnight incubation to allow organism to grow

35'C-37'C

indictates that a drug will be able to eradicate an organism if patient is compliant

indicates that a drug may work if combined with other anitmicrobials to increase its' effectiveness (synergism)

indicates the drug will not be effective in eradicating infection

*Based on the same theory as the disk diffusion test except that the method uses a liquid medium to determine drugs of choice to eradicate infection
*Quantitative measurement (an actual number)
*Standards are similar to disk diffusion test
-Amount of Organism
-Amount of Antibiotic
-Time of incubation
-Incubation Temperature (35'C-37'C)

minimum concentration of a drug that will prevent visable growth of the organism

minimum concentration of a drug that shows no growth from a tube when subcultured

*Selectively Toxic
*Soluble in Body Fluids
*Easily maintained at therapeutic dosage levels
*Inexpensive
*Does not elicit drug resistance
*Long shelf-life

-Thickens cell wall interfering with the intake of nutrients
-Increases cell wall permeablility
-Inhibits nucleic acid syntheis
Examples:
Amphotericin B
Nystatin (very effective for a yeast infection)

-Inhibits some phase of replication
-Inhibit attachment of virus to host cell
-Inhibit penetration of virus into host cell
Examples:
Acyclovir
Interferon- naturally produced antiviral agent

-Interfere with protein synthesis
-Interfere with folic acid synthesis
Examples:
Quinine
Metronidazole (Flagyl)

-Interfere with carbohydrate metabolism
-Paralyze worms (neurotoxins)
Examples:
Mebendazole (Vermox)
Piperazine (Antepar)