Lecture 9- Microbial Growth And Control Flashcards
To be a good chemical agent a disinfectant must be what?
Be effective against a wide variety of infectious agents at low concentrations.
What is the purpose of use dilution tests?
To determine the rate at which selected bacteria are destroyed by various chemical agents.
What are chemotherapeutic agents and what do they do?
Chemical agents used to treat disease.
They destroy pathogenic microbes or inhibit their growth within host.
Selective toxicity?
Ability of drug to kill or inhibit pathogen while damaging host as little as possible
Therapeutic dose/
Drug level required for clinical treatment.
Toxic dose?
Drug level at which drug becomes too toxic for patient (I.e., produces side effects)
Therapeutic index?
Ratio of toxic dose to therapeutic dose.
Side effects?
Undesirable effects of drugs on host cells.
Narrow-spectrum drugs?
Attack only a few different pathogens.
Broad-spectrum drugs?
Attack many different pathogens.
Cidal agents do what?
Kill microbes
Static agents do what?
Inhibit the growth of microbes.
Minimal inhibitory concentration (MIC)?
Lowest concentration of drug that inhibits growth of the pathogen.
Minimal lethal concentration (MLC)/ Minimal Bacteriocidal concentration (MBC)?
Lowest concentration of drug that kills pathogen.
List 4 mechanisms that that antimicrobial drugs can fall under.
- inhibitors of cell wall synthesis
- Protein synthesis inhibitors
- Metabolic antagonists
- Nucleic acid synthesis inhibition
Factors influencing antimicrobial drugs?
- Ability of drug to reach site of infection
- Susceptibility of pathogen to drug
- Ability of drug to reach concentrations in body that exceed MIC of pathogen
What are some mechanisms of rug resistance?
- Preventing entrance of the drug
- Drug efflux (pumping the drug out of the cell)
- Modification of target enzyme or organelle
- Use of alternative pathways or increased production of target metabolite
In terms of drug combinations, what is synergism?
When the effect of two drugs together is greater than the effect of either one alone.
In terms of drug combinations, what is antagonism?
When the effect of two drugs together is less than the effect of either alone.
Sterilization?
Destruction or removal of all viable organisms.
Disinfection?
Killing, inhibition, or removal of disease causing (pathogenic) organisms.
Sanitization?
Reduction of microbial population to levels deemed safe (based on public health standards).
Antisepsis?
Prevention of infection of living tissue by microorganism.
Chemotherapy?
Use of chemicals to kill or inhibit growth of micro organisms within host tissue.
Pateurization
Controlled heating a temperatures well below boiling
Does not sterilize but does kill pathogens present and slow spoilage by reducing the total load of the organisms present
