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Antimicrobial chemo
Chavez; Principles of Antimicrobial Chemotherapy
Question | Answer |
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Define Chemotherapy. | Chemotherapy: the use of drugs to eradicate pathogenic organisms or neoplastic cells in the treatment of infectious diseases or cancer. used in the treatment, relief, or prevention of a disease |
Define Prophylaxis. | Prophylaxis: Use of a drug to prevent imminent infection of a person at risk |
What are the sub-classes of antimicrobial drugs? | antibacterial, antifungal, & antiviral agents. |
Define antimicrobials? | All-inclusive term for any antimicrobial drug regardless of its origin. Includes antibiotics and synthetic compounds. |
Define antibiotics. | Substances produced by the natural metabolic processes of some microorganisms that can inhibit or destroy other microorganisms. |
Define synthetic drug. | The use of chemical reactions to synthesize antimicrobial compounds in the laboratory. |
Define semisynthetic drugs. | Drugs which are chemically modified in the laboratory after being isolated from natural sources. |
What is meant by Narrow Spectrum? | Narrow Spectrum; (limited spectrum) antimicrobials effective against a limited array of microbial types - for example, a drug effective mainly on gram-positive bacteria. |
What is meant by Broad spectrum? | Broad Spectrum: (extended spectrum) Antimicrobials effective against a wide variety of microbial types -- for example, a drug effectie against both gram-positive and gram-negative bacteria |
What is Paul Ehrlich (1854-1915) known for? | -1908 Nobel for studies of immunity. -Magic Bullets -Receptor theory. -Developed 1st theories for syphilis |
Who discovered penicillin? | Sir Alexander FLEMING, Sir Howard FLOREY, & Ernst CHAIN (1928) |
What year was penicillin discovered? | 1928 |
What year was sulfanilamide first used in clinical practice? | 1936 |
What year was penicillin first used in clinical practice? | 1941 |
What drugs did WWII introduce? | -Streptomycin -Chloramphenicol -Chlortetracycline |
What are some characteristics of the Ideal Antimicrobial Drug? | -nontoxic to host cells -Microbicidal -Relatively soluble. -Potent long enough -doesn't lead to resistance -readily delivered to site of infection -Reasonably priced -Remains active in bodily tissues and body fluids |
What is involved in choosing the right antimicrobial drug? | -ID infective organism and its sensitivity -Drug interactions/combinations -Site of infection -Toxicity of the drug -Patient factors -Cost |
What is the difference between a bactericidal drug and a bacteriostatic drug? | a bactericidal drug kilss sensitive organisms so that the number of viable organisms falls rapidly after exposure to the drug. A bacteriostatic drug INHIBITS the growth of bacteria but does not kill them. |
What is minimal inhibitory concentration (MIC)? | MIC is the lowest concetration of a drug that inhibits bacterial growth. |
MIC is categorized into three categories: susceptibility, intermedicate sensitivity, or resistance. What does this mean? | The catergories are based on the relationship between the MIC & the peak serum concentration of the drug after an initial dose. The peak serum concentration of the drug should be 4 to 10 times greater that the MIC in order for a pathogen to be susceptible |
Describe the disk diffusion method of determining microbial sensitivity. | Test organism streak on agar. Antiobiotic disks are added. Antiobiotic diffuses from the disk and inhibits bacterial growth. The zone diameter for each antibiotic is compared and determined susceptible, intermediated, or resistant. |
What antimicrobial drugs inhibit cell wall synthesis? | (beta-lactams)*Penicillins-(Penicillin G) Amoxicillin(Amoxil)- Amoxicillin+clavulanic acid(Augmentin) *Cephalosporins-Cephalexin(Keflex)–1 Cefaclor(Ceclor)–2 Cefotaxime(Claforan)-3 Cefepime(Maxipime) *Imipenem-Cilastin *Aztreonam *Vancomycin (Vancocin) |
What antimicrobial drug are inhibitors of nucleic acid function? | Fluoroquinolones- Ciprofloxacin (Cipro) |
What antimicrobial drugs are inhibitors of metabolism? (folate synthesis inhibitors) | Sulfonamides- Sulfisoxazole |
What antimicrobial durgs are protein synthesis inhibitors? | Tetracylines -Tetracycline. Aminoglycosides -Streptomycin. Macrolides -Erythromycin. - |
Should peak serum levels of a drug be below, at, or above their MIC levels to eliminate an organism? | The peak serum concentration of an antimicrobial drug should be several times greater than the MIC of the pathogenic organism from the drug to eliminate the organism. b/c tissue concentration of a drug are lower than plasma concentrations |
When thinking about patient factors what would be the difference between a yound child and an aging adult? | -The young have growing bones and low liver function. -The elderly have reduced kidney function |
What are some things you have to think about when the site of infection is the prostrate? | The prostate is in an acidic environment and favors bases. Bases such as Trimethoprim |
When combining drug therapies what is meant by antagonistic? | Therapies are antagonistic if the combined effect is less that the effect of either drug alone. |
When combining drug therapies what is meant by synergistic? | If the combined effect is greater than the sum of the independent effects |
When combining drug therapies what is meant by indifferent? | If the combined effect is similar to the greatest effect produced by either drug alone. |
When combining drug therapies what is meant by additive? | if the combined effect is equal to the sum of the independent effects |
What antimicrobial can be very toxic and is reserved for life threatening illnesses? | Chloramphenicol |
What is a chemotherapeutic agent that has a broad spectrum | Tetracycline |
What is a chemotherapeutic agent that has a Narrow spectrum? | Isoniazid |
What is a chemotherapeutic agents that has an extended spectrum? | Ampicillin |