ch 20 final
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Magic bullet, coined the term chemotherapeutic
Antibiosis --> antibiotic; discovered pencillin
1st sulfer drug
any drugs used in treatment of porphylaxis of disease.
What is prophylaxis?
preventing risk of infection.
All antimircobal drugs regardless of origin
microbe made substances again other microbes
Lab modified drugs after being ioslatd from natural sources
completely made in the lab
What are narrow spectrum drugs?
Broad spectrum drugs?
Effect against gram + and gram - ; may be against some fungi and protozoan.
What is an ideal antimircobial drug?
Selectively toxic, mircobicidal rather than microbistatic, not metabolized too quickley, doesnt lead to dev. of resistance and easily souble.
- Affect the bacterial cell wall
- ex. penicillin, bacitracin and vancomycin
what is a antibacterial drug that disrupts the cell membrane function?
Polymixin B- causes leakgae of cell contents
What do the drugs that block Protein synthesis do?
- Target the ribosmal messenger RNA complex.
- Most effective against gram - bacteria
- Block proetin synth.
- prevents the attachment of tRNA
- broad spect.
- toxicity- GIT problems, staining of teeth and photo senstive.
- prevents peptide bond formation
- broad spect
- highly toxic- irrevisable bone marrow damage.
- A marcolide
- narrow spect
- attaches to 50S ribosome (prevent movement of ribosome on mRNA)
- broad spect
- inhibit DNA synthesis
- ex. norfloxacin and ciprofloxacin
- Inhibits RNA synth
- Narrow spect
- effective against tuberculosis
Drugs that block metabolic pathways?
- They are bacteriostatic
- Sulfonamides (sulfa drugs)
- block syth of folic acid in bacteria
- most are narrow spect
Amphotericin B and Nystatin?
- Antifungal drug
- An Antiboiotic
- binds sterol in PM cause leakage of contents
- toxic to human cells
- used on surface and systemic infections
- interferes w/ mitosis
- used agaisnt ringworm and athletes foot
Antifungal : Synthetics
- Broad spect
- ex clotrimazole and miconazole
- analog of cytocine
- inhibits RNA syth
- used in combination w/ other antifungals
Antiprotazoan drugs ; Antimalaria
- 1) Quinine from cinchona tree
- 2) Doxycycline from prophylaxis
- Chloroquine- inhibits DNA syth
- Mefloquine- semisythetic; used to treat chloroquine resistant form
- Malarone- for prophylaxis
Challenges to treatment w/ Antihelmintic drugs?
- Size and similarity to human physiology
- Helminthes include: tapeworm, fluke and roundworms
Membendazole and thiabendazole?
- effective against round worms
- interfere w/ glucose metabolism in the intestines
- destorys scolex and attatched to proglottids
- effective against tapeworms
- may cause serve ab cramps
- Used for tapeworm and fluke infections
- disrupt plamsa membrane
What is a major problem with antiviral drugs?
Antiviral drugs; Non-nucloside agents
Amantadine & Rimantidine?
- Against type influeneza A virus
- block the H spikes
Relenza And Tamiflu?
- effective against both influenza a and b
- block the N spikes
What are the nucleoside angalogs?
- Purine (a or g)
- Pyrimdines (t, c and u)
- Block DNA and RNA syth
- Antiherpes drugs- used orally or locally
- blocks DNA syth
- Anti HIV
- ^^ prevent syth of DNA from RNA
- HIV is retro virus
- Anti HIV
- viral protease inhibitors: indinavir, saquinavir, nelfinavir, and crixivan
What is drug resistance?
mircobes tolerate drug amounts that usually inhibit them
How does resistance occur?
intermicrobial gene transfer in form or plasmids called resistance (r) factors or through mutations
What are the mechanisms of drug resistance?
- Activation of enzymes
- alteration of binding sites for drugs
- an affected metabolic pathway is shut down or alternated pathway is used
How to lower drug resistance?
- Use drugs only when necessary
- follow instructions for intake
- use combination therapy - for synergistic effect and to decrease toxicity
target mostly resistance microbes
What are the sources of new drugs?
plants, animals and sythetic cmpds such as: Synth DNA called triplex agent and antisense agent- those neutrilize genes and mRNAs that code for mircobial pathogenic proteins
- short peptides produced by bacteria against other bacteria
- used in food preservation
- have potential in chemotherapy
Probiotics and prebiotics?
Replace lost mircobes and add to those already there
What would you like to do?
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