ch 20 final
Card Set Information
ch 20 final
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
toxicity- GIT problems, staining of teeth and photo senstive.
prevents peptide bond formation
highly toxic- irrevisable bone marrow damage.
attaches to 50S ribosome (prevent movement of ribosome on mRNA)
inhibit DNA synthesis
ex. norfloxacin and ciprofloxacin
Inhibits RNA synth
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?
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
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
: 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
^^ prevent syth of DNA from RNA
HIV is retro virus
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