Chemical naturally produced by one microorganism that kills/inhibits another. Can also be a semi synthetic antibiotic, which is a naturally occurring antibiotic that has been slightly chemically altered.
What was Fleming growing on the petri dish that was affected by the penicillin?
Of all the antimicrobial drugs, this category is the largest
Drug/substance that are effective against ALL microbes
How does an antimicrobial differ from an antibiotic?
An antibiotic is only effective against bacteria; antimicrobial is effective against all microbes
Difference b/w antibiotic drugs and disinfectants/antiseptics?
Antibiotics are taken INTO the body. The others are for SURFACES
NAme 2 broad spectrum antibiotics and what they treat
Tetracycline: G-, G+, chlamydia, ricketsias (both of these are intracellular) Streptomyocin: mycobacterium, G- (causes deafness)
Name 2 narrow spectrum antimicrobial medicines
Isoniazid: Mycobacterium Acyclovir: viruses
name a negative and a postive in using a broad spectrum antibiotic
Neg: not only kills the pathogen but also your normal flora, setting you up for another infection Pos: you don't have to know the exact cause of the infection
Name a negative and a postive in using a narrow spectrum antibiotic
Neg: you have to know the exact cause of the infection Pos: it won't wipe out your normal flora, only kills the specific pathogen
2 categories of microbes that naturally produce antibiotics. Name specific genus and the antibiotic they produce
Name 3 antibiotics that interfere in cell wall synthesis
Penicillin: prevents cross bridges from forming Cephalosporin: interferes with production of peptidoglycan Isoniazid: interferes with production of mycolic acid (mycobacteria)
Name 4 antibiotics that interfere with protein synthesis/translation
Erythromycin Tetracycline Streptomyocin (toxic: causes deafness) Chloramphenical (toxic: stops blood cell production but is needed to treat Typhoid Fever)
Name an antibiotic that increases permeability of the plasma membrane
Polymyxin B (topical ONLY....very toxic)
Name 2 antibiotics that inhibit nucleic acid synthesis
Quinolones: inhibit production of DNA/replication (toxic) Rifampin: inhibit production of RNA/transcription (toxic) used to treat TB
Name 2 antibiotics that inhibit metabolic pathways
SMZ, TMP: compete with PABA in folic acid pathway Low toxicity since we don't have a folic acid pathway
Example of 2 antibiotics that are antagonistic to each other
tetracycline given first, then penicillin
Example of 2 antibiotics that are synergistic to each other
Define prophylaxis and 3 situations when it is needed
Antibiotics given BEFORE an infection as a preventative measure 1. Before colon/appendix surgery 2. Before dental work if you have heart valve condition (S. aureus in mouth will get into blood and attach to heart valves) 3. AIDS patients to prevent infections which in the past used to kill them
4 factors in the pathogens environment affecting antimicrobial activity/effectiveness
1. Metabolic state of pathogen: has it slowed down its metabolic activity? 2. Interfering substances: binding proteins in blood, acid in stomach reduce effectiveness 3. Location of pathogen: is it an intracellular pathogen hiding in host cell, evading drugs? 4. Distribution of drug through different tissues: if microbe is in brain, and IV won't work since it won't cross the blood brain barrier. *remember you want MILD not WILD pathogens
3 factors regarding the concentration of antibiotics and their effectiveness
1. Absorbtion, inactivation, excretion: will it be absorbed, inactivated by the liver, excreted by the kidneys? 2. Distribution of drug: systemic will not have as high of a concentration as a local or topical distribution 3. Dosage fluctuations: proper concentration must be maintained to reduce population by 90% *remember ADD=concentration
Where specifically in fungus is ergosterol found? Chitin?
plasma membrane, cell wall
Why are antifungals so toxic to humans?
Because they are eukaryotes just like us, therefore our cells are very similar with only a few differences (like ergosterol and chitin)
Name 3 antifungal medicines
Amphotericin B, Imidazole, Griseofulvin
5 ways microbes defend themselves against antibiotics/antimicrobials
1. change receptor for the drug 2. change target site (reshape their 70S ribosomes) 3. change metabolic pathways 4. produce enzymes to break down drug: beta lactamase breaks down penicilllin 5. multi drug resistance pump
7 reasons drug resistance has developed
1. over prescribed 2. people insist on them from doc 3. improper dosage: not taking all prescribed 4. used in animals which we ingest 5. no prescription needed in other countries 6. nocosomial infections due to chronically infected bringing their resistant bacteria into hospitals 7. overuse of antibiotic soaps with triclosan
2 antibiotic sensitivity tests
Kirby Baur Minimal Inhibitory Concentration
In order for an antibiotic to be effective it must reduce pathogen population by _____%
Staphylococcus first treated with this antibiotic _________, then after it became resistant it was treated with _______, now ___________is used.
Penicillin Methycillin Vancomyocin
MRSA stands for
Methycillin resistant Staphylococcus aureus
This antibiotic, which inhibits RNA synthesis, is used to treat TB
This antibiotic, which inhibits protein synthesis, is used to fight Typhoid Fever.
Topical antibiotics, like Polymyxin B, do THIS to the bacteria
Increase their plasma membrane permeability
This organ is responsible for detoxification
NAme a bacteria that can remain dormant on a dry surface for a very long time
Name a virus that becomes inactivated as soon as it touches a dry surface
If someone had meningitis, what would be the best way to deliver the antibiotics?
Needs to be put into the cerebrospinal fluid (epidural)
If someone has necrotic tissue, would it be best to give them IV antibiotics or topical?
Necrotic tissue lacks circulation so IV wouldn't work. Topical would be necessary.
Name two intracellular bacterial species
These two antifungals effect ergosterol production
Amphotericin B Imidazole
The danger of streptomyocin is that it can cause
Why are the antibiotics that inhibit protein synthesis potentially toxic to us?
They bind to 70S ribosomes, which we have in our mitochondria.
This antiviral is used to treat HIV. What "category" of antivirals is it in?
AZT, nucleotide analog
AZT, used to treat HIV, is a nucleotide analog which looks like
Acyclovir, an antiviral, is a nucleotide analog which looks like
Nucleotide analogs are SIMILAR to nucleotides this way but different in this way
similar in nitrogen base, different in their sugars and the phosphate group
T/F Interferons help us to feel better since they are fighting off viruses
False: they do fight viruses but they actually cause us to feel sick. This is to force us to rest.
How do nucleotide analogs combat viruses?
Cause mistakes as the viral genetic info is copied
This enzyme inhibitor antiviral is important in controlling HIV infections