Flashcards in L2: Antimicrobial Agents Deck (144)
Antibiotics and antimicrobial agents are different from disinfectants how?
They are specific for certain bacteria or microbes
Many antibiotics come from what?
What does this help explain?
Natural compounds made by bacteria or fungi to gain an evolutionary advantage in natural environments.
High resistance to some antibiotics since bacteria have been exposed to these compounds for millions of years
3 characteristics of the ideal antibiotic
1. Target a variety of pathogens but spare normal flora
2. Prohibit rapid development of resistance
3. Selective for bacteria and does not damage host
What is the ideal antibiotic?
No such thing
Antibiotics are generally targeted against what?
Systems in all bacteria
The broader the spectrum of an antibiotics, the more likely what will happen?
The antibiotic will be more likely to attack normal flora
Do all antibiotics have resistance somewhere?
Limiting resistance to a drug has more to do with what? 2
1. Prescribing practices of physicians
2. compliance of patients
Are all antibiotics toxic to the host?
Why or why not?
Since mitochondria are evolutionarily related to bacteria, many broad spectrum drugs affect mitochondria function
What are 4 of the main adverse effects of antibiotics?
1. Allergic reactions (penicillin)
2. Toxic (aplastic anemia, ototoxicity)
3. Suppression of normal flora: (colon)
4. Antimicrobial resistance
Antibiotics are split into what two categories?
What is difference between bacteriostatic and bactericidal?
bacteriostatic = inhibit growth
bacteriocidal = kill
Bacteriostatic drugs rely on what to eliminate pathogen?
Bactericidal drugs are useful when?
situations when host defenses cannot be relied upon to control the pathogen
What are the five main targets of an antibiotic?
1. Cell wall
2. protein synthesis
3. nucleic acid synthesis
4. metabolic pathways
5. Cytoplasmic membrane
Which is the least toxic target of an antibiotic?
Mitochondria do not make peptidoglycan so it doesn't attack them.
What is one side effect of a cell wall antibiotic?
Allergic reaction to peptidoglycan fragments
In terms of protein synthesis what is targeted in antibiotics? What will also be targeted?
Mitochondrial ribosomes are inhibited leading to side effects
How useful are the antibiotics against nucleic acids?
Not very because there aren't many conserved bacterial enzymes.
How useful are antibiotics against metabolic pathways?
Average, there are some unique bacterial metabolic enzymes
How are antibiotics used against cytoplasmic membranes?
In a topical manner
Bacterial membranes are similar to eukaryotic membranes.
3 parts of cell wall synthesis?
1. Cell wall subunits are made in cell cytoplasm
2. Bactoprenol transports the subunits from inside the cell to ouside the cell
3. Penicillin binding proteins link the subunits together into the existing cell wall
What anti-biotic attacks cytoplasmic synthesis of cell wall subunits?
What anti-biotic attacks BACTOPRENOL and the transport of subunits?
What do Beta-lactams do?
What antibiotic is used against crosslinking?
Beta-lactams contain a 4 membered ring called the what?
What does it mimic?
the terminal D-ala-D-ala of peptidoglycan side chains.
Where can beta-lactams bind?
transpeptidases and carboxypeptidases and inhibit their function.
Transpeptidases and carboxypeptidases are collectively known as what?
penicillin binding proteins or PBPs