Antimicrobial Chemotherapy Flashcards
Bactericidal
Will kill the bacteria (penicillins)
Bacteristatic
Will halt the bacteria’s growth (erythromycin)
Sensitive
Bacteria can be stopped or killed by the drug
Resistant
Bacteria will not be stopped or killed by the drug
MIC
Minimal inhibitory conc - minimum conc of antimicrobial needed to inhibit the growth
MBC
Maximum bactericidal conc - level of antimicrobial needed to kill the bacteria
Parenteral administration?
- IV
- Intramuscular
3 mechanisms of antibiotic action?
- Inhibition of cell wall synthesis
- Inhibition of protein synthesis
- Inhibition of nucleic acid reproduction
What are the b-lactams
- Penicillins
- Cephalosporins
How do B-lactams work
- Inhibit peptidoglycan synthesis
- Inhibit the enzymes
What are the proteins called that synthesis peptidoglycan?
- Penicillin binding proteins
What enzymes actually kill the bacteria when cell wall synthesis stops?
Autolytic enzymes
Why are many gram negative bacteria resistant to penicillin?
Gram negative wall is impermeable
What are vancomycin and teicoplanin examples of?
Glycopeptides
What is the difference between glycopeptides and b-lactams
Glycopeptides act on a different stage of cell wall synthesis
What do glycopeptides only work against
Gram positive
Why is vancomycin dodgy
Toxic as fuck
How do aminoglycosides work
Inhibit protein synthesis
e.g. of an aminoglycoside?
Gentamicin
How are aminoglycosides administered?
IV
Why do aminoglycosides require constant monitoring
Can be very toxic
How do macrolides and tetracyclides work?
Inhibit protein synthesis
Macrolides
- Erythromycin
- Clarythromycin
What are macrolides good against
- Gram positive
Oxazolidinones
- Inhibition of protein synthesis
Example of an oxazolidinone?
Linezolid
Linezolid acts good on?
MRSA
What is daptomycin an example of?
Cyclic lipopeptide
What 2 antibiotics inhibit nucleic acid synthesis?
- Trimethoprim
- Sulphamethoxazole
What synthesis do trimethoprim and sulphamethoxazole inhibit?
Purine synthesis
What is trimethoprim used to treat
UTI’s
What is co-trimoxazole used to treat
Chest infections
What is another class of antibiotics that inhibit nucleic acid synthesis?
Fluoroquinolones
Example of a fluoroquinolone?
Ciprofloxacin
What are fluoroquinolones used against?
Gram negative including pseudomonas
What do newer quinolones have an effect against?
Gram positive
Who can ciprofloxacin not be used on
Children
What are the 5 resistance mechanisms in bacteria
- Inherited
- Acquired
- B- lactamase production
- Alteration of penicillin binding sites
- Glycopeptide resistance
What is inherent resistance
- Some bacteria are just naturally resistant to antibiotic types
- Example streptococci are always resistant to aminoglycosides
What is always resistant to vancomycin?
Gram negative organisms
What is used to establish if a bacteria shows acquired resistance?
Lab testing
What are the 2 basic ways that resistance is acquired?
- Aspontaneous mutation
- Horizontal gene transfer
What is a b-lactamase resistant antibiotic that can be used to treat resistant types?
Flucloxacillin
What does ESBL stand for?
Extended spectrum beta lactamases
What cocci are resistant to vancomycin?
Some enterococci
What are some rare other mechanisms to resistance?
- Blocking the drug from entering the cell
- Actively transporting it out
List 4 adverse reactions to antibiotics
- Allergic
- GI tract problems
- Liver toxicity
- Thrush
- UTI’s
What bacteria can cause the GI problems?
C. Diff
How do you treat C. Diff?
Oral vancomycin
What antimicrobial therapy usually results in thrush?
- B lactams
- Cephalosporins
What are the 4 anti fungal drugs?
- Polyenes
- Azoles
- Allylamines
- Echiocandins
How do polyenes work?
- Bind to ergosterol
- Increase permeability of the membrane
What are the two polyenes currently used?
- Amphotericin B
- Nyastatin
What is a problem with amphostericin B?
It is EXTREMELY toxic
How is nystatin administered?
Topically
How do azoles work?
- Inhibit synthesis of ergosterol
What are the two types of azoles?
- Imidazoles
- Triazoles
What are the two imidazoles?
- Miconazole
- Ketoconazole
What are the three triazoles?
- Fluconazole
- Itraconazole
- Voriconazole
What can flucanozole be used to treat?
Yeast infection
What can itraconazole be used to treat?
Aspergillus
Dermatophytes
What can voricanozole be used to treat?
Aspergillosis
