Antimicrobials Flashcards
Beta Lactams inhibit what? and by?
Inhibt the synthesis of peptidoglycan by preventing the linkage of glycan sugar chains
How do beta lactams prevent the cross linkage of glycan sugar chains
They do this by acting as competitive inhibitors to enzymes that help form peptide bomds between NAM molecules. These enzymes are known as PBP
Name 2 examples of Beta-lactams
- Penicillins (PCNs)
- Cephalosporins
Anitmicrobial that is the preferred option for treating bacterial infection
Beta-lactams such as penicillin, and etc
Which betalactam is effective against gram postive and which one is more effective against gram negative
- Penicillins are more effective against gram postive
- Cephalosporins in later generation are generally less effective against gram positive but more effetive against gram negative.
Glycopeptide is…
effective against gram postive only
Glycopeptide inhibit what? by what?
Glycopeptides inhibit cell wall synthesis by binding to amino acid end of NAM molecules which prevents the cross linkage of adjacent of glycan chains.
2nd choice after B-Lactams
Glycopeptides
Examples of glycopeptides are..
- Telavancin
- Dalbavancin
- Oritavancin
- Vancomycin ( needs to be administered intravenously)
Glycopeptide: Vancomycin
- It is not very absorbed the GI tract
- It does not work well against G- bacteria
- Resistance can be formed against this medication when the bacteria change the composition of their peptide side chain
- side effects : red men syndrome
Bacitracin inhibt what? by what?
Bacitracin inhibits the transport of precursor molecules (NAM & NAG) used for the synthesis of peptidoglycan
Bacitracin is used only where and why
Bacitracin is used only on the surface of the skin due to its toxicity
Aminoglycosides are not effective against? why?
- anaerobes (enterocci and stretococci)
- b/c they enter bacterial cells by a process that requires respiratory metabolism
How do Aminoglycosides work?
Aminoglycosides work by irreversibly binding to the 30S ribosomal subunit causing to distort and malfunction
Examples of Aminoglycosides
- Streptomycin
- Gentamycin
- Tobramycin
Name some side effects Aminoglycosides cause
- Hearing loss
- Kidney damage
- Vertigo ( dizzy )
Aminoglycosides can be used synergistically with
penicillin
Tetracyclines inihibit what?
inhibit bacterial protein synthesis by preventing the association of aminoacyl-tRNA with the bacterial ribosome
Tetracyclines are effective against
Certain g+ and g- bacteria
Tetracyclines…?
- Tetracyclines reversibly bind to the 30S ribosomal subunit and prevent the continuation of translation.
- P
Bacteria can resist ________ by increasing the efflux of this drug from the cell.
they can resist tetracyclines
What is used when tetracycline resistanceoccurs
Glycylclines
Macrolides are effective against
Macrolides are effective against many gram+ as well as most common causes of atypical pneumonia
Macrolides reversibly..
Macrolides reversibly bind to 50S ribosomes and prevent the translation from continuing.
Macrolides are not effective against
members of the Enterobacteriaceae b/c they can’t penetrate the outer membrane
Examples of Macrolides are?
- Erythromycin
- Clarithmythroicn
- Azithromycin
What is the medication of choice for patients allergic to penicillins
Penicillins
Fidaxomicin is
A new bactericidal antibiotic that interferes with transcription by binding to RNA polymerase
Fidaxomicin passes
- passes through the intestinal tract without being absorbed and is particularly useful for treating C.difficile infection
Polymyxins are effective against
Polymyxins are effective against gram-negative bacteria by damaging cell membranes toxicity limits their use
Polymyxins bind to
the membranes of gram-negative cells
Fluoroquinolones are effective against what?
Are effective against a wide variety of bacteria including both gram+ and gram- organisms
Fluoroquinolones are?
Synthetic compounds that inhibit one or more of a group of enzymes called topoisomerase which maintains the supercoiling of DNA within the bacterial cell
Examples of Fluoroquinolones
Ciprofloxacin
Levofloxacin
Moxifloxacin
Rifamycins are?
are bactericidal effective against many Gram+ and some Gram- organisms as well as members of the genus Mycobacterium
Rifamycins are primarily used to treat what?
- Tuberculosis
- Hansen’s disease (leprosy)
Rifamycins do what?
are antibiotics that block bacterial RNA polymerase from initiating transcription
Metronidazole is?
a synthetic compound that interferes with DNA synthesis and function.
Tetracyclines inhibt what?
inhibit bacterial protein synthesis by preventing the association of aminoacyl-tRNA with the bacterial ribosome
Macrolides inhibit what?
protein synthesis by binding to the 30s RNA
