Drugs for bacteria treatment Flashcards
(27 cards)
Examples of beta lactase
- pencillins - these contain a similar peptide bond to transpeptidsase
- cephalosporins - 1st to 3rd generation
what do beta-lactams target
what is the action of beta lactams
what type of bacteria does betalactams target
is it bactericidal or
- Target – transpeptidase (pencillin-biding protein) is inhibited
- Action; competitive inhibitor of transpeptidase, covalently activates serine in the active site of the enzyme
- What does it target – gram negative, gram positive
- bactericidal
what are some examples of glycopeptides
- Vancomycin
- Teicoplanin
what do glycopeptides target
what is the action of glycopeptides
what type of bacteria does glycopeptides target
is it bactericidal or
- Target – D-Ala-D-Ala peptide
- Action – forms hydrogen bonds with D-Ala-D-Ala peptide thus preventing the transpeptidation of peptidoglycan layers, they bind to the things that should be cross-linked.
- What does it target – gram positive
- bactericidal
what is the clinical significance of glycopeptides
- IV administration (Not absorbed orally) Used to treat • Septicaemia • Lower Respiratory Tract Infections • Skin Infections • Bone Infections
what are examples of polymyxins
- Polymyxin B
* Polymyxin E (Colistin)
what do polymyxin target
what is the action of polymyxin
what type of bacteria does polymyxin target
is it bactericidal or bacteriostatic
Targets; LPS and phospholipids
Action
1. Binds to LPS or negatively charged phospholipids, displacing cations such as calcium and magnesium
2. Destabilises the outer plasma membrane of bacteria.
3. ↑ Permeability of membrane → leakage of ions.
Targets – gram negative bacteria
- bactericidal
what do chloramphenicol target
what is the action of chloramphenicol
what type of bacteria does chloramphenicol target
is it bactericidal or bacteriostatic
Targets; 50S ribsome subunit
- Action; inhibits the formation of peptide bonds in the growing polypeptide chains
- Bacteira that it effects include gram positive, gram negative,
- bacteriostatic
what is the clinical signficance of chloramphenicol
Cheap and broad spectrum
- Adverse effect – bone marrow suppression which can lead to aplastic anaemia
- Not to be used trivially
- Can be chemically synthesized or isolated from streptomcyes
- Low but serious risk of bone marrow suppression
what are the examples of macrocodes
- Erythromycin and clarithromycin
what do macrolides target
what is the action of macrolides
is it bactericidal or bacteriostatic
- Target 50s ribosome subunit (P site)
- Action – inhibits the translocation of the growing polypeptide chain
- bacteriostatic
what are the examples of linocosamides
clindamycin, lincomycin
what do linocosamdies target
what is the action of linocosamdies
what type of bacteria does linocosamdies target
is it bactericidal or bacteriostatic
Target – 50s ribsooem subunit (23S portion)
Action – leads to premature dissociation of peptidyl-tRNA from ribosome
Targets – gram negative and gram positive
can be both bactericidal or bacteriostatic
Achieve a high concentration in host tissue so it is good for intracellular pathogens
what are the examples of tetracyclines
doxycycline and minocycline
what do tetracyclines target
what is the action of tetracyclines
what type of bacteria does tetracyclines target
is it bactericidal or bacteriostatic
- Tagert – 30s ribosome subunit
- Action - Prevents aminoacyl-tRNA attaching to A site on ribosome → formation of non-functional proteins.
- Targets – gram negative and gram positive
what are the examples of aminoglycodies
gentamicin, tobramycin, amikacin, streptomycin
what do aminoglycosides target
what is the action of aminoglycosides
what type of bacteria does aminoglycosides target
is it bactericidal or bacteriostatic
- Target- 30s subunit
- Action - Change shape of 30S subunit → incorrect reading of mRNA code → inaccurate mRNA translation
- Targets – gram negative and gram positive
- bactericidal
what is the clinical significance of aminoglycosides
- Use: mostly against gram-negative bacteria, but Streptomycin may be used against M. tuberculosis.
- Administration: typically IV.
- Adverse Effect:
- Hearing loss
- Renal impairment
what are the types of quinolones
Ciprofloxacin, Gatifloxacin, Levofloxacin, Moxifloxacin
what do Quinolones/fluoroquinolones target
what is the action of Quinolones/fluoroquinolones
what type of bacteria does Quinolones/fluoroquinolones target
is it bactericidal or bacteriostatic
Target: Topoisomerase II (DNA Gyrase) + Topoisomerase IV
Action:
Prevents preventing bacterial DNA from unwinding and duplicating
Target bacteria – gram positive and gram negative
In gram negative bacteria what is the target
- DNA gyrase
In gram positive what is the target
- Topoisomerase iV is the target for many
- bactericidal
what are the clinical significance of quinolones
- Use: active against intracellular bacteria (Chlamydia spp., Legionella spp., Mycoplasma spp.)
- Widely used drug.
what do rifampicin target
what is the action of rifampicin
what type of bacteria does rifampicin target
is it bactericidal or bacteriostatic
Target: DNA-dependent RNA Polymerase
Action:
Suppresses RNA synthesis (transcription).
Target bacteria – gram negative and gram positive
In gram negative bacteria DNA gyrase is the target
In gram positive bacteria – topoisomerase IV is the target for many
- bactericidal
what is the clinical significance of rifampicin
• Use: treatment of tuberculosis.
Lipophillic drug → can cross BBB to treat TB meningitis
what are the types of sulphonamides
Sulfamethoxazole, Sulfasalazine, Sulfadoxine
