Antibiotics

Question 1

Beta Lactams
Moa
Use for
Types of Beta Lactams

Answer 1

Disrupt the bacterial cell wall- inhibits trasnpeptidases that cross link peptides to the peptidoglycan backbone

Bacteriocidal

Types:
Penicillins (amoxicillin) – renal excretion Use: S.pneumonia
Cephlasporins use: when people are sensitive to penicillin
Carbapenems- when bug has b-lactamases- penicillin resistant
Monobactams – usefully only gram neg bacteria, Is also resistant to beta lactamases

Question 2

Macrolides

Moa
Common uses
Names:

Answer 2

Binds to the 50s ribosomal Subunit resulting in inhibition of protein synthesis

CAP

Azithromycin, Clarithromycin

Question 3

Folic Acid Disruptors

MOA
Uses
Names

Answer 3

Inhibition of bacterial growth through substitution of sulphanilamide- usually needed for folic acid synthesis

used for : UTI,Otitis media

Common names:
Sulfonamides- inhibits dihydropteroate synthase
Trimethoprim- Inhbits Dihydrofolate reductase

Question 4

Topoisomerase II inhibitors
MOA
Uses
Names

Answer 4

Inhibits topoisomerase II- an enzyme involved in the formation of coiled NDA during the unfolding of strands = prevent DNA replication

Uses: Broad Spectrum- Klebsiella infections, UTI and Gonorrhoea

Names:
Cirprofloxacin, Levofloxacin, Norfloxacin

Question 5

Tetracyclines
MOA
Uses
Common Names:

Answer 5

Bacteriostatic
Reversibly blocks the 30S subunit of the ribosome preventing tRNA binding

Broad spectrum and sometimes Protozoal (Plasmodium falciparum)

Tetracycline, Doxycycline

Question 6

Glycopeptides
MOA
Uses
Common Names

Answer 6

Inhibits formation of Peptidoglycan polymers used in bacterial cell wall synthesis (transglycosidase inhibitor)
Bacteriocidal

Uses:
Primarily against Gram-Positive Bacteria
Serious infections that are resistant to penicillin- Useful for MRSA

Names: Vacomycin

Question 7

Beta-Lactamases

MOA

Answer 7

Enzyme that some bacteria have that causes resistance to Beta-Lactams
Is transferred to the bacterial chromosomal DNA

Use by bugs to for Resisting Penicillins

Question 8

RNA synthesis INhibitors
MOA
Used for:
Name:

Answer 8

Electively inhibits the RNA polymerase of Prokaryotic BUT NOT eukaryotic cells
Mycobacterial infections : TB and Leprosy
Resistance can develop rapidly

Rifampin

Question 9

AMinoglycasides
MOA
USe for
Common names:

Answer 9

Binds with the 30s ribosomal subunit- interfering with protein synthesis.

Effective in Gram negative including Klebsiella Pneumoniae
Used with Penicillin due to increase bactericidal effect ( be aware of nephrotoxicity and ototoxcitiy)
Streptomycin ( Mycobacteria- TB )

Gentamicin, Streptomycin

Question 10

Nitroimidazoles
MOA
Uses
Common Names:

Answer 10

Inactive initially then converted to a cytotoxic compound by transferrin enzymes involved in the anaerobic fermentation mechanism. Reduced to a nitro-radical anion Capable of damaging DNA.
Resistance increasing due to wide use for H.Pylori

Anti-Protozoal: Giardia lamblia and Entamoeba hystolytica
H.Pylori
Gram positives: Clostridium species

Other drug in this class: Tinidazole ]

Question 11

Treatment of TB- Mycobacteria

Answer 11

Treatment of TB- Mycobacteria

Rifampicin:
- binds and inhibits RNA polymerase in Prokaryotic- not eukaryotic
Isonazid:
- Bactericidal and interferes with lipid and inhibits synthesis of mycolic acid needed for cell wall
Ethambutol
- Bacteriostatic drug which inhibits mycobacterial cell wall synthesis- synthesis of Mycolic acid production

Combination: all three together

Question 12

What are the inhibitors of Cell wall synthesis

Answer 12

Vancomycin
Penicillins
Cephlasporins
Carbapentems
Monobactams

Question 13

What are the inhibitors of transcription and translation?

Answer 13

Rifampicin
Aminoglycasides
Tetracyclines
Macrolides

Question 14

What are the inhibitors of DNA synthesis and integrity?

Answer 14

Sulfonamides
Trimpethoprim
QUinolones