antimicrobial chemotherapu

Question 1

Explain the terms MIC/MBC, sensitive/resistant, bacteriocidal/bacteriostatic, synergy/ antagonism.

Answer 1

MIC: minimum inhibitory concentration- needed to inhibit the bacteria
MBC: minimum bactericidal concentration-
Sensitive: bacteria is affected by antibiotic
Resistant: bacteria is unaffected by antibiotic
Synergy: the action of two drugs put together is greater than the individual effect of both drugs
Antagonism: the two drugs put together cancel each other out

Question 2

Describe in outline the mechanisms of action of the major groups of antibacterial, antifungal and antiviral drugs.

Answer 2

Antibacterial:
-cell wall
peptidoglycan- B-lactams functional ring prevent peptidoglycan from assembling cell wall e.g. penicillin
glycopeptides- inhibit cell wall synthesis by inhibiting precursor for peptidoglycan.
-Protein synthesis: work on transcription of RNA at different stages
aminoglycosides
macrolides
tetracyclines
Oxazolidones
Cyclic Linopeptide
-Nucleic acid synthesis- interrupt supply of DNA precursors
Co-trimoazole
Fluoroquinoles

Question 3

Describe in outline any clinically signi cant resistance mechanism for particular groups of drugs.

Answer 3

Resistance: the microorganism does not respond to attainable levels of drug in system.
Inherent/intrinsic- bacteria naturally resistant
acquired- spontaneous mutation/transfer of plasmids
Bacteria:
-B-lactamase- alter penicillin binding site- overcome by attaching a functional group which inhibits the b-lactamase or by altering side chain
-Glycopeptide resistance-enterococci alter peptidoglycan precursor