Fundamentals of Antimicrobial Chemotherapy Flashcards
What are the targets in antimicrobial chemotherapy?
Kill or inhibit microbe
Bacteria cell wall
What is difference between Gram positive + Gram negative?
+ = thicker
= identified through staining
What is gram positive + gram negative cross-linked by?
Chain of peptidoglycan
= gives its strength
Describe structure of gram positive
Tightly cross-linked + interspersed with polysugarphosphates
Describe structure of gram negative
Relatively thin
Loosely crosslinked layer = less robust = easier to get through
What is the structure of peptidoglycan?
Lipopolysaccharide + lipoprotein
= prevent large hydrophilic molecules from reaching target
What are the most important antibiotics that interfere with cell wall synthesis?
Glycopeptides + β-lactams
What is bactericidal?
Kill bacteria
What is bacteriostatic?
Inhibit growth of reproduction
What are the different sources of antibiotics?
Microorganisms
Synthesis
Semisynthesis
What is semisynthesis?
Produced by microorganism then chemically synthesised
Describe penicillin
β-lactams
Natural + semisynthetic
Activity against gram positive + negative
What can some bacteria produce?
β-lactamase which may inactivate penicillin
= open β-lactam ring
What do all β-lactam antibiotics interfere with?
Final transpeptidation reaction that gives wall strength
= makes wall weak
= open to attack
What are examples of pencillins?
Amoxicillin
Flucloxacillin
Describe cephalosporins
β-lactams
Similar structure to penicillin
Can be modified to increase antibacterial activity
Modify to increase stability against β-lactamase
What is an example of cephalosporins?
Cephalexin
Describe clavams
β-lactams
Inhibits staphylococcal β-lactamase + gram negative β-lactamase
Combined with broad spectrum antibiotic
Describe Rifamycins
Bactericidal
Against gram positive + negative
What is an example of rifamycin?
Rifampicin
Describe aminoglycosides
Inhibit bacterial protein synthesis
Range of side effects that are dose related
What are examples of aminoglycosides?
Gentamicin
Tobramycin
Describe macrolides
Inhibit bacterial protein synthesis
Spectrum of activity
Why is it good that macrolides have a spectrum of activity?
Suitable for respiratory + soft-tissue disease
What are examples of macrolides?
Erythromycin
Clarithromycin
Describe tetracyclines
Broad spectrum against gram positive + negative
Inhibit bacterial protein synthesis
What are the side effects of tetracyclines?
Chelate with Ca2+
= discolours teeth
Describe glycopeptides
Active against gram positive
Inhibitor of bacterial cell wall peptidoglycan synthesis
Used in life-threatening infections
What is an example of glycopeptides?
Vancomycin
What are examples of gram-positive bacteria?
MRSA
C.difficile
Describe chloramphenicol
Broad spectrum bacteriostatic
Inhibit bacterial protein synthesis
Describe fusidic acid
Topical
Against gram-positive
Describe clindamycin
Against gram-positive cocci
Describe mupirocin
Eradicating skin + nasal MRSA
Describe Griseofulvin
Antifungal
Active against dermatophytic fungi
Orally
Deposits in deep layers of skin
Describe polyenes
Antifungal
Oral thrush
Mucosal membranes
