Pharmacology

• Natural Penicillins
• Antistaphylococcal penicillins
• Extendend spectrum penicillins:
• 1. Aminopenicillins
• 2. Carboxypenicillins
• 3. Ureidopenicillins

thick peptidoglycan cell wall

• Outer membrane: extra lipopolysaccharide membrane surrounding the cell wall and includes porins channels which allow entry into cell
• Inner membrane: thin peptidoglycan layer which makes up the cell wall

is composed of cross linked polysaccarides.

cause a change of PBP or an alteration

• cause the penicillin binding proteins to block/prevent or STOP crosslinking or formation of a rigid bacterica cell wall from occuring. No crosslinking of bacteria cell wall=bateria death. Crosslinking=viable bacterial
• B-Lactams prevent development of a normal bacterial cell wall

bacteria live, bacteria strong, bacteria spread

weak bacteria, death of bacteria

different penicillin binding proteins (PBP) and prevent cell wall synthesis

Are enzymes that break off a part of the polysaccaride wall to promote cross linking. There are thousands of different PBP. If crosslinking occurs then bacteria are viable and the infection spreads. PBP are different in gram+ bacteria, gram- bacteria and anaerobic bacteria

the bacteria is in the growing/active stage

bacteria need to be actively multiplying

change their PBP shape and therefore lower their affinity for B-lactams or lower their affininty to PCN. Now betalactam will no longer be effective. Now it will no longer prevent that crosslinking

Bacteria talk, they will share their knowledge of resistence mechanisms.

1. change shape of PBP. This causes B-Lactams to no longer be effective

2. Enzyme B-Lactamase breaks the B-Lactam ring. The bacteria produce this enzyme. If this ring is broken we lose our antibacterial activity. Very common

3. Gram- bacteria change the structure of their porins. So the antibiotic can no longer get through to the cell wall. this is called Decreased Antibiotic Permeabitity. Impaired B-lactam penetration. If antibiotics dont get to the cell wall they will have no effect on it.

4. Efflux Pump: bacteria has this pump. When antibiobics do get into the cell wall the bacteria just "PUMP" the antibiotic back out! This reduces the amount of intracellualar drug and there is never a strong enough concentration of antibiotic in the cell wall to have an effect.

combat resistance issues.

• PCN G-IV
• PCN VK-PO oral
• Benzathine PCN-IM: used to treat SYPHILLIS. SYPHILLIS is a slow grwoing bacteria slowly absorbed, long acting
• Procaine PCN-IM: not rx very often. slowly absorbed, prolonged low concentrations (weeks), contains local anesthetic

work on gram+. work well on strep but not the best for staph, limited to gram-

PCN was developed and we were using it. The staph got smart and started producing penicilinase which inactivated PCN