Beta lactam antibiotics

Question 1

natural penicillins

Answer 1

PCN G (IM/IV- not acid stable) and PCN V (oral - EWG increases acid stability). 
Spectrum: Gram positive aerobes that do not make beta lactamase, i.e. strep A+B, enterococcus. Some gram negative aerobes - Neisseria.
Some gram positive and gram negative anaerobes - actinomycetes, fusobacterium, treponima pallidum.

(enterococcus are growth inhibited, not lysed)

Question 2

aminopenicillins

Answer 2

derivatives of PCN G with polar groups that allow them to enter porins. Includes ampicillin and amoxicillin (+EWG = acid stable, better PO).

Spectrum: same as PCN G but with better gram negative activity: H influenzae, E coli, Proteus mirabilis.

No activity against Klebsiella pneumoniae.