Penicillins are a class of antibiotics with a common core structure called the beta-lactam ring. This class of antibiotics is widely used to treat bacterial infections and is divided into several subclasses based on their spectrum of activity and chemical structure. Here is a classification of penicillins:
I. Penicillinase-susceptible penicillins:
The general impact on antibacterial activity is as follows:
- Good gram-positive potency against susceptible Staphylococci and Streptococci
- Useful against some gram-positive cocci
- Not effective against gram-negative bacilli.
II. Penicillinase-resistant penicillins:
General impact on antibacterial activity is as follows:
- Decreased susceptibility to many penicillinases.
- Active against microorganisms, resistant to early penicillin.
- Oxacillin offers good oral activity.
III. Aminopenicillins:
The general impact on antibacterial activity is as follows:
- Extended spectrum of activity against some gram-negative bacteria and retention of gram-positive potency.
- Ineffective against Pseudomonas aeruginosa.
IV. Antipseudomonal penicillins (Carboxy Penicillins):
V. Ureidopenicillins:
The general impact on antibacterial activity is as follows:
- Enhanced spectrum of activity against P. aeruginosa and expanded activity against Klebsiella.
- Good potency against gram-positive bacteria, but generally not effective against penicillinase producers.
- Good pharmacokinetic profile.
- Good activity against Escherichia coli, Klebsiella, Shigella, Salmonella, and many other resistant species.
VI. Miscellaneous penicillins:
