Penicillin has become synonymous with modern medicine, but this wonder drug has only been around for roughly 70 years. Before penicillin the mode for treating infection was not nearly as effective. When it was first debuted, before WWII, it was the biggest thing to hit the medical community and became the number one choice for treating a wide range of infections. Some of the most popular prescriptions belonged to people suffering from Syphillis, Strep, or Staph, as well as other. The problem with Penicillin being so effective against all of the aforementioned "bad actors" is that it was used too much, and have lead to antibiotic resistance in several bacteria species.
Penicillin contains three chiral centers and S,R,S steriochemistry. Look to the diagram for exact locations.