Penicillin, antibiotic derived from Penicillium mold, one of the first antibiotics to be discovered. Penicillin is a type of antibiotic that treats bacterial infections like pneumonia and strep throat. Some bacteria have become resistant to penicillin, making the drug less effective. Penicillin V is one type of penicillin antibiotic and is used to treat a wide range of bacterial infections such as ear infections, throat infections, skin infections and preventing rheumatic fever. It should only used if the bacterial infection is sensitive to penicillin V. Penicillins are a group of antibacterial drugs that attack a wide range of bacteria. They were the first drugs of this type that doctors used. These drugs have saved millions of lives. While working at St Mary's Hospital in London in 1928, Scottish physician Alexander Fleming was the first to show experimentally that a Penicillium mould secretes an antibacterial substance, which he named penicillin. Penicillins are a type of antibiotic derived from Penicillium fungi. An antibiotic is a type of medicine that inhibits the growth of, or kills, bacteria. Penicillin G (also called benzylpenicillin) was discovered by accident in 1928. What is Penicillin? Penicillin is a group of antibiotics (medications used to treat bacterial infections) that work in a specific way to destroy bacteria in your body. Types of penicillin and drugs closely related to them are called “penicillins.” They’re a subclass of beta-lactam antibiotics. Penicillins are antibiotics used to treat bacterial infections that are derived from the antibiotic penicillin. Penicillin antibiotics stop bacteria from multiplying by preventing bacteria from forming the walls that surround them. Overview: Penicillin is an antibiotic that is used to treat bacterial infections. It kills certain types of bacteria by blocking their ability to create their cell wall. The most common side. Penicillins were among the first medications to be effective against many bacterial infections caused by staphylococci and streptococci. They are still widely used today for various bacterial infections, though many types of bacteria have developed resistance following extensive use.