pidsjournal.com
All About Development Studies    

Development Studies





Antibiotics


Video Description

Penicillin (sometimes abbreviated PCN) refers to a group of ß-lactam antibiotics used in the treatment of bacterial infections caused by susceptible, usually Gram-positive, organisms. The name “penicillin” can also be used in reference to a specific member of the penicillin group. All penicillins possess the basic Penam Skeleton, which has the molecular formula R-C9H11N2O4S, where R is a variable side chain. History The discovery of penicillin is usually att in 1928, though others had earlier noted the antibacterial effects of Penicillium. Fleming, at his laboratory in St. Mary's Hospital (now one of Imperial College teaching hospitals) in London, noticed a halo of inhibition of bacterial growth around a contaminant blue-green mould on a Staphylococcus plate culture. Fleming concluded that the mould was releasing a substance that was inhibiting bacterial growth and lysing the bacteria. He grew a pure culture of the mould and discovered that it was a Penicillium mould, now known to be Penicillium chrysogenum. Fleming coined the term "penicillin" to describe the filtrate of a broth culture of the Penicillium mould. Even in these early stages, penicillin was found to be most effective against Gram-positive bacteria, and ineffective against Gram-negative organisms and fungi. He expressed initial optimism that penicillin would be a useful disinfectant, being highly potent with minimal toxicity compared to antiseptics of the day, but particularly noted its laboratory value in the isolation of "Bacillus influenzae" (now Haemophilus influenzae).[1] After further experiments, Fleming was convinced that penicillin could not last long enough in the human body to kill pathogenic bacteria and stopped studying penicillin after 1931, but restarted some clinical trials in 1934 and continued to try to get someone to purify it until 1940. The first major development was ampicillin, which offered a broader spectrum of activity than either of the original penicillins. Further development yielded beta-lactamase-resistant penicillins including flucloxacillin, dicloxacillin and methicillin. These were important for their activity against beta-lactamase-producing bacteria species, but are ineffective against the methicillin-resistant Staphylococcus aureus strains that subsequently emerged. The line of true penicillins were the antipseudomonal penicillins, such as ticarcillin and piperacillin, useful for their activity against Gram-negative bacteria. However, the usefulness of the beta-lactam ring was such that related antibiotics, including the mecillinams, the carbapenems and, most importantly, the cephalosporins, have at the centre of their structures.

Video Code - Share This Video!

Feel free to share this video on your blog or website. Simply copy the HTML video code below and paste it into your blog post or website:

Search

Search the Web



Popular Searches



Buy This Website

The website pidsjournal.com may be for sale by its owner!



Navigation