Therapy Analysis - Antibiotic-resistance: fighting the superbugs
A clinical marvel
In 1928 in a basement laboratory of St Mary's Hospital, London, microbiologist Alexander Fleming noticed a halo of inhibition of growth around a culture of Staphylococcus aureus bacteria that had been contaminated by a blue-green mould. The mould, Penicillium notatum, appeared to be releasing a substance that was inhibiting the bacterial growth and causing lysis of bacterial cells. Naming the active substance penicillin, Fleming reasoned that it could have therapeutic potential if produced in large quantities. What followed was one of the greatest medical advances of all time - the discovery of antibiotics.
The clinical significance of Fleming's discovery was not immediately realised, and it was not until 1939 that Howard Florey and his colleagues at Oxford University demonstrated the ability of penicillin to kill infectious bacteria in mice. Subsequent isolation and mass production of the antibiotic led to its availability on the beaches of Normandy in the 1944 D-Day landings, saving many lives.
Penicillin belongs to a group of antibiotics called ß-lactams. These antibiotics are so-named due to the ß-lactam ring in their structure, and were originally found to be active against Gram positive bacteria. They are bactericidal, and act by inhibiting the synthesis of peptidoglycan, a key polymer in the structure of bacterial cell walls. The ß-lactam nucleus of the penicillin molecule acetylates a key serine residue, preventing the final cross-linking of the peptidoglycan layer, thus disrupting cell wall synthesis. In the years after the discovery of penicillin, availability of antibiotics allowed effective treatment for many previously untreatable diseases, such as meningitis, syphilis and gonorrhea, and revolutionized the treatment of bacterial infections.
