"A scientific experiment, briefly exposed to the air, became infected with a fungus whose spores had blown in through an open door... And left untended on a laboratory bench through the summer vacation, the fungus managed to destroy bacteria being grown as part of the experiment. The improbable results could not have been duplicated."
This account of the discovery of penicillin is adapted from Gilbert Shapiro's 1986 book, A Skeleton In The Darkroom.
Dr. Alexander Fleming was born August 6th, 1881 at Lochfield, in East Ayrshire, Scotland. When he was twenty years old he inherited some money from an uncle who had recently passed away. He had an older brother who was a physician and had suggested that Fleming follow the same career path. So he made the decision to enroll at St. Mary's Hospital, Paddington, London.
While there, Fleming had the option of becoming a surgeon. It was due to a suggestion from a fellow member of the rifle club, however, that Fleming instead joined the research department. During his time there, he became an assistant bacteriologist to Sir Almoth Wright. Wright is regarded in these days as a pioneer in vaccine therapy and immunology.
Fleming served throughout World War I as a captain in the Army Medical Corps. He worked in the battlefield hospitals of the Western Front in France. During this time, he saw many soldiers die as a result of septicemia, also referred to as blood poisoning, from infected wounds.
There is no doubt that Fleming's experiences during the war led to his personal desire to discover anti-bacterial agents.
Fleming's main focus at this point in his career became staphylococci, the germs that cause boils, carbuncles, and other surface infections. He was considered an expert when it came to staph bacteria and was known to be a brilliant researcher. He was also known to "play" with microbes as much as he conducted medical experiments with them
One of his favorite pastimes was to make what he called "germ paintings." To do so, he would draw a simple picture, such as a landscape, a ballerina, or a flag, on the surface of a four-inch glass petri dish. He would then fill each area of the drawing with a culture medium and seed it with the right strain of bacteria.
A day later, the maturing colonies would be visible, each with it's own distinct color, together forming the image of the sketch Fleming had made on the bottom of the dish.
Fleming also discovered that once the cultures had matured, he could preserve the "paintings" by spraying them with a chemical which killed the bacteria, but prevented the culture from deteriorating.
He was rather proud of his germ paintings and at any given time he often displayed several around his laboratory. He also made sure to have several paintings ready on special occasions and for royal visitors. Dr. Fleming's work was once featured at the opening of a new building and he included several of his germ paintings in the exhibition. There, Fleming had the opportunity to show them to Queen Mary.
She seemed puzzled by his enthusiasm for the paintings and as she was leaving, Fleming overheard her say, "Yes... But what good is it?"
Little did Her Majesty know, that the answer to her question was soon to be applied.
In 1928, Fleming was going to spend part of the summer away from London and his laboratory. He planned on lending the use of his lab to a colleague named Dr. Stuart Craddock while he was out of town. Before he left for his vacation though, he started growing a species of staphylococci called S. Aureus on some culture plates.
Fleming had read a report about color changes in this variation of staph which normally produces golden yellow colonies. The paper suggested that if you cut the incubation short and left the culture at room temperature for several days, interesting color changes took place.
Fleming wanted to see these color changes for himself. If nothing else came of it, at least he might be able to add a few more colors to his painting palette.
In September, Fleming returned to London and set to work preparing his lab for new research. There had been a heat spell in the few weeks before he returned. This was counter active to the color change experiment he was conducting as the changes were supposed to take place only at cool temperatures.
Fleming took all of the cultures and set them into a tub of lysol to kill the bacteria so the experiment could be started over. It was then that a colleague dropped in unannounced to see how the summer research was going. Fleming told his colleague that the heat spell had ruined his latest experiment and reached for one of the cultures at random to show him.
The dish that he happened to pick up was on the top of the pile of cultures and hadn't yet been submersed in the lysol. A fungus had contaminated the dish while Fleming had been away. This was not unusual, as spores floating around in the air often landed on plates while they were uncovered and started to grow.
Fleming noticed the large mold spot on the dish and started to reach for another in the pile to show to his friend, probably thinking that he could at least show him a better example of why the color change experiment had gone wrong.
But something caught Fleming's eye. "That's strange," he muttered
Half the dish was covered with yellow colonies of staph, like all the other dishes. But near the edge of the moldy spot on the dish, the staph cells had become translucent and some of them even looked like they were starting to dissolve away. Even stranger than that, inside a circle about an inch in diameter in the center of the mold spot, there no staph cells visible at all.
There could only be one explanation for why this was happening: something near the mold that had landed on the dish was killing off the staph bacteria.
It was an incredibly lucky accident that brought that particular mold spore to land on one of Fleming's experiments. Even more incredible that Fleming had grabbed that culture dish out of the pile considering that after inspection, it was the only one that the fungus had started to grow on.
Fleming immediately took action to preserve the mold. He scraped samples from the culture dish and placed them in test tubes with a liquid used to grow samples of fungi.
The mold that Fleming managed to preserve was a species of Penicllium. These types of molds usually grow on cheese, decaying fruit, and stale bread. The name comes from the same Latin root that gives us the word "pencil."
So, Fleming decided to name his discovery "Penicillin."
The truly astonishing part of this story is that that specific mold, happened to land in Fleming's culture plate. Because none of the other molds that Fleming or his colleague could come up with were able to kill bacteria. In fact, in the years since then, even though intensive searches have been conducted, not one species of fungus that produces Penicillin has been found anywhere in the Old World.
Not since that September day in 1928, has Fleming's particular species, now known as Penicillium Notatum, ever been found outside of laboratory-grown cultures.
In 1943, a strain called Penicillium Crysogenum was found in Illinois that is even more potent that Fleming's strain and is now used in the commercial manufacture of Penicillin.
Fleming was always modest, preferring to give credit to the scientists who furthered his research and were responsible for the formulation of the drug.
He would later say of his discovery,
"When I woke up just after dawn on September 28, 1928, I certainly didn't plan to revolutionize all medicine by discovering the world's first antibiotic, or bacteria killer...But I guess that was exactly what I did."
Many people consider the discover of penicillin the most important discovery of that millennium. In the year 2000, the number estimated to have been saved through the use of the drug was as high as 200 million lives.
There is no doubt that his discovery changed the world of modern medicine by introducing useful antibiotics. To this day, Penicillin has saved and is still saving millions of people all over the world.
No comments:
Post a Comment