Fleming named the still-unidentified substance “penicillin” after the fungus that was growing in the dish, Penicillium chrysogenum. Next, he conducted a series of experiments to test out the bacteria-fighting properties of penicillin. To his delight, penicillin snuffed out a range of different pathogenic bacteria. Fleming published his optimistic findings in 1929 in the British Journal of Experimental Pathology.
Yet, even though Fleming’s penicillin exhibited potency against nasty ailments like diphtheria, rheumatoid fever, and strep throat, there were still a couple of obstacles preventing it from being converted into a commercial drug. First, it was not clear how to manufacture penicillin on a large scale. Salvarsan was a synthetic molecule, the product of chemically twiddling a molecule of dye, which meant that it was straightforward to manufacture as much Salvarsan as you wanted as long as you had the necessary base chemicals. But penicillin was produced by a tiny fungus. The only way to get more penicillin was to grow a lot more fungus and then extract the bacteria-fighting compound from the P. chrysogenum culture. When Fleming made his discovery, there were no known ways of growing the massive amount of fungus that would be necessary to produce enough penicillin to benefit a small town, let alone all of England. In fact, you could count the number of infected people who would be cured by the existing fungus-growing techniques on a single hand.
Second, Fleming found that penicillin took a long time to stamp out bacteria. We now know that this mistaken conclusion was due to Fleming’s faulty method of administration. Instead of dosing his subjects with penicillin through an injection or a pill—methods that deliver the medicine into the patient’s bloodstream—Fleming administered penicillin as a topical agent. He chose to rub penicillin on his sick subjects’ skin because he was worried that the human body would break down the drug before it could start to work. Fleming’s penicillin was further weakened as a consequence of him using low doses, a necessity due to the difficulty of producing the antibiotic.
Because of the difficulty of growing P. chrysogenum and the seemingly sluggish effects of the drug, Fleming could not persuade a chemist to help him create a more purified version. Discouraged, Fleming continued to work intermittently on his fungal antibiotic throughout the 1930s, but the medical community ignored his work. They presumed penicillin would never be useful as a commercial medicine. From 1929 to 1940, penicillin remained on the shelf, little more than a laboratory oddity—unused and virtually unexamined. It might never have become one of the most famous drugs in history if a pair of immigrants had not decided to take a second look.
Howard Florey and Ernst Boris Chain were both scientists and both born outside of Britain, but other than that their backgrounds could not have been more different. Chain was born in 1906 to a Jewish family in Berlin. Howard Florey was born in 1898 in Adelaide, South Australia. Chain’s father was a chemist who owned a number of chemical factories; Chain followed in his father’s footsteps and in 1930 received a chemistry degree from Friedrich Wilhelm University. The Nazis came to power soon after, driving Chain to cross the English Channel to the United Kingdom in 1933 with just £10 in his pocket. Florey, in contrast, studied medicine at the University of Adelaide, where he received a Rhodes scholarship that funded his graduate studies in pathology in England.
In 1939, the Rhodes Scholar and the Jewish refugee joined forces in Florey’s pathology laboratory at Oxford to pursue a single mission: testing whether penicillin might actually be useful as a general-purpose antibiotic. After reading Fleming’s papers, they speculated that a more purified and concentrated version of penicillin might be more effective at killing bacteria than the diluted and adulterated version that Fleming used. Since Chain was highly trained in chemistry, he set to work preparing a more highly purified version of the compound. When he finished, the two scientists tested their preparation on mice. Their stronger version of penicillin—which today is known as benzylpenicillin—demonstrated that they could cure bacterial infections much faster and more completely than Fleming’s formulation ever did. They published their impressive new results in 1940.
On seeing this report, an excited Fleming immediately telephoned Florey to say he would be visiting their pathology lab within a few days. More than a decade had passed since Fleming had published his initial paper about penicillin, so when Chain learned of Fleming’s impending visit he remarked, “Good God! I thought he was dead.”
In 1941, Florey and Chain treated their first patient. Albert Alexander had scratched his face on a rose thorn. Unfortunately for the ill-fated Alexander, the thorn was infested with malignant bacteria. The scratch became infected and the infection spread rapidly. In a few days, his entire face, scalp, and eyes were severely swollen. His eye soon became so badly infected, that the doctors feared the infection might spread into his brain and kill him, so they performed an enucleation—they surgically removed his eyeball. Even this extreme operation failed to halt the voracious bacteria. Facing death, with no other known treatment, Alexander was the perfect candidate for a penicillin trial.
Florey and Chain administered the drug through an injection directly into Alexander’s bloodstream. In less than 24 hours, he started to recover. Unfortunately, Florey and Chain had used their entire supply of purified penicillin on their initial dose, which today we recognize was both too little and too brief to wipe out such an advanced infection. Despite the promising start, Alexander relapsed. Though some of the bacteria had been stopped by the influx of penicillin, the remaining bacteria inexorably continued their invasion. A few days later, Alexander died. Florey and Chain realized that if they wanted to fully test the antibiotic properties of penicillin, they needed to come up with a way to generate more of the compound.
The only known way to make penicillin from the fungus was through “surface fermentation,” which meant growing P. chrysogenum on agar plates. Florey and Chain filled entire bedpans with agar to maximize the surface area, but even this expanded growth medium would never serve as a scalable way to produce the drug. They decided to conduct all their future experiments on children, since their small bodies required less of the drug. Soon, Florey and Chain were able to show that penicillin was very effective at curing a variety of bacterial infections, as long as it was injected directly into the bloodstream (their benzylpenicillin preparation did not work orally) and as long as the dose was high enough. The need for high doses exacerbated the penicillin shortage even further.
Now that penicillin was proven to be an even better miracle drug than Salvarsan, every hospital clamored for some of the woefully insufficient supply. During the early years of World War II, the best source of penicillin was the urine of patients already treated with the drug, since the active compound is excreted into the urine largely unchanged. As a result, hospital staffs conducted great efforts to collect every drop of urine from their patients in order to recycle their precious contents.
The manufacture of penicillin quickly turned into an exasperating problem of industrial production. England was at war with Nazi Germany and fighting for its very survival. It did not have the ability to divert its limited industrial resources from the desperate war effort to the manufacture of a drug, no matter how important. The Rockefeller Foundation, which had been funding Florey’s research, urged him to visit the United States and seek help from England’s ally. In July of 1941, Florey flew to New York, where he met with government agencies and private firms. Fortunately for Florey and Great Britain, the United States Department of Agriculture decided to get involved.
The USDA had already been working on fermentation methods to increase the growth of fungal cultures in its Peoria, Illinois laboratory; now the Peoria team set to work looking for ways to increase the growth of P. chrysogenum. The USDA scientists eventually made two major contributions. First, they found a strain of P. chrysogenum growing on a moldy cantaloupe in a Peoria fruit market that produced far more penicillin than any prior strain of the fungus. Second, they discovered that they could produce much more penicillin m
uch more quickly if they cultured the fungus in deep vats containing corn steep liquor (a cheap byproduct of corn milling) and then pumped air through the fungus-infused liquor (a process known as sparging). Best of all, this deep vat fermentation method was scalable. It finally lead to the industrial manufacture of the world’s first expanded-spectrum antibiotic.
A consortium of major American drug manufacturers began to work together and share information on the production of penicillin. These companies—Merck, Squibb, Pfizer, Abbott, Eli Lilly, Parke Davis, and Upjohn—came to be known in the pharma industry as “the penicillin club” and represented the Big Pharma firms of the era. It is an interesting comment on the evolution of Big Pharma that only two of these former giants, Abbott and Eli Lilly, still exist as independent companies. Squibb was eventually taken over by Bristol Myers. Merck was forced to merge with Schering. Parke Davis was once the world’s largest pharmaceutical company, but it was absorbed by Pfizer, which is now the largest pharmaceutical company of all time.
During the first five months of 1943, enough penicillin was produced in America to treat about four patients. Over the next seven months, enough penicillin was produced to treat 20 patients. Production methods continued to improve so that by the time the Allies invaded France on D-Day, there was enough penicillin to meet all the needs of the Allied forces. For the first time, wounded soldiers could recover rapidly from infections arising from battlefield wounds. Although Chain later learned that his mother and sister had been killed in German concentration camps, he could know that his research played a meaningful role in defeating the Nazis.
By the end of 1944, the deep vat method of production was finally perfected and Pfizer became the world’s largest penicillin producer by churning out enough doses for 100 patients every month. Though penicillin was a true miracle drug, some bacteria-borne diseases remained impervious to it. Perhaps the most dreadful of these diseases was tuberculosis, known as the “White Death” because of the anemic pallor of its victims. In the nineteenth century it was also regarded as “the romantic disease” because the thin, wan, melancholy appearance it bestowed upon the afflicted was often considered a “terrible beauty.” Dramatists and poets were drawn to the disease because of its tragic and doleful qualities and because it killed slowly, giving its victims time to tidy up their affairs in life and mend broken relationships before their dramatic demise. The heroines in Puccini’s La Bohème and Verdi’s La Traviata die of tuberculosis in each opera’s final scene; in La Traviata, the curtain falls as the doctor makes his pronouncement of death. Who knows—without tuberculosis, the world’s great opera houses might be dark today.
In reality, there is very little about the disease that might be considered romantic or beautiful. The tuberculosis bacteria infect the lungs, where they slowly but ineluctably eat away the air passages, causing its victims to cough up blood as they painfully waste away, growing ever paler and thinner. They appear as if they are being consumed, giving rise to the most common epithet for the sickness: consumption. It is also highly contagious, since the pathogen is readily transmitted to others whenever an infected person coughs, sneezes, or spits. (Anti-spitting laws were originally enacted to fight the spread of tuberculosis and remain on the books in most American municipalities.) When penicillin was invented, the only known treatment was to isolate infected patients in a sanatorium and hope for the disease to spontaneously remit. It rarely did.
The tuberculosis bacterium is a very slow-killing pathogen, which tells us that it is also a very highly evolved pathogen. Newly evolved germs like HIV, SARS, and the Nipah virus tend to kill their victims rapidly. This is a faulty strategy from the pathogen’s point of view, the equivalent of ripping up its own meal ticket. Fast-acting pathogens kill their host before they have a chance to spread to many other hosts. In contrast, highly evolved diseases milk their host for as long as possible, giving the pathogen a more prolonged opportunity to infect others. Tuberculosis is one of the most advanced of human diseases and seems to be as old as humanity itself. Even today, roughly one out of every three people on Earth is infected, with a new infection occurring once per second. Fortunately, most cases of consumption do not produce any symptoms, but even so, in 2016 there are fourteen million chronic cases worldwide producing about two million deaths each year.
In 1905 Robert Koch was awarded the Nobel Prize for discovering that Mycobacterium tuberculosis caused consumption. Scientists tried Salvarsan and, later, penicillin on the bacteria, but neither antibiotic could touch this unusually hearty and resilient germ. Many researchers suggested that certain breeds of bacteria, like M. tuberculosis, simply could not be killed by drugs. But one man held a contrarian view.
Selman Abraham Waksman was born in Priluka, near Kiev, Russia, but immigrated to the United States to attend Rutgers College in New Jersey. He received a bachelor’s degree in agriculture in 1915. The growth of crops depends on the interaction of the crop and its soil, including the microbes that inhabit the soil. Waksman became interested in this interaction, particularly in dirt, the rich, dark earth that nurtured crops. He began his research career studying soil—in particular, the bacteria in the soil. Soil microorganisms are essential to breaking down organic matter that falls onto the ground and converting them into the nutrients that plants need to grow. Working at an agricultural school, Waksman hoped that achieving a better understanding of soil microbiology would eventually provide a path to improving crop yields.
In science, the greatest discoveries are often obtained by scientists who started out studying one thing and unexpectedly stumble upon something else. For example, biologist Barbara McClintock set out to understand why kernels of corn were different colors, and ended up discovering one of the most important findings in modern biology—transposons, genetic elements that move from one DNA site to another. Similarly, neurologist Stanley Prusiner was doing his residency when a patient with Creutzfeldt-Jakob (CJD) disease came to see him. CJD is a neurodegenerative disease that is always fatal. At the time, nobody had any idea what caused this strange and incurable disease, since its pathogen had never been identified, but in an exhaustive attempt at helping his patients, Prusiner ended up discovering prions, an entirely new protein-based pathogen previously unknown to science. Both McClintock and Prusiner received Nobel Prizes for their unintended discoveries, and Waksman would eventually receive a Nobel Prize for his.
When Waksman learned about the success of penicillin, a compound produced by a familiar dirt-dwelling fungus, he immediately wondered if there might be other soil microorganisms with antibiotic properties. One group of microorganisms that Waksman had been studying for years is known as the Streptomycetes. These bacteria are so abundant that they produce the distinctive “earthy” odor that we associate with freshly turned soil. In 1939, he decided to investigate whether any of the Streptomycetes might kill bacteria. And not just any bacteria—from the start, Waksman hunted for a cure for tuberculosis, the most destructive of the diseases that penicillin failed to tame.
Waksman already knew how to grow and isolate soil microorganisms, since that was his field of expertise. What he did not know was how to develop an effective assay to test whether any Streptomycete-produced compound could kill the tuberculosis pathogen. Though in principle Waksman could simply grow M. tuberculosis in a petri dish, then add the test compound—this was how Fleming had discovered the effects of penicillin—Waksman rightly feared that working with large-scale cultures of living tuberculosis bacteria would be dangerous and could lead to the infection of the entire laboratory staff.
This was ultimately a screening problem. Waksman solved it by screening the Streptomycete compounds on a bacterium known as M. smegmatis, a species that is closely related to M. tuberculosis but is not harmful to humans. As a bonus, M. smegmatis grows much faster than M. tuberculosis, making it easier to carry out experiments. Waksman hoped that anything that killed the substitute bacteria would also kill tuberculosis. Fortunately for us all, his hypothesis turned ou
t to be correct.
Waksman’s laboratory discovered its first antibiotic candidate in 1940, a compound known as actinomycin. It was very effective against a broad variety of pathogens, including tuberculosis, but Waksman’s excitement was short-lived. When they tested actinomycin on animals, it turned out to be far too toxic to be useful as a drug. He returned to screening other Streptomycete compounds. In 1942, his laboratory found another antibiotic candidate that we now call streptothricin. This compound was also a very effective bacteria-killer, and this time when it was tested out on animals, the animals didn’t die. Not at first, anyway.
Eventually, Waksman’s team learned that streptothricin slowly damaged the kidneys. Animals could tolerate a dose of the antibiotic if it was brief, but if they had to be steadily dosed over an extended period of time, the animals’ kidneys failed, killing them. Antibiotics kill bacteria by attacking them when the bacteria are growing; when bacteria are dormant, such as in a spore or cyst state, they cannot be killed by antibiotics. The faster a bacterium grows, the easier it is for an antibiotic to kill it, generally speaking. Unfortunately, the highly-evolved tuberculosis bacterium is extremely slow-growing, which meant that any antibiotic would require a particularly long period of treatment to rub out all the bacteria. Streptothricin would not work, either.
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