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- A 48 year old policeman presents to Urgent Care with a small cut on his
face after shaving
- The cut is slightly red and draining a small amount of pus
- Before the 1940s this small, infected cut could lead to a swift death
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3
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- For the first time, doctors had a way to treat infections and
miraculously save lives
- Prior to the discovery of penicillin patients often died from trivial
injuries or infections
- Today in the United States, deaths by infectious bacterial diseases are one-twentieth
what they were in 1900
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- Physicians had little ability to
help patients suffering from infection
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- Folk remedies using fungi have been used for thousands of years
- 3000 years ago, the Chinese were using moldy soybean curd on boils and
other skin infections
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- Alexander Fleming was born in Lochfield Scotland in 1881, the son of a
pig farmer
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- The seventh of eight children, Fleming received a very good education
and was able to attend the University of London on scholarship
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- In 1900 the Boer War started between the UK and the colonies in Southern
Africa
- Fleming and his two brothers joined a Scottish regiment
- They never saw a battlefield and instead spent lot of time swimming,
shooting and playing water polo
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- Fleming was left money after his uncle died and his older brother
(already an MD) recommended he go to medical school
- Fleming got very high scores on his entrance exams and was able to
choose from three medical schools
- He chose St Mary’s in London because he had once played water polo
against them
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- Water polo was created in England during the 1860's because swimming was
becoming a popular sport
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- Fleming graduated from medical school in 1906 at the age of 25
- He was offered a job as research assistant at the inoculation department
at St Mary’s Hospital in London not just for his medical background but
also because he was a very good shot – his shooting skills would
strengthen the hospital’s rifle team
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- Fleming was working for Sir Almroth Wright who had discovered an
anti-typhoid vaccine in 1896
- Both Fleming and Wright went to France during WWI to treat wounded
soldiers and saw firsthand there was no effective treatment for most
infections
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- Unlike Wright who had an arrogant, forceful personality, Fleming was a
shy man
- Fleming also was a lackluster lecturer who was described by one student
as “a shocking lecturer, the worst you could possibly imagine”
- Nevertheless, Fleming inspired many by his future work
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- Incidentally, St Mary’s was one of the first places salvarsan was used
to treat syphilis
- Fleming had published on this topic and was considered an expert at
administrating salvarsan
- If fact, Fleming made quite a bit of extra income treating members of
the London Arts community for syphilis
- Often, artists would give him paintings as payment for his services
- Fleming’s background in administering salvarsan exposed him to the
ill-effects of substances that interfere with natural host defense
processes
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- In 1922 Fleming described lysozyme
- Lysozymes are enzymes present in diverse materials such as tears,
mucous, egg whites etc that cause bacteria to lyse
- His lysozyme research grew out of his interest in showing the
ineffectiveness of chemical antiseptics to treat infection
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- The idea of using chemical antiseptics to kill germs was a revolutionary
idea of the late 19th century popularized by Joseph Lister
- Lister was a Scottish surgeon, influenced by Pasteur, who believed that
germs caused infection
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- In 1874 he developed the method of using carbolic acid to kill germs and
prevent wound infections after surgery
- Lister’s theories revolutionized surgery
- Lister argued that antiseptics could also be used on wounds to kill
bacteria
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- Based on Lister’s theory, physicians of the time generally believed that
if antiseptics killed germs they were therefore useful in treating wound
infections
- Fleming strongly disagreed with this idea
- Fleming and his mentor, Wright, argued that the best way to treat wound
infections was to enhance the body’s natural immune response
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- Fleming and Wright noted that, although antiseptics kill bacteria, they
also kill leukocytes of the immune system more rapidly than they kill
invading bacteria
- They recommended using saline solution to cleanse wounds instead of
antiseptic solutions
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- Few accepted Wright and Fleming’s recommendation for wound care
- This rejection fueled Fleming’s search for antibacterial agents and
particularly his interest in lysozyme
- Like leukocytes, lysozyme was an endogenous way to treat infections
- Fleming believed that the best way to treat wound infections was to
enhance the body’s natural immune response
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- In 1922 Fleming described lysozyme when he noted that
lysozyme-containing material would interfere with the growth of
bacterial cultures
- Fleming found that a culture of his own nasal mucous inhibited the
growth of staph cultured from that same mucous
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- Fleming was fortunate in that the strain of bacteria he was culturing
was particularly sensitive to lysozyme
- However, Fleming was disappointed in that the bacteria most susceptible
to lysozyme were those that aren’t as infectious in humans
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- Fleming’s background with lysozyme research prepared him for his next
major discovery
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- Fleming had a notoriously disorganized lab
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- In 1928 after returning to his lab following a two week vacation Fleming
encountered the place in its usual disarray
- Fleming had a inoculated a number of petri dishes with
staphylococci prior to leaving on
vacation
- He hadn’t placed them in an incubator because he knew that the staph
would sufficiently multiply over the long vacation
- Little did he know that penicillium mold grows well at room temperature
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- Fleming returned to his lab to find many of his culture plates
contaminated with fungus
- He immediately started preparing to clean all his plates but it happened
that a former member of his lab was visiting that day
- Fleming took some of the contaminated cultures to show his visitor and
that’s when he noticed the inhibition zone around the fungus
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- Fleming was not very knowledgeable about fungi but knew that the mold in
his dish was a species of penicillin
- Eventually determined to be Penicillium notatum
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- Fleming’s observation was made under some accidental circumstances but
clearly made sense in light of Fleming’s research background
- Fleming had the sophistication to realize that anti-bacterial agents
existed – this view was really fueled by his background in lysozyme
research
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- It was obvious to Fleming that penicillin was much more powerful than
lysozymes because his crude extracts could be diluted 1000 times and
still be effective in killing bacteria
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- In 1929 Fleming published a paper detailing his discovery
- This was also a crucial moment because his ideas reached a large
audience
- But it wasn’t until ten years later that other scientists began trying
to use penicillin to treat clinical disease
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- Fleming continued to work on and off with penicillin during this time
but was never able to produce it in quantities necessary for practical
testing or applications
- Fleming found that many of his cultures were unstable and stopped
producing mold after eight days
- Interestingly, Fleming initially conceived of penicillin as a topical
agent and did not think of using it as an injectable or ingestible
medication
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- Fleming did inject one rabbit and one mouse with penicillin to make sure
there were no ill effects (there were none) but never injected these
animals with a simultaneous bacterial strain
- Ironically, even though Fleming was an expert at administering
intravenous salvarsan to syphilis patients, he only thought of
penicillin as an external germicide
- Fleming, in his 1929 article, compares penicillin’s effects to carbolic
acid (anti-septic favored by Lister and his followers for treating wound
infections)
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- Fleming, when asked why he abandoned his initial research, noted that
his preparations quickly lost their antibacterial effects
- He lacked the help of a biochemist to assist him with penicillin
extraction
- Wright wouldn’t allow the presence of a biochemist is the lab because he
thought chemists lacked humanism
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- Paine - student of Fleming who was first to demonstrate the value of
penicillin in medicine
- After reading Fleming’s article, Paine obtained from Fleming a sample of
the PCN mold, made cultures and used it to treat the lacerated eye of a
local miner. The miner still had
a piece of the stone in his eye with a severe pneumococcal infection
- Paine irrigated the eye with crude PCN extract “mold juice” and the
patient’s eye was saved
- Paine also irrigated the eyes of a baby born to a mother with gonorrhea
and saved the child’s eyes
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- Paine never published his results but did share them with Dr. Howard
Florey at Oxford who became actively interested in penicillin in the
1930s
- Coincidentally, a researcher at Oxford Ms. Campbell-Renton had some of
Fleming’s original mold passed down to her from an old boss who had used
it for some unsuccessful research
- Dr Ernst Chain, a talented biochemist who fled Nazi Germany, persuaded
by Dr. Florey to join his Oxford team
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- Chain accidentally bumped into Cambell-Renton in the hall one day while
she was carrying a flask of Fleming’s mold
- Chain went to Florey with the idea to research biochemical and
biological properties of antibacterial substances produced by
microorganisms
- Funding was obtained and research began
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40
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- Soon after beginning his research, Chain discovered that penicillin was
not an enzyme but a molecule
- He was intrigued by the fact that penicillin was a very unstable
molecule
- Chain was able to freeze- dry the penicillin and produce a stable brown
powder
- Tested on mice, a huge dose proved safe
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41
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- Another important observation was that the penicillin powder turned the
mice’s urine brown – it passed unaltered and without loss of effects
into the urine
- This meant that PCN could pass through the body and fight infections
wherever they were
- The Oxford team was ecstatic about their discovery and began work
immediately to prove their findings were correct
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42
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- Florey next experimented with mice and lethal doses of streptococci
- Eight mice were injected with the bacteria and only four mice received
penicillin prior to the bacterial injection: the four “PCN mice” survived and the
others all died
- The first landmark paper detailing the mice experiments were published
in August 1940
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43
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- England was very close to jeopardy at this point in WWII and members of
this Oxford team all rubbed penicillin mold on the inside of their
clothing fearing that if Germany should invade and occupy Britain one
might be able to escape to North America with mold spores!
- They know that PCN had the potential to save millions of lives
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44
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- After the researchers were confident that PCN was safe in mice they
began human testing
- 48 y/o policeman with bacterial sepsis after cutting himself while
shaving improved dramatically after treatment with the PCN but he
required such high doses that the supply was quickly gone
- The researches even tried to recrystallize the PCN from this patient’s
urine to give back to him but the patient didn’t survive
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45
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- The researchers continued but changed their patient focus to small
children thinking they required less PCN for good outcomes
- Almost all the children were miraculously cured of infection
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46
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- Penicillin Production began in Britain on a small scale in 1941
- The British government encouraged the development of a number of small
production facilities at this time.
Large scale companies could easily be bombed by German war
planes.
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- Florey’s visited the US and Canada with a vial of the sample mold July
1941
- It was recommended by an American professor that Florey meet with the
head of the USDA research laboratory in Peoria, IL Dr. Robert Coghill
- Coghill suggested deep fermentation would likely make the production of
penicillin more efficient and convenient
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48
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- The search was on for even better sources for penicillin producing
Penicillium
- The best specimen was mold found on a cantaloupe purchased at a Peoria
market
- Penicillium chrysogenum
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- From January to May 1943 only 400 million units of penicillin had been
made
- By the time the war ended US companies were making 650 billion units a
month!
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- During WWI the death rate from pneumonia in the US Army totaled 18%
- During WWII the death rate fell to less than 1%
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- Fleming and Florey were knighted in 1944
- Chain was later knighted in 1965
- The Nobel Prize in Physiology or Medicine was awarded to Fleming, Florey
and Chain in 1945
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- Although the discovery of penicillin is arguably one the greatest
discoveries of humankind, drug resistance poses an enormous problem
- In 1994, 13,300 patients died of drug-resistant bacterial infections
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53
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- A 48 year old policeman presents to Urgent Care with a small cut on his
face after shaving
- Today: prescribe antibiotics
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54
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