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Penicillin: The World's First Wonder Drug?

Medically reviewed by Carmen Fookes, BPharm. Last updated on April 29, 2022.

Dirty Petri Dishes Responsible for One of the World's Greatest Discoveries

We have Alexander Fleming to thank for the discovery of penicillin in 1928, the world's first antibiotic.

Despite the link between bacteria and disease being established in the late 1800s, effective treatments for infections were lacking, and death from blood poisoning due to a simple cut or scratch, commonplace.

Dr. Fleming's job involved culturing pus extracted from skin infections such as boils and abscesses. He left dirty petri dishes in the sink, and after returning from a holiday, he found one set of his cultures had been contaminated by a mold. But the zone immediately around the mold was clear. Had something secreted by the mold inhibited the growth of bacteria? Indeed, this "mold-juice" was later termed penicillin.

International Collaboration the Key

As it turned out, discovering penicillin was the easy part. Extracting it and making it into a commercially viable product proved to be difficult, especially with World War II on London's doorstep.

As a result, production was shifted to the U.S., and producing adequate supplies of the drug in time to treat soldiers involved in the D-Day invasion of Europe became a major goal. By 1945, production had increased to 6.8 trillion units, and use of this "miracle drug" became widespread.

Which Came First? The Antibiotic or Resistance?

There is no question that the discovery of antibiotics revolutionized medical treatment and saved millions of lives. But equally noteworthy is the speed at which widespread antibiotic resistance has developed.

Antibiotic resistance is traditionally defined as the ability of bacteria to modify themselves in some way to resist the effects of antibiotics. Eventually, the original antibiotic is no longer effective.

However, even before penicillin was used therapeutically, two members of the penicillin discovery team identified bacteria resistant to penicillin. More recent research suggests resistant bacteria are a natural feature of all microbial populations, rather than a modification of existing bacteria.

Antibiotic Resistance Spreading Like Wildfire

According to reports from the World Health Organization (WHO), resistance rates to Streptococcus pneumoniae - the bacteria responsible for causing pneumonia, meningitis, and otitis media - exceed 50% in some countries and are increasing annually.

These high resistance rates are a cause for concern for all antibiotics, not just penicillin, and even more worrying when you consider that the discovery rate of new antibiotics has dramatically slowed. It is a real possibility that the 21st century may see a return to pre-antibiotic days when common infections and minor injuries could kill.

Growing the Penicillin Family

In an effort to combat resistance and extend the spectrum (bacteria-fighting ability) of penicillin, several other penicillin-like antibiotics have been developed.

Amoxicillin (Amoxil) is active against a wider range of bacteria than penicillin.

Amoxicillin combined with clavulanate (Augmentin), extends the spectrum even further. Although clavulanate has minimal antibacterial activity, it prevents bacteria from breaking down amoxicillin.

Penicillin V is an enhancement of the original penicillin and was developed to be able to withstand stomach acid so that it can be taken orally.

Other penicillin-type antibiotics include dicloxacillin, piperacillin (discontinued) and ticarcillin (discontinued).

Penicillin Today

Penicillin and penicillin-type drugs are still widely used today, although resistance has limited their use in some populations and for certain diseases. Penicillin-type drugs are preferred if treatment is needed for:

  • Respiratory infections such as pneumonia and acute exacerbations of chronic obstructive pulmonary disease (COPD)
  • Pharyngitis (sore throat), otitis media (ear infection), and sinusitis
  • Meningitis
  • Boils, cellulitis or animal bites
  • Syphilis.

Aren't a Lot of People Allergic to Penicillin?

Although approximately 10% of the population say they have an allergy to penicillin, the American Academy of Allergy, Asthma & Immunology (AAAAI) estimates that most of these people (greater than 90%) are unlikely to be truly allergic. Many people also lose their penicillin allergy with time, even those who have reported severe reactions, such as anaphylaxis, to penicillin. True penicillin allergy causing life-threatening anaphylaxis is rare (around 1 out of every 10,000 patients, or 0.01%).

The most common type of reaction happens 7 to 10 days after first taking penicillin (or within 2 days if the person has taken penicillin before). Symptoms include a rash, fever, and painful joints.

If you think you are allergic to penicillin, talk to your doctor about it. They can do tests to determine whether you are actually allergic to penicillin.

Antibiotics and The Environment: What Have We Been Feeding Our Livestock?

Unfortunately, past authorities have tended to ignore the effects of antibiotics on the environment. Antibiotics have been added to livestock feed to promote growth and counteract unsanitary living conditions since 1946.

In 2009, approximately 80% of all antibiotics used in the U.S. were fed to farm animals. But in 2017, the FDA banned the use of antibiotics to make animals grow quicker. Regulation now means that antimicrobials can only be given to food-producing animals under the guidance of a veterinarian.

But a lot of damage has already been done. Wide-spread overuse and misuse has affected our waterways and is expected to be especially disruptive to aquatic ecosystems and impact on organisms that are exposed throughout their life cycle. Not to mention the long-term impact on human health.

More Care Needed In The Way We Dispose Of Antibiotics

While it is pleasing to see the farming industry cleaning up its act, we as humans can probably do more to limit the environmental effects of antibiotics. A HealthDay/Harris Poll showed more than two-thirds of U.S. adults knew "little" or "nothing" about superbugs - bacteria that are resistant to many or all antibiotics.

Contamination of the sewage system with excreted and unused antibiotics and other medicines is of real concern. Thirty to sixty percent of antibiotics taken to treat infections pass through the human body unchanged. Unused medicines are disposed down the drain instead of being handed over at prescription Take-Back Days. Even the huge array of chemicals used to produce the antibiotic are an environmental hazard.

Unfortunately, any drug not broken down through sewage treatment has the potential to end up back in our drinking water.

Use Antibiotics Wisely

Antibiotics are a valuable resource that should only be used when absolutely necessary.

Here are some ways you can minimize your need for antibiotics:

  • Practice good hygiene in the first place to reduce your risk of catching infection - always wash your hands before eating and after toileting
  • Cover your mouth and nose when you sneeze or cough and stay away from work or school while sick
  • Keep your immunizations up-to-date and get an annual flu vaccine
  • Do not take antibiotics that are not specifically prescribed for you
  • If prescribed a course of antibiotics, take them exactly as directed and finish the entire treatment
  • Do not discard unused antibiotics down the drain or in landfill sites; take them to an authorized collector or wait for a medicine Take-Back Day

Finished: Penicillin: The World's First Wonder Drug?

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.