Interesting Facts About Antibiotics

by eMedExpert staff
Medical references reviewed: August, 2018

Antibiotics are an essential part of modern medicine and they are the only cure for numerous infectious diseases. Since the discovery of penicillin in the 1940s, scientists from many countries have developed more than 150 different antibiotics to help stop the spread of infections.

The ability of antibiotics to cure infectious diseases that were previously fatal has led to the notion that they are ‘miracle drugs’. And that they possess "powers" widely exceeding those which can be attributed to their actual pharmacological properties. In most developed countries, antibiotics are the second most widely used class of drugs after simple analgesics.

These drugs have saved millions of lives. However, the misuse of antibiotics has led to serious problems.

1 Virtually all current antibiotics act only on replicating bacteria

Antibiotics are generally active against multiplying bacteria, but are much less effective against non-replicating (latent) bacteria.


2 Antibiotics can't distinguish between the "good" and the "bad" bacteria

There is a delicate balance of billions of bacteria inside our digestive tract. Bifido bacteria in the large intestine and acidophilus in the small intestine and vagina protect against infection by yeast and other bad bacteria. "Friendly" bacteria on the skin also protect against bad bacteria, yeast, and fungal infections. Continued use of antibiotics, especially broad-spectrum antibiotics, can seriously disrupt the normal ecology of the body and render anyone more susceptible to pathogenic (disease causing) bacteria, yeast, and viral infection.

3 Bacteria produce antibiotics

Antibiotics are common metabolic product of bacteria (e.g. Streptomyces, Bacillus) and fungi. Bacteria produce antibiotics as their defense mechanism against competitors9.

4 The worst thing one can do is to take only a few of the antibiotic prescribed

At the beginning of treatment antibiotic wipes out the most vulnerable and weakest bacteria. Stopping antibiotic course prematurely will allow relatively resistant bacteria to survive and multiply.

Most people either forget to take pills, or stop taking them intentionally once they begin to feel better -- they think the infection is gone. But when medication is not taken long enough, the most resistant bacteria are not killed. Not only do they survive, but since they have "seen" the antibiotic, they can change their structure so that the same antibiotic will not kill them in the future.

5 How antibiotic resistance happens

Bacterial resistance to antibiotics is produced by changes in the bacterium’s DNA, called ‘Mutations’. One bacterium with a mutation can survive the antibiotic and reproduces millions more with the same resistance within the space of a day.

Antibiotic resistance results from gene action. Bacteria acquire genes conferring resistance in any of three ways:

  • In spontaneous DNA mutation, bacterial DNA may mutate spontaneously. Drug-resistant tuberculosis arises this way.
  • In a form of microbial sex called transformation, one bacterium may take up DNA from another bacterium. Penicillin-resistant gonorrhea results from transformation.
  • Most frightening, however, is resistance acquired from a small circle of DNA called a plasmid that can flit from one type of bacterium to another. A single plasmid can provide a slew of different resistances. In 1968, 12,500 people in Guatemala died in an epidemic of Shigella diarrhea. The microbe harbored plasmid-carrying resistances to four antibiotics!

6Antibiotics are not completely metabolized in the body and are released as active compounds into the environment

Many antibiotics are stable chemical compounds that are not broken down in the body, but remain active long after being excreted. At present, antibiotics make a considerable contribution to the growing problem of active medical substances circulating in the environment. Very little is actually known about the occurrence, fate, effects and risks associated with the release of antibiotics and other drugs into the environment (after being used in human).

7Bacteria subsisting on antibiotics

Scientists found several strains of bacteria in the soil which can not only tolerate antibiotics, but can actually make a meal of the world's most potent antibiotics5. This phenomenon suggests that this unappreciated reservoir of antibiotic-resistance determinants can contribute to the increasing levels of multiple antibiotic resistance in pathogenic bacteria.

8Proper dosage is very important for antibiotic effectiveness

If the dosage of the antibiotic is not adequate, it will not be effective for treatment of the infection and bacteria are more likely to develop resistance. This is because the bacteria can continue to grow and develop ways to disrupt the antibiotic's effects.

According to the Centers for Disease Control and Prevention, 18 million courses of antibiotics are prescribed (by doctors!!!) for the common cold in the United States per year, despite the almost universal belief in medical circles that colds are caused by viruses. In addition, an estimated 50 million unnecessary antibiotics are prescribed for viral respiratory infections. These and other needless antibiotic prescriptions, on top of the many "correct" ones, are responsible for the increasing resistance of bacteria to many widely-used antibiotics, especially in hospitals.

9 Who prescribes antibiotics inappropriately? Foreign, extra-busy and older MD

Proper (or improper) antibiotic prescribing depends on the physician. Canadian study7 found that doctors most likely to prescribe antibiotics in error are those who've been in practice longer, see more patients or trained outside Canada or the US.

The study found that international medical graduates are a shocking 78% more likely than Canadian- and American-trained MDs to give antibiotics inappropriately. This happens not because of poor knowledge, however. Some countries, Spain foremost among them, simply have more liberal attitudes to antibiotics use. The study also found that doctors who see an average of 34 or more patients per day are 20-27% more likely to give antibiotics where they're not appropriate. The research also showed that for each year a physician is in practice, their rate of inappropriate prescribing increases by 4%.

10 No new classes of antibiotics have been discovered in recent years

The discovery of new antibiotics has slowed down significantly (even dramatically). Developing new antibiotics has become too expensive and unattractive for pharmaceutical companies. At the same time, the government has reduced investment in infectious diseases because they have largely been viewed as treatable diseases. The combination has led to a decline in interest in antibiotic discovery. The antibiotic development pipeline has dried up. This means that for at least the next 10 years no new antibiotic classes will come to market.

Here is the timeline of introduction of new classes of antibiotics1

Year introduced Antibiotic class
1935 Sulphonamides
1941 Penicillins
1944 Aminoglycosides
1945 Cephalosporins
1949 Chloramphenicol
1950 Tetracyclines
1952 Macrolides/lincosamides/streptogramins
1956 Glycopeptides
1957 Rifamycins
1959 Nitroimidazoles
1962 Quinolones
1968 Trimethoprim
2000 Oxazolidinones
2003 Lipopeptides


11 Antibiotics may promote growth/obesity in humans as an inadvertent result of antibiotic pollution

The growth promoting effects of antibiotics were first discovered in the 1940s. The twentieth-century increase in human height and the obesity of the population is roughly observed since the mass consumption of antibiotics 40-50 years ago2.

12 Green tea boosts the bacteria-killing activity of the antibiotics

Green tea can help antibiotics be more effective in fighting bacteria. Researchers have found that green tea and antibiotics may work synergistically against certain pathogenic bacteria 10.

13 Antibiotics may interfere with immune system development

Children who are given broad-spectrum antibiotics before two years of age are three times more likely to develop asthma than children who are not given such antibiotics3-4.

14 Antibiotic "spectrum of activity" and "potency" are not the same

A broad spectrum antibiotic is one that can kill many different types of bacteria. A narrow spectrum antibiotic is one that kills only a small variety of germs. Many people refer to a broader spectrum antibiotic as a stronger antibiotic, but spectrum and strength are NOT exactly the same. If an organism is sensitive to narrow spectrum antibiotic like penicillin using a broader spectrum antibiotic will not result in any better cure. Antibiotics may have a similar spectrum of activity, but they may vary in potency.

15 Antibiotics are life-savers

Antibiotics have saved countless lives worldwide. When antibiotics were first used to treat bacterial infection they were hailed as the greatest lifesavers of all time. Before penicillin was discovered, infections were a leading cause of death. In 1900, the three leading causes of death were pneumonia, tuberculosis, diarrhea, and enteritis, which (together with diphtheria) caused one third of all deaths6.

And at the same time...

16 Penicillin is the #1 cause of life-threatening anaphylactic shock

Penicillins and cephalosporins have the highest rate of allergic reaction. Approximately 1 in 5000 exposures to a parenteral dose of penicillin or cephalosporin antibiotic causes anaphylactic shock8. Anaphylactic shock (also called anaphylaxis) is a rapid and severe allergic reaction, and one of the scariest health emergencies. Anaphylaxis starts when the immune system mistakenly responds to a harmless substance as if it were a serious threat.

17 More antibiotics are used on animals than on humans

In fact, more antibiotics are used on animals than on humans. The WHO says more than half of global production is used on farm animals. In the last 30 years the use of penicillin-type drugs in farm animals has increased by 600%, and of tetracyclines by 1,500%. Antibiotics are largely used in raising pigs and chickens.

  • 1. Conly J, Johnston B. Where are all the new antibiotics? The new antibiotic paradox. Can J Infect Dis Med Microbiol. 2005 May;16(3):159-60. PubMed
  • 2. Ternak G. Antibiotics may act as growth/obesity promoters in humans as an inadvertent result of antibiotic pollution? Med Hypotheses. 2005;64(1):14-6. PubMed
  • 3. Kozyrskyj AL, Ernst P, Becker AB. Increased risk of childhood asthma from antibiotic use in early life. Chest. 2007 Jun;131(6):1753-9. PubMed
  • 4. Early life exposure to antibiotics and the subsequent development of eczema, wheeze, and allergic sensitization in the first 2 years of life: the KOALA Birth Cohort Study. Pediatrics. 2007 Jan;119(1):e225-31.
  • 5. Dantas G, Sommer MO, Oluwasegun RD, Church GM. Bacteria subsisting on antibiotics. Science. 2008 Apr 4;320(5872):100-3. PubMed
  • 6. Achievements in Public Health, 1900-1999: Control of Infectious Diseases
  • 7. Cadieux G, Tamblyn R, Dauphinee D, Libman M. Predictors of inappropriate antibiotic prescribing among primary care physicians. CMAJ. 2007 Oct 9;177(8):877-83.
  • 8. Anaphylaxis eMedicine
  • 9. Coates AR, Hu Y. Novel approaches to developing new antibiotics for bacterial infections. Br J Pharmacol. 2007 Dec;152(8):1147-54. PubMed
  • 10. Tiwari TP, Bharti SK, Kaur HD, Dikshit RP, Hoondal GS. Synergistic antimicrobial activity of tea & antibiotics. Indian J Med Res. 2005 Jul;122(1):80-4.

Published: 2009
Last updated: February 18, 2016


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