What Should I Know About Antimicrobial Stewardship?

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1) What is the difference between bacteria and viruses?

Picture Source: static.guim.co.uk

Viruses are microorganisms that are very small in size and can only survive by infecting a “host cell”,e.g., a human cell.

Viruses lack basic cellular machinery, therefore they cannot reproduce or create proteins on their own. They survive and multiply by entering a host cell and taking over its cellular machinery. The infected host cell is then forced to make thousands of copies of the virus, spreading it within the body.

Since viruses use our body’s own cellular functions to reproduce, there are only a few antimicrobials that can effectively kill viruses (i.e., antivirals).

Picture Source: SPL / BARCROFT MEDIA

Bacteria are single-celled microorganisms that can survive in many different environments. Unlike viruses, bacteria do have their own cellular machinery, allowing them to create their own proteins and reproduce without the requirement of a host cell.

Bacteria reproduce very quickly; within one day, one bacterial cell can divide to produce more than 10 million identical copies. Most bacteria are harmless, but some can cause infections like bacterial pneumonia, urinary tract infections, and gastroenteritis (food poisoning). 

What's the difference between bacteria and viruses?

2) How do antibiotics work and why don't they kill viruses?

How do antibiotics work?

Antibiotics are drugs that treat infections caused by bacteria, such as bacterial pneumonia, urinary tract infections, and Strep throat. They work by either killing bacteria directly or preventing them from reproducing, making it easier for our immune system to eliminate the bacteria.

Antibiotics are only effective against bacteria, not viruses. This is because viruses lack the physical structures and cellular machinery that antibiotics interfere with in order to prevent bacterial growth and replication. 


If you have a viral infection, antibiotics…

  • Will not relieve your symptoms.
  • Will not prevent others from getting sick.
  • May cause side effects and toxicity, such as abdominal cramps, rash, headache and C. difficile-associated diarrhea.

3) What is antibiotic resistance?

Simply put, antibiotic resistance is when certain bacteria are no longer eliminated by certain antibiotics.  For example, in the case of Methicillin-Resistant Staphylococcus aureus (MRSA), the bacterium, S. aureus, is no longer killed by the antibiotic, methicillin.

This is a natural phenomenon that can occur when bacteria develop (or otherwise acquire) a genetic mutation (a random change in genetic information, usually occuring during replication) that makes the bacteria resistant to an antibiotic. The longer and more often that bacteria are exposed to antibiotics, the quicker the process of "natural selection" for antibiotic resistance can occur. This means that antibiotic resistance is fueled by our own use and misuse of antibiotics, including:

  • Taking antibiotics when it is unnecessary (e.g., for viral infections like the common cold or flu)
  • Taking antibiotics inappropriately (e.g., wrong antibiotic, dose or duration)
  • Sharing and re-using previous antibiotic prescriptions

4) How does antibiotic resistance occur?

Bacteria can become resistant to antibiotics in two ways: through genetic mutation during replication or by acquiring antibiotic-resistance genes from other bacteria.

  1. Genetic mutation: Bacterial colonies contain great numbers of bacteria that can replicate very quickly. During this process, some bacteria can aquire genetic mutations (spontaneous changes in bacterial genes), which can create resistance to certain antibiotics. 
  2. Obtaining the resistance genes from other bacteria: Bacteria can transfer genetic material to one another in three ways: transformation, transduction and conjugation. This means that antibiotic-resistant bacteria can share their resistance genes with other non-resistant bacteria, creating new antibiotic-resistant bacteria, without the need for replication.
Time-lapse video of antibiotic resistance forming in E. coli bacteria.
What causes antibiotic resistance?

5) How does antibiotic resistance spread?

Source: Centers for Disease Control and Prevention
Source: European Centre for Disease Prevention and Control

6) What are some common antibiotic-resistant organisms?

The Government of Canada has outlined a few antibiotic-resistant bacteria that are common in Canada.

1. Methicillin-Resistant Staphylococcus aureus

Staphylococcus aureus is a type of bacteria that is frequently found on the skin and in the nose and respiratory tract of people. Although it does not always cause disease, it is often the cause of skin infections and respiratory tract infections. Methicillin-Resistant Staphylococcus aureus is resistant to the antibiotic methicillin and is commonly found is hospital settings.  If it’s not treated properly, MRSA can lead to fatal infections of the bloodstream, bones, lungs, and heart.

2. Vancomycin-Resistant Enterococci (VRE)

Enterococci are a group of bacteria that are normally present in human intestines. Pathogenic (disease-causing) enterococci may cause urinary tract infections, bacteremia (blood infection) and meningitis (inflammation of the protective layer covering the brain and the spinal cord). Vancomycin-Resistant Enterococci are resistant to the antibiotic vancomycin. This creates a problem since vancomycin is usually prescribed for infections that cannot be treated with other antibiotics, such as penicillin.

3. Clostridioides difficile

Clostridioides difficile (C. difficile or C. diff) is a type of bacteria that is normally present in human intestines. They are harmless when they exist in balance with other bacteria; however, when there is an excess of C. difficile bacteria, they produce toxins that affect the intestinal lining. This can lead to symptoms such as diarrhea and severe abdominal pain. C. difficile infections occur most frequently in patients who take antibiotics for an extended period of time.

Contact Us

Regina Area:

Phone us at 306-766-3520

Email our team at Antimicrobial.Stewardship@saskhealthauthority.ca

We are located at:

Regina General Hospital
4B32, 1440 14th Ave
Regina, SK, S4P 0W5

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