Whenever someone with cold symptoms asks me if they need an antibiotic, I am reminded of a funny line I once heard about a doctor responding to a patient making a similar request.
"If I treat you with an antibiotic," says the doc, "this infection will be gone in seven days. If I don't, it will take a week."
The joke is meant to underscore the fact antibiotics can't "cure" us of every infection that comes along. Of course, patients can't always see the humour in that line when they are as sick as a dog and want something -- anything -- for their illness.
With that in mind, I'd like to explain why antibiotics don't always work and why doctors are reluctant to prescribe them -- even when their patients are clearly ill.
The first thing to remember is antibiotics only work on infections caused by bacteria as opposed to those caused by a virus. That's because bacteria are microscopic organisms with their own internal "factories." They are living organisms that can take in food, metabolize it, reproduce, and, of course, cause infection.
Viruses, on the other hand are really just "storage containers" that house DNA or RNA (depending on the type). On their own, they cannot reproduce. So viruses basically "inject" their DNA or RNA into a human's cells and force those cells to reproduce more viral particles.
This difference is the simple answer as to why antibiotics don't work to kill viruses. The viruses are effectively "hidden" within our own cells. Our immune system doesn't recognize their presence until they reappear in our bloodstream after using our cells to reproduce. Antibiotics cannot penetrate our cells to kill the viruses. Bacteria, on the other hand, are present in the bloodstream and can be attacked by antibiotics.
So what happens when antibiotics are used inappropriately? There are several issues here. First, it's never a good idea to take an antibiotic (or any other drug) for a problem if it doesn't require treatment. Second, individuals who take an antibiotic run the risk of developing an allergy to the drug. Third, the overuse of antibiotics contributes to the development of drug-resistant infections. And that's really no laughing matter.
MRSA (methicillin-resistant staphylococcus aureus) is a well-known example of bacteria that have become resistant to the penicillin group of antibiotics. At first, this was only an issue in hospitals. But the MRSA has now become a major public-health concern, with many people carrying these bacteria and spreading them to family members and friends.
Gonorrhea is another example. These sexually transmitted bacteria have developed a resistance to many antibiotics. Only a group of antibiotics called cephalosporins are effective against this "bug" and there are now reports some strains are developing a resistance to even that drug.
Tuberculosis is another example of bacteria that has developed resistance to many antibiotics.
Of course, trying to determine whether an infection is caused by bacteria or a virus is not always a simple thing -- for patients or doctors.
Influenza and colds are always caused by viruses and don't need antibiotics. And we know 85 per cent to 90 per cent of bronchitis and sinus infections are also caused by viruses. Those caused by bacteria are usually accompanied by a high fever or last longer than one week.
So if antibiotics aren't the answer for viral infections, what is?
Careful handwashing is one of the most useful strategies. Whenever we cough, sneeze, or are in contact with anyone who is ill, we should wash with soap and water or an alcohol-based solution. Getting immunized for influenza and pneumonia bacteria (for those at high risk) also helps prevent infections that would otherwise make us seek medical advice.
If prevention doesn't work, seek appropriate help from your health-care provider. If you are told you have a virus and don't need antibiotics, don't fret. Sometimes the best medicine is none at all.
Dr. Harold Nyhof is a medical consultant for Health Links and the medical director of primary care clinics for the Northern Health Authority.