Summary: In most instances, antibiotics do not work against viral infections (colds, flu, etc.). Antibiotics work well against bacterial infections, but realize that most respiratory illnesses are not bacterial. Rather than expecting an antibiotic when you visit a physician, it would be preferable to expect an understandable explanation of the cause of your child's illness and the best treatment that will be beneficial.
Microorganisms (germs) can basically be classified into four basic types: 1) viruses, 2) bacteria, 3) protozoans, and 4) fungi/yeast. The first two, viruses and bacteria, account for the vast majority of infectious disease in humans in the U.S.A. These four classes of microorganisms respond very differently to antibiotics.
Viruses are the smallest microorganisms. Viruses cannot be grown on a petri plate in a lab and they cannot be seen with a lab microscope. Viruses can only grow inside other living cells. Only a few hospitals are able to "grow" viruses in the lab. Viruses are so small, they can only be seen with an electron microscope (which most hospital labs do not have). Viruses cause infections such as colds, flu, pink eye, chicken pox, measles, herpes, polio and AIDS. Most viruses CANNOT be treated with antibiotics. Because of this, it is fortunate for us that the body's immune system is capable of fighting off nearly all viruses to restore us back to normal health. Unfortunately, there are some viruses which the body's immune system cannot remove satisfactorily. These viruses can cause complications such as brain damage, weakening of the immune system or overwhelming infection.
Bacteria are larger than viruses, but they are still very small. They can be grown on petri plates in a lab and they can be seen using high grade laboratory microscopes at maximum power. Bacteria cause infections such as boils, strep throat, tuberculosis, gonorrhea and impetigo. Nearly all bacteria can be treated with antibiotics. Infections such as pneumonia (infection in the lungs), meningitis (brain infection), sinusitis (sinus infection), gastroenteritis (intestinal infection), ear infections, and many other types of infections can be caused by viruses or bacteria.
Most of the serious infections of the past are less threatening now because vaccines against many of these illnesses are routine and antibiotics have provided physicians a way to effectively treat most bacterial infections.
Antibiotics are drugs which kill or suppress microorganisms without significantly harming the host (us). Something like alcohol or iodine solution might be considered to be an antibiotic because when applied to the skin, it kills most germs without much harm to the skin. The same thing applies to antibacterial soap. However, for germs inside the body, alcohol and iodine are too toxic to be swallowed in an amount large enough to kill germs. This is very different than one of the first antibiotics, penicillin, which is truly a magic bullet since it is highly effective at killing bacteria while being essentially non-toxic to the body.
In today's practice of medicine, antibiotics are used excessively because in many instances, physicians prescribe antibiotics in situations where they provide no benefit. Bacteria have the ability to slowly mutate and acquire resistance against antibiotics. We know for a fact that the bacteria that exist today are more resistant to antibiotics compared to bacteria 50 years ago. Why are antibiotics used excessively? There are several reasons for this.
1) Some physicians are not aware of the correct indications for antibiotics and thus, these physicians will prescribe antibiotics when they provide no benefit. Unfortunately, as in any profession, there are physicians who practice according to well established standards and there are those who do not.
2) There are many illnesses that are very common which benefit from antibiotics, but only slightly. The best known example of this is ear infections. Middle ear infection (otitis media) has a cure rate of about 70% after 10 days of antibiotics, but the cure rate without antibiotics is about 60% or possibly, 65%! This means that most ear infections will cure themselves and only sometimes, antibiotics are beneficial. It doesn't appear to matter much whether otitis media (OM) is treated with a $75 antibiotic or the usual $8 amoxicillin antibiotic; the cure rate is still about 70% after 10 days. Since otitis media is very common and most of the time antibiotics are not needed, this results in lots of unnecessary antibiotic use. It is now recommended that only the more severe otitis media infections be treated with antibiotics. Minor ear infections should not be treated in most instances. This will drastically cut down on unnecessary antibiotic usage.
3) Patients often pressure their physician to prescribe antibiotics even if the physician feels that it is not indicated. I have had patients who have demanded antibiotics, but I could not find evidence of any type of infection that would benefit from antibiotics.
4) Doctors often think that patients want antibiotics. To make them happy, they prescribe unnecessary antibiotics so that they will continue to be good "customers." Some doctors have stated in research interviews that patients must be coming to the doctor for antibiotics or a prescription medicine when they have a cold because all the other medicines are available to them at the drug store without a prescription. However, the research interviews with these patients indicate that patients really want an explanation of what they have, why they are sick and what medications would be useful. They actually prefer an explanation over a quick "prescription for antibiotics."
Using antibiotics excessively is bad. This accelerates the emergence of resistant bacteria. The bacteria are becoming resistant faster than new antibiotics can be developed. By using antibiotics excessively now, we doom future generations to infections that cannot be easily treated. Newer antibiotics might become available, but it is likely that these antibiotics will be very expensive and much more toxic. It is common for antibiotic prescriptions to cost $100 nowadays. Basic antibiotics are still only about $12, but many of these will not be effective if the resistance problem worsens.
How can you help to prevent antibiotic over usage? You should tell your physician that you would like an explanation of what is causing your child's illness and what is the best way to treat this. Don't demand antibiotics, but rather ask whether antibiotics would be useful for this particular illness. Ask about the side effects of the antibiotic and ask if these side effects are outweighed by the benefit of the antibiotics. It would also be beneficial if you could understand how most physicians make the decision to prescribe antibiotics (see below).
This next section is optional: How do physicians decide on prescribing antibiotics?
By far, most infections in humans are caused by viruses and bacteria. On average, most bacterial infections are more serious than most viral infections. Although we currently have hundreds of different antibiotics, nearly all of them work only against bacteria. Well trained physicians prescribe antibiotics in a three step process: 1) diagnosis of a clinical entity, 2) determination of the microorganisms that are most likely to cause this disease, 3) determine which antibiotics will effectively kill these microorganisms with the least amount of side effects.
Diagnosing a clinical entity involves interviewing the patient to find out what their symptoms are, then examining the patient for signs of infection. Based on the history and examination, the physician will make a diagnosis of a clinical entity. Let's use four different infections as examples: a) common cold, b) tonsillitis, c) bronchitis, d) pneumonia. Note the sample histories and examination findings below:
a) Common cold. History: no fever or mild fever, runny nose, mild cough and congestion. Exam: child does not look very ill, lung sounds are normal and no other signs of a more serious respiratory infection.
b) Tonsillitis. History: sore throat, fever, difficulty swallowing. Exam: child does not look very ill, tonsils are enlarged, there may be pus on the tonsils, neck glands (lymph nodes) are enlarged.
c) Bronchitis. History: coughing up green mucus, no fever or mild fever. Exam: child does not look very ill, lung sounds are normal. If a chest X-ray is done, it is usually normal, showing clear lungs.
d) Pneumonia: History: coughing up thick mucus, fever, chills. Exam: rapid breathing, spongy/bubbly sounds in the lungs. A chest X-ray is often ordered to confirm or rule out the presence of pneumonia. On chest X-ray, a pneumonia will show areas of the lung that are partially collapsed or filled with mucus or fluid.
The next step is to determine which microorganisms are causing this type of infection. Then, an antibiotic that is effective against these microorganisms must be selected. This can be looked up in a handbook, but most physicians know most of this information without looking it up.
a) The common cold is always caused by viruses so antibiotics are never helpful in colds.
b) Tonsillitis is often caused by "group A Strep", commonly known as strep throat which can be treated with many different antibiotics, but penicillin is most commonly used. Tonsillitis can also caused by viruses which cannot be treated with antibiotics. Patients exposed to gonorrhea (a sexually transmitted disease) in the mouth, may have tonsillitis due to gonorrhea. A special type of culture is required to identify this. Higher level (broad spectrum) antibiotics can treat gonorrhea, but penicillin will probably not work. So in summary, some causes of tonsillitis respond to antibiotics and some causes do not. Based on other subtle risk factors, the doctor will need to make a decision on whether antibiotics are likely to be beneficial.
c) Bronchitis has been traditionally treated with antibiotics, but many research studies have convincingly demonstrated that the type of bronchitis most commonly encountered in outpatient offices is overwhelmingly viral and it does not benefit from antibiotics. Many patients are used to the practice that doctors prescribe antibiotics for bronchitis. Just because this has been done for years, does not make it correct. Nearly all cases of bronchitis are just bad colds that do not benefit from antibiotics.
d) Pneumonia sounds like a very serious illness. True, pneumonia can be very serious and life threatening, but usually it is not very serious. Pneumonia means that there is an infection in the lungs. This infection can be minimal, mild, moderate or severe and thus, the severity of the pneumonia is highly variable. Most pneumonias are diagnosed early, so most often, pneumonia is not serious and it can be treated at home (in other words, without hospitalization). Pneumonia can be caused by viruses and bacteria. Given the clinical symptoms and signs exhibited by the patient, physicians can estimate the likelihood that the cause of the pneumonia is viral or bacterial. In some instances, the appearance of the pneumonia on a chest X-ray and the result of a blood count test can also help to distinguish a viral versus a bacterial cause. In adults with pneumonia, a sample of sputum (thick phlegm coughed up from deep in the lungs) can be used to identify the germ causing the pneumonia; however, this test cannot be done in children because they cannot bring up sputum. Since it is not easy to definitely distinguish viral from bacterial pneumonia, physicians often decide to treat most pneumonias with antibiotics to cover the possibility that the pneumonia is due to a treatable cause. If the pneumonia is viral, the body's immune system will usually fight off the pneumonia. If the pneumonia is bacterial, the antibiotics should cover it unless it is a very unusual germ (such as Legionnaire's disease or tuberculosis).
Most viruses cannot be treated with antibiotics. Medications which have beneficial effects against viruses are called antiviral agents. We currently have a few antiviral agents available and more are being developed. While previously, viral infections were largely untreatable, a few viruses are treatable and in the future, it is likely that many viral infections will be treatable. Acyclovir is a commonly used antiviral drug with activity against herpes virus and chickenpox. Acyclovir is very safe and is priced similar to a modestly priced antibiotic. HIV is a virus, thus, anti-HIV drugs are antiviral. AZT is one of the many drugs showing some beneficial effects against HIV. There are other antiviral drugs against the flu virus, respiratory syncytial virus (known as RSV), and a few other viruses. Hopefully, more antiviral agents will be available in the future. When considering how many viruses are out there, most viruses are still untreatable. Don't expect antiviral agents to be routine soon. Even for several years to come, antibiotics will largely be limited to bacterial infections with a few viral infections that can be treated with antiviral agents.
While viruses and bacteria cause most human infections, protozoans and fungi/yeast cause many infections as well. Protozoans include amebiasis, giardiasis and toxoplasmosis. Fungi/yeast include ringworm (tinea of the skin), athlete's foot, cryptococcus and candida. Candida is a common yeast that causes vaginal yeast infections, yeast (monilial) diaper rash and thrush (white yeast patches in the mouth). Since fungi and yeast most commonly cause infections outside the body, these infections can usually be treated with anti-fungal/yeast creams and sprays such as miconazole (Micatin, Monistat) and clotrimazole (Mycelex, Lotrimin). Older medications such as undecylenic acid (Desenex) and tolnaftate are effective against fungi, but not yeast. Nystatin (Mycostatin) is effective against yeast, but not fungi.