|MadSci Network: Microbiology|
You address an interesting and extremely timely question. First of all, bacteria are always mutating and changing. The ways in which bacteria pick up new DNA (e.g. through plasmid exchange or by simply taking up extracellular DNA) in addition to their short generation time means that bacteria are masters at adapting to their environment. While this is a naturally occurring process, in the face of strong selective pressures (e.g. antibiotic treatment) if there happens to be a bacteria which has a mutation which makes it resistant to the harsh conditions in the environment then that bacteria will survive and shortly dominate the bacterial population. Again, this is a result of the short generation time of bacteria (in some cases, it only takes 20 minutes for a bacteria to divide). Antibiotics revolutionized the fight against bacterial infections. Unfortunately over the past 40 years, there has been an increasing abuse of antibiotics. Antibiotics are put in cattle feed and people often take antibiotics for infections that cannot be cured by antibiotics (viral infections CANNOT be cured by taking penicillin, for example). In the case of antibiotics in cattle feed, the antibiotics have been used to prevent infections in cattle populations. Nonetheless, the massive use of antibiotics has lead to a situation today where there are an increasing number of bacteria that are resistant to antibiotics that worked previously. We've seen this with a number of bacteria (including Neisseria which causes gonorrhea and Mycobacterium tuberculosis which causes tuberculosis). This has been a frightening discovery, but in retrospect this shouldn't come as a surprise. The plasticity of bacteria to adapt and change to the environment (especially given their very short life cycles!) would naturally adapt to our use of antibiotics. Indeed antibiotics were first discovered as naturally occurring substances that certain bacteria, fungi, etc, use to kill off other bacteria. There were natural forces selecting for antibiotic resistance before we stumbled upon antibiotics and used them for our own purposes. Your question asks whether there is any value in taking a full course of antibiotics. The answer is YES! The reason that it is important to take a full course of antibiotics is as follows. Antibiotics can adversely impact the survival of specific bacteria, but an antibiotic does not kill off every bacteria immediately. Although during the first days of taking antibiotics you might kill a lot of bacteria, some of the bacteria in your system take longer to kill off. Maybe they are growing more slowly and therefore are affected less quickly by the antibiotic. IF YOU DO NOT TAKE THE FULL COURSE OF ANTIBIOTICS, YOU MAY EXPERIENCE A RELAPSE OF YOUR INFECTION! Now I know it's easy to think you have cleared an infection when you start feeling better, but the full antibiotic treatment is a precaution to make sure that ALL the bacteria are killed off in your infection. If anything not taking the full course of antibiotics may even facilitate antibiotic resistance! When your infection comes back, you might take the same antibiotics as you did initially. If you don't take the full course of antibiotics this time, you are giving the bacteria chance after chance to mutate in such a manner to develop antibiotic resistance. There is the chance that your infection is resistant to some sorts of antibiotics. However, it is possible for a doctor to do tests to determine what the bacteria is sensitive to and what it is resistant to. If the bacteria is resistant to certain antibiotics, a person can usually take a different antibiotic which is effective against the bacteria. So, yes use of antibiotics has lead to antibiotic resistant bacteria. However, the amount of good that antibiotics have done in the past and continue to do today account for the reason that they are still used today. There is also a good basis for why you should take the full course of antibiotics. If you don't you might get a relapse of your infection. You might also unwittingly help the bacteria adapt to any attempts to heal you. Hope that helps. etc
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