• Question: So... is it correct that if humans take too many antibiotics that the bactirea may become imune

    Asked by to Jim on 17 Jun 2011. This question was also asked by .
    • Photo: Jim Caryl

      Jim Caryl answered on 17 Jun 2011:

      As a population, the over-use or incorrect use of antibiotics can lead to the evolution of bacteria resistance to antibiotics. It doesn’t necessarily mean that every single person who takes antibiotics will get antibiotic resistant bacteria, but when there are millions of people, the chances of a particularly resistant bacteria evolving is higher, and then this bacteria becomes the dominant bacteria that can spread between people.

      There is nothing wrong with taking an antibiotic when it is necessary, they are an amazing drug that serve an important purpose, but they should be used carefully, and the doctor’s instructions always followed.

      If you are given an antibiotic for a particular infection for which an antibiotic is the correct choice, the antibiotic pill will be designed to kill (or stop from growing) the bacteria causing the infection. This only works if the correct dose (i.e. the right number of pills) is taken, and as long as you finish the full course of antibiotic and don’t forget to take any.

      However, many people do not complete their full course of antibiotics, or they take less than the recommended dose to make them last longer. Or they forget to take them. It is in these circumstances that the antibiotic level can decrease to the point where bacteria that have a low-level of resistance to the drug can survive, and then next time the antibiotic concentration drops again (either from forgetting more pills, or stopping the antibiotic), some of those bacteria might have evolved high-level resistance to the antibiotic. In effect, they will no longer be killed.

      People should not expect to get antibiotics for infections that cannot be treated with antibiotics, so a cold or the flu cannot be treated with antibiotics as these infections are caused by viruses. There are also bacterial infections where the use of antibiotics makes very little difference to the outcome, such as childhood ear infection. In Europe we don’t tend to prescribe antibiotics for ear infections, but in the USA they always do – and yet American kids with ear infections don’t recover any quicker than European kids – so this is an unnecessary use.

Comments