In our previous post, we talked about the different ways that antibiotics could kill bacteria*. Antibiotics have been very helpful to combat bacterial infections. However, they should be handled carefully and following the dosage prescribed by the physician. Actually, antibiotics may attack not only the bacteria that is causing the illness but also the normal “good” bacteria in our body. Moreover, inadequate use of antibiotics could contribute to the development of multi-resistant bacteria.
Indeed, one of the greatest problems in antibiotic resistance is the excessive use of antibiotics [1], which is yet another reason why people should not self-medicate. Imagine a person that is prescribed an antibiotic. When a certain antibiotic is killing the bacteria population, only the “fittest” bacteria will be able to withstand the drug without dying. If this person stops taking the antibiotic prematurely, they have taken just enough antibiotics to kill the most vulnerable bacteria, but not enough to kill the truly resistant bacteria. By this intermittent use of antibiotics, they are putting a “selection pressure” over the bacteria. In other words, they are helping select the most resistant bacteria by killing the bacteria that were less resistant. The resistant bacteria will reproduce, and “share” the secret of resistance to the next generation of bacteria. If the antibiotic is needed again, it is possible that it is no longer effective because the bacteria are already resistant.
There are several alternatives to help prevent the rise of antibiotic resistance. First, the doctor should assess the need for an antibiotic on a case-by-case basis. If the patient has a viral infection, an antibiotic will not make them feel better: The antibiotic will not combat the virus but it could contribute to select resistant bacteria (please see this post for more information). However, if the patient has a bacterial infection, it is important that the doctor critically determines the optimal time for the prescription (e.g., how many days the antibiotic is prescribed for).
Furthermore, Holmes et al. (2015) summarized several recommendations to delay antimicrobial resistance, including: better surveillance, diagnosis, and prescription; discovering and validating new drugs with antimicrobial properties; and decreasing the use of antimicrobial drugs in agricultural and aqua cultural practices [2].
Vaccination is another strategy with important advantages. Vaccination can help prevent infection and thus decrease the need for antibiotics. For example, pneumococcal infections are treated with antibiotics like penicillin, but there has been an increase in pneumococcal resistance to penicillin. The pneumococcal conjugate vaccine (PCV) has helped obtain immunity against some pneumococcal serotypes (i.e., bacterial “strains” or sub-types). After many people were vaccinated, the cases of penicillin-resistant pneumococcal infections associated with these bacterial sub-types decreased substantially [3,4]. In other words, there were fewer cases of those antibiotic-resistant pneumococcal bacteria after the vaccine was introduced.
*Bacteria - microorganisms invisible to the naked eye that consist of a single cell, though they can group together to form colonies or biofilms. Some bacteria are pathogenic and cause disease, like Salmonella enterica, while others are beneficial to our health, like the ones normally found in the guts.
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Written by: Nicole
Edited by: María and Natasha
BioDecoded is a volunteer group committed to sharing accurate scientific information. If you have any questions about this topic, please comment or send them to our email.
References:
Llor, C. & Bjerrum, L. Antimicrobial resistance: risk associated with antibiotic overuse and initiatives to reduce the problem. Therapeutic Advances in Drug Safety 5, 229-241 (2014). https://doi.org/10.1177/2042098614554919
Holmes, A. et al. Understanding the mechanisms and drivers of antimicrobial resistance. The Lancet 387, 176-187 (2016). https://doi.org/10.1016/S0140-6736(15)00473-0
Lobanovska, M. & Pilla, G. Penicillin’s Discovery and Antibiotic Resistance: Lessons for the Future?. The Yale journal of biology and medicine 90, 135-145 (2017). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5369031/pdf/yjbm_90_1_135.pdf
Kyaw, M. et al. Effect of Introduction of the Pneumococcal Conjugate Vaccine on Drug-Resistant Streptococcus pneumoniae. New England Journal of Medicine 354, 1455-1463 (2006). https://www.nejm.org/doi/full/10.1056/nejmoa051642
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