Skirting the Resistance

In 1928, Alexander Fleming found that the fungus 'penicillin' could be used to kill bacteria — and thus the first antibiotic was born. Since then, there has been a staggering increase in the use of antibiotics throughout medicine; unfortunately many times they are used inappropriately. For instance , many people still believe that antibiotics will help their cold or other viral infection. In reality, not only will they not do anything, they will in fact contribute to one of the largest rising concerns in medicine today: antibiotic resistance. Researchers at Penn State are trying to find out the best way to utilize current antibiotics in order to prevent antibiotic resistance.

Image Courtesy of ZME Science

In any colony of bacteria, there are likely a few of them that are resistant or immune to a certain antibiotic (due to mutations in genetic code). In this 'normal' state, these antibiotic resistant bacteria are kept at bay as they compete with the rest of the non-resistant bacteria. However, a very common practice for antibiotic administration is to prescribe a patient the very maximum dosage that they are able to handle. In some cases, as Penn State researchers have found, this practice of 'hitting hard' can in fact promote this antibiotic resistance. When these large doses of antibiotics kill off the non-resistant bacteria, they leave just the resistant bacteria to propagate now that there is no competition for resources. However, there are still cases when these large doses are the most effective option, like with HIV, where you can "kill everything by hitting it hard with a cocktail of medications."

Image Courtesy of CDC and Penn State

From mathematical models utilizing variables like probability of drug resistance by random mutation and the ability of these mutated bacteria to multiply, Dr. Andrew Read  has been able to determine what size the dose of antibiotics should be in order to reduce the proliferation of antibiotic resistance and also kill the infection as quickly as possible. From these models, he has found that the best course of action is either to give patients the maximum safe dose, or the lowest effective dose. Everything in the middle has been found to be sub-optimal. Whether a particular infection needs the maximum dose or the minimum will require individual clinical assessment.

While it may not seem like much, it may go a long way to reducing the unnecessary antibiotic resistance that is developing all of the time in the world. Antibiotics are one of the most important (if not the most important) medical tool, and it is critical that we continue to be able to use them in the decades to come.

If you'd like to read more about this study, you can find the full paper here.