In a new study, researchers from the Israel Institute of Technology have developed a new technique to measure the long-term effects of using antibiotic combinations. These antibiotic combinations attract great interest from the scientific and medical community, as the use of a single antibiotic often leads to the rapid development of bacterial resistance to this class of drugs. The results were recently published in the Nature journal under the title "Antibiotic combinations reduce Staphylococcus aureus clearance".
These authors found that in many cases, several combinations of antibiotics may actually reduce the long-term effectiveness of this treatment — meaning that the combination of several antibiotics may prove less successful when each antibiotic is used alone. However, they noted that some specific combinations of antibiotics do prevent the production of drug resistance, thus protecting patients from invasive bacteria for a long period of time.
The bacteria tested in the new study are Staphylococcus aureus, a particularly ferocious bacterium that has become resistant to many types of antibiotics. A large proportion of infections in the nasal cavity (in hospitals or in clinics) are caused by the bacteria. The new study was conducted in a laboratory culture of the bacterium and in an animal model, the wax moth (Galleria mellonella) larvae.
Antibiotics play a vital role in modern medicine, saving lives every day. The natural antibiotics produced during the evolution of the fungi and yeasts in question were discovered about a century ago by British Sir Alexander Fleming, Australian-born Howard Walter Florey, and Ernst Boris Chain, a Russian-German-Jewish immigrant from Berlin, Germany.
Antibiotic therapy has saved hundreds of millions of people over the past century. However, the success of antibiotic therapy became a double-edged sword, as the widespread use of these antimicrobial agents has led to bacterial resistance during evolution. This trend raises legitimate concerns about the post-antibiotic era, or one in which bacteria will no longer respond to antibiotic drugs, and that people will die as before from infections that are now considered mild and not dangerous.
Corresponding author and Professor Roy Kishony, from the Department of Biology at the Israel Polytechnic Institute, is one of the leading experts in the field of antibiotic resistance, and he and his team developed the method to estimate the resistance of a bacterium to a current antibiotic in advance, or even predict the level of resistance it is expected to produce in the future. In this study, they studied the combinations of different antibiotic drugs that prevent the formation of drug resistance.
These authors indicated that the COVID-19 pandemic increased the use of antibiotics, although SARS-CoV-2 is not affected by antibiotics because it is a virus rather than a bacterium. However, taking antibiotics helps in COVID-19 patients to avoid secondary bacterial infections. As antibiotic use increases, the evolution of the resistant S. aureus strains also accelerates.
In summary, these authors found that the combinatorial use of antibiotics may compromise the effect of this treatment, and point to specific combinations of antibiotics that accelerate or inhibit the production of resistant bacteria. By doing so, they help pave the way for the development of more effective treatment and containment of "resistant bacterial epidemics" that threaten humans.
