Scientists have figured out how to fight antibiotic-resistant bacteria

Antibiotic resistance poses a serious threat to human health globally. Resistant infections have been predicted to cause 10 million deaths per year by 2050. Given that antibiotics are critical in many areas of medicine, it is important to understand how antibiotic use affects the likelihood of resistance in response to treatment. Scientists have found that moderate doses of antibiotics limit the appearance of antibiotic-resistant bacteria. This limitation arises because antibiotic exposure harms resistant cells by limiting the ability of individual resistant cells to create successful populations. The scientists’ findings are published in the journal PNAS.

The generally accepted paradigm for antibiotics has been the very aggressive treatment of bacterial infections with large doses of antibiotics. This study suggests that using milder doses of antibiotics may be a good way to prevent resistance from developing during treatment while minimizing the harmful side effects of aggressive antibiotic treatment.

The study highlights the importance of studying the effects of antibiotics on individual bacterial cells. Only by understanding the effect of antibiotics on individual cells can scientists understand how their effect affects the emergence of resistance.

Our research is trying to figure out how the intensity of antibiotic treatment affects the emergence of antibiotic-resistant bacterial populations. Other researchers have explored this problem, but we took a unique perspective, which included studying the emergence of resistant populations from individual bacterial cells.

Professor Craig McLean of the Department of Zoology, University of Oxford and lead author of the research

The scientists obtained the results using large-scale laboratory experiments in which they measured the ability of individual antibiotic-resistant cells to create successful populations. Their focus on individual bacterial cells allowed them to understand how the effects of antibiotics on the growth and death of individual cells can limit the emergence of resistant populations of bacteria.

The job was challenging because the bacteria are so small (1 millionth of a meter long), but there were two big surprises during this project. First, I was surprised by the fact that even low doses of an antibiotic can have very detrimental effects on certain resistant cells. Second, I was surprised at how different individual cells respond to antibiotics and how they increase, affecting the growth of bacterial populations.

Professor Craig McLean of the Department of Zoology, University of Oxford and lead author of the research

The scientists hope their work will pave the way for future clinical work exploring how antibiotic doses affect the emergence of resistance in systems with direct clinical relevance.

They note that this study studied resistant bacteria in isolation and that in reality pathogenic bacteria often invade complex communities such as the gut microbiome. The next step is to understand how these bacteria affect the emergence of resistance.