A study from Uppsala University has identified two newly discovered mechanisms in bacteria that can contribute to the development of antibiotic resistance. These mechanisms involve changing the number of copies of resistance genes in bacteria, which can increase antibiotic resistance quickly. The researchers found that these mechanisms, along with a third known mechanism, can occur independently of each other, even within the same bacterial cell. This discovery sheds light on how bacteria can develop antibiotic resistance and the complexity of the mechanisms involved.
The researchers studied heteroresistance, a phenomenon where a small subpopulation of bacteria in a population exhibits increased antibiotic resistance while the majority remains sensitive to antibiotics. This small number of resistant bacteria can continue to grow despite antibiotic treatment, making heteroresistance challenging to treat and potentially accelerating the development of antibiotic-resistant bacteria. The study, which also involved animals, highlights how these mechanisms can promote heteroresistance and accelerate the selection and growth of resistant bacteria during antibiotic treatment, with implications for human health.
Bacteria can spread resistance genes to each other through plasmids, which are small DNA rings that bacteria use to store some of their genes outside the chromosome. The researchers identified two new mechanisms involving plasmids in which the number of copies of plasmids carrying resistance genes can increase up to 90 times. These mechanisms, along with a third known mechanism involving gene amplification, can operate in parallel within the same bacterial cell, showing the complexity of how bacteria can develop antibiotic resistance.
The study found that all three mechanisms are unstable and can quickly revert to sensitivity in the absence of antibiotics. This instability makes it challenging to detect resistant bacteria during clinical examinations, as they can disappear rapidly. The researchers emphasize the importance of developing better diagnostic methods that can detect increased antibiotic resistance to effectively combat the spread of antibiotic-resistant bacteria. Understanding these mechanisms and developing strategies to detect and treat antibiotic resistance is crucial in ensuring effective antibiotic treatment for patients in the face of the growing threat of antibiotic resistance.
Overall, the study sheds light on the complexity of mechanisms involved in bacteria developing antibiotic resistance and highlights the challenges posed by heteroresistance. By identifying and understanding these mechanisms, researchers can work towards developing better diagnostic methods and treatment strategies to combat antibiotic resistance effectively. The findings from this study provide valuable insights into how bacteria can develop resistance to antibiotics and underscore the importance of addressing this issue to protect human health and ensure the effectiveness of antibiotic treatment.