When we take antibiotics to fight a bacterial infection, we rarely consider the microscopic war raging within our bodies. Recent research from the Department of Clinical and Molecular Medicine at the Norwegian University of Science and Technology in Trondheim, Norway sheds new light on how bacteria respond to antibiotic attacks, particularly focusing on the widely used antibiotic Ciprofloxacin, according to a recent article on phys.org.
Ciprofloxacin works by targeting the DNA of bacterial cells, binding to a protein crucial for maintaining DNA structure. This interference creates chaos within the bacterial cell, leading to the formation of incomplete DNA strands. The presence of these damaged DNA fragments triggers an alarm system in the bacteria, known as the SOS response.
During this response, the bacteria undergo visible changes. E. coli, typically rod-shaped, elongate into filaments as they prioritize damage repair over normal functions. If repair efforts fail, the bacteria resort to altering their DNA through mutation, potentially leading to antibiotic resistance.
The study, published in Frontiers in Microbiology, reveals new insights into this process. Contrary to previous beliefs, researchers found that all 60 genes involved in the SOS response activate simultaneously, with regulation occurring at the protein level rather than the gene level. This discovery was made possible by growing bacteria in a bioreactor with tightly controlled conditions, allowing for more reproducible results.
The research team employed a comprehensive approach, measuring gene activation, proteins, and small molecules frequently over two hours following antibiotic exposure. This method provided a detailed timeline of the bacterial response, offering the most complete picture of the SOS response to date.
Understanding these mechanisms is crucial in the fight against antimicrobial resistance. While high doses of antibiotics can overwhelm bacteria, not all bacteria in an infection are exposed equally due to varying tissue uptake and natural resistance levels. This uneven exposure can allow some bacteria to develop resistance, even during treatment.
Moreover, the presence of low-dose antibiotics in water and sewage systems creates opportunities for bacteria to develop resistance in nature, highlighting the importance of reducing antibiotic use overall.
This new knowledge about the SOS response opens avenues for developing new medicines. Researchers suggest that substances called inhibitors could be created to target the SOS mechanisms. These inhibitors, when administered alongside antibiotics like Ciprofloxacin, could potentially prevent the development of resistance.
Commenting on this story, one national food safety lawyer said, “With the growing threat of antibiotic-resistant bacteria, studies like this provide valuable insights into bacterial behavior and survival characteristics that should enable scientists to develop more effective treatments and strategies to combat drug resistance.”
