Images show rifampicin's effects on E. coli bacteria
Scientists have captured the first detailed images revealing how the common antibiotic rifampicin disrupts E. coli bacteria at a molecular level. Using advanced cryo-electron tomography, researchers visualized the drug binding to bacterial machinery, halting growth. The findings, published in Nature, offer new insights into antibiotic mechanisms.
Researchers at the University of Basel in Switzerland have produced extraordinary microscopic images demonstrating the action of rifampicin, a widely used antibiotic, on Escherichia coli (E. coli) bacteria. Rifampicin, known for treating tuberculosis and other bacterial infections, targets the enzyme RNA polymerase, essential for bacterial transcription.
The study employed cryo-electron tomography, a technique that freezes samples in vitreous ice to preserve their natural state and allows three-dimensional imaging at high resolution. This method revealed rifampicin binding directly to RNA polymerase, trapping it in a stalled complex and preventing the elongation of messenger RNA strands. As a result, the bacteria cannot produce necessary proteins, leading to halted growth and eventual death.
Lead researcher Stefan Rieder from the University of Basel explained the significance: "These images provide unprecedented insight into the mechanism of action of one of the most important antibiotics in clinical use." The visuals show dense clusters of stalled transcription complexes accumulating inside the E. coli cells shortly after exposure to the drug, contrasting with untreated cells where transcription proceeds smoothly.
The research, detailed in a paper published in Nature on October 16, 2024, builds on decades of biochemical knowledge about rifampicin but marks the first direct visualization of its effects in live bacterial environments. Previously, scientists relied on indirect methods like X-ray crystallography of isolated components. This breakthrough could inform the development of new antibiotics amid rising antimicrobial resistance, though the study focused solely on E. coli and rifampicin's specific interactions.
No prior timelines for the experiment were specified beyond the imaging process, which occurred over several hours post-exposure. The work highlights the potential of cryo-electron tomography for studying drug-bacteria interactions, offering a balanced view of antibiotic efficacy without addressing broader resistance issues directly.