McMaster researchers discover manikomicin, antibiotic with novel mechanism against resistant bacteria

A team at McMaster University in Canada has identified a compound that attacks drug-resistant bacteria in a way no existing antibiotic does. The molecule, called manikomicin, emerged from research led by Gerry Wright and has shown early promise against dangerous pathogens including Salmonella, E. coli, and Klebsiella. The findings, published this week in Nature, represent a potential turning point in the escalating battle against bacterial resistance—one of the most pressing public health crises globally.

What makes manikomicin fundamentally different is its mechanism. Rather than targeting the same vulnerabilities in bacterial ribosomes that conventional antibiotics exploit, it blocks the exit site—the point where finished proteins leave the ribosome's assembly line. Think of a bacterial ribosome as a factory production line, Wright explains. Finished components must leave before the next piece can move forward. Manikomicin jams that exit, halting the entire assembly process. Without the ability to manufacture proteins, bacteria cannot survive. No antibiotic currently prescribed in clinics works this way. Not azithromycin, not tetracycline, not any of the drugs doctors routinely reach for. The research team emphasizes they have not merely found a new drug candidate—they have identified an entirely new target within bacteria that other researchers might exploit to develop additional treatments.

The reason this matters becomes clear when you understand how resistance develops. Most antibiotics in use attack a small cluster of the same bacterial vulnerabilities. Over decades, bacteria have evolved elaborate defense strategies against these familiar assaults. But because no antibiotic has ever pressured this particular exit site, bacteria have developed no existing resistance mechanisms to counter manikomicin. Even newly discovered drugs targeting those old, well-worn targets face rapid resistance. This one does not—at least not yet, and perhaps not for a long time.

The discovery itself rests on a decision to revisit work abandoned long ago. More than 75 years ago, scientists found that a soil bacterium called Streptomyces rimosus produced oxytetracycline, a powerful compound that helped usher medicine into the antibiotic age. That breakthrough, along with similar discoveries in the mid-twentieth century, seemed to exhaust the potential of these soil bacteria. The scientific consensus hardened: these organisms had been fully exploited, their secrets already extracted. Wright's laboratory disagreed. Using an advanced technique called fractionation, his team—working with collaborators at the University of Illinois Chicago and the University of Hamburg—filtered out the abundant, well-known compounds like oxytetracycline from the chemical mixtures produced by S. rimosus. What remained were rare molecules that had escaped notice for decades. Manikomicin was among them.

For Manpreet Kaur, a postdoctoral researcher in Wright's lab and the study's lead author, the discovery signals something larger: that sources long considered exhausted may still harbor viable drug candidates. The implication extends beyond this single compound. If soil bacteria thought to be fully studied still contain novel antibiotics, the same may be true elsewhere in nature. The research suggests that the hunt for new treatments need not always point toward exotic organisms or cutting-edge synthetic chemistry. Sometimes the answer lies in looking more carefully at what was already there.