New Antibiotics Against Bacterial Resistance: the Potential of Gold Molecules

Can gold save lives? A new antibiotic developed by ISGlobal could help stop resistant bacteria. Discover this innovative source of hope.

[This text was written jointly by Enmanuel Cornielle, predoctoral researcher at ISGlobal, Yaiza Gabasa, lab technician, and Sara M. Soto, Associate Research Professor and Director of the Viral and Bacterial Infections Programme at ISGlobal]

In a world where antibiotic-resistant bacteria have quickly become one of the top ten global health challenges, one might assume that new antibiotics are being developed at the same pace. However, the reality is surprisingly different.

Of the thirteen antibiotics that received marketing approval since 2017, only two belong to a novel chemical class not derived from existing molecules, which is one of the four criteria set by the World Health Organization (WHO) for antibiotics to be considered truly innovative. And none of the thirteen met the other three criteria: targeting essential bacterial components not affected by conventional antibiotics, having novel mechanisms of action, and not generating cross-resistance with existing antibiotics. This is deeply concerning.

Why is developing new antibiotics so difficult?

Innovating in antibiotic development also involves numerous scientific and technical challenges, such as:

• the creation of chemical structures that are non-toxic to human cells while remaining active against various pathogens
• economic obstacles like limited investment (chronic treatments tend to be more profitable)
• lengthy regulatory processes
• high cost of preclinical and clinical testing needed to prove efficacy and safety

While we move forward slowly, bacteria are evolving rapidly, indifferent to our efforts

In addition, some bacteria are capable of developing resistance to different antibiotics in just three days, highlighting the stark reality: we are fighting an unequal race. While we advance slowly, bacteria evolve at full speed, unconcerned by our progress.

Gold molecules: a solution against multidrug-resistant bacteria

The ISGlobal research team specializing in the transmission of antibiotic resistance, led by Sara Soto, has achieved a major breakthrough in collaboration with the Organic Chemistry Department of the University of Oviedo. Together, they have developed a new class of chemical compounds: gold (III) complexes, which have shown powerful antibiotic activity. This breakthrough could mark a turning point in the fight against one of the greatest health threats of the 21st century: infections caused by multidrug-resistant bacteria.

Gold (III) complexes are molecules whose chemical properties allow them to act as antibiotics, even against multidrug-resistant bacteria

Gold (III) complexes are molecules with chemical properties that enable them to act as antibiotic agents—even against bacteria resistant to multiple antibiotics. They also meet all four innovation criteria established by the WHO for the development of new antibiotics. In tests conducted by Soto’s team, no development of bacterial resistance was observed even after 30 days of continuous exposure to the compounds. This finding is especially significant, as one of the main issues with current antibiotics is how quickly bacteria develop mechanisms to neutralize them.

In a global context where antibiotic resistance is reaching alarming levels, this discovery represents genuine hope: the possibility of having a new generation of effective and long-lasting antibiotics.

The gold molecules have already been patented, which will allow for further stages of preclinical—and eventually clinical—research. At ISGlobal, this milestone strongly motivates us to keep researching innovative solutions to address one of the most pressing health challenges of our time.