Plant toxin called “new weapon” in the war of antibiotics with bacteria

Scientists have discovered a plant toxin whose unique method of killing bacteria could be used to create a powerful new group of antibiotics. The prospect of developing new antibacterial drugs has been welcomed in this way by physicians, who have warned for years that the steady rise in drug-resistant pathogens such as E. coli now poses a dangerous public health threat across the planet.

A new antibiotic – albicidin – affects bacteria in a completely different way than existing drugs, as shown by a group of British, German and Polish scientists in a paper recently published in the journal Nature Catalysis. This suggests that a new path can be used to combat bacterial diseases.

“We have not been able to detect any resistance to albicidin in the lab,” said Dmitry Gilarov, whose research team is based at the John Innes Center in Norwich. “That’s why we’re really excited – because we think it will be very difficult for bacteria to develop resistance to antibiotics derived from albicidin.”

Albicidin is produced by a bacterial plant pathogen called Xanthomonas albilineans, which causes a devastating disease in sugar cane known as leaf scorch. The pathogen uses albicidin to attack the plant, but decades ago it was also found to be very effective in killing bacteria.

“The problem was that at that time we didn’t know exactly how albicidin attacks bacteria, and therefore we couldn’t use it as a basis for new antibiotics, because they could cause all sorts of complications in the human body,” Gilarov said.

Working with scientists from the Technical University of Berlin in Germany and the Jagiellonian University in Krakow, Poland, Gilarov and his team used a number of cutting-edge methods to figure out how albicidin kills.

“Now we have an understanding of the structure, we can create modifications of albicidin to improve its effectiveness and pharmacological properties,” Gilarov said. “We think this is one of the most exciting new antibiotic candidates in years. It is extremely effective at low concentrations and is very effective against pathogenic bacteria, even those that are resistant to commonly used antibiotics such as fluoroquinolones.”