Scientists develop a new class of antibiotics
No new classes of antibiotic have come onto the market for more than 25 years.
US scientists have made a breakthrough in the fight against antibiotic resistance. A new class of antibiotics has been developed, leading to fresh hope for new drugs to treat resistant bacteria.
Led by Timothy Lu, a team of researchers from the Massachusetts Institute of Technology (MIT) have found a new approach to tackling antibiotic resistance. It is hoped their findings, published in Nature Biotechnology, may lead to new drugs for treating resistant infections.
Using a gene editing system called CRISPR, scientists are able to identify combinations of genes that work together to make bacteria more vulnerable to antibiotics. The system works by targeting specific genes that allow bacteria to survive antibiotic treatment.
“This is a pretty crucial moment when there are fewer and fewer new antibiotics available, but more and more antibiotic resistance evolving,” Professor Lu says.
No new classes of antibiotics have come onto the market for more than 25 years and some 25,000 people in Europe die every year due to antibiotic-resistant infections.
The CRISPR system involves a set of proteins used by bacteria to protect themselves from viruses (bacteriophages). One protein, the DNA-cutting enzyme Cas9, binds to short RNA guide strands that target certain sequences.
Prof Lu and his team designed RNA guide strands to target genes for antibiotic resistance, including the enzyme NDM-1. This enzyme is responsible for resistance to a range of beta-lactam antibiotics.
The team found that they were able to kill more than 99 per cent of bacteria carrying NDM-1.
Researchers also managed to target SHV-18, a mutation in bacterial chromosomes that provides resistance to quinolones and is a virulence factor in enterohaemorrhagic E. coli.
The system is currently being tested on mice. It is hoped that it may be eventually adapted to treat infections and remove unwanted bacteria in humans.
“This work represents a very interesting genetic method for killing antibiotic-resistant bacteria in a directed fashion, which in principle could help to combat the spread of antibiotic resistance fuelled by excessive broad-spectrum treatment,” says Ahmad Khalil, an assistant professor of biomedical engineering at Boston University who was not part of the research.
Veterinary practices are being urged to help owners safely dispose of any unused and expired pet medicines - not just antibiotics - during November's Animal Medicines Amnesty. 
