It is the first time the predatory bacterium Bdellovibrio bacteriovorus has been successfully used as an injected anti-bacterial therapy. This is an important step in the fight against drug-resistant infections, or 'superbugs'.
In the study, published today in Current Biology, researchers injected zebrafish larvae with a lethal dose of a strain of the Shigella bacterium that is resistant to both streptomycin and carbenicillin antibiotics.
The zebrafish were then treated with Bdellovibrio, which reduced the numbers of Shigella bacteria. In the absence of Bdellovibrio, zebrafish were unable to control the replication of Shigella and levels of the bacteria rose.
Shigella infection is responsible for over 160 million illnesses and over 1 million deaths every year – and is a common cause of 'travellers' diarrhoea'. Cases of drug-resistant Shigella are also on the rise.
Successful use of Bdellovibrio highlights its potential for tackling a range of drug-resistant Gram-negative bacterial infections that can develop in hospital patients.
Wellcome Research Career Development Fellow Dr Serge Mostowy from Imperial College London is the co-lead author of the study. He said it was an "important milestone" in research into the use of a living antibiotic that could be used in animals and humans.