Bdellovibrio bacteriovorus protects Caenorhabditis elegans from bacterial pathogens

Bdellovibrio bacteriovorus is a naturally predatory bacterium that multiplies inside Gram negative prey bacteria. There is much interest in using Bdellovibrio as a living antibiotic to control infections by Gram negative pathogens. In recent years Caenorhabditis elegans has proven to be an attractive animal model of bacterial pathogenesis for a range of pathogens. We have used the C. elegans animal pathogenesis model to examine the ability of B. bacteriovorus to protect nematodes from four bacterial pathogens. In all cases, nematodes treated with B. bacteriovorus and the pathogen survived at a significantly higher level than nematodes treated with the pathogen alone. Treatment with B. bacteriovorus alone was nontoxic to the worms. We monitored the persistence of E. coli K-12 and E. coli OP50 in both B. bacteriovorus treated nematodes and control nematodes. E. coli K-12 levels were significantly lower in B. bacteriovorus treated nematodes than in control nematodes one day after Bdellovibrio exposure and E. coli K-12 was eliminated from the worm gut two days faster in B. bacteriovorus treated nematodes. E. coli OP50 also demonstrated significantly lower levels in B. bacteriovorus treated nematodes and faster elimination from the worm gut. The successful use of B. bacteriovorus as a therapeutic agent in C. elegans indicates that it may be useful as a living antibiotic in other animal systems