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Colonies of the bacterium V. cholerae (purple) insulate E. coli (yellow) from its natural predator Image Credit: James Winans |
Efforts to fight disease-causing bacteria by harnessing their natural predators could be undermined when multiple species occupy the same space, according to a study by Dartmouth College researchers.
When growing in mixed colonies, some harmful bacteria may be able to withstand attacks from the bacteria and viruses that target them by finding protection inside groups of rival species, according to a report published in the Proceedings of the National Academy of Sciences.
The researchers found that the intestinal bacterium Escherichia coli became surrounded by tightly packed colonies of Vibrio cholerae — which causes the deadly disease cholera — when the species were grown together. These clusters protected E. coli from the bacteria Bdellovibrio bacteriovorus that preys on both species individually, but in the study could only kill the outer layer of V. cholerae. This left the unscathed cells of E. coli and V. cholerae insulated within the colonies free to multiply.