Strain ZP - the first bacterial conjugation-based kill-anti-kill antimicrobial system

As multidrug resistant bacteria pose one of the greatest risks to human health new alternative antibacterial agents are urgently needed. One possible mechanism that can be used as an alternative to traditional antibiotic therapy is transfer of killing agents via conjugation. Our work was aimed at providing a proof of principle that conjugation-based antimicrobial systems are possible. We constructed a bacterial conjugation-based kill-anti-kill antimicrobial system employing the well known Escherichia coli probiotic strain Nissle 1917 genetically modified to harbor a conjugative plasmid carrying the kill gene (colicin ColE7 activity gene) and a chromosomally encoded anti-kill gene (ColE7 immunity gene). The constructed strain acts as a donor in conjugal transfer and its efficiency was tested in several types of conjugal assays. Our results clearly demonstrate that conjugation-based antimicrobial systems can be highly efficient. (C) 2015 Published by Elsevier B.V.