Phage-mediated intergeneric transfer of toxin genes

Area of Science:

• Microbiology
• Genetics
• Evolutionary Biology

Background:

• Bacteriophages typically infect specific bacterial hosts, leading to the assumption that genetic exchange is limited to within-species transfer.
• Mobile genetic elements, including pathogenicity islands, are crucial for bacterial adaptation and virulence.

Purpose of the Study:

• To investigate the potential for interspecies gene transfer mediated by bacteriophages.
• To assess the transfer frequency of staphylococcal pathogenicity islands into Listeria monocytogenes.
• To explore the implications of phage-mediated gene exchange for pathogen evolution.

Main Methods:

• Experimental transduction assays using staphylococcal phages and Listeria monocytogenes.
• Quantification of pathogenicity island transfer frequencies between Staphylococcus aureus and L. monocytogenes.
• Modeling of phage therapy conditions in raw milk to observe interspecies transfer.

Main Results:

• Staphylococcal pathogenicity islands and mobile elements transferred to Listeria monocytogenes at high frequencies, comparable to within-species transfer.
• Staphylococcal phages successfully transduced L. monocytogenes, although plaque formation was not observed.
• Pathogenicity island transfer between S. aureus and L. monocytogenes was confirmed in a raw milk model simulating phage therapy.

Conclusions:

• Bacteriophages facilitate extensive genetic information exchange among different bacterial species, challenging previous assumptions.
• This interspecies gene transfer mediated by phages has significant implications for the evolution of bacterial pathogens, including human pathogens.
• The findings suggest a broader role for phages in bacterial evolution and adaptation than previously recognized.