a toxic protein, pyocin S5, is activated together
with the action of another E7 protein, which
causes the E. coli to explode and to lyze. In this
way the pyocin S5 is released into the external
medium, which kills Pseudomonas (unlike
what happens with traditional antibiotics,
resistance to pyocins is infrequent). Following
this strategy, the E. coli release the toxic pyocin
only in the presence of Pseudomonas. The
pyocin does not affect other microbes, which
means that this treatment should not kill other
bacteria that are beneficial to the organism.
Furthermore, the researchers have demonstrated
that this system not only works when
Pseudomonas is growing freely in liquid culture
media, but also when the bacterium forms
biofilms when it multiplies inside the organisms.
It has still not been tried in experimental
infections in animals but if it were found to
work, one possibility would be to administer
the treatment as a probiotic drink to immunocompromised
patients to prevent Pseudomonas
infections.