Bacteria-caused intestinal inflammation may
lead to diarrhea, fever and abdominal cramps. Few treatments exist for this condition. But University of
California, Irvine microbiologists have demonstrated a new approach that
may lead to more effective remedies.
In the journal Nature
, Manuela Raffatellu, associate
professor of microbiology & molecular genetics, and colleagues
provide the first evidence that small protein molecules called
microcins, produced by beneficial gut microbes, play a critical part in
blocking certain illness-causing bacteria in inflamed intestines.
‘Small protein molecules called microcins, produced by beneficial gut microbes, play a critical part in blocking certain illness-causing bacteria in inflamed intestines.’
In their study, the researchers show that a probiotic strain of E. coli
called Nissle 1917 utilizes microcins to inhibit the pathogen salmonella and an invasive form of E. coli
(isolated from patients with inflammatory bowel disease).
"Although an in vivo role for microcins has been suggested for 40
years, it has never been convincingly demonstrated," said Raffatellu,
who's affiliated with UCI's Institute for Immunology. "We hypothesize
that their role was missed because, as our data indicate, microcins do
not seem effective in noninflamed intestines. In contrast, we show that
in an inflamed intestine, microcins help a probiotic strain limit the
growth of some harmful bacteria."
She added that microcins are essential for the therapeutic activity of E. coli
Nissle, and her next step is to purify microcins and test whether they can be given as targeted antibiotics.