INFECTED meat can pass on antibiotic-resistant bacteria to people who eat it.
Danish researchers studying how this happens have found that resistant bacteria
from chickens can flourish in the human gut.
Drugs such as vancomycin, which doctors often use when other antibiotics
fail, are sometimes completely ineffective because bacteria have evolved genes
to give them immunity. Researchers already suspected that antibiotics fed to
animals to fatten them up are encouraging strains of resistant bacteria that
pass to people in meat. Now a Copenhagen team led by Marianne Blom of the State
Serum Institute and Thomas S酶rensen of the Danish Veterinary Lab have proved
that this happens. 鈥淚t鈥檚 kind of the missing link,鈥� says S酶rensen.
They asked 12 volunteers to drink a glass of whole milk contaminated with the
bacterium Enterococcus faecium. Half the volunteers got a strain that could be
treated with vancomycin, while the other half drank two vancomycin-resistant
strains. All the bacteria came from chickens and were at levels within Danish
legal limits.
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The researchers collected stools from the volunteers before the experiment
began, and for up to two weeks afterwards. All the volunteers who ate resistant
strains developed a colony of the same bacteria in their guts, peaking on day 2
or 3.
S酶rensen says this increases the risk that the genes coding for vancomycin
resistance can transfer to other more dangerous bacteria. 鈥淭he presence of
[vancomycin-resistant bacteria] in the gut could ultimately lead to treatment
failure,鈥� he says.