story to find out more.
Protozoa such this Ophyroscolex species
that live in the gastrointestinal system of cows have been found capable of
transferring antibiotic resistance to bacteria that are susceptible to the
antibiotics. Click the image for more information about it.
Cattle Protozoa Help Shift Antibiotic Resistance
By Luis Pons
October 3, 2006
Agricultural Research Service (ARS) scientists in Ames, Iowa, have made
another big finding about protozoasingle-celled predatory
organismsfound in the gastrointestinal tract of cattle. They've
discovered that the protozoa can facilitate the transfer of antibiotic
resistance from resistant bacteria to susceptible types.
Veterinary medical officer
Carlson at ARS' National Animal Disease Center (NADC)
in Ames is the first scientist to document the role rumen protozoa play in
transferring this resistance within cattle. Rumen protozoa live in the first
stomach (rumen) of cattle. They engulf and destroy most bacteria.
But Carlson and colleagues have identified and described the transfer of
resistance to ceftriaxone, an antibiotic used to treat pneumonia, from
gastrointestinal tract bacteria known as Klebsiella to rumen-dwelling
Salmonella that are sensitive to the antibiotic.
Last year, Carlson teamed with microbiologist
Rasmussenwho's no longer with ARSin a study that revealed for
the first time that disease-causing bacteria can strengthen from interaction
with protozoa that are naturally inside animals.
In that work, an antibiotic-resistant strain of Salmonella became
especially virulent when tucked within rumen protozoa. That discovery suggests
that naturally occurring digestive tract protozoa may be a place where
dangerous bacteria can lurk and develop.
These studies exemplify how NADC is helping to make meals worry-free for
people who enjoy meat and poultry. Its scientists continue to break new ground
in protecting consumers against Salmonella, Escherichia coli,
Campylobacter and other harmful foodborne bacteria.
Cutting-edge research there includes studies on how animal diets affect
disease-causing pathogens and immunity, as well as molecular analyses of
microbial virulence, antibiotic resistance and host response.
more about the latest work at the Ames center and other ARS research
related to food safety in the October 2006 issue of Agricultural
ARS is the U.S. Department of
Agricultures chief scientific research agency.