Antibiotic Resistant Genes Traced from Farms to Groundwater

[geno@zap.a2000.nl]

AmeriScan: May 1, 2001

ANTIBIOTIC RESISTANT GENES TRACED FROM FARMS TO 
GROUNDWATER

CHAMPAIGN, Illinois, May 1, 2001 (ENS) - Genes resistant to
tetracycline, a common antibiotic, have been found in groundwater 
as
far as a sixth of a mile downstream from two swine facilities that 
use
antibiotics as growth promoters. 

The finding shows the potential for spreading antibiotic resistance
back into the food chain of animals and people, researchers say. 

For more than 50 years, U.S. farmers have used tetracycline and 
other
antibiotics to enhance the growth of livestock. In humans, an 
overuse
of antibiotics is blamed for a growing resistance to many antibiotics,
and agricultural use has been suspected in the spread of resistance
genes. 

The European Union is phasing out such agricultural use, while 
Sweden
banned it in the 1980s. 

Researchers from the University of Illinois (UI) and Illinois State
Geological Survey used a DNA amplification technique to analyze
samples from lagoons, wells and groundwater on and near two 
Illinois
facilities, said Rustam Aminov, a visiting professor of animal
sciences at the UI. Their research appeared in the April issue of
"Applied and Environmental Microbiology." 

"The use of tetracycline on farms is pushing the evolution of these
genes," said Aminov. "We found tetracycline resistance genes in soil
and groundwater bacteria. The genes are transferred to this type of
bacteria, where they can survive and travel long distances in the
environment." 

"It has been suggested that there is horizontal transfer of antibiotic
resistance genes, but we had only seen it in laboratory 
experiments,
not in in-situ studies," added Aminov. "Here, we see such a transfer
is occurring in the environment." 

The researchers were able to identify the trail taken by the
resistance genes. The DNA fingerprints in the samples matched
resistance genes previously identified in livestock and feed. 

"These genes were found to be predominant in the gastrointestinal
tracts of pigs and steers," the authors wrote. "The elevated
frequencies of these genes in the environment surrounding the 
farms
were consistent with the hypothesis that this occurrence was the
result of gene flow from the animals." 

Once resistance genes make their way into drinking water, they will
find their way into the guts of the people, animals and wildlife that
drink it, Aminov said. 

"We are potentially passing on resistance in a continuous gene 
cycle
in the environment," said Aminov. 

Source: http://ens.lycos.com/ens/may2001/2001L-05-01-09.html