Using an advanced genetic screening technique, the U.S. Department of
Agriculture’s (USDA’s) Agricultural Research Service scientists
have detected–for the first time–over 700 genes that give microbes
like Salmonella and E. coli the ability to resist antibiotics and other
The new screening technique, called DNA microarray technology, allowed
scientists to hone in on resistance genes in organisms that pose a
threat to public health including: Salmonella, E. coli, Campylobacter,
Listeria, and Enterococcus, among others.
USDA scientists expressed worry over the findings, released last week.
“Researchers are concerned that some of these organisms have acquired
genetic resistance to the antibiotics used to kill them,” said the Agricultural Research Service, the
main research arm of the agency, in a statement. “Finding the genes
that confer resistance is an important step for scientists looking for
new ways to control these organisms.”
According to the Agricultural Research Service, all genes identified in organisms are logged into
GenBank, a gene database administered by the National Center for
Biotechnology Information at the National Institutes of Health (NIH).
A DNA microarray is a small glass slide used to test genetic samples
for the presence of specific genes. To use the array, DNA extracted
from the bacterium to be tested is tagged with fluorescent dyes and
then put into contact with the slide containing DNA probes designed to
detect genes that are known to confer antimicrobial resistance.
This work was published in the scientific journal Microbial Drug Resistance.