Beneficial microbes found in
swine manure may help control Salmonella in swine waste lagoons.
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Phages Eyed as New Way to Control
April 28, 2006
Agricultural Research Service (ARS) scientists and university cooperators
have collected and partially characterized beneficial viruses, called
bacteriophages, that could help control Salmonella bacteria in swine
Disease caused by Salmonella costs pork producers an estimated
$100 million annually. Reports of human outbreaks of salmonellosis linked to
pork consumption are rare, but the U.S. Centers
for Disease Control and Prevention estimate that foodborne outbreaks of
salmonellosis from all sources affect 1.4 million consumers annually.
McLaughlin, a virologist in ARS'
Management and Forage Research Unit at Mississippi State, Miss., and
collaborators from Western Kentucky
Universitys Department of
Biology in Bowling Green, Ky., have devised and adapted methods to collect,
isolate and identify bacteriophages that attack and kill Salmonella
strains. Salmonella causes illness in livestock, pets and people, but
its hosts often show no signs of disease, complicating detection and control
Bacteriophagesor "phages," for shortinvade bacteria,
multiply and eventually rupture bacterial walls, releasing multiple copies of
new phages capable of invading more bacteria. Most phages only attack specific
species and strains of bacteria. Knowledge of this host- specificity allows
specialists in agriculture, medicine and food safety to apply specific phages
to help identify, trackand even treat or preventbacterial
McLaughlin and his team examined the bacterial host-specificity of the
phages found in swine manure and, using electron microscopy, classified the
phages according to their unique sizes and shapes. Information from their study
will enable scientists to better understand the microbial ecology within swine
effluent lagoons. They'll use the phages that have now been characterized to
develop new tools to control Salmonella.
This research, part of the ARS national program on manure and
byproduct utilization, is reported in this months Journal of Environmental Quality,
published jointly by the American Society of
Agronomy, the Crop Science Society of
America and the Soil Science Society of
ARS is the U.S. Department of
Agriculture's chief scientific research agency.