
Moreabout this research in Agricultural Research. Bovine Staph, Beware: Test
Vaccine Promising Against MastitisBy Judy McBride November 22, 2000Bessie will chew her cud in more
comfort if early tests pitting a new vaccine against the most stubborn cases of
mastitis--those caused by Staphylococcus aureus bacteria--are any
indication of its efficacy. The vaccine promises to catch the 50 to 60 percent
of staph-caused mastitis cases in the United States that have eluded
todays commercial vaccines. Agricultural Research Service dairy
scientist Albert J. Guidry developed the vaccine with the biotechnology company
Nabi in Rockville, Md. Nabi identified a single staph strain, or serotype, that
appears to provide the component missing in earlier vaccines. Guidry and coworkers at ARS
Henry A. Wallace
Beltsville (Md.) Agricultural Research Center formulated this
serotype--336--with the two known mastitis serotypes into a vaccine.
Large-scale tests to confirm its ability to prevent infection have not yet been
done. But it is proving effective at curing intractable mastitis cases when
combined with antibiotics, according to studies by
Michigan State University veterinary
scientist Phil Sears. Antibiotics are often ineffective against staph because the bacteria have
become resistant or they have holed up in places the drugs cant reach. In
Sears studies, he cured more than half of infected cows by isolating the
causative S. aureus strain from a dairy herd, killing it, then injecting
it back into the infected cows a few weeks before administering antibiotics.
But this procedure is too cumbersome for commercial use. The new vaccine solves that problem. And it proved as effective as
Sears herd-specific vaccine, curing 55 to 60 percent of infected cows. It
cleared up staph infections in about 10 percent of infected cows in the herds
in Sears study--even before he administered antibiotics. ARS is now looking for a partner in the agricultural arena to fund further
testing and develop a commercial vaccine. ARS is the
U.S. Department of Agricultures chief
scientific research agency. More about this research is in the November issue of Agricultural Research magazine. Scientific contact: Albert J. Guidry,
ARS Immunology and Disease
Resistance Laboratory, Beltsville, Md., phone (301) 504-8285, fax (301)
504-9498, [email protected]. U.S. Department of Agriculture |