Serotyping scheme for Staphylococcus aureus isolated from cows with mastitis.
OBJECTIVE
To identify the Staphylococcus aureus capsular serotypes that are not typable, using capsular serotypes 5 and 8, which are currently used to type S aureus isolated from cows with mastitis.


METHODS
Milk samples (n = 273) from cows with mastitis in 178 dairy herds in California, Wisconsin, Michigan, Texas, and New York that were collected by state diagnostic laboratories and S aureus-positive milk samples collected by Veterinary Health Services in the United Kingdom (15), France (22), The Netherlands (36), and Germany (21).


METHODS
Capsular serotyping of coded isolates was performed by use of direct cell agglutination and immunoprecipitation of cell extracts with antisera specific for capsular types 5 and 8 and a newly developed S aureus serotyping antiserum 336.


RESULTS
In the United States, S aureus capsular types 5 and 8 accounted for 18 and 23% of the isolates, respectively, and type 336 accounted for 59%. Percentage of capsular serotypes in European samples were as follows: type 5 = 34%, type 8 = 34%, type 336 = 30%, and nontypable = 2%.


CONCLUSIONS
Serotypes 5 and 8 accounted for only 41% of S aureus isolates from US milk samples, but accounted for 70% of isolates from European milk samples. Addition of the newly developed serotyping antiserum 336 to the typing scheme accounted for 100% of US samples and 98% of European samples and will enable development of a more comprehensive S aureus vaccine.
Guidry
A
A
Immunology and Disease Resistance Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705, USA.
Fattom
A
A
Patel
A
A
O'Brien
C
C
Shepherd
S
S
Lohuis
J
J
D000372:Agglutination Tests; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis* / Q000382:microbiology; D005060:Europe; D005260:Female; D008414:Mastitis, Bovine / Q000382:microbiology*; D008892:Milk / Q000382:microbiology*; D011135:Polysaccharides, Bacterial / Q000032:analysis; D012703:Serotyping; D013203:Staphylococcal Infections / Q000175:diagnosis / Q000382:microbiology / Q000662:veterinary*; D013211:Staphylococcus aureus / Q000145:classification / Q000302:isolation & purification; D014481:United States
D011135:Polysaccharides, Bacterial