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ARS Home » Research » Publications at this Location » Publication #74981
Title: PREVALENCE OF CAPSULAR SEROTYPES AMONG STAPHYLOCOCCUS AUREUS ISOLATES FROM MASTITIC COWS IN THE UNITED STATES

Author
item Guidry, Albert
item FATTOM, A - NABI
item PATEL, A - NABI
item Obrien, Celia

Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/28/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Development of a Staphylococcus aureus vaccine for bovine mastitis has eluded researchers for decades. The ability of S. aureus to form a protective exopolysaccharide capsule has posed a major obstacle because of multiple capsule serotypes and the poor immune response elicited by exopolysaccharides. Methods have been developed to increase the immunogenicity of exopolyysaccharides, but the S. aureus capsule serotypes causing bovine mastitis are still in question. This study characterized S. aureus serotypes isolated from cases of bovine mastitis obtained from veterinary diagnostic laboratories that screen 44% of the dairy cattle in the United States. Subsamples of mastitic milk identified as S. aureus positive were frozen and sent to our laboratory for serotyping. The only serotyping of S. aureus from bovine mastitis to date was done in France and Israel. The primary serotypes found were types 5 and 8. Antiserum to S. aureus serotypes 5 and 8 were used to type the isolates in this study. Serotype 8 was the dominant serotpye (23%). More importantly 59% of the isolates were not typeable with either 5 or 8. This data indicate that further serotyping is needed before effective S. aureus mastitis vaccines can be developed.

Technical Abstract: Development of a Staphylococcus aureus vaccine for bovine mastitis has eluded researchers for decades. The ability of S. aureus to form a protective capsule upon entering the mammary gland has posed a major obstacle because of multiple capsule types and the poor immune response they elicit. Methods have been developed to increase the animal's immune response to capsule, but the capsule types causing bovine mastitis are still in question. This study characterized S. aureus capsule types isolated from cases of bovine mastitis obtained from veterinary diagnostic laboratories that screen 44% of the dairy cattle in the United States. Subsamples of mastitic milk identified as S. aureus positive were frozen and sent to our laboratory for identification. The only capsule typing of S. aureus from bovine mastitis to date was done in France and Israel. The primary types found were types 5 and 8. This resulted in the development of vaccines that included these two types. Antiserum to types 5 and 8 were used to type the isolates in this study. Type 8 was the dominant capsule type (23%). More importantly 59% of the isolates were not typeable with either 5 or 8. This data indicate that the vaccines currently under investigation in the US have little chance of success. Further typing is needed before effective S. aureus mastitis vaccines can be developed for use in the US.