Diagnosis of Staphylococcus aureus Intramammary Infection by Detection of Specific Antibody Titer in Milk

• Published in: Journal of dairy science Vol. 75; no. 6; pp. 1430 - 1435
• Main Authors: El-Rashidy, A.A., Fox, L.K., Gay, J.M.
• Format: Journal Article
• Language: English
• Published: Savoy, IL Elsevier Inc 01.06.1992; Am Dairy Sci Assoc; American Dairy Science Association
• Subjects: Animals; Antibodies, Bacterial - analysis; antibody; BACTERIA; Biological and medical sciences; Cattle; CONTEO DE CELULAS; diagnosis; Female; Food industries; Fundamental and applied biological sciences. Psychology; GLANDE MAMMAIRE; GLANDULAS MAMARIAS; LAIT; LECHE; MAMMITE BOVINE; mastitis; MASTITIS BOVINA; Mastitis, Bovine - diagnosis; Milk - immunology; Milk - microbiology; Milk and cheese industries. Ice creams; NUMERATION CELLULAIRE; Predictive Value of Tests; REPONSE IMMUNITAIRE; RESPUESTA INMUNOLOGICA; Sensitivity and Specificity; Staphylococcal Infections - diagnosis; STAPHYLOCOCCUS AUREUS; Staphylococcus aureus - immunology; Staphylococcus aureus - isolation & purification; VACAS LECHERAS; VACHE LAITIERE; Staphylococcus aureus; diagnosis; Staph-ab; antibody; mastitis; Staphylococcus aureus; Mastitis; Antibody; Ox; Cow; Assay; Vertebrata; Mammalia; Analytical method; Bacteria; Micrococcales; Micrococcaceae; Artiodactyla; Diagnosis; Ungulata; Milk
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(92)77897-7

The diagnostic value of the determination of Staphylococcus aureus antibody titer in milk as a method for identification of mammary quarters with S. aureus IMI was evaluated. Ten cows with a history of S. aureus IMI and 9 cows with no history of S. aureus IMI were sampled daily for 10 d. Quarter and composite milk samples were collected and processed by standard methods for concentration of S. aureus, S. aureus antibody titer (percentage of positive laboratory control), and SCC (cells per milliliter). Microbiologic culture identified 13 S. aureus-infected quarters from the 10 cows with a history of S. aureus IMI. Only 2 of the 130 samples (1.5%) from these infected quarters had undetectable concentrations of S. aureus. Antibody titers in milk from infected quarters of infected cows were below the previously established level considered to be indicative of IMI in 6 of 130 samples (4.6%). Four samples from infected quarters of infected cows had titers considered to be in the suspect range. The sensitivity of the antibody test was 83% (13% SE) when the suspect samples were included and 86% (12% SE) when they were not. Milk from uninfected quarters of cows with S. aureus IMI tended to have S. aureus antibody titers greater than the test's positive control, which would suggest that the quarters were infected with S. aureus. Antibody titer was below the infection threshold level in all pooled samples of uninfected cows, suggesting that the test correctly identified all cows free of S. aureus IMI. Results indicate that detection of milk S. aureus antibody was very accurate in identifying cows without S. aureus IMI but less accurate in identifying cows with IMI.