Evaluation the latex agglutination test for detection of the causative agents of bacterial mastitis in milk samples

Mastitis is the main disease in dairy farms that causes serious losses. The early diagnosis and specific treatment can prevent the spread of the disease and the economic losses. The aim of this study was to evaluate the accuracy of the latex agglutination assay for detection of the main bacterial mastitis agents. The antiserum against Staphylococcus aureus, Trueperella pyogenes, Streptococcus agalactiae and Escherichia coli were prepared from immunized rabbits. The couplings of antibodies to latex particles were optimized and after that, the limit of detection (LOD) of latex agglutination test was evaluated for detection of the mentioned bacteria. The detection limit for the Streptococcus agalactiae, E. coli, Staphylococcus aureus and T. pyogenes were respectively 1.3×103, 2×107, 1.58×104 and 5.4×104 colony-forming unit per each milliliter of the bacterial suspensions. The prepared latex test has more sensitivity in the setting of phosphate buffered saline than in contaminated milk samples. This method can be used for the fast detection of the mentioned bacteria in bacterial cultures and milk samples. The latex agglutination test could be evaluated as a fast, cost benefit, and practical method in dairy farms.