Improvement Of Rapid Diagnostic And Antibiotic Sensitivity Tests For Bovine Mastitis-Related Streptococcus

Bovine mastitis is a highly prevalent disease in dairy cattle, and one of the most important diseases affecting the world’s dairy industry. It causes considerable economic losses due to decreases in the quality and quantity of milk production, increases in the cost of treatment and veterinary services, and cow culling. Mastitis-causing pathogens include bacterial and non-bacterial pathogens, and Streptococcus is one of the important bacterial pathogens. Quick and accurate diagnosis is very significant for proper treatment of bovine mastitis and reduction of the associated economical losses.On the basis of Streptococcus selective medium EN and using resazurin as the indicator, in this study more rapid tests were established for diagnostic and antibiotic sensitivity testing bovine mastitis-related Streptococcus. The improved medium, called EN-RS, remained the excellent selective property of original medium, and did not support growth of non-Streptococcus such as E. coli and Staphylococcus aureus. After incubation for a few hours, the diagnosis could be obtained according to color change of the medium. The rapid diagnosis of121clinical milk samples showed that EN-RS medium can diagnose whether Streptococcus exists in mastitis clinical milk in6hours, the result not only can be clearly observed with the naked eye, but also by spectrophotometer. Compared with the standard method of detection, the coincidence rate were92.9%and91.1%. In121clinical milk samples, the amount of samples infected by Streptococcus, E. coli and Staphylococcus aureus is50,12and64, and37milk samples were infected by mixed bacteria species.We use different concentration antibiotics to do experiment based on EN-RS medium. Compared with standard disk diffusion susceptibility test, it is proved that improve select media EN-RS has vary degrees of impact to10kinds of antibiotics for mastitis treatment antimicrobial activity, and it is necessary to adjust the concentration of some kinds of antibiotics. Adjusting the volume can be obtained with standard methods of antibiotic use and consistent results, the coincidence rate is93.3%to standard disk diffusion susceptibility test.The improved rapid diagnostic antibiotic sensitivity tests for bovine mastitis-related Streptococcus could be applied for fast-detection of Streptococcus and measurement the antibiotics sensitivity, which is particularly suitable for under-medium-size diary farm with practical prospects.