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

Based on the previously developed Staphylococcus selective mBP medium, this research is to improve the rapid diagnostic and antibiotic sensitivity tests for bovine mastitis-related Staphylococcus by using resazurin as the indicator. Improved mBP-RS medium is characterized by good specificity, sensitivity, and strong selection, which did not support the growth of E. coli,Streptococcus andother bacteria.By using the improved mBP-RS medium, Staphylococci could be distinguished from mixed bacteria with the diagnostic result of simulated milk samples consistent with that of pure bacterial cultures. The rapid diagnosis of 101 clinical milk samples showed that mBP-RS medium can diagnose whether Staphylococi were present in clinical mastitis milk in 12 hours, and the result could be observed with naked eye or by spectrophotometry. In 101 clinical milk samples, the detection rates of Staphylococci, Streptococci and E. coli were 30.7%,31.7% and 5.0%, respectively, and 32.7%milk samples were infected by mixed bacteria. Compared with the standard method, the coincidence rate of sensitivity and speciality was up to 98.3% and 95.0%?To establish rapid drug sensitivity method for Staphylococci, we investigated the influence of mBP-RS medium on 10 antibiotics needed for the drug sensitivity test with standard disk diffusion susceptibility test as the reference. By using the adjusted concentrations of some antibiotics, the coincidence rate of mBP-RS medium-based quick method with standard disk diffusion susceptibility test wasup to95.8%. The results of 101 clinical milk samples infected by Staphylococcuswere tested to be resistant to ampicillin and penicillin, susceptible to ofloxacin, cefamezin and cefotaxime. The sensitivities to straptomycin, erythromycin, novobiocin, tetracycline and were dependent on bacterial isolates.The improved rapid diagnostic antibiotic sensitivity tests could be applied for fast detection of Staphylococcus and their antibiotics sensitivities, which is particularly suitable for small diary farms with practical prospects.