Discipline: Veterinary Medicine
Conventional identification of a total of 132 bacterial isolates recovered from subclinical mastitis cases were compared with the rapid and automated identification using a commercially available microbial identification kit (BBL Crystal ID®). Overall, organisms identified through conventional methods were in agreement with the commercial kit at 86.4% and 63.6% for the genus and species level, respectively. One hundred percent of conventionally identified Bacillus cereus and Klebsiella pneumonia were confirmed as correct, while an agreement of 89.5% for Escherichia coli, 70.7% for Staphylococcus aureus, 41.2% for Streptococcus species, 37.5% for Staphylococcus albus, and 6.7% for Pseudomonas aeruginosa were obtained. Organisms which conventional methods failed to identify and were misclassified as another organism included: Pseudomonas stutzeri, Acinetobacter iwoffi, Shigella sp. Lactococcus lactis ssp. cremoris, Aerococcus urinae, Corynebacterium striatum, Aerococcus viridans, Staphylococcus hemolyticus and Staphylococcus warneri. This shows that identification of microorganisms from mastitis cases by conventional methods should be taken with caution as this could sometimes be misleading, particularly for many significant mastitis pathogens such as staphylococci and streptococci. Other biochemical and enzymatic tests, in addition to standard conventional approaches for bacterial identification, should be done in order to achieve better accuracy in identification.