Identification of Streptococci Causing Mastitis in Bulk Tank Milk by Molecular Method

Background: Mastitis is the most common infectious disease affecting dairy cows, causing significant economic losses in the dairy industry worldwide. The main cause of mastitis is breast infection by pathogenic bacteria, with the most common pathogenic agents of mastitis being Streptococcus agalactiae, Streptococcus dysgalactiae, and Streptococcus uberis. Conventional culture-based methods play an important role in the diagnosis of Streptococcus species, but these methods are time-consuming and have low sensitivity. Polymerase chain reaction (PCR) has been widely used in the detection of pathogens. Compared to culture-based methods, PCR methods are more sensitive and require less time. This study aims to identify the streptococci causing mastitis in bulk tank milk samples using the PCR method. Methods: In this study, ۹۰ samples of bulk tank milk were collected. Then, their DNA was extracted using a DNA extraction kit (DNP Kit EX۶۰۷۱), and PCR was performed using species-specific primers. The PCR products were electrophoresed and finally visualized with UV. Results: Of the ۹۰ bulk tank milk samples collected, ۱۶ samples were contaminated with Streptococcus agalactiae (۱۴.۴%), ۱۱ samples were contaminated with Streptococcus uberis (۹.۹%), and none were contaminated with Streptococcus dysgalactiae. Conclusion: Diagnosis of mastitis, especially subclinical mastitis, is not easily detectable by the farmer. Using the most effective and efficient method for diagnosis will help ensure timely treatment and prevent potential future losses. The PCR method is an accurate, highly sensitive, and rapid method for identifying pathogens.

کلیدواژه ها:

Streptococci ، Mastitis ، PCR ، Bulk tank