Identification of Bacterial and Yeast Agents Isolated from the Milk of Cowswith and without Mastitis in Dairy Herd of Tehran Province

Background and Objective: Since mastitis disease in Iran and many countries of the world is known asone of the most common and harmful infections among dairy cows, it is very important to identify thecausative agent and treat it quickly. Because by reducing the quality of milk and animal health, manylosses will be caused to the field of dairying, animal husbandry, and as a result, the country's economy.Therefore, the aim of this study is to identify the bacterial and yeast agents isolated from the milk of cowssuffering from bovine mastitis using phenotypic and molecular Multiplex-PCR methods in Tehranprovince.methods: In this research, ۶۰ cows with mastitis and ۶۰ healthy cows were selected from the industrialcattle farms of Tehran province during initial screening based on somatic cell count. Then, following thecold chain and sterile conditions, the collected milk samples were transferred to the laboratory. In order toisolate and identify bacterial and fungal agents, after centrifuging the milk at ۴۰۰۰ rpm for ۱۰ minutes,the sediment obtained was used for culture on nutrient agar (containing nystatin) and Sabouraud Dextroseagar with chloramphenicol. The plates were kept at ۳۷°C for ۴ to ۷ days. Then, while examining theappearance of the colonies, phenotypic methods such as staining (gram and lactophenol cotton blue) andspecific bacterial (blood agar, McConkey agar, etc.) and fungal (corn mill agar and Candida chrome agar)culture media to identify Disease agents were used. Finally, in order to more accurately identify theobtained yeast species, the Multiplex-PCR molecular technique was used.Results: The results showed that in general, Candida albicans (۱۱.۶۶%), other Candida species (۵%),Geotrichum (۳.۳۳%), Rhodotroella (۳.۳۳%), and Other non-candidal yeasts (۱۳.۳۳%) were isolated.Streptococcus disgalactiae (۲۵%), Escherichia coli (۲۸.۳۳%), Bacillus cereus (۱۵%), Enterobacteraerogenes (۳۶.۶۶%), and Staphylococcus epidermidis (۲۱.۶۶%) were also detected in these samples.Became during the examination of the milk of cows without mastitis, apart from Candida albicans whichwas not detected, other species of Candida (۱.۶۶%), Geotrichum (۱۳.۳۳%), Rhodotroella (۳.۳۳%), andother non-candidal yeasts (% ۵) It was isolated. Streptococcus dysgalactiae (۸.۳۳%), Escherichia coli(۳۰%), Bacillus cereus (۲۳.۳۳%), Enterobacter aerogenes (۲۶.۶۶%), and Staphylococcus epidermidis(۱۵%) were also reported.۱۰۹Conclusion: According to the results obtained in this study and comparing it with other similar studies,the percentage of presence of yeast and bacteria in the milk of cows with and without mastitis is notstatistically significant (P-value ≥ ۰.۰۵). Therefore, it can be concluded that because most of the yeast andbacterial species isolated in this research are saprophytes, the animal's physical conditions (such as stressand fatigue), lack of hygiene, unprincipled maintenance, racial differences, and weak immune systemmay be, to be involved in some of them suffering from mastitis. While saprophyte species are not able toshow disease symptoms in some cows that had better physical and health conditions.

Keywords:

Bacterial and yeast agents , Bovine mastitis , Milk , Multiplex-PCR