Determinación de la prevalencia y perfil de resistencia antibiótica de Staphylococcus coagulasa negativo (SCN) en muestras de leche

Abstract

The growing importance of coagulase-negative Staphylococcus as an opportunistic agent in intramammary infections in dairy cows is addressed. Traditionally considered less pathogenic than other bacteria such as Staphylococcus aureus, coagulase-negative Staphylococcus has shown a significant impact on reducing milk production and damaging mammary tissues. The objective is to determine the frequency of isolation of SCN (coagulase-negative Staphylococcus) species from cows with subclinical mastitis in herds located in the Tungurahua province, Pucarumí, using biochemical tests. The study focuses on the prevalence of coagulase-negative Staphylococcus in milk samples and its resistance profile to various antibiotics, which is crucial for the management and treatment of subclinical mastitis in dairy cattle. Through biochemical tests, antibiograms, and species identification using the presence of Novobiocin, the study analyzes recommended management practices and the need for effective control strategies to prevent and treat subclinical mastitis. The research reveals that coagulase-negative Staphylococci exhibit a high resistance capacity to the selected antibiotics, which were Tetracycline (46%), Oxacillin (66%), and Penicillin (73%), complicating their treatment. Through the Novobiocin test, it was determined which strains prevail in the isolates based on their sensitivity or resistance (S 93%; R 7%). Additionally, the risk factors associated with coagulasenegative Staphylococcus infections and the importance of hygiene during milking and cattle management to minimize the prevalence of these infections are discussed.