Pathogenic and Antimicrobial Resistance Profiles of Bacterial Strains in Bovine Mastitis: Insights from the Stepanavan Region of Armenia

Abstract

Mastitis is a major concern in the dairy industry, impacting milk quality and economic stability. This study investigates the bacterial composition and antimicrobial resistance (AMR) profiles of raw milk samples from cows with subclinical mastitis in the Stepanavan region of Armenia. Raw milk samples were collected from three local farms and analyzed microbiologically to identify pathogenic bacteria and assess their resistance to common antibiotics using the Kirby-Bauer disk diffusion method. The most prevalent bacterial strains identified include Staphylococcus aureus, Enterococcus faecalis, and Pantoea agglomerans. The results reveal significant antimicrobial resistance, with strains showing resistance to Cephalosporin, Amoxicillin, Doxycycline, Erythromycin, and Tetracycline. The study highlights the complex nature of AMR in Armenian dairy farming, particularly in Lori province, and underscores the urgent need for improved diagnostic and management strategies to address both mastitis and AMR. Additionally, the role of biofilm formation and hemolytic activity in the pathogenicity and resistance mechanisms of mastitis-causing bacteria is discussed. This research provides valuable insights into the microbiological landscape of subclinical mastitis and AMR in Armenia, offering recommendations for future research and disease control strategies to mitigate the risks associated with antimicrobial resistance in dairy farming.