Most common pathogens from cows with subclinical mastitis in northwestern Paraná, Southern Brazil and their antimicrobial susceptibility

Considering the high prevalence of subclinical mastitis and its impacts on milk production, thematic studies are needed and can provide strategic data for its control. This study aimed at investigating the most frequent microorganisms associated with subclinical mastitis in dairy cows in the northwest State of Paraná, Brazil and its sensitivity to antibiotics. A total of 478 foremilk samples were tested. Streptococci were the most frequently genus observed (63%), followed by staphylococci (31%). Streptococcus mutans, S. sanguis, and S. uberis were the most frequently identified species. For Streptococcus spp., the antimicrobial resistance was higher for Ceftiofur, whereas for Staphylococcus spp. it was also possible to verify a high occurrence of resistance for Gentamicin + Amoxicillin. Our results strengthen the knowledge of the microbiological agent and antibiotic-resistance patterns of pathogens at regional level, targeting future strategies to reduce the environmental spread of pathogenic strains resistant to antibiotics.