Antimicrobial Resistance Profiles and Genes in Associated With Bovine Mastitis in Thailand.

is recognized as an environmental mastitis pathogen in dairy cattle. The varied success rate of antibiotic treatment for intramammary infection may be associated with the antimicrobial resistance (AMR) of these bacteria. This observational study aimed to analyze 228 strains associated with bovine mastitis in northern Thailand from 2010 to 2017. AMR and AMR genes were determined by the minimum inhibitory concentration (MIC) using a microdilution method and polymerase chain reaction, respectively. The majority of strains were resistant to tetracycline (187/228, 82.02%), followed by ceftiofur (44/228, 19.30%), and erythromycin (19/228, 8.33%). The MIC50 and MIC90 of ceftiofur in 2017 were 2-4-fold higher than those in 2010 ( < 0.01). Resistance to tetracycline and ceftiofur significantly increased between 2010 and 2017 ( < 0.05). The most common gene detected in was (199/228, 87.28%), followed by (151/228, 66.23 %) and (15/228, 6.58 %). The association between tetracycline resistance and detection was statistically significant ( < 0.01). The detection rates of significantly increased, while the detection rates of and significantly decreased during 2010-2017. AMR monitoring for bovine mastitis pathogens, especially , is necessary to understand the trend of AMR among mastitis pathogens, which can help create an AMR stewardship program for dairy farms in Thailand.