Abstract: In order to determine the etiological agent associated with the death of mink with pneumonia, the dead mink was autopsied. A gram-positive cocci was isolated from the clinical sample, and it was subsequently subjected to colony morphology observation, biochemical identification and 16S rDNA sequence analysis. The phylogenetic tree based on the 16S rDNA sequence was constructed, and the homology analysis was performed. The antimicrobial sensitivity test of the isolated strain was also carried out. The results showed that based on the morphological and biochemical characteristics of the isolate, combined with 16S rDNA sequencing and phylogenetic tree analysis, the isolates were identified as Streptococcus dysgalactiae subsp. equisimilis. Antimicrobial sensitivity test showed that the strain was sensitive to penicillin, amoxicillin, moxifloxacin and some other antibiotics, but had strong resistance to tetracycline.

Key words: Streptococcus dysgalactiae subsp. equisimilis, mink, isolation, identification