ISOLATION AND IDENTIFICATION OF AEROMONAS SALMONICIDA SUBSP. ACHROMOGENES FROM ICTALUNES PUNCTATUS AND ITS ANTIMICROBIAL SUSCEPTIBILITY

The isolated bacterial strain ry01 from Ictalunes punctatus with ulcer disease was identified as Aeromonas salmonicida subsp. achromogenes by analyzing biochemical reactions and 16S rDNA gene sequence. The ry01-injected fish showed similar morphological and biochemical characteristics to those from naturally infected fish, supporting that Aeromonas salmonicida subsp. achromogenes was the pathogen to Ictalunes punctatus. The LD₅₀was 4.17×10⁶ CFU/mL according to the Reed-Muench method. The isolated bacterial strain ry01 was highly sensitive to doxycycline and levofloxacin. This study provides theoretical basis for the prevention and control the disease of Ictalunes punctatus.