Isolation and Identification of Aeromonas hydrophila from Infected Tilapia in Early Spring

In early spring 2012,a disease outbreak occurred at a tilapia farm in Liuzhou of Guangxi province.A gram-negative bacillus was isolated from liver,kidney and spleen of infected tilapia.The isolate was identified as Aeromonas hydrophila by biochemical assays and 16SrDNA sequencing.Healthy tilapia injected with 1×109 CFU of the isolate reached a mortality of 100% in just 24h.Drug sensitivity experiment showed that the isolate was only resistant to ampicillin and sensitive to 15types of antibiotics such as aztreonam,ofloxacin,etc.This study provided a basis for the prevention and control of tilapia diseases in early spring.