Isolation and Identification of Pathogens from an Outbreak Deaths of Sinilabeo decorus tungting

PurposeTo find out the cause of outbreak deaths of Sinilabeo decorus tungting in pond culture, the isolation, purification, identification and artificial infection test of pathogenic bacteria were carried out.

MethodThe dominant bacteria were isolated and purified from the diseased tissues of the dying S. decorus tungting. The dominant bacteria were identified through morphological characteristics, physicochemical characteristics and 16S rDNA sequence analysis. And the toxicity and drug sensitivity of dominant bacteria were evaluated by artificial infection and drug sensitivity test.

ResultThe dominant bacteria XHL-01 and XHL-02 were isolated and identified as Aeromonas hydrophila and A. veronii, respectively. The results of artificial infection test showed that the symptoms of artificial infection S. decorus tungting were similar to clinical symptoms, so the two strains were pathogenic to S. decorus tungting. The drug sensitivity results showed that the two strains were resistant to penicillin, ampicillin, clindamycin and vancomycin, but highly sensitive to 9 drugs such as cefotaxime, ceftazidime, doxycycline.

ConclusionThe pathogenic bacteria XHL-01 and XHL-02 isolated from the diseased S. decorus tungting are pathogenic to S. decorus tungting, which may be the bacterial pathogen of the outbreak death. The drug sensitive results can provide guidance for the prevention and control of the disease.