ARS | Publication request: Molecular identification and virulence of three Aeromonas hydrophila isolates cultured from infected channel catfish during a disease outbreak in West Alabama in 2009

Submitted to: Genbank
Publication Type: Other
Publication Acceptance Date: September 1, 2010
Publication Date: September 6, 2010
Citation: Wei Pridgeon, Y., Klesius, P.H. 2010. Molecular identification and virulence of three Aeromonas hydrophila isolates cultured from infected channel catfish during a disease outbreak in West Alabama in 2009. Genbank. Accession Nos. HM856359 - HM 856374.

Technical Abstract: Three isolates (AL09-71, AL09-72, and AL09-73) of Aeromonas hydrophila were cultured from infected channel catfish during a disease outbreak in West Alabama in August 2009. Sequence analysis of 16S-23S rDNA intergenic spacer region (ISR), cpn60, gyrB, and rpoD genes of the three strains revealed that the three strains were closely related to each other, sharing 97 to 99% nucleotide sequence similarities. However, ISR sequences of the three 2009 isolates shared only 64% nucleotide sequences with AL98-C1B, a 1998 isolate from diseased fish in Alabama, although sequences of cpn60, gyrB, and rpoD sequences of the three 2009 isolates shared 91 to 95% homologies with AL98-C1B. Virulence studies revealed that the LD50 values of the three 2009 isolates were significantly lower than that of AL98-C1B. Based on LD95 values, the virulence of the three 2009 isolates was not significantly different from each other. However, the LD95 values of the three 2009 isolates were significantly lower than that of AL98-C1B, suggesting that the three 2009 isolates of A. hydrophila were highly virulent to channel catfish.