development and efficacy of novobiocin and rifampicin-resistant aeromonas hydrophila as novel vaccines in channel catfish and nile tilapia.three attenuated aeromonas hydrophila vaccines were developed from the virulent 2009 west alabama isolates through selection for resistance to both novobiocin and rifampicin. when channel catfish (ictalurus punctatus) were ip injected with 4×105 colony-forming unit (cfu) of the mutants, no fish died. however, when the same age and size matched channel catfish were ip injected with similar amount of their virulent parents, 80-100% fish died. similarly, when nile tilapia (oreochromis niloticus) we ...201121872628
identification of unique dna sequences present in highly virulent 2009 alabama isolates of aeromonas 2009, a disease outbreak caused by aeromonas hydrophila occurred in 48 catfish farms in west alabama, causing an estimated loss of more than 3 million pounds of food size channel catfish. virulence studies have revealed that the 2009 isolates of a. hydrophila are at least 200-fold more virulent than a 1998 alabama isolate al98-c1b. however, up to now, no molecular markers have been identified to differentiate the highly virulent 2009 isolates from other isolates of a. hydrophila. to understan ...201121561726
molecular identification and virulence of three aeromonas hydrophila isolates cultured from infected channel catfish during a disease outbreak in west alabama (usa) in 2009.three isolates (al09-71, al09-72, and al09-73) of aeromonas hydrophila were cultured from infected channel catfish ictalurus punctatus during a disease outbreak in west alabama, usa, in august 2009. sequence analysis of the 16s-23s rdna intergenic spacer region (isr), cpn60, gyrb, and rpod genes of the 3 strains revealed that the 3 strains were closely related to each other, sharing 97 to 99% nucleotide sequence similarities. however, isr sequences of the 3 isolates from 2009 shared only 64% nuc ...201121790073
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