Pridgeon Julia W, Klesius Phillip H
Aquatic Animal Health Research Unit, USDA-ARS, 990 Wire Road, Auburn, Alabama 36832, USA.
Dis Aquat Organ. 2011 May 9;94(3):249-53. doi: 10.3354/dao02332.
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% nucleotide sequences with AL98-C1B, a 1998 isolate of A. hydrophila cultured from diseased fish in Alabama. Sequences of cpn60, gyrB, and rpoD from the 3 isolates from 2009 shared 91 to 95% homologies with AL98-C1B. Based on both LD50 and LD95 values of intraperitoneal injection assays, the virulences of the 3 isolates from 2009 were not significantly different from each other, but were at least 200-fold more virulent than AL98-C1B, indicating that the 3 west Alabama isolates of A. hydrophila from 2009 were highly virulent to channel catfish.
2009年8月，在美国阿拉巴马州西部的一次疾病爆发期间，从感染的斑点叉尾鮰中培养出了3株嗜水气单胞菌分离株（AL09 - 71、AL09 - 72和AL09 - 73）。对这3个菌株的16S - 23S rDNA基因间隔区（ISR）、cpn60、gyrB和rpoD基因进行序列分析后发现，这3个菌株彼此密切相关，核苷酸序列相似度为97%至99%。然而，2009年的这3个分离株的ISR序列与1998年从阿拉巴马州患病鱼类中培养出的嗜水气单胞菌分离株AL98 - C1B仅共享64%的核苷酸序列。2009年的这3个分离株的cpn60、gyrB和rpoD序列与AL98 - C1B的同源性为91%至95%。根据腹腔注射试验的半数致死剂量（LD50）和95%致死剂量（LD95）值，2009年的这3个分离株的毒力彼此之间无显著差异，但比AL98 - C1B的毒力至少高200倍，这表明2009年来自阿拉巴马州西部的这3株嗜水气单胞菌分离株对斑点叉尾鮰具有高度毒性。
