Identification and characterization of Vibrio harveyi associated with diseased abalone Haliotis diversicolor

Abstract

Mass mortality of farmed small abalone Haliotis diversicolor occurred in Fujian, China, from 2009 to 2011. Among isolates obtained from moribund abalones, the dominant species AP37 exhibited the strongest virulence. After immersion challenge with 10 6 CFU ml −1 of AP37, abalone mortalities of 0, 53 and 67% were induced at water temperatures of 20°C, 24°C, and 28°C, respectively. Following intramuscular injection, AP37 showed a low LD 50 (median lethal concentration) value of 2.9 × 10 2 CFU g −1 (colony forming units per gram abalone wet body weight). The LT 50 (median lethal time) values were 5.2 h for 1 × 10 6 CFU abalone . For further analysis of virulence, AP37 was screened for the production of extracellular factors. The results showed that various factors including presence of flagella and production of extracellular enzymes, such as lipase, phospholipase and haemolysin, could be responsible for pathogenesis. Based on its 16S rRNA gene sequence, strain AP37 showed > 98.8% similarity to Vibrio harveyi, V. campbellii, V. parahaemolyticus, V. algi nolyticus, V. na trie gens and V. rotiferianus, so it could not be identified by this method. However, multi-locus sequence analysis (MLSA) of concatenated sequences, including the rpoD, rctB, gyrB, toxR and pyrH genes, identified strain AP37 as V. harveyi. Phenotypic characters of AP37 were identified by API 20E. In antibiotic susceptibility tests, strain AP37 exhibited susceptibility to 7 antibiotics and resistance to 13. This is the first report of a V. harveyi-related species being linked with the mass mortality of adult abalone H. diversicolor in southern China.

Microbial community of Pacific abalone (Haliotis discus hannai) juveniles during a disease outbreak in South China

“…; Jiang et al . ). V. alginolyticus, V. parahaemolyticus and V. carchariae were referred to be related to postlarvae abalone disease (Nishimori, Hasegawa, Numata & Wakabayashi ; Cai et al .…”

“…Bacterial species represented the most important opportunistic pathogens related to abalone disease, including Rickettsiaceae (Friedman, Andree, Beauchamp, Moore, Robbins, Shields & Hedrick ; Balseiro, Aranguren, Gestal, Novoa & Figueras ), Pseudomonas fluorescens (Ye, Yu, Wang, Liu, Zou, Liang & Chen ) and Vibrio genus (Nicolas, Basuyaux, Mazurie & Thebault ; Handlinger, Carson, Donachie, Gabor & Taylor ; Sawabe, Inoue, Fukui, Yoshie, Nishihara & Miura ; Jiang, Shi, Ke, You & Zhao ). Among these, some of vibrio species are recognized as the most extensive causative agents inducing abalone disease (Li, Ding, Zhang, Xiang & Liu ; Liu, Chen, Huang & Lee ; Sawabe et al .…”

Isolation and characterisation of Vibrio harveyi as etiological agent of foot pustule disease in the abalone Haliotis discus hannai Ino 1953

“…The LD50 values of many V. harveyi strains were reported to range from 10 4 to 10 6 CFU ml −1 (Sawabe et al, 2007). In this study, symptoms caused by BV2 was different from that caused by other pathogenic V. harveyi strains (Sawabe et al, 2007;Travers et al, 2009;Qiang, 2013).…”

Physiological, biochemical and HSP70 and HSP90 gene expression profiles of tropical abalone Haliotis squamata in response to Vibrio alginolyticus infection

“…Mass mortality among cultured small abalone H. diversicolor supertexta with abscess/ulcers in the man tle in 1998 at KaoHsiung Taiwan was caused by V. al ginolyticus (Liu et al 2001). In China, V. alginolyticus and V. parahaemolyticus were associated with a severe epidemic in farmed H. diversicolor supertexta in Fujian Province (Zhang et al 2001), and a Vibrio harveyirelated species was linked with the mass mortality of farmed adult H. diversicolor in Fujian (Jiang et al 2013). Those data supported that Vibrio spp caused diseases on abalones.…”