The large yellow croaker (Larimichthys crocea) is an economically important maricultured fish in China, with the highest annual production among maricultured fish species (Ao et al., 2015). With the rapid development of large yellow croaker farming, the bacterial diseases are becoming more and more serious (Mu et al., 2018). At present, the most serious bacterial disease is visceral white nodules disease (VWND) characterized by white nodules in the internal organs, including spleen, kidney and liver, of infected fish. The VWND has caused high mortality in the cage-cultured large yellow croaker, resulting in significant economic losses (Zhang, Zhou, An, Chen, & Wang, 2014). As early as 2002, the VWND was epidemic in cultured large yellow croaker in Fujian, China, with a high mortality rate of about 70%-80% (Liu, Yu, Lin, Chen, & Xie, 2004). The obvious symptoms included many white nodules with a diameter of 1-2 mm observed in spleen, kidney and liver, congestion in mandible and gill cover, and inflammation in intestine. Two Pseudomonas strains (BP-1 and BS-2) were isolated and identified as the aetiological agents of this disease (Liu et al., 2004). In 2005, an outbreak of the VWND occurred in farmed large yellow croaker in Zhejiang, China, and its pathogen was identified as Pseudomonas putida (Shen
