Aeromonas veronii associated with red gill disease and its induced immune response in Macrobrachium nipponense

Abstract

Aeromonas veronii is a freshwater bacterium associated with many diseases in aquatic animals. In this study, the pathogenic of A. veronii was isolated from diseased Macrobrachium nipponense showing signs of weakness, poor appetite and red gills in some farms in Jiangsu province, China. The pathogenicity of A. veronii to M. nipponense was determined by challenge experiments. Results of artificial challenge showed A. veronii NJ1 was pathogenic to M. nipponense, and the LD50 was 4.5 × 106 CFU/ml at 7 d post infection. Detection virulence factors of the A. veronii NJ1 showed that A. veronii NJ1 produced caseinase, lipase, amylase, lecithinase, gelatinase and haemolysin. Detection of virulence‐related genes showed that A. veronii NJ1 was positive for aerolysin (aer), outer membrane protein (ompA), adhesin (aha), flagellin (flaA, flgH, flgM, flgN), lipoidase (lip), cytotonic enterotoxins (act, alt, ast), serine protease (ser), DNases (exu), haemolysin (hlyA), type IV pilus (tapA) and fimbrillin (fim). Antibiotic sensitivity testing indicated A. veronii NJ1 was susceptible to quinolones, but resistant to penicillins. Additionally, the immune‐related gene expression in M. nipponense was evaluated, and the results showed that anti‐lipopolysaccharide factor (ALF1, ALF2, ALF3), Cusrin1, Cusrin2, Cusrin3, Haemocyanin, i‐lysozyme and Prophenoloxidase were significantly upregulated from 6 to 24 hr after A. veronii infection. The results of our study suggested that A. veronii was an aetiological element in the mass mortalities of M. nipponense and this study provided preliminary insights into the diversity in the immune response of M. nipponense to the A. veronii infection.

Comparative Pathogenicity of Aeromonas spp. in Cultured Red Hybrid Tilapia (Oreochromis niloticus × O. mossambicus)

“…Therefore, this characteristic has been used to screen vAh isolates among A. hydrophila [24,26,28]. Nevertheless, the only known vAh strains are among A. hydrophila, while A. dhakensis, A. hydrophila, A. jandaei, A. veronii, A. sobria and A. caviae were believed to be unable to utilize inositol [10,[29][30][31]. However, with more recent data, there is a possibility that horizontal gene transfer may have happened between vAh and other notorious virulent Aeromonas spp., such as A. dhakensis.…”

Prevalence and genetic diversity of Aeromonas veronii isolated from aquaculture systems in the Poyang Lake area, China

“…The high diversity of A. veronii poses a problem for disease control. Different types of bacteria have different properties and environmental adaptabilities and correspondingly can infect a wide range of hosts, which is in line with the prevalence of A. veronii infection in a variety of aquatic animals in southern China in recent years ( Ran et al, 2018 ; Gao et al, 2020 ; Wang et al, 2021 ).…”

“…The major bacterial infections of freshwater fish generally involve one of several species of the genus Aeromonas , such as A. veronii and A. hydrophila ( Fernández-Bravo and Figureueras, 2020 ). A. veronii is the primary pathogen isolated from freshwater fish in South China, including Jiangxi Province ( Ran et al, 2018 ; Xu et al, 2018 , 2019 , 2021 ; Gao et al, 2020 ; Rao et al, 2020 ; Wang et al, 2021 ). The cultured fishes in the Poyang Lake area are also affected by A. veronii , which is the most frequently detected bacterium in freshwater ( Ran et al, 2018 ; Pessoa et al, 2020 ).…”

Characteristics and Complete Genome Analysis of a Pathogenic Aeromonas Veronii SJ4 from Diseased Siniperca Chuatsi

“…The extracellular enzymatic activities including phospholipase, lipase, amylase, hemolysin, urease, caseinase, dnase, and gelatinase, were screened by the methods described by Gao et al (2020). LB agar plates were supplemented with 10% egg yolk, 1% Tween-80, 2% starch, 7% rabbit erythrocytes, 2% urea, 10% skim milk, 0.05% DNA, 1% gelatin, respectively.…”