The stress hormone norepinephrine increases the growth and virulence of Aeromonas hydrophila

Abstract

Stress is an important contributing factor in the outbreak of infectious fish diseases. To comprehensively understand the impact of catecholamine stress hormone norepinephrine (NE) on the pathogenicity of Aeromonas hydrophila, we assessed variations in bacterial growth, virulence-related genes expression and virulence factors activity after NE addition in serum-SAPI medium. Further, we assessed the effects of NE on A. hydrophila virulence in vivo by challenging fish with pathogenic strain AH196 and following with or without NE injection. The NE-associated stimulation of A. hydrophila strain growth was not linear-dose-dependent, and only 100 μM, or higher concentrations, could stimulate growth. Real-time PCR analyses revealed that NE notably changed 13 out of the 16 virulence-associated genes (e.g. ompW, ahp, aha, ela, ahyR, ompA, and fur) expression, which were all significantly upregulated in A. hydrophila AH196 (p < 0.01). NE could enhance the protease activity, but not affect the lipase activity, hemolysis, and motility. Further, the mortality of crucian carp challenged with A. hydrophila AH196 was significantly higher in the group treated with NE (p < 0.01). Collectively, our results showed that NE enhanced the growth and virulence of pathogenic bacterium A. hydrophila.

Effect of catecholamine stress hormones (dopamine and norepinephrine) on growth, swimming motility, biofilm formation and virulence factors of Yersinia ruckeri in vitro and an in vivo evaluation in rainbow trout

“…Aeromonas hydrophila (Gao et al, 2018). Furthermore, our findings are in agreement with previous works reporting the effect of the catecholamines on biofilm formation in Staphylococcus epidermidis , Vibrio campbellii and V. anguillarum (Pande et al, 2014) and V. harvei (Yang et al, 2014).…”

“…Norepinephrine and dopamine caused Y. ruckeri to grow in the presence of serum (which is added to mimic the host body condition through limiting the availability of iron by high‐affinity ferric iron‐binding proteins such as transferrin (Freestone, Sandrini, Haigh, & Lyte, ), and the addition of inhibitors of eukaryotic catecholamine receptors with the catecholamines could partially block this effect. Catecholamines have been found to induce the growth of different Gram‐negative bacteria such as Vibrio parahaemolyticus, V. mimicus, V. harvei, Aeromonas hydrophila, V. campbellii and V. anguillarum in medium containing serum (Kinney et al, ; Lyte, ; Nakano, Takahashi, Sakai, & Nakaya, ; O'Donnell, Aviles, Lyte, & Sonnenfeld, 2006; Pande et al, ; Yang et al, ; Gao et al, ). This growth stimulation in the serum‐supplemented medium may be justified through facilitating the availability of iron for bacteria by the catecholamines (Lyte, ; Nakano, Takahashi, Sakai, & Nakaya, ).…”

“…Besides, the similar results obtained in another research revealed that the virulence of V. harveyi enhanced towards gnotobiotic brine shrimp larvae when was pretreated with the catecholamines. Gao et al () found that injection of A. hydrophila into crucian carp followed by NE resulted in a significant increase in fish mortality rate compared to other groups. Additionally, in our work, the antagonists were able to decrease the effect induced by the stress hormones.…”

Epinephrine affects motility, and increases adhesion, biofilm and virulence of Pseudomonas aeruginosa H103

“…Bacteria can be exposed to a multitude of host cell molecules such as catecholamines 7 that could enhance the growth of many gram-negative bacteria 8,9,12,17,18,23–26 as well as their virulence 19,27 . Till now, only few studies were conducted on the effect of these molecules on P. aeruginosa , which is an opportunistic pathogen, often found in hospital-acquired infections.…”

Advances on Vibrio parahaemolyticus research in the postgenomic era

“…Norepinephrine (NE) was first described as a host‐derived factor that affects T3SS2‐mediated virulence . NE is a catecholamine that functions as a major neurotransmitter in the gastrointestinal tract and promotes the virulence of several pathogens, including enterohemorrhagic E. coli , Campylobacter jejuni , and Aeromonas hydrophila . NE does not affect the expression of T3SS2‐related genes in vitro .…”