Defensive Effects of Human Intestinal Antimicrobial Peptides against Infectious Diseases Caused by Vibrio mimicus and V. vulnificus

Abstract

Of human pathogenic Vibrio species, V. mimicus causes gastroenteritis whereas V. vulnificus causes fatal septicemia after consumption of contaminated seafood. These two pathogens produce hemolytic toxins termed V. mimicus hemolysin VMH and V. vulnificus hemolysin VVH , respectively. These toxins elicit the cytolysis of various eukaryotic cells, as well as erythrocytes. The human intestine secretes cationic antimicrobial peptides AMPs to prevent infectious diseases. Paneth cells in the small intestine secrete -defensin 5 HD-5 and epithelial cells in the large intestine produce LL-37. In the present study, we examined the bactericidal activities of AMPs against V. mimicus and V. vulnificus. Although HD-5 showed no bactericidal activity, LL-37 revealed significant activity against both Vibrio species, suggesting that neither V. mimicus nor V. vulnificus can multiply in the large intestine. We also tested whether AMPs had the ability to inactivate the hemolytic toxins. Only HD-5 was found to inactivate VMH, but not VVH, in a dose-dependent manner through the direct binding to VMH. Therefore, it is considered that V. mimicus cannot penetrate the small intestinal epithelium because the cytolytic action of VMH is inactivated by HD-5.

Effective method to control Vibrio mimicus infection in channel catfish Ictalurus punctatus

“…mimicus can cause human gastroenteritis, ear infections, and severe cholera-like diarrhea (Austin 2010;Hasan et al, 2010). V. mimicusis is also associated with disease in aquatic animals, which are potential sources of infection to humans after ingestion (Miyoshi et al, 2014). Effective prophylaxis methods are needed to control V. mimicus epidemics.…”

Vibrio vulnificus Hemolysin: Biological Activity, Regulation of vvhA Expression, and Role in Pathogenesis

“…However, while HD-5 inactivated the Vibrio mimicus hemolysin, it had no effect on VVH. The inability of V. mimicus to penetrate the small intestinal epithelium suggests that the cytolytic activity of the V. mimicus hemolysin is abolished by HD-5 (61). In contrast, V. vulnificus causes intestinal tissue damage and inflammation, which then promotes dissemination of the pathogen from the small intestine into the bloodstream and other organs in infected mice (6,7).…”

Visual LAMP Method for Detection of Vibrio vulnificus in Aquatic Products and Environmental Water

“…At least 12 pathogenic Vibrio species have been reported, which are not only a public health issue, but also cause huge economic losses to the aquaculture industry [1][2][3][4]. V. vulni cus is responsible for more than 50% of infectious diseases in aquaculture [5][6] and has the highest fatality rate of any foodborne pathogen [7][8][9].…”