Logo of the Information System for Agriculture and Food Research

Information System for Agriculture and Food Research

Information platform of the Federal and State Governments

Optimization of detection procedures for enteropathogenic bacteria of the genera Vibrio and Aeromonas in seafood and fish products

Project

Food and consumer protection

This project contributes to the research aim 'Food and consumer protection'. Which funding institutions are active for this aim? What are the sub-aims? Take a look:
Food and consumer protection


Project code: BfR-BIOS-08-1322-673
Contract period: 01.01.2017 - 31.12.2017
Purpose of research: Applied research

Since the early 1970s, the consumption of fishery products has increased worldwide. However, eating raw or undercooked fish as well as aquatic mollusks and crustaceans is critical because these foods very frequently harbour vibrios and aeromonads as potential human pathogens. The genera Vibrio and Aeromonas within the class of Gammaproteobacteria comprise gram-negative, nonsporeforming, facultatively anaerobic rod-shaped bacteria with a growth temperature range between 0 °C and 45 °C. Both genera are ubiquitiously distributed in aquatic ecosystems, with Aeromonas spp., V. cholerae and V. mimicus found both in marine or estuarine and in freshwater environments (Farmer et al., 2015; Martin-Carnahan and Joseph, 2015). So far, 44 validated Vibrio species had been described, at least 10 of which are associated with human clinical samples. The two most frequently isolated enteropathogenic species are V. cholerae and V. parahaemolyticus (Farmer et al., 2015). The genus Aeromonas currently comprises 21 validated species, 11 of which are related to human clinical samples (Martin-Carnahan and Joseph, 2015). In the context of severe diarrhea and gastrointestinal infections respectively, A. hydrophila, A. caviae and A. veronii biovar sobria are most often isolated (von Graevenitz, 2007). For vibrios, a number of enteropathogenicity-associated, chromosomally encoded virulence factors are described, as for instance the cholera toxin and the toxin coregulated pilus in toxigenic V. cholerae O1, O139 strains or the hemolysins TDH and TRH in clinical V. parahaemolyticus strains (Farmer et al., 2015). In aeromonads, not only the enterotoxins Act, Alt and Ast but also hemolysins such as AerA and HlyA are of clinical relevance (von Graevenitz, 2007). In the scientific literature, the load of retailed seafood in Germany with enteropathogenic Vibrio species was pointed out repeatedly (Sieffert and Stolle, 2002; Mitzscherling and Kühne, 2008). In contrast, little is known about the prevalence of potentially enteropathogenic Aeromonas spp., both as sole bacterial genus and in combination with Vibrio spp.. Whereas for the detection of potentially enteropathogenic Vibrio parahaemolyticus, Vibrio cholerae and Vibrio vulnificus an international draft standard (ISO/DIS 21872:2016) exists, no standardized detection procedure is described for aeromonads. A great problem for the detection of vibrios and aeromonads in foods is the possible presence of VBNC (viable but non-culturable) cells. After catching or harvesting, the cold chain is usually consistently maintained for fish and fishery products. Consequently, it can be assumed that vibrios or aeromonads present in such products will rapidly enter the VBNC status or already entered the status before start of harvesting (Burnham et al., 2009; Meng et al., 2015). The aim of this project is to develop protocols for the isolation of vibrios and aeromonads from fish products and seafood which also include VBNC bacteria. Besides, the prevalence of Aeromonas spp. and Vibrio spp. in fishery products should be investigated. Finally, all strains should be characterized by use of genotypic and phenotypic tests.

show more show less

Subjects

Framework programme

BMEL Frameworkprogramme 2008

Advanced Search