Antimicrobial resistant bacteria in seafood are a major public health concern worldwide. Reports on use of antimicrobials in aquaculture and residue findings in the products have indicated food safety threat to the consumers. In aquaculture, the use of wide array antimicrobials leading to development of bacterial resistance, use of resistant probiotic resistant strains and contamination of resistant pathogenic bacteria e.g. Salmonella spp. as input have facilitated to development of pool of resistant bacteria. Indicator bacteria are a useful tool to monitor antimicrobial resistance in any animal originated products. E. coli and Enterococci have been proven useful bacterial indicators in livestock and other animal husbandry practices excluding seafood. Therefore, it is urgently needed to identify and validate a potential bacterial indicator of antimicrobial resistance in seafood. The aim of the PhD study was to identify and validate a potential bacterial indicator of antimicrobial resistance to monitor the introduced antimicrobial resistance in aquaculture produce as input. For this reason, four studies were carried out and the main findings of these studies are summarized in the following paragraphs.
The first study (Manuscript I) investigated the diversity of the bacterial flora in imported raw frozen fish and shrimp products and to identify potential bacterial indicators of antimicrobial resistance. The cultureable bacterial flora were characterized from a variety of local and imported fish and shrimp products available in the Danish market and antimicrobial susceptibility patterns of the most common bacterial genera found in these products were determined. The bacterial flora determined by 16S rRNA sequence analysis of 84 is...
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... Weltevreden 3:r,z6 and S. Agona 4,12:f,g,s. Surprisingly, the same Salmonella Weltevreden 3:r,z6 was found in epidemiological unrelated extensive and intensive shrimp farms located in different provinces. The most common serotypes found in human and animals i.e. S. Typhimurium, and S. Enteritidis were not identified in this study.
The general conclusions of the PhD study are presented in conclusion chapter of the thesis. Perspectives of the findings and future research priority are presented including the application of non-culture approach in monitoring antimicrobial resistance in seafood, and needs to assess the safety and quality of probiotics used in Vietnamese shrimp culture in large scale and finally further characterization of Salmonella spp. identified in this study including its ecology, survival in shrimp farm environments as well as source or origin.
Unprotected foodstuffs will cause the bacteria and fungi colonize in the food rapidly which increase the bacteria population and produce toxic and distasteful chemicals (Janzen,1977). Obstructing colonization by reducing access to susceptible foodstuffs and inhibiting and limiting the population growth and size by creating an unfavorable environment is the two main strategies to prevent food spoilage cause by microorganisms. Microbes often disperse as resistant air, water, or soil-borne spores where
By 1943 and 1976, wound botulism and infant botulism were also respectively described. (1) Organism Description The bacterium Clostridium botulinum is a strict anaerobic Gram-positive bacillus. (1,2,4) A noteworthy feature is the ability to form resistant sub-terminal endospores. (1,4) The species is classified into four different groups, based on physiological, metabolic, and genetic characteristics. (2) Group I strains are proteolytic in culture, produce toxin types A/B/F, and form heat-stable endospores