Grants and Fellowships | 2014

19 Identification, Isolation and Epidemiological Study of the Invasive Human Pathogen, Vibrio Vulnificus , from Water Resources Vibrio vulnificus is a worldwide highly invasive human pathogen, with one of the highest mortality rates. Human infections are acquired through consumption of contaminated seafood or through skin wounds. It is considered as an important emerging environmental and food safety issue around the world. Strains of V. vulnificus are divided into three different biotypes. The highly virulent Biotype 3 was isolated until now only in Israel and is responsible for numerous infections each year. Our recent genomic study suggests the existence of an additional new virulent group, clade A. The objective of the research was to follow the route of contamination of the water associated pathogen, V. vulnificus in Israel. The heterogeneity of the bacterial population in different water bodies was studied through genomic diversity in comparison with clinical samples. We developed rapid identification and typing method based on three technologies; SSR molecular markers, MLST and on a custom genome-wide single nucleotide polymorphisms (SNP) genotyping array. 254 clinical and environmental isolates with worldwide distribution recovered over a 30-year period were successfully genotyped by the array. This powerful high-throughput approach enabled us to simultaneously cover 570 SNPs randomly distributed throughout the entire genome of V. vulnificus among a diverse and large number of isolates. Our data demonstrate that the developed SNP genotyping technology could be utilized for accurate strain identification, for inferring phylogenetic relationships among strains and for epidemiology studies. Analyses of the array data together with our recently draft genome sequence of biotype 3 strain VVyb1(BT3), suggest that biotype 3 as created bade on biotype 1 genome that gained rather small number of genes from other bacterial species sharing the same niche, e.g., Shewanella. Results support the recent emergence of new pathogenic groups (clade A) within this species as a recurrent phenomenon. These results emphasize the rapid genetic change of such pathogenic bacteria in their natural ecological niche, in this case artificial fish aquaculture farms in Israel. The results specifically contribute to the broad understanding of the evolution of this human pathogen. The ongoing intervention in environmental niches like these requires our continuous preparedness to cope with such emerging risks. Research publications (1) Broza, Y.Y., Danin-Poleg, Y., Lerner, L., Valinsky, L., Broza, M., & Kashi, Y. (2009). Epidemiological study of Vibrio vulnificus infections by using variable number tandem repeats. Emerging Infectious Diseases, 15 (8), 1282-1285. (2) Broza,Y.Y., Raz, N., Lerner, L., Danin-Poleg,Y., & Kashi,Y. (2012). Genetic diversity of the human pathogen Vibrio vulnificus: A new phylogroup. International Journal of Food Microbiology, 153 , 436–443. (3) Danin-Poleg, Y., Elgavish, S., Raz, N., Efimov, V., & Kashi, Y. (2013). Genome sequence of the pathogenic bacterium Vibrio vulnificus biotype 3 strain. Genome Announcements, 1 (2), e00136-13. Yechezkel Kashi 1 Meir Broza 2 Hannah Sprecher 3 Ruti Yishai 4 1. Technion – Israel Institute of Technology 2. University of Haifa - Oranim 3. Rambam Health Care Campus 4. Israel Ministry of Health 2008-2012 Multi-Year Research Grants