Environmental Health in Israel

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

Meir Broza

Hannah Sprecher

Ruti Yishai

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