Location: Egg Safety & Quality ResearchTitle: Integrative Analysis of Salmonellosis Outbreaks in Israel 1999-2012 Revealed an Invasive S. enterica Serovar 9,12:l,v:- and Endemic S. Typhimurium DT104 strain) Author
|Schorr, Yosef i|
Submitted to: Journal of Infectious Diseases
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/29/2014
Publication Date: 4/9/2014
Citation: Marzel, A., Desai, P.T., Nissan, I., Schorr, Y., Suez, J., Valinsky, L., Reisfeld, A., Agmon, V., Guard, J.Y., Mcclelland, M., Rahav, G., Gal-Mor, O. 2014. Integrative Analysis of Salmonellosis Outbreaks in Israel 1999-2012 Revealed an Invasive S. enterica Serovar 9,12:l,v:- and Endemic S. Typhimurium DT104 strain. Journal of Infectious Diseases. p. 2078-2088. Interpretive Summary:
Technical Abstract: Salmonella enterica is the leading etiologic agent of bacterial foodborne outbreaks worldwide. Methods. Laboratory-based statistical surveillance, molecular and genomics analyses were applied to characterize Salmonella outbreaks pattern in Israel. 65,087 Salmonella isolates reported to the National Salmonella Reference Center 1995-2012 were analyzed by a quasi-Poisson regression algorithm (Farrington) to identify putative outbreaks. Validation of 28 predicted outbreaks was performed using Pulse-Field Gel Electrophoresis. Whole genome sequencing was applied for further genetic characterization. Results. Altogether, 384 aberrant clusters were identified, representing an average of 27 (95% CI 24 to 31) putative Salmonella outbreaks per year. S. enterica serovar 9,12:l,v:- was found to be associated with the utmost outbreaks, but also presented the highest extraintestinal infections proportion among non-typhoidal serovars. We show that S. 9,12:l,v:- belongs to clade B of S. enterica subsp. enterica and possesses a unique composition of virulence genes. Furthermore, we identified a prevalent S. Typhimurium DT104 endemic clone, which is responsible for recurring outbreaks in Israel and that is genetically distinct from the reference DT104 sequenced strain (NCTC 13348). Conclusions. These findings suggest a severe under-reporting of Salmonella outbreaks in Israel and shed light over the epidemiology and genomics of two prevalent serovars of high morbidity toll.