Whole genome sequencing of Shigella sonnei through PulseNet Latin America and Caribbean: advancing global surveillance of foodborne illnesses.

OBJECTIVES: Shigella sonnei is a globally important diarrhoeal pathogen tracked through the surveillance network PulseNet Latin America and Caribbean (PNLA&C), which participates in PulseNet International. PNLA&C laboratories use common molecular techniques to track pathogens causing foodborne illness. We aimed to demonstrate the possibility and advantages of transitioning to whole genome sequencing (WGS) for surveillance within existing networks across a continent where S. sonnei is endemic. METHODS: We applied WGS to representative archive isolates of S. sonnei (n = 323) from laboratories in nine PNLA&C countries to generate a regional phylogenomic reference for S. sonnei and put this in the global context. We used this reference to contextualise 16 S. sonnei from three Argentinian outbreaks, using locally generated sequence data. Assembled genome sequences were used to predict antimicrobial resistance (AMR) phenotypes and identify AMR determinants. RESULTS: S. sonnei isolates clustered in five Latin American sublineages in the global phylogeny, with many (46%, 149 of 323) belonging to previously undescribed sublineages. Predicted multidrug resistance was common (77%, 249 of 323), and clinically relevant differences in AMR were found among sublineages. The regional overview showed that Argentinian outbreak isolates belonged to distinct sublineages and had different epidemiologic origins. CONCLUSIONS: Latin America contains novel genetic diversity of S. sonnei that is relevant on a global scale and commonly exhibits multidrug resistance. Retrospective passive surveillance with WGS has utility for informing treatment, identifying regionally epidemic sublineages and providing a framework for interpretation of prospective, locally sequenced outbreaks.

Cost analysis of an integrated vaccine-preventable disease surveillance system in Costa Rica.

INTRODUCTION: Following World Health Organization recommendations set forth in the Global Framework for Immunization Monitoring and Surveillance, Costa Rica in 2009 became the first country to implement integrated vaccine-preventable disease (iVPD) surveillance, with support from the U.S. Centers for Disease Control and Prevention (CDC) and the Pan American Health Organization (PAHO). As surveillance for diseases prevented by new vaccines is integrated into existing surveillance systems, these systems could cost more than routine surveillance for VPDs targeted by the Expanded Program on Immunization. OBJECTIVES: We estimate the costs associated with establishing and subsequently operating the iVPD surveillance system at a pilot site in Costa Rica. METHODS: We retrospectively collected data on costs incurred by the institutions supporting iVPD surveillance during the preparatory (January 2007 through August 2009) and implementation (September 2009 through August 2010) phases of the iVPD surveillance project in Costa Rica. These data were used to estimate costs for personnel, meetings, infrastructure, office equipment and supplies, transportation, and laboratory facilities. Costs incurred by each of the collaborating institutions were also estimated. RESULTS: During the preparatory phase, the estimated total cost was 128,000 U.S. dollars (US$), including 64% for personnel costs. The preparatory phase was supported by CDC and PAHO. The estimated cost for 1 year of implementation was US$ 420,000, including 58% for personnel costs, 28% for laboratory costs, and 14% for meeting, infrastructure, office, and transportation costs combined. The national reference laboratory and the PAHO Costa Rica office incurred 64% of total costs, and other local institutions supporting iVPD surveillance incurred the remaining 36%. CONCLUSIONS: Countries planning to implement iVPD surveillance will require adequate investments in human resources, laboratories, data management, reporting, and investigation. Our findings will be valuable for decision makers and donors planning and implementing similar strategies in other countries.