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

Immobilization of Lead by Phosphated Biochar Produced from Fish Farming Sludge and Sewage Sludge in a Contaminated Urban Soil

An evaluation was conducted on the application of phosphate biochar produced from Sewage Sludge (SS) of a Wastewater Treatment Plant (WWTP) for lead immobilization in contaminated soils of the Human Settlement (HS) Virgin of Guadalupe, in the district of Mi Peru. Biochar was generated by a slow pyrolysis process at 500°C. The biochar was dosed at 10% biochar/soil on lead-contaminated soil, and the factors studied were the type of biochar and time of application. A complete factorial design was performed, and the data were processed using Design Expert v11 software. The results showed that the maximum lead immobilization was 50.83% for BSS for 20 days at a dose of 10% biochar/soil. According to the factorial model, an R² of 0.85, an adjusted R² of 0.83, an F-value of 79.64, and p-values lower than 0.05 (95%) were obtained, indicating that the factor (F2) of application time is significant for the treatment. It was concluded that both types of sludge have the potential for lead immobilization in contaminated soil, and the application time is significant for lead immobilization