Pathogenic Escherichia coli and enteric viruses in biosolids and related top soil improvers in Italy

Aims to investigate the presence of genomic traits associated with a set of enteric viruses as well as pathogenic Escherichia coli in Top Soil Improvers (TSI) from Italy Methods 24 TSI samples originating from municipal sewage sludges, pig manure, green and household wastes were analysed by Real Time PCR for the presence of Hepatitis E virus, porcine and human adenovirus, norovirus, rotavirus and diarrheagenic E. coli. Results None of the samples was found positive for Hepatitis E virus, and rotavirus. Four samples were positive for the presence of nucleic acids from human norovirus, two of them being also positive for human adenovirus. Real Time PCR screening gave positive results for many of the virulence genes characteristic of diarrheagenic E. coli in 21 samples. These included the Verocytotoxin-coding genes, in some cases associated with intimin-coding gene, and markers of enteroaggregative, enterotoxigenic, and enteroinvasive E. coli. Conclusions These results provide evidence that enteric viruses and pathogenic E. coli may be released into the environment through the use of sludges-derived TSI. Significance and Impact of the Study Our results highlight that the TSI-related environmental risk for the food chain should be more deeply assessed. This article is protected by copyright. All rights reserved.