Application of integrated diagnostic approaches for monitoring the genomic traits of Streptococcus equi subsp. zooepidemicus and Echinococcus granulosus in Veterinary Public Health

Streptococcus equi subsp. zooepidemicus (SEZ) is a commensal bacterium commonly found in various animal species and in humans and for this reason it is not often considered an etiological agent of disease. However, growing evidence supports the key role of SEZ in developing severe clinical manifestations of diseases highlighting the importance of characterizing the different circulating strains. In an outbreak involving 37 people (including five deaths) in the Province of Pescara, Abruzzo (Italy), the zoonotic ST61 SEZ was isolated by IZSAM (Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise). This enabled tracing the origin of infection in consumption of soft cheeses produced with unpasteurized milk from cows with mastitis and preventing the further spread of this life-threatening disease. SEZ was also responsible for death of four donkeys in the same Province, but in this case, the ST525 sequenced was different from the previous one, and genomic analysis showed virulence genes that are not present in other strains. In both cases, results were achieved through a diagnostic process involving an integrated approach, including bacteriological isolation and characterization with MALDI-TOF-MS and genome sequencing by Next-Generation Sequencing (NGS) performed through the Illumina platform. Correlations between strains were also determined by performing a single-nucleotide polymorphism (SNP) analysis through the CFSAN pipeline. Echinococcosis is a neglected zoonotic disease caused worldwide by tapeworms of Echinococcus Genus, parasites of both domestic and wild animals as well as humans. One of its forms is represented by Cystic Echinococcosis (CE), caused by E. granulosus sensu lato (E.g.s.l.) and characterized by important consequences on human health, considerable economic impact and indirect repercussions on livestock productivity. Within the E.g.s.l. group, Echinococcus granulosus sensu stricto, consisting of two genotypes (G1 and G3), causes approximately 20 cases of patients hospitalised/yearly in the Abruzzo region. For this reason, measures of surveillance were included at slaughterhouses and kennels aimed at analyzing tissue cysts of intermediate hosts and dog feces (definitive hosts), as part of Regional Surveillance Plan. In addition, further samples were obtained during necropsies as part of monitoring plans for infectious diseases in domestic animals and wildlife. Even in this case the application of a multi-methodology process including validation of a Real-Time PCR and genotyping by a TaqMan Real-Time PCR led to defining the predominantly circulating genotypes in the territory, confirming that Echinococcus granulosus s.s (G1 and G3) appears to be the only ones currently present in Abruzzo.