Background: Salmonella enterica serovar Napoli (S. Napoli) is uncommon in Europe except in Italy, where it ranks among the top five serovars causing human infection. However, information about its epidemiology, ecology and virulence is poor, and no foodborne or environmental factor has been identified so far. Importantly, recent studies conducted by our group have revealed that S. Napoli and typhoid serovars are highly related, in terms of genomics and clinical characteristics. Material/methods: Forty-four S. Napoli strains isolated from human cases in Lombardy and Emilia-Romagna, Italy (2012-2014), were subjected to whole-genome sequencing (WGS) using the Illumina MiSeq platform. Bayesian SNP-based phylogeny was reconstructed using the kSNP software. A comparative genomic analysis was performed to detect the differences between the S. Napoli genomes, in terms of nucleotide variations. Results: Phylogenetic analysis revealed that S. Napoli isolates are grouped in two main clades that strongly correlate with their geographic origin (Figure 1). Clade A (n=16 isolates) included most of the isolates from Emilia-Romagna, and clade B (n=28 isolates) comprised most of the isolates from Lombardy, including the strain SMOUT310_MI, responsible for causing a recent outbreak in Milan (2014). Conclusions: In the present study, we compared S. Napoli isolates from two different Italian regions by SNP typing based on WGS. The results indicate that WGS coupled to SNP-based phylogeny seems an excellent approach to infer the genomic and geographic distribution of serovar Napoli isolates, and that our analysis can provide valuable supplemental information about this emerging public health concern in Italy. Future studies are needed to further improve the usefulness of WGS analysis, in particular regarding genetic changes over time and diversity within regions, in order to make hypothesis regarding the origin and the geographical dispersion of this poorly studied serovar.
Whole-genome sequencing and comparative genomic analysis of Salmonella enterica serovar Napoli strains isolated from human cases occurred in Lombardy and Emilia-Romagna, Northern Italy / M. Gori, E. Scaltriti, P. HUEDO MORENO, L. Bolzoni, G. Ciceri, E. Ebranati, G. Zehender, S. Pongolini, M.M. Pontello. ((Intervento presentato al 27. convegno European Congress of Clinical Microbiology and Infectious Diseases tenutosi a Wien nel 2017.
Whole-genome sequencing and comparative genomic analysis of Salmonella enterica serovar Napoli strains isolated from human cases occurred in Lombardy and Emilia-Romagna, Northern Italy
M. Gori;P. HUEDO MORENO;G. Ciceri;E. Ebranati;G. Zehender;M.M. Pontello
2017
Abstract
Background: Salmonella enterica serovar Napoli (S. Napoli) is uncommon in Europe except in Italy, where it ranks among the top five serovars causing human infection. However, information about its epidemiology, ecology and virulence is poor, and no foodborne or environmental factor has been identified so far. Importantly, recent studies conducted by our group have revealed that S. Napoli and typhoid serovars are highly related, in terms of genomics and clinical characteristics. Material/methods: Forty-four S. Napoli strains isolated from human cases in Lombardy and Emilia-Romagna, Italy (2012-2014), were subjected to whole-genome sequencing (WGS) using the Illumina MiSeq platform. Bayesian SNP-based phylogeny was reconstructed using the kSNP software. A comparative genomic analysis was performed to detect the differences between the S. Napoli genomes, in terms of nucleotide variations. Results: Phylogenetic analysis revealed that S. Napoli isolates are grouped in two main clades that strongly correlate with their geographic origin (Figure 1). Clade A (n=16 isolates) included most of the isolates from Emilia-Romagna, and clade B (n=28 isolates) comprised most of the isolates from Lombardy, including the strain SMOUT310_MI, responsible for causing a recent outbreak in Milan (2014). Conclusions: In the present study, we compared S. Napoli isolates from two different Italian regions by SNP typing based on WGS. The results indicate that WGS coupled to SNP-based phylogeny seems an excellent approach to infer the genomic and geographic distribution of serovar Napoli isolates, and that our analysis can provide valuable supplemental information about this emerging public health concern in Italy. Future studies are needed to further improve the usefulness of WGS analysis, in particular regarding genetic changes over time and diversity within regions, in order to make hypothesis regarding the origin and the geographical dispersion of this poorly studied serovar.
Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
