Comparative genomic analysis of Salmonella enterica subsp. enterica serovar Weltevreden foodborne strains with other serovars

Salmonella enterica subsp. enterica serovar Weltevreden is a dominant serovar associated with foodborne gastroenteritis in South-East Asia and emerging in Europe associated with fresh vegetables. Here we compared the genome of strain 2007-60-3289-1 linked to an alfalfa sprout outbreak in Scandinavia with a S. Weltevreden strain isolated from scallops in the USA and with other S. enterica serovars. A unique plasmid pSW82 was identified for S. Weltevreden carrying a two-component type II non-ribosomal peptide synthase/polyketide synthase. Analysis of all available complete S. enterica genomes identified differences for presence of type VI secretion systems and carbohydrate metabolic pathways. Differential transcription thereof was observed when S. Weltevreden strains were grown in vitro or on sprouts. ► Comparative analysis of S. Weltevreden yielded indications to host specificity. ► Serovar-specific genomic islands were identified and characterized by RT-PCR. ► Carbohydrate metabolism varies between serovars but also within S. Weltevreden. ► A unique plasmid was identified that is of diagnostic value for S. Weltevreden.