A national outbreak of multi-resistant Salmonella enterica serovar Typhimurium definitive phage type (DT) 104 associated with consumption of lettuce. by Horby, P, O'Brien, S, Adak, G, Graham, C, Hawker, J, Hunter, P, Lane, C, Lawson, A, Mitchell, RT, Reacher, M, Threlfall, E, Ward, L