- Absence of clonality of Campylobacter jejuni in serotypes other than HS:19 associated with Guillain-Barré syndrome and gastroenteritis. Engberg, J., Nachamkin, I., Fussing, V., McKhann, G.M., Griffin, J.W., Piffaretti, J.C., Nielsen, E.M., Gerner-Smidt, P. J. Infect. Dis. (2001)