A new type of Salmonella (S. ballerup) with Vi-antigen

Abstract

1. A description is given of a new Salmonella type (S. ballerup) with Vi-antigen which was probably the cause of an attack of gastro-enteritis in man.2. S. ballerup contains a new O- and a new H-antigen, so that the antigenic formula reads XXIX.[Vi].Z14. There is also a slight O-antigen relationship with the XIX-antigen of S. senftenberg.3. Like S. typhi, S. ballerup has the V-W change of form, as colonies occur with or without Vi-antigen; of these the V forms are much more stable than the W forms. The V forms are O-inagglutinable.4. As with S. typhi, the V and W forms are already distinguishable macroscopically on agar plates, the V forms being opaque, whereas the W forms are translucent.5. S. ballerup's Vi-antigen is serologically identical with S. typhi and S. paratyphi C's Vi-antigen.6. By means of the V form of S. ballerup it is easy to demonstrate Vi- agglutinin in typhoid sera, as there is no need to fear disturbances from O- and H-antibodies.7. By means of a V form vaccine of S. ballerup mice can be immunized actively against a lethal infection with the typhoid V form.8. The mouse pathogenity of S. ballerup is very low. There is no distinct difference in the pathogenity of the V and W forms of S. ballerup.