Synthetic disaccharide - protein antigens for production of specific 04 and 09 antisera for immunofluorescence diagnosis of Salmonella

The synthetic disaccharides abequose \(1\mathop \to \limits_a 3\) mannose and tyvelose \(1\mathop \to \limits_a 3\) mannose, representative ofSalmonella O-antigen 4 and 9 respectively, were covalently linked to bovine serum albumin (BSA). Antisera from rabbits immunized with these immunogens were used in indirect immunofluorescence assay for the identification of group B (O-antigen 4) and D (O-antigen 9)Salmonella. A total of 1030 enteric bacterial strains were tested, including 207 group B and 55 group DSalmonella The anti-abequose-mannose-BSA serum correctly identified allSalmonella group B strains tested. The anti-tyvelose-mannose-BSA serum correctly identified allSalmonella group D bacteria examined with the exception of 11 of 18 Vi-positiveS. typhi strains which did not stain until the Vi-antigen was removed by boiling. Among the 768 strains representingSalmonella other than groups B and D,E. coli, Shigella, Citrobacter, Klebsiella, Enterobacter, Serratia, Proteus, Vibrio, Pseudomonas, Aeromonas, Yersinia, Bacteroides andFusobacterium only 5 positive reactions were found. These were observed withY. pseudotuberculosis strains which have the same disaccharide antigenic determinants asSalmonella O-antigen 4 and 9 respectively. The high specificity of the antisera elicited by the synthetic disaccharide-BSA immunogens make them suitable for a specific and rapid identification ofSalmonella bacteria belonging to serogroups B and D.