Diagnosis of Salmonella bacteria: antibodies against synthetic Salmonella O-antigen 8 for immunofluorescence and co-agglutination using sensitized protein A-containing staphylococci.

An antiserum against the synthetic disaccharide abequose 13 rhamnose (AR), representative of Salmonella O-antigen 8, coupled to bovine serum albumin (BSA) was used for diagnosis of Salmonella bacteria by indirect immunofluorescence (IFL) and by co-agglutination (COA) using sensitized protein A-containing staphylococci. Among the 1150 enteric bacteria tested in IFL, the antiserum correctly identified all 99 Salmonella serogroup C 2 and C 3 bacteria with O-antigen 8. No fluorescence was seen with 484 Salmonella bacteria belonging to other serogroups or 567 non-Salmonella enteric bacteria. The anti-AR-BSA serum was favourable as compared to a conventional Salmonella factor O8 serum as regards both titre and specificity. In the COA test, all 22 Salmonella serogroup C 2 and C 3 strains agglutinated strongly and within seconds, whereas no agglutination could be seen when 93 Salmonella bacteria representing other serogroups were tested.