title: Comparing validation of four ELISA-systems for detection of Salmonella derby- and Salmonella infantis-infected pigs.
abstract: The objective of this study was the comparative evaluation of four indirect Salmonella ELISA tests at study time approved in Germany to detect Salmonella infection in pigs.Three tests are based on a LPS-antigen mix and directed against specific IgG antibodies. The fourth test is based on a purified S. Typhimurium whole-cell lysate antigen and discriminates between Salmonella-specific IgM-, IgA-, and IgG- antibodies. In a longitudinal study, two groups of six weeks old hybrid piglets were orally infected with a porcine S. Infantis or S. Derby strain. Clinical and bacteriological parameters were monitored weekly during an observation period of 130 days after infection and serum samples were investigated in parallel with the respective ELISAs. Apparently, the LPS-based ELISA systems used in this study failed to recognize S. Infantis-infected pigs although those animals shed the pathogen in high amounts throughout the study until day 81 post infection (p. i.). In contrast, the isotype-specific Salmonella Typhimurium whole-cell-lysate based ELISA was capable of detecting Salmonella-infected pigs from day ten p. i. at all tested serotypes and revealed the highest sensitivity in detection of S. Infantis-infected pigs. Furthermore, it became apparent that the often used surveillance cut-off value of 40 OD% is not appropriate for intra-vitam detection of S. Infantis- and S. Derby-infected pigs. In contrast, the cut-off values of the ELISAs given by the suppliers result in considerable higher detection rates.
authors.affiliation: Institute of Animal Hygiene and Environmental Health, Free University Berlin, Berlin, Germany. tierhygiene@vetmed.fu-berlin.de
authors.forename: Uwe
authors.initials: U
authors.lastname: Roesler
authors.forename: Istvan
authors.initials: I
authors.lastname: Szabo
authors.forename: Claudia
authors.initials: C
authors.lastname: Matthies
authors.forename: Kerstin
authors.initials: K
authors.lastname: Albrecht
authors.forename: Martin
authors.initials: M
authors.lastname: Leffler
authors.forename: Kathrin
authors.initials: K
authors.lastname: Scherer
authors.forename: Karsten
authors.initials: K
authors.lastname: Nöckler
authors.forename: Jörg
authors.initials: J
authors.lastname: Lehmann
authors.forename: Ulrich
authors.initials: U
authors.lastname: Methner
authors.forename: Andreas
authors.initials: A
authors.lastname: Hensel
authors.forename: Uwe
authors.initials: U
authors.lastname: Truyen
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay / Q000592:standards / Q000662:veterinary*; D005243:Feces / Q000382:microbiology; D012475:Salmonella / Q000302:isolation & purification / Q000502:physiology; D012481:Salmonella Infections, Animal / Q000175:diagnosis*; D012680:Sensitivity and Specificity; D013552:Swine; D013553:Swine Diseases / Q000175:diagnosis*; D013997:Time Factors
chemical_list: D000907:Antibodies, Bacterial