World Health Organisation – supervised interlaboratory comparison of ELISAs for the serological detection ofSalmonella entericaserotype Enteritidis in chickens

Abstract

SUMMARYA collaborative exercise, supervised by the World Health Organisation, was set up to compare ELISAs used for the serological detection of Salmonella enteritica serotype Enteritidis in chickens. The aim was to ascertain how far agreement could be reached on the interpretation of optical density readings for high titre, intermediate titre and low titre sera. Two sets of sera were sent to 14 participants. The first set compared high, medium and low titre sera raised in specified-pathogen-free and commercial broiler breeder chickens. The second set comprised 20 sera of different antibody titres raised in commercial birds reared under laboratory conditions and sent blind. Both indirect and double-antibody sandwich blocking ELISAs were used with a number of different detecting antigens. With a few exceptions good agreement was reached on the interpretation of results obtained from high and low titre sera from the optical density obtained with a single serum dilution. Differences were observed in the interpretation of medium titre sera. The results suggested that most ELISAs produce reasonably comparable results and that practical problems may arise from interpretation of the results mainly as a result of the choice of the criteria used for differentiating sera obtained from infected and uninfected chickens. These problems are discussed.

Interlaboratory and between-specimen comparisons of diagnostic tests for leptospirosis in sheep and cattle

“…This comparison demonstrated good agreement on the interpretation of optical density readings of high and low titer sera, but differences in the interpretation of medium titer sera. 5 A study was performed on epithelial specimens to investigate the interlaboratory comparison of qPCR assays and cultures that were routinely performed in 5 European laboratories for foot-and-mouth disease. Comparable results for qPCR assays, but variable sensitivity for cultures across laboratories, were demonstrated in this study.…”

Comparison of methods for the detection ofSalmonella in poultry

“…The identification sequence is based on ISO 6579 for conventional testing. In experimental infection trials, the inoculation rates ranged from 10 6 to 10 9 cfu/mL [13][14][15][16][17][18]; we used 3.4 × 10 6 cfu/mL as our inoculation rate. Individual circumstances in combination with different age groups of animals tested may explain the low colonization rates at the first sampling occasions.…”

Evaluation of a serological Salmonella Mix-ELISA for poultry used in a national surveillance programme

“…Numerous ELISAs using different salmonella antigens for detection of salmonella infection in poultry have been described, some of which have been used in national control programmes for salmonella [1,5,6]. These assays have often been developed with the aim of detecting infection with a single serotype.…”