Evaluation of commercial antisera for Shigella serogrouping.
Shigella serogrouping antisera from six companies (Becton Dickinson, Denka, Difco, Murex, Roach, and Sanofi-Pasteur) intended for the slide agglutination test and those of the Wellcolex Colour Shigella latex agglutination test were evaluated to identify quality products for Shigella identification. Forty-six reference Shigella strains (one for each serotype and species), 50 clinical strains (21 S. flexneri, 21 S. sonnei, 4 S. dysenteriae, 4 S. boydii) representing the most prevalent species and serotypes encountered in Quebec, and 9 non-Shigella strains were tested according to the manufacturers' instructions. A 3+ reaction (> or = 75% agglutination) was considered positive for the slide agglutination tests. Sensitivity varied from 47% (Roach) to 94% (Difco). For the 105 strains tested, accuracy ranged from 53% (Roach) to 91% (Wellcolex). Specificity varied from 97 to 100% for group A antisera, from 96 to 100% for group B antisera, from 88 to 100% for group C antisera, and from 95 to 99% for group D antisera. The costs of reagents required to test one strain varied from $3.50 to $13.20 (in Canadian dollars). In conclusion, Roach reagents proved to be unsatisfactory for Shigella serogrouping. Among those from the remaining companies, the Denka, Difco, and Wellcolex reagents met a performance standard of 90% accuracy.
Lefebvre
J
J
Bacterial Identification Section, Laboratoire de Santé Publique du Québec, Ste-Anne-de-Bellevue, Canada.
Gosselin
F
F
Ismaïl
J
J
Lorange
M
M
Lior
H
H
Woodward
D
D
D000372:Agglutination Tests / Q000379:methods / Q000706:statistics & numerical data; D000907:Antibodies, Bacterial; D000918:Antibody Specificity; D004405:Dysentery, Bacillary / Q000175:diagnosis / Q000382:microbiology; D005069:Evaluation Studies as Topic; D006801:Humans; D007202:Indicators and Reagents; D007841:Latex Fixation Tests / Q000379:methods / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012703:Serotyping / Q000379:methods* / Q000706:statistics & numerical data; D012760:Shigella / Q000145:classification* / Q000276:immunology*; D012761:Shigella boydii / Q000145:classification / Q000276:immunology; D012762:Shigella dysenteriae / Q000145:classification / Q000276:immunology; D012763:Shigella flexneri / Q000145:classification / Q000276:immunology; D012764:Shigella sonnei / Q000145:classification / Q000276:immunology; D013045:Species Specificity
D000907:Antibodies, Bacterial; D007202:Indicators and Reagents