[Comparative evaluation of latex reagents of Wellcolex Color Salmonella and Latex Salmonella used for detection and identification of Salmonella rods].
The aim of this study is to compare the sensitivity and specificity of the Wellcolex Colour Salmonella (WCS) set produced by Murex with the Latex Salmonella (LS) set developed by the Polish company Biomex and commonly used in sanitary and epidemiological stations. An attempt is also made to determine the possible usefulness of the WCS test in routine diagnostic of salmonellosis and of S. typhi carrier. The sensitivity and specificity of latex reagents of both sets were determined basing on reactions with the suspensions of 17 selected Salmonella strains representing the A-E and G serological groups and with Salmonella O antigen preparations obtained using the Boivin method. Both reagents from the WCS set were found to detect Salmonella bacteria in a suspension having a minimal density of 7.5-60 x 10(7) cfu/ml while both the polyvalent reagent B-E and monovalent reagents from the LS set still reacted with suspensions of 0.47-15 x 10(7) cfu/ml density. Comparison of the sensitivity of both tests basing on reactions with Salmonella O antigen specimens from the B to E groups revealed that the latex reagents from the two sets detected antigens from the C2 and C3 groups and the E group in concentrations of 1 microgram/ml and 0.5 microgram/ml respectively. In the case of antigen specimens from group B, group C and group D, the LS test detecting these antigens in concentrations of 0.25-1 microgram/ml turned out to be four to eight times more sensitive in reaction with a polyvalent agent and two to eight times more sensitive in reaction with monovalent reagents than the WCS set. The evaluated latex reagents from the WCS set and LS set reacted specifically with both cell suspensions and Salmonella antigen preparations. Also, the applicability of the two latex sets to detect and identify Salmonella antigens in liquid and mixed bacterial cultures of these germs in selenite broth was compared. A positive result of the WCS test was obtained in 41% of Salmonella culture samples whereas Salmonella antigens were found in all the studied culture samples when the polyvalent reagent B-E from the LS set was used and in 97.5% of the samples when monovalent reagents were used. The study showed that in spite of the comparable specificity of the WCS test with respect to the LS set produced in Poland, the latex reagents from the WCS set turned out to be of little use in detecting and identifying Salmonella antigens in mixed bacterial cultures in selenite broth.
Szych
J
J
Zakład Bakteriologii PZH w Warszawie.
Jagielski
M
M
Cieślik
A
A
D000942:Antigens, Bacterial / Q000032:analysis; D005069:Evaluation Studies as Topic; D006801:Humans; D007841:Latex Fixation Tests; D012475:Salmonella / Q000145:classification / Q000302:isolation & purification*; D012480:Salmonella Infections / Q000175:diagnosis*; D012680:Sensitivity and Specificity
D000942:Antigens, Bacterial