Simulated positive blood cultures with 84 known stock strains of streptococci were used to comparatively evaluate the direct identification of these organisms by fluorescein-tagged antibody staining (immunofluorescence [IF]) and latex agglutination (LA). IF was not evaluated for Lancefield group D strains (a total of 81 strains tested) and had 89% sensitivity and 91% specificity. IF was least sensitive for the identification of Lancefield group F, in which three of seven strains showed no fluorescence with the group F reagent. Since LA was more convenient and revealed comparable sensitivities and specificities on 84 simulated cultures, we tested this procedure using an additional 29 fresh positive clinical blood cultures, for a total of 113 cultures tested by this technique. Of 11 Streptococcus pneumoniae strains, 9 reacted with the LA group C reagent, a problem not observed with IF. However, all these strains were identified by a rapid modified bile solubility test. Of the 12 Streptococcusfaecalis strains, 4 were falsely negative with the group D reagent, but all were correctly identified by a rapid litmus milk reduction test. Of 12 group A strains, 1 was not detected. Of all 113 strains tested by LA, eliminating S. faecalis and S. pneumoniae, the sensitivity and specificity were 97 and 98%, respectively. LA was simple and reliable in the rapid identification of streptococci from blood cultures and appeared to be preferable to IF. When LA is used, the group D reagent should not be used, and all samples reacting with the group C reagent should be tested by a modified rapid bile solubility test to exclude S. pneumoniae.
Bluetongue (BT) is an infectious, non-contagious disease of domestic and wild ruminants. Bluetongue virus (BTV) causes severe disease in sheep, which is transmitted by insect vector belonging to Culicoides spp. It is particularly a viral disease of sheep, occasionally affecting cattle, buffaloes, goats, camels and other wild ruminants. Out of 377 (364-blood, 5-spleen and 8-pooled Culicoides) samples 110 (29.18%) and 28 (7.42%) were found positive for BTV antigen by s-ELISA and BT-AGID respectively. Species wise incidence by s-ELISA recorded was 48.20 per cent in sheep, 57.14 per cent in goats and 2.60 per cent in cattle however, none of the blood sample found positive from buffalo and camel. Species wise incidence by BT-AGID recorded was 12.23 per cent in sheep and 15.71 per cent in goats however, none of the blood sample found positive for BTV antigen from cattle, buffalo and camel. Higher incidence seen in goats by both the test. s-ELISA proved to be the most sensitive in detecting BTV antigen than BT-AGID. Considering s-ELISA as the reference test, the relative sensitivity, specificity and overall agreement between both the tests were 25.45 per cent, 100 per cent and 78.24 per cent respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.