Evaluation of the Biken test to detect heat-labile (LT) enterotoxin produced by porcine and human Escherichia coli strains.
Fifty-seven strains of enterotoxigenic Escherichia coli isolated from humans and pigs and producing thermolabile (LT) enterotoxin were used to ascertain the efficiency of the Biken test compared to the passive immune haemolysis test (PIH), considered as very sensitive for detecting that enterotoxin. The two assays were carried out using anti-porcine (anti-LTp), anti-human (anti-LTh), anti-cholera toxin (anti-CT) and anti-choleragenoid (anti-Cg) antisera. Our results showed that the Biken test was very irregular, with many false-negative results. Positive results (ranging from 78.9 to 22.8) were dependent upon the antiserum used. Conversely, the PIH test was much more efficient in the detection of LT, since 100% of the LT+ strains were positive in this test whatever the antiserum used.
Said
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AC
Department of Microbiology and Immunology, University of Campinas, São Paulo, Brazil.
Serafim
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MB
Pestana de Castro
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AF
D000818:Animals; D001427:Bacterial Toxins / Q000032:analysis* / Q000276:immunology; D002772:Cholera Toxin / Q000276:immunology; D004768:Enterotoxins / Q000032:analysis* / Q000276:immunology; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D005188:False Negative Reactions; D006461:Hemolysis; D006801:Humans; D007106:Immune Sera; D007159:Immunologic Tests; D011233:Precipitin Tests; D013552:Swine
D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D007106:Immune Sera; D002772:Cholera Toxin; C027538:heat-labile enterotoxin, E coli