RESUMEN
Sera from 65 patients with upper gastrointestinal tract symptoms and proven Helicobacter pylori infection, and from 42 negative controls were tested with two commercial EIAs (GAP test, BioRad; and ECP test, Biometra) and two non-commercial EIAs, one performed with whole sonicated cells and the other with acid extract of Helicobacter pylori as antigen. The GAP assay showed a sensitivity of 83.1% and a specificity of 47.6%. The ECP assay showed a sensitivity of 87.7% and a specificity of 61.9%. For both non-commercial EIAs these figures were 87.7% and 88.1%, respectively. Independent of the interpretive criteria established by the manufacturers, receiver operating characteristic curves were plotted for better evaluation of the four methods. Both commercial tests showed a lower probability of yielding a correct diagnosis than the non-commercial tests (p less than 0.05). Although commercial EIAs are convenient for the diagnosis of Helicobacter pylori infection, the accuracy of the two commercial tests evaluated in this study was lower compared to that of the two non-commercial EIAs.
Asunto(s)
Anticuerpos Antibacterianos/análisis , Infecciones por Helicobacter/diagnóstico , Helicobacter pylori/inmunología , Adulto , Preescolar , Estudios de Evaluación como Asunto , Humanos , Técnicas para Inmunoenzimas , LactanteRESUMEN
Four hundred thirty-two lactose-negative colonies isolated from human feces on stool differential agar media were flooded with one drop of MUCAP Test reagent (Biolife Italiana S.r.I., Milan, Italy) and observed under a Wood lamp for the development of a blue fluorescence over or around the colony. On the basis of manual and automated conventional tests for the screening of Salmonella spp., the MUCAP Test yielded the following results: 79 true-positives, 314 true-negatives, 35 false-positives, and 4 false-negatives (sensitivity, 95%; specificity, 90%; positive predictive value, 69%; negative predictive value, 99%). The specificity of the test performed on colonies isolated on MacConkey agar (95%) was higher than that performed on colonies isolated on SS agar (88%; P less than 0.03). The MUCAP Test is an easy, rapid, and sensitive method for the screening of colonies suspected of being Salmonella spp., reducing the number of biochemical tests needed.
Asunto(s)
Técnicas Bacteriológicas , Salmonella/aislamiento & purificación , Agar , Errores Diagnósticos , Estudios de Evaluación como Asunto , Heces/microbiología , Fluorescencia , Humanos , Sulfuro de Hidrógeno/metabolismo , Salmonella/metabolismo , Infecciones por Salmonella/diagnósticoRESUMEN
A disk method for detecting hippurate hydrolysis by Campylobacter spp. was evaluated and compared with the conventional tube test used at the Centers for Disease Control (CDC) (G.K. Morris and C.M. Patton, p. 302-308, in E.H. Lennette, A. Balows, W.J. Hausler, Jr., and H.J. Shadomy, ed., Manual of Clinical Microbiology, 4th ed., 1985) and high-performance liquid chromatography (HPLC). A total of 118 Campylobacter strains were tested. Eighty-seven strains (74%) were hippurate positive by the HPLC method, and the remaining 31 (26%) were found to be hippurate negative. By using HPLC as the reference technique, the CDC method showed a sensitivity of 80% and a specificity of 81%; the disk method showed a sensitivity of 93% and a specificity of 94%. The disk method can be performed with a small inoculum of bacteria, did not present problems of interpretation, and showed better results than the CDC method (P = 0.015).