Rapid detection ofShigella dysenteriae andShigella flexneri in faeces by an immunomagnetic assay with monoclonal antibodies
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A rapid and sensitive method for the detection ofShigella dysenteriae type 1 andShigella flexneri serotypes in faeces based on capture of the bacteria with immunomagnetic particles is described. The particles were coated with either of two different monoclonal antibodies specific for the O-antigens ofShigella dysenteriae type 1 andShigella flexneri serotypes. Captured bacteria were detected by an enzyme immunoassay with O-antigen specific rabbit antiserum. The whole assay required 2 to 3 hours to perform and the sensitivity limit was 103 cfu/ml as determined by viable cell counting. One hundred and fifty enterobacteria strains, including 100Shigella strains from a strain collection, and 302 fresh faecal samples were used for the study. AllShigella dysenteriae type 1 andShigella flexneri culture-positive faecal samples were positive in the immunomagnetic assay. In addition 18 of 252 culture-negative faecal samples were positive. The immunomagnetic assay was compared with latex agglutination and indirect immunofluorescence using culture as the reference method. The immunomagnetic assay had a sensitivity of 100%, latex agglutination a sensitivity of 72% with 28% false-negative results, and indirect immunofluorescence a sensitivity of 95%. The immunomagnetic assay was superior in sensitivity since it also detectedShigella in faecal samples up to two days after antibiotic therapy had been started, which both latex agglutination and indirect immunofluorescence failed to do. The high sensitivity in detecting live and dead bacteria, and the ease of performance of the immunomagnetic assay render it an attractive method for detection ofShigella.
KeywordsAntibiotic Therapy Faecal Sample Enzyme Immunoassay Reference Method Indirect Immunofluorescence
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- 1.Rahman MM, Greenough WB, Novak NR, Rahman S Shigellosis: a continuing global problem. International Centre for Diarrhoeal Disease Research, Dhacca, Bangladesh, 1983.Google Scholar
- 2.Ronsmans C, Bennish ML, Wierzba T Diagnosis and management of dysentry by community health workers. Lancet 1988, ii: 552–555.Google Scholar
- 4.Sack RB, Tilton RC, Weissfeld AS Laboratory diagnosis of bacterial diarrhea. Cumitech 12. American Society for Microbiology, Washington, DC, 1980, p. 1–16.Google Scholar
- 10.Westphal O, Jann K Bacterial lipopolysaccharide: extraction with phenol water and further applications of the procedure. Methods Carbohydrate Chemistry 1965, 5: 83–91.Google Scholar
- 11.Edwards PR, Ewing WH Identification ofEnterobacteriaceae. Burgess Publishing, Minneapolis, 1972, p. 113–115.Google Scholar
- 12.Carlin NI, Lindberg AA Monoclonal antibodies specific forShigella flexneri lipopolysaccharides: clones binding to type IV, V and VI antigens, group 3,4 antigens, and an epitope common to allShigella flexneri andShigella dysenteriae type-1 strains. Infection and Immunity 1987, 55: 1412–1420.PubMedGoogle Scholar
- 14.Harlow E, Lane D A laboratory manual. Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 1988, p. 298–299, 308.Google Scholar
- 15.Ugelstad J, Berge A, Ellingsen T, Bjorgum J, Schmid R, Stenstad P, Aune O, Nilsen PN, Funderud S, Nustad K Biomedical applications of monodisperse magnetic polymer particles. In: El Affer MS, Fitch RM (ed): Future directions in polymer colloids in biochemical field. NATO, ASI, Series E, Applied Science no. 138. Nijhoff, Dordecht, The Netherlands, 1987, p. 355–370.Google Scholar
- 16.Ugelstad J, Mork PC, Kaggerud KH, Ellingsen T, Berge A Swelling of oligomer-polymer particles. New methods of preparation of emulsions and polymer dispensions. Advances in Colloid Interface Science 1980, 13: 101–140.Google Scholar
- 17.Fundered S, Nustad K, Lea T, Vartdal F, Gaudernack G, Stenstad P, Ugelstad J Fraction of lymphocytes by immunomagnetic beads. In: Klaus GGB (ed): Lymphocytes: a practical approach. IRL Press, Oxford, 1987, p. 55–65.Google Scholar