Rapid serodiagnosis of leptospirosis by latex agglutination test and flow-through assay

Abstract

Purpose: Diagnosis of leptospirosis facilitates patient management and initiation of therapy. The microscopic agglutination test (MAT) is the serological test used in reference laboratories because of its high degree of sensitivity and speciÞ city. But the results are not available quickly for patient management. In the present study, in order to develop a simple, rapid immunodiagnostic assay, one of the outer membrane proteins (OMPs), recombinant LipL41 (rLipL41) has been utilised in latex agglutination test (LAT) and ß ow-through assay. Methods: Part of LipL41 gene was expressed in Escherichia coli system and puriÞ ed. The rLipL41 antigen of pathogenic Leptospira interrogans serovar Icterohaemorrhagiae, which is conserved in all pathogenic Leptospira spp. was used as capture antigen in the LAT and ß ow-through test. Both tests are very rapid and could be completed within 5 minutes. The sensitivity and speciÞ city of rLipL41 was assessed and evaluated in LAT and ß ow-through assay in comparison with standard MAT. Results: The sensitivity and speciÞ city of the LAT were 89.70 and 90.45% and ß ow-through assay were 89.09 and 77.70%, respectively. Conclusions: The developed LAT and ß ow-through assays were simple, rapid and economical for the detection of leptospira infection and suitable for large-scale screening of samples in endemic areas without any sophisticated equipment.

Evaluation of Leptospiral Recombinant Antigens MPL17 and MPL21 for Serological Diagnosis of Leptospirosis by Enzyme-Linked Immunosorbent Assays

“…ificity was detected with MPL21 when the same serum samples were tested. The specificities of recombinant LipL41 by the latex agglutination test and a flowthrough assay were reported to be 90.45% and 77.70%, respectively (41). The specificities of the IgG antibody responses to recombinant LigB were 100%, 94%, and 88% with sera from healthy individuals from the United States, from residents of Salvador, Brazil, and from individuals in high-risk slum communities in Salvador, Brazil (9).…”

“…As a result, there is an urgent need for an improved and accurate test for the diagnosis of leptospirosis. The search for conserved antigens that could be produced by recombinant technologies, thus avoiding the problems associated with whole-cell preparations, is under way (9,14,32,34,41,44). Nevertheless, difficulties associated with a low sensitivity of detection during the early stage of the disease, poor protein conservation among Leptospira strains, and cross-reactivity with serum from individuals with unrelated febrile illness have, to date, hampered the identification of the ideal antigen to be used for diagnosis.…”

Leptospirosis in children: A review for family physicians

“…Serological tests for leptospirosis are done if more than 4-5 days have elapsed since the onset of fever as it takes that much time for antibodies to start developing. [3,43] For the specific diagnosis of leptospirosis the following tests are available:Serological tests: Serologic testing is mostly used for diagnosis. [1,3,44] Enzyme-linked immunosorbent assay (ELISA) for detection of IgM antibodies (which is positive from the Þ fth day of illness onwards) and IgM-specific dot-ELISA tests are now recommended in clinical practice; these tests have a sensitivity > 80-90% and are done at many regular pathological and microbiological laboratories.…”

“…[1][2][3][4][5][45][46][47] The slide agglutination method, Dri-Dot assay, LEPTO Dipstick, latex agglutination, complement fixation assay, indirect immunofluorescent test, and indirect hemagglutination test are also available; these tests too have good sensitivity of up to 85%. [2,3,5,43,44,[46][47][48][49] However, the microscopic agglutination test (MAT) (serogroup-speciÞ c assay) using live antigen suspension of leptospiral serovars is the reference method. [1,44,46] This test is available only in a few research institutes and is not helpful for diagnosing leptospirosis during the acute illness; however, it remains important for epidemiological research purposes.…”

Proteinuria in early detection of human leptospirosis

“…3 Due to the strong humoral immune response, several serological assays have been developed for detecting the rise of serum antibodies such as Flowthrough, Ig dipstick immunoflurescence, latex agglutination, microcapsule agglutination test, the direct enzyme linked immune sorbent assay (ELISA) for immunoglobulin IgM antibodies, and dot ELISA for IgM. [4][5][6][7][8][9][10][11] These methods are being questioned, thinking that appropriate immune response might not yet have been elicited by the time of specimen collection. Immunochromatography based methods for detection of Leptospiral lipopolysaccharide antigen in urine have also been developed.…”