| 2008 |
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| Recombinant ligA for leptospirosis diagnosis and ligA among the Leptospira spp. clinical
isolates. |
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| Srimanote, P., Wongdeethai, N., Jieanampunkul, P., Samonkiert, S., Leepiyasakulchai, C.,
Kalambaheti, T., and Prachayasittikul, V. |
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| Faculty of Allied Health Sciences, Thammasat University, Rangsit Campus, Pathumthani, Thailand
psrimanote01@yahoocomau |
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| Abstract: Rapid diagnosis for differentiation of leptospirosis from other pyrogenic infections
prevailing in the same locality is imperative for proper treatment. During infection, the pathogenic Leptospira spp. express virulence factors which induce
antibody responses in the infected host. In this study, 50 referenced Leptospira spp. belonging to six genomospecies and 10 L. interrogans clinical
isolates were studied for the presence of a gene encoding an in vivo expressed, surface exposed, immunoglobulin-like protein, LigA, by using PCR and
southern hybridization specific to the 5' terminus sequence of the DNA. LigA was also detected in the Leptospira spp. whole cell homogenates by a direct
ELISA using a mouse antiserum to the C-terminal portion of recombinant LigA (cLigA) as a detection reagent. All pathogenic Leptospira spp. except one
of the two strains of L. santorasai were positive for the gene and its phenotype while all of the L. borgpetersenii and L. biflexa strains were negative.
Recombinant cLigA was used as an antigen in ELISAs for detecting IgM and IgG in the sera of leptospirosis patients and in the sera of patients with other
febrile illnesses and healthy subjects. When acute phase sera were tested by the cLigA IgM- and IgG-ELISAs, 92% and 100% of the MAT-positive sera
were positive, respectively. The diagnostic sensitivity was 100% when both IgM- and IgG-ELISAs were performed on the same acute phase sera and the
results were combined. Acute and convalescence sera of patients who were Leptospira culture positive but MAT/IgM-dipstick negative gave 88% and
100% positives by combined cLigA IgM/IgG ELISAs. The diagnostic specificities for the cLigA IgM- and IgG-ELISAs were 98% and 100%, respectively. Our
cLigA based-serology has a high potential for early diagnosis of leptospirosis especially when the culture and MAT results are not yet
available |
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| Published in:J.Microbiol.Methods 72[1], 73-81. 2008. |
