1732. Assessment of Modified Immunofluorescent Technique for Detection of Human Leptospirosis in Febrile Patients in Chennai, India
Session: Poster Abstract Session: Novel Diagnostics for Uncommon Bacteria
Saturday, October 10, 2015
Room: Poster Hall
Posters
  • IDWeek 2015_POSTER.pdf (467.7 kB)
  • Background: Several techniques are available for the diagnosis of human leptospirosis. Microscopic Agglutination Test (MAT) is considered as gold standard worldwide. However it is time consuming, requires sophisticated laboratory skills and has to maintain live cultures. This study was carried out to assess the sensitivity, specificity and efficiency of modified Immunofluorescent Test (IFT) and also to compare its results with MAT.

    Methods: Blood samples were collected from febrile patients who were clinically suspected of leptospirosis. IFT, MAT, Macroscopic Slide Agglutination test (MSAT) and Dark field microscopy (DFM) tests were performed. For IFT, four serovars of L.icterohaemorrhagiea, canicola, australis and autumnalis were grown separately and mixed in equal volume and used as an antigen. Aluminium coated micro titer plate sealers were punched to have 10 holes (wells) and fixed onto a clean glass slide. One drop of mixed antigen was dropped into the wells and allowed to dry. Then it was fixed in cold acetone and followed standard IFT procedure, MAT and MSAT. DFM was performed in centrifuged serum samples.

    Results: A total of 319 febrile patients were tested. Their age ranged from 4-86 years with a mean of 32.7 years. About 55% were males. One hundred and twenty eight (40.1%) were found to be leptospira positive by MAT, 120 (37.62%) by IFT, 139 (43.57%) by MSAT and. 111 (34.79%) by DFM, When compared with MAT, the sensitivity and specificity of IFT was 99.22% and 98.45% respectively. Whereas the sensitivity and specificity of MSAT was 90.14% and 92.27% and DFM showed 88.28% and 100% respectively.  The positive predictive value for modified IFT was 97.71 (CI=93.44- 99.50) and negative predictive value was 99.48 (CI=97.12- 99.91).

    Conclusion: Modified Immunofluoresence test with its high sensitivity and specificity can be used for the diagnosis of human leptospirosis. Hence we recommend IFT with DFM as a useful diagnostic test in resource limited settings for early and accurate diagnosis of leptospirosis.

    Table : Measurement of agreement kappa of IFT v/s MAT, DFM, MSAT methods.

    S.No

    Testing  methods

    Measurement of agreement kappa

    1

    IFT v/s MAT

    0.974

    2

    IFT v/s DFM

    0.860

    3

    IFT v/s MSAT

    0.792

    4

    MAT v/s DFM

    0.887

    5

    MAT v/s MSAT

    0.805

    6

    DFM v/s MSAT

    0.701

    Arumugam Ganesan, MSc, MPhil1, Saramma Mini Jacob, MD1, S Baskaran, MD MSc2, K Sivasangeetha, MD1, K Mary Sushi, PhD1 and D Anitha, PhD1, (1)Experimental Medicine, TN Dr.MGR Medical University, Chennai, India, (2)Epidemiology, TN Dr.MGR Medical University, Chennai, India

    Disclosures:

    A. Ganesan, None

    S. Mini Jacob, None

    S. Baskaran, None

    K. Sivasangeetha, None

    K. Mary Sushi, None

    D. Anitha, None

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