Publication: Molecular detection and speciation of pathogenic Leptospira spp. in blood from patients with culture-negative leptospirosis
Issued Date
2011-12-13
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ISSN
14712334
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2-s2.0-83255164933
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Mahidol University
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SCOPUS
Bibliographic Citation
BMC Infectious Diseases. Vol.11, (2011)
Suggested Citation
Siriphan Boonsilp, Janjira Thaipadungpanit, Premjit Amornchai, Vanaporn Wuthiekanun, Wirongrong Chierakul, Direk Limmathurotsakul, Nicholas P. Day, Sharon J. Peacock Molecular detection and speciation of pathogenic Leptospira spp. in blood from patients with culture-negative leptospirosis. BMC Infectious Diseases. Vol.11, (2011). doi:10.1186/1471-2334-11-338 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/12153
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Title
Molecular detection and speciation of pathogenic Leptospira spp. in blood from patients with culture-negative leptospirosis
Abstract
Background: Pathogenic Leptospira spp. present in the blood of patients with leptospirosis during the first week of symptoms can be detected using culture or PCR. A proportion of patients who are positive by PCR are negative by culture. Leptospira spp. are fastidious bacteria, and we hypothesized that a false-negative culture result may represent infection with a distinct bacterial subset that fail to grow in standard culture medium.Methods: We evaluated our hypothesis during a prospective study of 418 consecutive patients presenting to a hospital in northeast Thailand with an acute febrile illness. Admission blood samples were taken for Leptospira culture and PCR. A single tube nested PCR that amplified a region of the rrs gene was developed and applied, amplicons sequenced and a phylogenetic tree reconstructed.Results: 39/418 (9%) patients were culture-positive for Leptospira spp., and 81/418 (19%) patients were culture-negative but rrs PCR-positive. The species associated with culture-positive leptospirosis (37 L. interrogans and 2 L. borgpetersenii) were comparable to those associated with culture-negative, PCR-positive leptospirosis (76 L. interrogans, 4 L. borgpetersenii, 1 unidentified, possibly new species).Conclusion: Molecular speciation failed to identify a unique bacterial subset in patients with culture-negative, PCR-positive leptospirosis. The rate of false-negative culture was high, and we speculate that antibiotic pre-treatment is the most likely explanation for this. © 2011 Boonsilp et al; licensee BioMed Central Ltd.