Molecular detection and speciation of pathogenic Leptospiraspp. in blood from patients with culture-negative leptospirosis

BMC Infectious Diseases

Research Article

Vanaporn Wuthiekanun¹  Premjit Amornchai¹  Nicholas P Day²  Wirongrong Chierakul³  Siriphan Boonsilp⁴  Sharon J Peacock⁵  Direk Limmathurotsakul⁶  Janjira Thaipadungpanit⁷ 

[1] Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand;Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand;Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Churchill Hospital, Oxford, UK;Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand;Department of Clinical Tropical Medicine,Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand;Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand;Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK;Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand;Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand;Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Bangkok, Thailand;

关键词: Polymorphic Site;    Leptospirosis;    Sequence Trace;    Microscopic Agglutination Test;    Acute Febrile Illness;   

DOI  :  10.1186/1471-2334-11-338

 received in 2011-08-03, accepted in 2011-12-13,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundPathogenic 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.MethodsWe 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.Results39/418 (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).ConclusionMolecular 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.

【 授权许可】

Unknown   
© Boonsilp et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.