title: Accuracy of loop-mediated isothermal amplification for diagnosis of human leptospirosis in Thailand.
abstract: There is a lack of diagnostic tests for leptospirosis in technology-restricted settings. We developed loop-mediated isothermal amplification (LAMP) specific for the 16S ribosomal RNA gene (rrs) of pathogenic and intermediate group Leptospira species. The lower limit of detection was 10 genomic equivalents/reaction, and analytical specificity was high; we observed positive reactions for pathogenic/intermediate groups and negative reactions for non-pathogenic Leptospira species and other bacterial species. We evaluated this assay in Thailand by using a case-control study of 133 patients with laboratory-proven leptospirosis and 133 patients with other febrile illnesses. Using admission blood, we found that the rrs LAMP showed positive results in 58 of 133 cases (diagnostic sensitivity = 43.6, 95% confidence interval [CI] = 35.0-52.5) and in 22 of 133 controls (diagnostic specificity = 83.5, 95% CI = 76.0-89.3). Sensitivity was high for 39 patients who were culture positive for Leptospira spp. (84.6, 95% CI = 69.5-94.1). The rrs LAMP can provide an admission diagnosis in approximately half of patients with leptospirosis, but its clinical utility is reduced by a lower specificity.
authors: Department of Clinical Tropical Medicine, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, 420/6 Rajvithi Road, Mahidol University, Bangkok, Thailand. piengchan@tropmedres.ac
authors: Piengchan
authors: P
authors: Sonthayanon
authors: Wirongrong
authors: W
authors: Chierakul
authors: Vanaporn
authors: V
authors: Wuthiekanun
authors: Janjira
authors: J
authors: Thaipadungpanit
authors: Thareerat
authors: T
authors: Kalambaheti
authors: Siriphan
authors: S
authors: Boonsilp
authors: Premjit
authors: P
authors: Amornchai
authors: Lee D
authors: LD
authors: Smythe
authors: Direk
authors: D
authors: Limmathurotsakul
authors: Nicholas P
authors: NP
authors: Day
authors: Sharon J
authors: SJ
authors: Peacock
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001483:Base Sequence; D006801:Humans; D007919:Leptospira / Q000235:genetics*; D007922:Leptospirosis / Q000175:diagnosis* / Q000453:epidemiology* / Q000382:microbiology; D008875:Middle Aged; D008969:Molecular Sequence Data; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012680:Sensitivity and Specificity; D013785:Thailand / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S