Comparative analysis of a novel N-butanol-prepared antigen vs thermo-resistant and sonicated antigens for human leptospirosis detection

• Published in: Letters in applied microbiology Vol. 77; no. 1
• Main Authors: Blanco, Roberta Morozetti, Lima, Elaine Dos Santos, de Haro, Gabriela Nogueira, Kamikawa, Camila Mika, Blanco, Rodrigo Morozetti, Vincentini, Adriana Pardini, Romero, Eliete Caló
• Format: Journal Article
• Language: English
• Published: England 02-01-2024
• Subjects: dot-blot; serodiagnosis; leptospirosis; N-butanol; leptospiral antigens
• ISSN: 1472-765X; 1472-765X
• DOI: 10.1093/lambio/ovae004

The diagnosis of human leptospirosis is mainly based on serological assays. Since the extraction by N-butanol has only been studied as an antigen for the diagnosis of cattle leptospirosis, this study aimed to investigate the feasibility of the N-butanol preparation for the diagnosis of human leptospirosis and compare it with sonicated and thermo-resistant antigens in IgM dot-blot test. Paired serum samples from 147 laboratory-confirmed leptospirosis cases were tested. The control group consisted of 148 serum samples from healthy individuals and nonleptospirosis cases. N-butanol antigens from serovar Copenhageni (ButC3) and serovar Patoc (ButP3) showed reactivity with antileptospiral antibodies from patients with confirmed leptospirosis. In the acute phase, sensitivities of IgM dot-blot assay with ButC3 and ButP3 antigens were 47.6% and 51.0%, respectively. In the convalescent phase, sensitivities were 95.9% (ButC3) and 93.2% (ButP3), and no significant differences were observed among the IgM dot-blot tests with other antigens. The specificity of the IgM dot-blot test with ButC3 antigen was good (92.6%), but with ButP3 (83.1%), it was significantly lower than with the other tests. The IgM dot-blot test described in this study is simple to perform and presents reliable visual results. Antigens prepared by N-butanol proved to be valuable diagnostic markers of leptospirosis.