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Detection of Leptospira in urine using anti-Leptospira-coated gold nanoparticles
Chintana Chirathaworn1, Tanompong Chantaramalai, Amornpun Sereemaspun
1Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. cchinta1@chula.ac.th
Abstract:
Serological assays for antibody detection have been widely used for Leptospirosis diagnosis. However, antibody is usually undetectable during the first week after infection. Detection of Leptospira DNA can be done by PCR but this technique requires special equipments and the cost is still relatively high. Here we demonstrate that gold nanoparticles can be used to facilitate Leptospira detection. Gold nanoparticles were coated with rabbit antibody specific to Leptospira interrogans serovar Bratislava and these coated particles were used to detect Leptospira in urine. Agglutination of gold particles indicated the presence of Leptospira in samples tested. The sensitivity of detection was 10 leptospires/ml. No agglutination was observed when anti-Leptospira-coated particles were tested with urine containing the organisms commonly found in urine such as Klebsiella pneumoniae, Escherichia coli and Enterococcus faecalis. This assay is very easy to perform and results could be observed with the naked eyes. Fresh or frozen urine samples could be used. The stability of antibody-coated particles was at least 2 months when kept at 4°C. In conclusion, we have demonstrated that the technique using antibody-coated gold nanoparticles is a promising tool for further validation as a rapid assay for Leptospirosis diagnosis.
Insights
This study introduces a rapid, cost-effective method for diagnosing Leptospirosis using antibody-coated gold nanoparticles. The assay detects Leptospira bacteria in urine with high sensitivity, offering a promising alternative to traditional diagnostic techniques.
Area of Science:
- Nanotechnology
- Infectious Disease Diagnostics
- Microbiology
Background:
- Current Leptospirosis diagnosis relies on serological assays detecting antibodies, which are often undetectable early in infection.
- Polymerase Chain Reaction (PCR) for Leptospira DNA detection is accurate but requires specialized equipment and is costly.
- There is a need for rapid, accessible diagnostic tools for Leptospirosis.
Purpose of the Study:
- To develop and evaluate a novel diagnostic assay for Leptospira using antibody-coated gold nanoparticles.
- To assess the sensitivity, specificity, and practicality of the gold nanoparticle-based assay for Leptospirosis detection in urine.
Main Methods:
- Gold nanoparticles were functionalized with antibodies specific to Leptospira interrogans serovar Bratislava.
- The antibody-coated gold nanoparticles were used to detect Leptospira in urine samples via an agglutination assay.
- The assay's sensitivity was determined, and specificity was tested against common urinary tract organisms.
Main Results:
- The gold nanoparticle assay detected Leptospira with a sensitivity of 10 leptospires/ml.
- No cross-reactivity was observed with common urinary tract bacteria like Klebsiella pneumoniae, Escherichia coli, and Enterococcus faecalis.
- The assay is easy to perform, results are visible to the naked eye, and antibody-coated particles are stable for at least two months at 4°C.
Conclusions:
- Antibody-coated gold nanoparticles offer a promising, rapid, and sensitive method for Leptospirosis diagnosis.
- This technique presents a viable alternative to conventional diagnostic methods, particularly for early-stage infections.
- Further validation is recommended for clinical application of this nanotechnology-based diagnostic tool.
