Utility of a modified silver staining technique for detection of Leptospira (2024)

FAQs

What is the silver stain for Leptospira? ›

Background: Leptospira are spiral thin and highly motile pathogenic bacteria that are best visualized by dark ground microscopy. Although these bacteria are not stained by the Gram's stain, the Fontana stain, which is a silver impregnation staining method, can be used successfully for light microscopy.

Leptospires are not stained by conventional Gram staining. Available staining methods to increase the sensitivity of direct examination are: immunofluorescence, immunoperoxidase, silver staining, Warthin-Starry staining, immunohistochemistry, and in situ hybridization.

Most cases of leptospirosis are diagnosed by serology. Antibodies can become detectable by the 6th to 10th day of disease and reach peak levels within three to four weeks. Antibody levels may then gradually decline but remain detectable for years.

The microscopic agglutination test (MAT) remains the reference serological method for diagnosis of leptospirosis with isolation providing the gold standard for definitive evidence of infection.

Abstract. Silver staining is an excellent technique for detecting proteins which are separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis due to its efficiency of detecting proteins present in nanograms.

Silver staining is a special yet powerful staining technique that is used for the detection and identification of proteins in gels. This is because silver binds to the chemical terminal or side chains of amino groups i.e carboxyl and sulfhydryl groups.

Leptospirosis typically presents as a nonspecific, acute febrile illness characterized by fever, myalgia, and headache and may be confused with other entities such as influenza and dengue fever. Newer diagnostic methods facilitate early diagnosis and antibiotic treatment.

Staining takes 25 minutes. The leptospirae are coloured violet. C. Fontana's silver solution: To a solution of 1 % silver nitrate in distilled water add, drop by drop, a 10% solution of ammonia until the precipitate which forms in the first placedisappears and the solution becomes clear.

Dark Field Microscopy is one of the diagnostic methods used to detect the presence of Leptospira bacteria in the blood or urine of a patient. This technique allows for the visualization of the bacteria, which are often too small to be seen clearly using conventional light microscopy.

The most common early indicators of Leptospira infection are: loss of appetite, increase or decrease in urine production, uncharacteristic inactivity, vomiting, and diarrhea. Even with prompt, exhaustive medical care, 10 to 15 percent of infected dogs may die.

Is leptospirosis hard to diagnose? ›

Leptospirosis can be acquired through contact with water contaminated by infected animal urine. Laboratory diagnosis of leptospirosis is difficult and usually retrospective.

Traditional serological methods, such as the ELISA, are widely used to diagnose leptospirosis. Antileptospires IgM may be detected 4 to 5 days after the onset of symptoms, before detection of IgG and agglutinating antibodies, and persist at least 5 months in patients ⁶.

Screening tests for leptospirosis, which are easy to perform and provide results relatively rapidly, include the macroscopic slide agglutination test, the Patoc-slide agglutination test, the microcapsule agglutination test, latex agglutination tests, dipstick tests, and the indirect hemagglutination test.

Application of the dipstick assay for the detection of acute leptospirosis enabled the accurate identification, early in the disease, of a high proportion of the cases of leptospirosis. Analysis of a second serum sample is recommended, in order to determine seroconversion or increased staining intensity.

This occurs early in the course of the illness. Occasionally patients develop a transient petechial rash (small red, purple, or brown spots) that can involve the palate. If present, the rash often lasts less than 24 hours. Later in severe disease, jaundice and extensive purpura can develop.

Leptospira is a flexible, spiral-shaped, Gram-negative spirochete with internal flagella.

Leptospirosis typically presents as a nonspecific, acute febrile illness characterized by fever, myalgia, and headache and may be confused with other entities such as influenza and dengue fever. Newer diagnostic methods facilitate early diagnosis and antibiotic treatment.

Silver stains are still the major light microscopic procedure for direct demonstration of neuronal degeneration. They are based on the fact that degenerating neurons become argyrophilic.

Syphilis (Treponema pallidum)

Silver impregnation is the traditional method for detection of T. pallidum in formalin-fixed tissues. The Dieterle technique is believed to be more sensitive than the Warthin-Starry stain.