Comparison of Two Enzyme Immunoassays and Four Lysate Antigens for the Detection of Antibody in Canine Blastomycosis

Matthew Day,Arin Esterbrook,Bryn Kennell,Abdullah Saleh Albqomi,Russ Manteca,Geoffrey M Scalarone,Heaton Oakes,Gene M Scalarone,Ignatius Bisharat

doi:10.4236/ojvm.2021.114009

Abstract

Blastomycosis, the systemic fungal disease of humans and animals caused by Blastomyces dermatitidis and the cryptic species Blastomyces gilchristii, is often misdiagnosed as a bacterial or viral pulmonary disease. Therefore, the development of improved immunodiagnostic assays for this disease has been the primary focus of research in our laboratory. The present study was designed to evaluate four Blastomyces yeast-phase lysate antigenic preparations (human, 597, Eagle River, WI; dog, ERC-2, WI; Human, B5927, Mountain Iron, MN; soil, 85, Georgia, ATCC 56920) for their ability to detect antibody in 48 serum specimens from dogs with diagnosed blastomycosis using an indirect ELISA (STD) compared to a biotin-streptavidin ELISA (B-SA). All four lysate antigens were able to detect antibodies in the specimens with mean absorbance values ranging from 0.930 (B5927) to 1.142 (ERC-2) with the STD ELSA and from 1.395 (B5927) to 1.775 (85) with the B-SA ELISA. The results indicated that both ELISA methods could be utilized for antibody detection, but the B-SA ELISA exhibited greater sensitivity than the STD ELISA with all four of the lysates.

Highlights

Blastomyces dermatitidis and a recently described cryptic species, Blastomyces gilchristii, are thermally dimorphic fungal organisms and the causative agents of blastomycosis in humans and animals
The results indicated that both ELISA methods could be utilized for antibody detection, but the biotin-streptavidin ELISA (B-SA) ELISA exhibited greater sensitivity than the STD ELISA with all four of the lysates
The plates were again washed as above and 100 ul of peroxidase labeled streptavidin (1:400, KPL) was added to each well, incubated at 37 ̊C for 30 min, plates washed, substrate added (KPL), incubated for approximately 3 minutes, stop solution added and absorbance read. Both ELISA methods were very efficient with regard to the detection of antibodies in the dog serum specimens, but the BS-A method produced mean absorbance values considerably greater than the STD assay in all instances

Summary

Introduction

Blastomyces dermatitidis and a recently described cryptic species, Blastomyces gilchristii, are thermally dimorphic fungal organisms and the causative agents of blastomycosis in humans and animals. Blastomycosis is difficult to diagnose in a clinical environment and is often misdiagnosed as a bacterial or viral disease. It may be fatal if proper diagnosis and treatment are not initiated especially in immunocompromised individuals. Culturing and histologic techniques are effective, but in some instances may not provide a suitable diagnosis and may delay treatment. The fungus is often difficult to culture. A more immediate diagnosis (before dissemination) can lead to better patient outcomes due to more timely administration of treatment

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