Electrochemical Detection of Serum Antibodies Against Mycobacterium avium Subspecies paratuberculosis.

Kaoru Hatate,J Jayne Wu,Judith R Stabel,Karsten Parker,Shigetoshi Eda,J Hunter Rice,Amy Turner

doi:10.3389/fvets.2021.642833

Abstract

Mycobacterium avium subsp. paratuberculosis (MAP) causes a chronic inflammatory intestinal disease, called Johne's disease (JD) in many ruminants. In the dairy industry, JD is responsible for significant economic losses due to decreased milk production and premature culling of infected animals. Test-and-cull strategy in conjunction with risk management is currently recommended for JD control in dairy herds. However, current diagnostic tests are labor-intensive, time-consuming, and/or too difficult to operate on site. In this study, we developed a new method for the detection of anti-M. paratuberculosis antibodies from sera of M. paratuberculosis-infected animals. M. paratuberculosis antigen-coated magnetic beads were sequentially reacted with bovine serum followed by a horseradish peroxidase (HRP)-labeled secondary antibody. The reaction of HRP with its substrate was then quantitatively measured electrochemically using a redox-active probe, ferrocyanide. After optimization of electrochemical conditions and concentration of the redox-active probe, we showed that the new electrochemical detection method could distinguish samples of M. paratuberculosis-infected cattle from those of uninfected cattle with greater separation between the two groups of samples when compared with a conventional colorimetric testing method. Since electrochemical detection can be conducted with an inexpensive, battery-operated portable device, this new method may form a basis for the development of an on-site diagnostic system for JD.

Highlights

A bacterial pathogen, Mycobacterium avium subsp. paratuberculosis (MAP) infects the intestinal tissue of animals and causes a chronic wasting disease called Johne’s disease (JD)
The solution was reacted with TMB solution, mixed with a ferrocyanide solution, and loaded onto an IDE microelectrode followed by an electrochemical impedance spectroscopy (EIS) measurement
Rapid screening of animals for JD before importing them into a new dairy herd, [2] examining dams for JD status to avoid feeding calves with colostrum/milk contaminated with MAP, and [3] segregating anti-MAP antibody-positive and negative cattle within maternity pens [16]

Summary

Introduction

A bacterial pathogen, Mycobacterium avium subsp. paratuberculosis (MAP) infects the intestinal tissue of animals and causes a chronic wasting disease called Johne’s disease (JD). JD affects domestic animals such as farm deer, sheep, and dairy cattle. The prevalence of JD in cattle in Australia, New Zealand, Europe, and the United States was estimated to range from 10 to 60% [1,2,3,4]. United States Department of Agriculture (USDA) reported that 68.1% of dairy herds in the US are contaminated with MAP, and the most recent report estimated that the actual herd-level prevalence of MAP was higher than 90% [5]. Clinical symptoms of JD include submandibular edema, emaciation, severe diarrhea, and reduction in milk production [6]. Economic loss caused by JD in dairy herds is mostly due to the reduced milk production and premature

Objectives

Methods

Results

Conclusion