Analytical evaluation of an immunomagnetic separation PCR assay to detect pathogenic Leptospira in cattle urine samples obtained under field conditions. (January 2021)

• Record Type: Journal Article
• Authors: Tomckowiack, Camilo; Henriquez, Claudio; Ramirez-Reveco, Alfredo; Muñoz, Priscila; Collado, Bernardita; Herzberg, Daniel; Folch, Hugo; Salgado, Miguel
• Is Part Of: Journal of veterinary diagnostic investigation. Volume 33:Number 1(2021)
• Page Start: 52
• Page End: 58
• Publication Date: 2021-01
• Subjects: immunomagnetic separation qPCR -- Leptospira -- leptospirosis -- LipL32; Veterinary medicine -- Diagnosis -- Periodicals; 636.0896075
• DOI: 10.1177/1040638720966299
• Languages: English
• ISSNs: 1040-6387

Abstract

Clinical manifestations of leptospirosis are diverse and very similar to other febrile diseases, hence early and accurate detection of subclinical infections is a key element in disease control. We evaluated immunomagnetic separation (IMS) capture technology coupled with a standard quantitative PCR (qPCR) system for the detection of pathogenic Leptospira in urine samples from 803 cows from dairy herds with a history of clinical cases of leptospirosis. The urine samples were first processed in a purification step, then subdivided into 2 subsamples, one that continued to DNA extraction and direct qPCR, and one that was pretreated by IMS before continuing to DNA extraction and qPCR. Overall, 133 of 803 (16.6%) samples were IMS-qPCR positive, whereas only 92 of 803 (11.5%) were positive when using direct qPCR. Statistically significant differences were observed between the mean estimated Leptospira load between the IMS-qPCR and the direct qPCR positive urine samples. The IMS-qPCR technology revealed a larger number of positive results and higher bacterial loads than direct qPCR. This difference is most likely the result of the high antigen-binding capacity and capture efficiency of the IMS system. The use of polyclonal antibodies produced by the inoculation of 3 synthetic peptides, which make up the extracellular regions of the LipL32 protein, provided a high detection capacity to the IMS-qPCR technique, resulting in performance superior to direct qPCR.