Bovine mastitis (BM) is the most common inflammatory disease in the dairy sector worldwide, originated from bacterial invasion onto the mammary gland. Early BM detection is crucial for identifying new pathogenic infections within the dairy herd, which can be alleviated by antimicrobial therapy. N-acetyl-β-D-glucosaminidase (NAGase) is a prominent BM inflammatory biomarker secreted onto the blood circulation upon pathogenesis and then released into milk, capable of separating healthy quarters from subclinical and clinical BM cases. Herein, we report on a sensitive differentiation assay of BM severity based on enhanced fluorescence emission of a conventional NAGase activity assay. The addition of silica-coated zinc oxide nanoparticles induces non-radiative energy transfer to the lysosomal reaction products, thus leading to enhanced fluorescence (above 3-fold). Various milk qualities within the entire inflammatory spectrum were evaluated by the modified fluorescence assay with respect to non-infected milk. The amplified emission values differentiate between two predominant BM causative pathogens (Streptococcus dysgalactiae and Escherichia coli) at various somatic cell counts. In general, the presented concept offers an efficient, simple, cost-effective fluorescence signal augmentation for mastitis identification, thus offering means to diagnose the severity of the associated disease.
Keywords: Bovine mastitis; Fluorescence amplification; NAGase; Pathogens; Zinc oxide nanoparticles.
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