Simple detection and differentiation of Aeromonas caviae infection and contamination with specific monoclonal antibodies by dot blotting

Abstract

Aeromonas spp. are well-known pathogenic bacteria that cause severe infectious diseases in humans and animals through ingestion or contact with contaminated food and water; thus, detecting contamination in suspected samples is essential. This study developed a new detection tool by creating three strong monoclonal antibody (mAb) clones—AC-19, AC-4, and AC-16—by injecting mice with Aeromonas caviae antigens. The dot blot test using antigens from different gram-negative bacteria showed that AC-19 could detect all 88 samples of five Aeromonas species (A. caviae, Aeromonas hydrophila, Aeromonas sobria, Aeromonas veronii, and Aeromonas jandaei), but it also reacted with Plesiomonas shigelloides. Importantly, AC-4 and AC-16 each demonstrated 100% specificity to A. caviae and exhibited 100% sensitivity (31/31 isolates) and 64.52% sensitivity (20/31 isolates), respectively. These results suggest that AC-4 is the most promising mAb for A. caviae detection. Testing the limit of detection by dot blotting against A. caviae antigen exhibited the following. AC-19 at 3 × 10⁷ CFU/ml, AC-4 at 1 × 10⁷ CFU/ml, and AC-16 at 5 × 10⁶ CFU/ml. Furthermore, their application was demonstrated by spiking tests for A. caviae contamination in contact lens samples, which proved their advantages in practical utilization. Thus, with high sensitivity and specificity, these mAbs constitute convenient immunological tools that could be used for simple, rapid, and simultaneous direct detection and differentiation of A. caviae and Aeromonas spp. in complex subjects, such as food and clinical samples, as well as infected animals, without the need for sophisticated bacterial separation, isolation, and biochemical characterization procedures.