DEVELOPMENT OF A LATERAL FLOW ASSAY FOR DETECTING STAPHYLOCOCCUS AUREUS

Abstract

Staphylococcus aureus is a gram-positive, immobile, and round-shaped bacterium. It is responsible for a variety of human illnesses, such as infective endocarditis, osteomyelitis, septic arthritis, prosthetic device infections, pulmonary infections, skin, and soft tissue infections, etc. Alpha-hemolysin (also called alpha-toxin), a common pore-forming toxin which can penetrate the host cell membrane, leading to osmotic swelling, rupture, lysis, and subsequently cell death, appears to be a potential biomarker for S. aureus detection. Based on a sandwich assay format, this study developed a lateral flow assay (LFA) targeting alpha-hemolysin to detect S. aureus at a laboratory scale. Moreover, silver enhancement technology was applied to improve the detection limit and maximize the assay's effectiveness. The developed LFA test could detect the target antigen within approximately 15 – 20 minutes with no cross-reactivity. The limit of detection (LOD) was increased 10- fold after the silver enhancement technology was utilized, from 105 to 104 CFU/mL of S. aureus suspensions. Compared to other conventional bacteria detection methods, the LFA combining silver enhancement technique seems convenient, straightforward to use, and takes a short time to complete with uncomplicated protocols. Our study results indicated that alpha toxin is a promising target to detect S. aureus by LFA.