Development of an Assay Involving Loop-Mediated Isothermal Amplification with a Lateral Flow Dipstick for Detection of the vanA Gene in Vancomycin-Resistant Enterococci.

Vancomycin-resistant enterococci (VRE) have emerged as major nosocomial pathogens worldwide, primarily due to the acquisition of the vanA gene, which confers high-level resistance to vancomycin. Rapid detection of the vanA gene, which is associated with vancomycin resistance, is crucial for timely clinical management and infection control. Through this research, we aimed to develop an assay combining loop-mediated isothermal amplification and a lateral flow Dipstick (LAMP-LFD) for the rapid detection of the vanA gene in VRE. Genomic DNA was extracted and amplified from 100 clinical urine samples by LAMP targeting vanA under optimized, constant-temperature conditions, with the amplified product then detected using a lateral flow Dipstick assay based on probe pairing. The diagnostic performance of the LAMP-LFD method was evaluated and compared with a conventional PCR reference method. The LAMP-LFD assay successfully detected the vanA gene in all positive samples, with negative samples showing no assay cross-reactivity with 12 species of bacteria commonly found in clinical settings. The developed LAMP-LFD assay showed promising diagnostic performance for detecting the vanA gene in Enterococcus isolates, demonstrating complete agreement with the reference PCR method in this study. Owing to its rapid turnaround time, simplicity, and visual readout, the assay has potential as a molecular screening tool for VRE. However, further validation in larger, multicenter studies and comparison with phenotypic antimicrobial susceptibility testing are required before routine clinical implementation.