Establishment and application of recombinase polymerase amplification combined with a lateral flow dipstick for the detection of mcr-1 in uncultured clinical samples

Abstract

Objectives: The rapid dissemination of the mcr-1 gene via plasmid-mediated transfer has raised concerns regarding the efficacy of colistin as a last-resort treatment for multidrug-resistant Gram-negative bacterial infections. Current mcr-1 gene detection methods mainly focus on cultured bacteria, which is a complex and time-consuming process requiring skilled personnel, making it unsuitable for field analysis.

Methods: A rapid detection technique combining recombinase polymerase amplification with a lateral flow dipstick targeting uncultured clinical samples was developed.

Results: This new method targeting the mcr-1 gene region (23 232-23 642 bp, no. KP347127.1) achieved a low detection limit of 10 copies/μL. The whole process was carried out with high specificity and was completed within 20 min. The evaluation assay was conducted using 45 human faecal samples; 16 strains yielded a 98% accuracy, closely matching antimicrobial susceptibility outcomes.

Conclusions: The novel method integrates nucleic acid extraction, isothermal amplification, and a test assay, suggesting the potential for timely colistin resistance surveillance in frontline disease control and healthcare settings, supporting future prevention and clinical standardization efforts.

Keywords: Colistin; Lateral flow dipstick; Recombinase polymerase amplification; Uncultured; mcr-1.