Rapid Detection of Multi-Resistance Strains Carrying mcr-1 Gene Using Recombinase-Aided Amplification Directly on Clinical Samples

Abstract

With the increasingly severe problem of bacterial resistance, colistin, as the last line of defense, has attracted attention again. Mobile colistin resistance (mcr-1) gene is involved in the horizontal transmission of colistin resistance in Gram-negative bacteria (GNB), which is a serious threat to human health. Therefore, rapid detection of mcr-1 gene presence in clinical samples is crucial. In this study, a Recombinase-aided amplification(RAA) method for mcr-1 was successfully constructed, with sensitivity of 20 copies/reaction. In addition, amplification signal could only be detected in the strain containing mcr-1 gene among 14 different bacterial species. The method was then used to test a total of 672 clinical samples from a pediatric hospital in Beijing. Five strains harbored mcr-1 genes were isolated from mcr-1-positive clinical samples and identified as Escherichia coli. Multi-locus sequence typing (MLST) analysis showed that the five E. coli belonged to different ST types. Notably, the mcr-1 gene from the isolates could be transferred conjugately to the recipient strain E. coli J53, with highest transfer efficiency up to 57–58%, suggesting that the mcr-1 gene was located on the plasmid. These findings showed that the RAA assay has potential to be a rapid and sensitive mcr-1 gene screening test for clinical samples, and mcr-1 could be transmitted vertically and horizontally between and within bacterial species in a plasmid-mediated manner.

A Review on Colistin Resistance: An Antibiotic of Last Resort

“…Numerous PCR variants have been developed [161] to increase the detection of mcr genes and variants in a single reaction. These include multiplex PCR and real-time PCR, which uses SYBR Green, probes, or Taqman probes [162].…”

Rapid detection of mpox virus using recombinase aided amplification assay

“…Recombinase-aided amplification (RAA), a rapid and efficient isothermal amplification technique, can detect specific target genes within 10-30 min at 39°C (Xue et al, 2020a). This technology has been used in the clinical detection of pathogens such as SARS-CoV-2, noroviruses, hepatitis B virus, and other pathogens (Xue et al, 2020a;Xue et al, 2020b;Qin et al, 2021;Fan et al, 2022).…”