A simple cut and stretch assay to detect antimicrobial resistance genes on bacterial plasmids by single-molecule fluorescence microscopy
Journal article, 2022

Antimicrobial resistance (AMR) is a fast-growing threat to global health. The genes conferring AMR to bacteria are often located on plasmids, circular extrachromosomal DNA molecules that can be transferred between bacterial strains and species. Therefore, effective methods to characterize bacterial plasmids and detect the presence of resistance genes can assist in managing AMR, for example, during outbreaks in hospitals. However, existing methods for plasmid analysis either provide limited information or are expensive and challenging to implement in low-resource settings. Herein, we present a simple assay based on CRISPR/Cas9 excision and DNA combing to detect antimicrobial resistance genes on bacterial plasmids. Cas9 recognizes the gene of interest and makes a double-stranded DNA cut, causing the circular plasmid to linearize. The change in plasmid configuration from circular to linear, and hence the presence of the AMR gene, is detected by stretching the plasmids on a glass surface and visualizing by fluorescence microscopy. This single-molecule imaging based assay is inexpensive, fast, and in addition to detecting the presence of AMR genes, it provides detailed information on the number and size of plasmids in the sample. We demonstrate the detection of several beta-lactamase-encoding genes on plasmids isolated from clinical samples. Furthermore, we demonstrate that the assay can be performed using standard microbiology and clinical laboratory equipment, making it suitable for low-resource settings.

Author

Gaurav Goyal

Chalmers, Biology and Biological Engineering, Chemical Biology

Elina Ekedahl

My Nyblom

Chalmers, Biology and Biological Engineering, Chemical Biology

Jens Krog

Lund University

Erik Frobrant

Lund University

Magnus Brander

Lund University

Tsegaye Sewunet

Karolinska Institutet

Teerawit Tangkoskul

Mahidol University

Christian G. Giske

Karolinska Institutet

Karolinska University Hospital

Linus Sandegren

Uppsala University

Visanu Thamlikitkul

Mahidol University

Tobias Ambjornsson

Lund University

Fredrik Westerlund

Chalmers, Biology and Biological Engineering, Chemical Biology

Scientific Reports

2045-2322 (ISSN) 20452322 (eISSN)

Vol. 12 1 9301

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Swedish Research Council (VR) (2019-04150), 2020-01-01 -- 2022-12-31.

Subject Categories

Infectious Medicine

Microbiology

Microbiology in the medical area

DOI

10.1038/s41598-022-13315-w

PubMed

35660772

More information

Latest update

6/28/2022