An efficient and versatile CRISPR-Cas9 system for genetic manipulation of multi-drug resistant Klebsiella pneumoniae

Multi-drug resistant (MDR) Klebsiella pneumoniae remains an urgent public health threat. While whole-genome sequencing has helped identify genetic changes underlying resistance, functional validation remains difficult due to a lack of genetic manipulation systems for MDR K. pneumoniae. CRISPR-Cas9 has revolutionized molecular biology, but its use was only recently adapted in bacteria by overcoming the lack of genetic repair systems. We describe a CRISPR-Cas9/lambda recombineering system utilizing a zeocin resistance cassette allowing efficient and versatile genetic manipulation of K. pneumoniae. For complete details on the use and execution of this protocol, please refer to McConville et al. (2020). [Display omitted] •Gene editing for multi-drug resistant Klebsiella pneumoniae utilizing CRISPR-Cas9•Description of plasmid design, cloning, genetic manipulation, and mutant confirmation•Approach allows for gene knockouts and single nucleotide polymorphism editing•“Scarless” editing allows for serial modifications in a single bacterial isolate Multi-drug resistant (MDR) Klebsiella pneumoniae remains an urgent public health threat. While whole-genome sequencing has helped identify genetic changes underlying resistance, functional validation remains difficult due to a lack of genetic manipulation systems for MDR K. pneumoniae. CRISPR-Cas9 has revolutionized molecular biology, but its use was only recently adapted in bacteria by overcoming the lack of genetic repair systems. We describe a CRISPR-Cas9/lambda recombineering system utilizing a zeocin resistance cassette allowing efficient and versatile genetic manipulation of K. pneumoniae.