CRISPR/cas9 cassette targeting Escherichia coli^blaCTX-M specific gene of mastitis cow milk origin can alter the antibiotic resistant phenotype for cefotaxime

Abstract

CTX-M beta-lactamases are one of the most important extended spectrum beta-lactamase (ESBL) resistance enzymes found in E. coli. In the present study, 59% of E. coli isolates from mastitis cow milk were reported to be positive for ESBL types. The prevalence of beta-lactam (β-lactam) antibiotic resistance was reported to be 84%, 72.7%, 52.27%, 50%, and 45.4% for cefotaxime, cefepime, cefuroxime, oxacillin, and cephalexine, respectively. The ^blaCTX-M gene was found in 65% (n = 17) of the E. coli isolates when they were genotyped. Further, the use of a CRISPR/cas9 cassette to target the E. coli ^blaCTX-M gene revealed changes in antibiotic phenotypes for cefotaxime.

Keywords:

• CRISPR/cas9
• CTX-M beta-lactamases
• mastitis
• E. coli
• ^blaCTX-M gene

Acknowledgements

The authors are thankful to Director, ICAR-National Dairy Research Institute, Karnal, Haryana, India for providing the necessary facilities to conduct the experiment.

Disclosure statement

We declare that none of the authors have any conflict of interest for the present study.

Additional information

Funding

The authors acknowledge the financial support received from the Indian Council of Agricultural Research, New Delhi, India as ICAR-Post Doctoral Fellowship to RD during this study period. The authors are also thankful to Science and Engineering Research Board, Department of Science and Technology, Government of India for the financial assistant to SD for the ongoing project code [EMR/2017/004602].