Background: Bacterial resistance to antibiotics has become a major public health concern. This study aimed to determine the resistance mechanisms to carbapenem in clinical isolates of Pseudomonas aeruginosa. Methods: A total of 62 clinical isolates of carbapenem-resistant P. aeruginosa (CRPA) were collected from 2015 to 2017. Imipenem (IPM)–EDTA disk synergy test was used to screen strains that produced metallo-β-lactamase. In addition, the genes for outer membrane protein OprD2, metallo-β-lactamase and mexR gene were amplified and sequenced. Expression of mexA was detected by real-time PCR. Results: Disk synergy test showed that 51.6% (32/62) of the strains were positive for metallo-β-lactamase. PCR showed that 84.4% of the strains were SIM-positive (27/32), 15.6% of the strains were IMP-positive (5/32), and 12.5% of the strains were VIM-positive (4/32). SPM-positive and GIM-positive strains were not detected. In addition, 5 of the 62 strains had small deletions and/or point mutations in OprD2. Three strains had a high expression of mexA, while eight strains were positive for the regulatory gene mexR with no mutations detected by DNA sequencing. Conclusion: Expression of metallo-β-lactamase is the main resistance mechanism of P. aeruginosa to carbapenem. Mutations in OprD2 and/or the overexpression of efflux pump MexAB-OprM may contribute to P. aeruginosa resistance to carbapenem.
CITATION STYLE
Xu, Y., Niu, H., Hu, T., Zhang, L., Su, S., He, H., … Zhang, D. (2020). High expression of metallo-β-lactamase contributed to the resistance to carbapenem in clinical isolates of pseudomonas aeruginosa from baotou, China. Infection and Drug Resistance, 13, 35–43. https://doi.org/10.2147/IDR.S233987
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