Background: Uropathogenic Escherichia coli (UPEC) are frequent pathogens worldwide, impacting on the morbidity and economic costs associated with antimicrobial treatment.
Objectives: We report two novel mutations associated with polymyxin-B resistance in an UPEC isolate collected in 2019.
Methods: Isolate was submitted to antimicrobial susceptibility testing including broth microdilution for polymyxin B. Whole genome was sequenced and analyzed.
Results: Polymyxin-B total inhibition occurred at 16 mg/L (resistant). UPEC isolate was assigned to the phylogroup D, serotype O117:H4, and Sequence Type 69. mcr genes were not detected, but two novel mutations in the pmrA/basS (A80S) and pmrB/basR (D149N) genes were identified.
Conclusions: The occurrence of non-mcr polymyxin resistance in E. coli from extraintestinal infections underscores the need of a continuous surveillance of this evolving pathogen.
Keywords: Antimicrobial resistance; Escherichia coli; Polymyxin B; Uropathogenic Escherichia coli; Whole-genome sequencing.
© 2021 S. Karger AG, Basel.