A shared mechanism of multidrug resistance in laboratory-evolved uropathogenic Escherichia coli

ABSTRACT

The emergence of multidrug-resistant bacteria poses a significant threat to human health, necessitating a comprehensive understanding of their underlying mechanisms. Uropathogenic Escherichia coli (UPEC), the primary causative agent of urinary tract infections, is frequently associated with multidrug resistance and recurrent infections. To elucidate the mechanism of resistance of UPEC to beta-lactam antibiotics, we generated ampicillin-resistant UPEC strains through continuous exposure to low and high levels of ampicillin in the laboratory, referred to as Low Amp^R and High Amp^R, respectively. Whole-genome sequencing revealed that both Low and High Amp^R strains contained mutations in the marR, acrR, and envZ genes. The High Amp^R strain exhibited a single additional mutation in the nlpD gene. Using protein modeling and qRT-PCR analyses, we validated the contributions of each mutation in the identified genes to antibiotic resistance in the Amp^R strains, including a decrease in membrane permeability, increased expression of multidrug efflux pump, and inhibition of cell lysis. Furthermore, the Amp^R strain does not decrease the bacterial burden in the mouse bladder even after continuous antibiotic treatment in vivo, implicating the increasing difficulty in treating host infections caused by the Amp^R strain. Interestingly, ampicillin-induced mutations also result in multidrug resistance in UPEC, suggesting a common mechanism by which bacteria acquire cross-resistance to other classes of antibiotics.

KEYWORDS:

• Antibiotic resistance
• uropathogenic Escherichia coli
• efflux pump
• adhesion
• type 1 fimbriae

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

E.-J.L. designed the research, analyzed the data, and wrote the manuscript; N.C. and E.C. performed the experiments and wrote the manuscript; Y.-J.C. analyzed the whole-genome sequencing; H.W.C wrote the manuscript; M.J.K. performed the in vivo experiment.

Data availability statement

The data that support the findings of this study are available in the NCBI SRA database at https://www.ncbi.nlm.nih.gov/sra (reference number PRJNA987582).

Supplemental data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/21505594.2024.2367648

Additional information

Funding

This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT, and Future Planning [NRF-2022R1A2B5B02002256, NRF-2022R1A4A1025913, and NRF-2020M3A9H5104235 to E.-J.L., NRF-2021R1I1A1A01043879 to E.C., and RS-2023-00260267 to Y.-J.C.], the Korea National Institute of Health [2024ER210600 to Y.-J.C.], and a grant from Korea University [K2404611 to E.-J.L.].