Determination of the De Novo Minimum Selection Concentration of Trimethoprim In Vivo for <i>Escherichia coli</i> Using <i>Galleria mellonella:</i> A Pilot Study
We investigated whether the maximum residual levels of trimethoprim permitted in food (Acceptable Daily Intake—ADI) could select for de novo trimethoprim resistance in <i>Escherichia coli</i> in vivo. We designed chronic infection models of <i>E. coli</i> in <i>Galleria...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
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| Series: | Microorganisms |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-2607/13/1/3 |
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| Summary: | We investigated whether the maximum residual levels of trimethoprim permitted in food (Acceptable Daily Intake—ADI) could select for de novo trimethoprim resistance in <i>Escherichia coli</i> in vivo. We designed chronic infection models of <i>E. coli</i> in <i>Galleria mellonella</i> and exposed them to sub-ADI doses of trimethoprim through a single-dosing regimen. The emergence of trimethoprim resistance was determined by isolating the target bacteria on selective agar plates, followed by species confirmation using MALDI-TOF mass spectrometry. The minimum inhibitory concentration (MIC) was assessed via the E-test to determine <i>E. coli</i> susceptibility to trimethoprim. Notably, exposure to as low as one-tenth of the ADI dose through a single-dosing regimen resulted in the selection of trimethoprim-resistant <i>E. coli</i>. Our findings indicate that trimethoprim doses ten-fold lower than the established ADI threshold could induce resistance to trimethoprim in <i>E. coli</i>. These results highlight the importance of considering antimicrobial resistance induction as a key factor when determining ADI levels in food. |
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| ISSN: | 2076-2607 |