Evolutionary trajectories of β-lactam resistance in Enterococcus faecalis strains
ABSTRACT Resistance to ampicillin and imipenem in Enterococcus faecalis is infrequent. However, the evolution of resistance can occur through prolonged antibiotic exposure during the treatment of chronic infections. In this study, we conducted a long-term evolution experiment using four genetically...
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American Society for Microbiology
2024-12-01
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| Series: | mBio |
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| Online Access: | https://journals.asm.org/doi/10.1128/mbio.02897-24 |
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| author | Paul Ugalde Silva Charlene Desbonnet Louis B. Rice Mónica García-Solache |
| author_facet | Paul Ugalde Silva Charlene Desbonnet Louis B. Rice Mónica García-Solache |
| author_sort | Paul Ugalde Silva |
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| description | ABSTRACT Resistance to ampicillin and imipenem in Enterococcus faecalis is infrequent. However, the evolution of resistance can occur through prolonged antibiotic exposure during the treatment of chronic infections. In this study, we conducted a long-term evolution experiment using four genetically diverse strains of E. faecalis with varying susceptibilities to ampicillin and imipenem. Each strain was subjected to increasing concentrations of either ampicillin or imipenem over 200 days, with three independent replicates for each strain. Selective pressure from imipenem led to the rapid selection of highly resistant lineages across all genetic backgrounds, compared to ampicillin. In addition to high resistance, we describe, for the first time, the evolution of a β-lactam-dependent phenotype observed in lineages from all backgrounds. Whole-genome sequencing and bioinformatic analysis revealed mutations in three main functional classes: genes involved in cell wall synthesis and degradation, genes in the walK/R two-component system, and genes in the c-di-AMP pathway. Our analysis identified new mutations in genes known to be involved in resistance as well as novel genes potentially associated with resistance. Furthermore, the newly described β-lactam-dependent phenotype was correlated with the inactivation of c-di-AMP degradation, resulting in high levels of this second messenger. Together, these data highlight the diverse genetic mechanisms underlying resistance to ampicillin and imipenem in E. faecalis. The emergence of high resistance levels and β-lactam dependency underscores the importance of understanding evolutionary dynamics in the development of antibiotic resistance.IMPORTANCEEnterococcus faecalis is a major human pathogen, and treatment is frequently compromised by poor response to first-line antibiotics such as ampicillin. Understanding the factors that play a role in susceptibility/resistance to these drugs will help guide the development of much-needed treatments. |
| format | Article |
| id | doaj-art-1ed2e69d21f54318a48a0457c8d554b1 |
| institution | Kabale University |
| issn | 2150-7511 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | mBio |
| spelling | doaj-art-1ed2e69d21f54318a48a0457c8d554b12024-12-11T14:02:31ZengAmerican Society for MicrobiologymBio2150-75112024-12-01151210.1128/mbio.02897-24Evolutionary trajectories of β-lactam resistance in Enterococcus faecalis strainsPaul Ugalde Silva0Charlene Desbonnet1Louis B. Rice2Mónica García-Solache3Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USADepartment of Medicine, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USADepartment of Medicine, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USADepartment of Medicine, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USAABSTRACT Resistance to ampicillin and imipenem in Enterococcus faecalis is infrequent. However, the evolution of resistance can occur through prolonged antibiotic exposure during the treatment of chronic infections. In this study, we conducted a long-term evolution experiment using four genetically diverse strains of E. faecalis with varying susceptibilities to ampicillin and imipenem. Each strain was subjected to increasing concentrations of either ampicillin or imipenem over 200 days, with three independent replicates for each strain. Selective pressure from imipenem led to the rapid selection of highly resistant lineages across all genetic backgrounds, compared to ampicillin. In addition to high resistance, we describe, for the first time, the evolution of a β-lactam-dependent phenotype observed in lineages from all backgrounds. Whole-genome sequencing and bioinformatic analysis revealed mutations in three main functional classes: genes involved in cell wall synthesis and degradation, genes in the walK/R two-component system, and genes in the c-di-AMP pathway. Our analysis identified new mutations in genes known to be involved in resistance as well as novel genes potentially associated with resistance. Furthermore, the newly described β-lactam-dependent phenotype was correlated with the inactivation of c-di-AMP degradation, resulting in high levels of this second messenger. Together, these data highlight the diverse genetic mechanisms underlying resistance to ampicillin and imipenem in E. faecalis. The emergence of high resistance levels and β-lactam dependency underscores the importance of understanding evolutionary dynamics in the development of antibiotic resistance.IMPORTANCEEnterococcus faecalis is a major human pathogen, and treatment is frequently compromised by poor response to first-line antibiotics such as ampicillin. Understanding the factors that play a role in susceptibility/resistance to these drugs will help guide the development of much-needed treatments.https://journals.asm.org/doi/10.1128/mbio.02897-24Enterococcusbeta-lactamsdrug resistance evolutionantibiotic dependencec-di-AMPlong-term evolution experiment |
| spellingShingle | Paul Ugalde Silva Charlene Desbonnet Louis B. Rice Mónica García-Solache Evolutionary trajectories of β-lactam resistance in Enterococcus faecalis strains mBio Enterococcus beta-lactams drug resistance evolution antibiotic dependence c-di-AMP long-term evolution experiment |
| title | Evolutionary trajectories of β-lactam resistance in Enterococcus faecalis strains |
| title_full | Evolutionary trajectories of β-lactam resistance in Enterococcus faecalis strains |
| title_fullStr | Evolutionary trajectories of β-lactam resistance in Enterococcus faecalis strains |
| title_full_unstemmed | Evolutionary trajectories of β-lactam resistance in Enterococcus faecalis strains |
| title_short | Evolutionary trajectories of β-lactam resistance in Enterococcus faecalis strains |
| title_sort | evolutionary trajectories of β lactam resistance in enterococcus faecalis strains |
| topic | Enterococcus beta-lactams drug resistance evolution antibiotic dependence c-di-AMP long-term evolution experiment |
| url | https://journals.asm.org/doi/10.1128/mbio.02897-24 |
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