Regulation of AmpC-Driven β-Lactam Resistance in <named-content content-type="genus-species">Pseudomonas aeruginosa</named-content>: Different Pathways, Different Signaling
ABSTRACT The hyperproduction of the chromosomal AmpC β-lactamase is the main mechanism driving β-lactam resistance in Pseudomonas aeruginosa, one of the leading opportunistic pathogens causing nosocomial acute and chronic infections in patients with underlying respiratory diseases. In the current sc...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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American Society for Microbiology
2019-12-01
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| Series: | mSystems |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/mSystems.00524-19 |
| _version_ | 1818424892116172800 |
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| author | Gabriel Torrens Sara Belén Hernández Juan Alfonso Ayala Bartolome Moya Carlos Juan Felipe Cava Antonio Oliver |
| author_facet | Gabriel Torrens Sara Belén Hernández Juan Alfonso Ayala Bartolome Moya Carlos Juan Felipe Cava Antonio Oliver |
| author_sort | Gabriel Torrens |
| collection | DOAJ |
| description | ABSTRACT The hyperproduction of the chromosomal AmpC β-lactamase is the main mechanism driving β-lactam resistance in Pseudomonas aeruginosa, one of the leading opportunistic pathogens causing nosocomial acute and chronic infections in patients with underlying respiratory diseases. In the current scenario of the shortage of effective antipseudomonal drugs, understanding the molecular mechanisms mediating AmpC hyperproduction in order to develop new therapeutics against this fearsome pathogen is of great importance. It has been accepted for decades that certain cell wall-derived soluble fragments (muropeptides) modulate AmpC production by complexing with the transcriptional regulator AmpR and acquiring different conformations that activate/repress ampC expression. However, these peptidoglycan-derived signals have never been characterized in the highly prevalent P. aeruginosa stable AmpC hyperproducer mutants. Here, we demonstrate that the previously described fragments enabling the transient ampC hyperexpression during cefoxitin induction (1,6-anhydro-N-acetylmuramyl-pentapeptides) also underlie the dacB (penicillin binding protein 4 [PBP4]) mutation-driven stable hyperproduction but differ from the 1,6-anhydro-N-acetylmuramyl-tripeptides notably overaccumulated in the ampD knockout mutant. In addition, a simultaneous greater accumulation of both activators appears linked to higher levels of AmpC hyperproduction, although our results suggest a much stronger AmpC-activating potency for the 1,6-anhydro-N-acetylmuramyl-pentapeptide. Collectively, our results propose a model of AmpC control where the activator fragments, with qualitative and quantitative particularities depending on the pathways and levels of β-lactamase production, dominate over the repressor (UDP-N-acetylmuramyl-pentapeptide). This study represents a major step in understanding the foundations of AmpC-dependent β-lactam resistance in P. aeruginosa, potentially useful to open new therapeutic conceptions intended to interfere with the abovementioned cell wall-derived signaling. IMPORTANCE The extensive use of β-lactam antibiotics and the bacterial adaptive capacity have led to the apparently unstoppable increase of antimicrobial resistance, one of the current major global health challenges. In the leading nosocomial pathogen Pseudomonas aeruginosa, the mutation-driven AmpC β-lactamase hyperproduction stands out as the main resistance mechanism, but the molecular cues enabling this system have remained elusive until now. Here, we provide for the first time direct and quantitative information about the soluble cell wall-derived fragments accounting for the different levels and pathways of AmpC hyperproduction. Based on these results, we propose a hierarchical model of signals which ultimately govern ampC hyperexpression and resistance. |
| first_indexed | 2024-12-14T14:05:15Z |
| format | Article |
| id | doaj.art-f099b4421f5d48b49781ba0b96cb367e |
| institution | Directory Open Access Journal |
| issn | 2379-5077 |
| language | English |
| last_indexed | 2024-12-14T14:05:15Z |
| publishDate | 2019-12-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | mSystems |
| spelling | doaj.art-f099b4421f5d48b49781ba0b96cb367e2022-12-21T22:58:35ZengAmerican Society for MicrobiologymSystems2379-50772019-12-014610.1128/mSystems.00524-19Regulation of AmpC-Driven β-Lactam Resistance in <named-content content-type="genus-species">Pseudomonas aeruginosa</named-content>: Different Pathways, Different SignalingGabriel Torrens0Sara Belén Hernández1Juan Alfonso Ayala2Bartolome Moya3Carlos Juan4Felipe Cava5Antonio Oliver6Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, SpainLaboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, SwedenDepartamento de Virología y Microbiología, Centro de Biología Molecular Severo Ochoa, Madrid, SpainServicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, SpainServicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, SpainLaboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, SwedenServicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, SpainABSTRACT The hyperproduction of the chromosomal AmpC β-lactamase is the main mechanism driving β-lactam resistance in Pseudomonas aeruginosa, one of the leading opportunistic pathogens causing nosocomial acute and chronic infections in patients with underlying respiratory diseases. In the current scenario of the shortage of effective antipseudomonal drugs, understanding the molecular mechanisms mediating AmpC hyperproduction in order to develop new therapeutics against this fearsome pathogen is of great importance. It has been accepted for decades that certain cell wall-derived soluble fragments (muropeptides) modulate AmpC production by complexing with the transcriptional regulator AmpR and acquiring different conformations that activate/repress ampC expression. However, these peptidoglycan-derived signals have never been characterized in the highly prevalent P. aeruginosa stable AmpC hyperproducer mutants. Here, we demonstrate that the previously described fragments enabling the transient ampC hyperexpression during cefoxitin induction (1,6-anhydro-N-acetylmuramyl-pentapeptides) also underlie the dacB (penicillin binding protein 4 [PBP4]) mutation-driven stable hyperproduction but differ from the 1,6-anhydro-N-acetylmuramyl-tripeptides notably overaccumulated in the ampD knockout mutant. In addition, a simultaneous greater accumulation of both activators appears linked to higher levels of AmpC hyperproduction, although our results suggest a much stronger AmpC-activating potency for the 1,6-anhydro-N-acetylmuramyl-pentapeptide. Collectively, our results propose a model of AmpC control where the activator fragments, with qualitative and quantitative particularities depending on the pathways and levels of β-lactamase production, dominate over the repressor (UDP-N-acetylmuramyl-pentapeptide). This study represents a major step in understanding the foundations of AmpC-dependent β-lactam resistance in P. aeruginosa, potentially useful to open new therapeutic conceptions intended to interfere with the abovementioned cell wall-derived signaling. IMPORTANCE The extensive use of β-lactam antibiotics and the bacterial adaptive capacity have led to the apparently unstoppable increase of antimicrobial resistance, one of the current major global health challenges. In the leading nosocomial pathogen Pseudomonas aeruginosa, the mutation-driven AmpC β-lactamase hyperproduction stands out as the main resistance mechanism, but the molecular cues enabling this system have remained elusive until now. Here, we provide for the first time direct and quantitative information about the soluble cell wall-derived fragments accounting for the different levels and pathways of AmpC hyperproduction. Based on these results, we propose a hierarchical model of signals which ultimately govern ampC hyperexpression and resistance.https://journals.asm.org/doi/10.1128/mSystems.00524-19AmpC β-lactamasePseudomonas aeruginosamuropeptidepeptidoglycan |
| spellingShingle | Gabriel Torrens Sara Belén Hernández Juan Alfonso Ayala Bartolome Moya Carlos Juan Felipe Cava Antonio Oliver Regulation of AmpC-Driven β-Lactam Resistance in <named-content content-type="genus-species">Pseudomonas aeruginosa</named-content>: Different Pathways, Different Signaling mSystems AmpC β-lactamase Pseudomonas aeruginosa muropeptide peptidoglycan |
| title | Regulation of AmpC-Driven β-Lactam Resistance in <named-content content-type="genus-species">Pseudomonas aeruginosa</named-content>: Different Pathways, Different Signaling |
| title_full | Regulation of AmpC-Driven β-Lactam Resistance in <named-content content-type="genus-species">Pseudomonas aeruginosa</named-content>: Different Pathways, Different Signaling |
| title_fullStr | Regulation of AmpC-Driven β-Lactam Resistance in <named-content content-type="genus-species">Pseudomonas aeruginosa</named-content>: Different Pathways, Different Signaling |
| title_full_unstemmed | Regulation of AmpC-Driven β-Lactam Resistance in <named-content content-type="genus-species">Pseudomonas aeruginosa</named-content>: Different Pathways, Different Signaling |
| title_short | Regulation of AmpC-Driven β-Lactam Resistance in <named-content content-type="genus-species">Pseudomonas aeruginosa</named-content>: Different Pathways, Different Signaling |
| title_sort | regulation of ampc driven β lactam resistance in named content content type genus species pseudomonas aeruginosa named content different pathways different signaling |
| topic | AmpC β-lactamase Pseudomonas aeruginosa muropeptide peptidoglycan |
| url | https://journals.asm.org/doi/10.1128/mSystems.00524-19 |
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