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| Status |
Public on Apr 25, 2024 |
| Title |
Coordinated regulation of osmotic imbalance by c-di-AMP shapes ß-lactam tolerance in Group B Streptococcus |
| Organisms |
Streptococcus agalactiae; Streptococcus agalactiae NEM316 |
| Experiment type |
Expression profiling by high throughput sequencing
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| Summary |
Streptococcus agalactiae is among the few pathogens that have not developed resistance to ß-lactam antibiotics despite decades of clinical use. The molecular basis of this long-lasting susceptibility has not been investigated, and it is uncertain whether specific mechanisms constraint the emergence of resistance. In this study, we first report a conserved role of the signaling nucleotide cyclic-di-AMP in the sensitivity of S. agalactiae to ß-lactam. Specifically, we demonstrate that inactivation of the phosphodiesterase GdpP confers ß-lactam tolerance. Characterizing the signaling pathway revealed an antagonistic regulation by the transcriptional factor BusR, which is activated by c-di-AMP and negatively regulates ß-lactam susceptibility. Furthermore, we show that simultaneous inhibition of osmolyte transporters activity and transcription by c-di-AMP has an additive effect, sustaining ß-lactam tolerance. Finally, transposon mutagenesis for ß-lactam reduced susceptibility reveals a convergent pattern of mutations, including in the KhpAB small RNA chaperone and the protein S immunomodulator. Overall, our findings suggest mechanisms that may foster antibiotic resistance in S. agalactiae and demonstrate that c-di-AMP acts as a turgor pressure rheostat, coordinating an integrated response to cell wall weakening due to ß-lactam activity.
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| Overall design |
To investigate the c-di-AMP signaling pathway in Group B Streptococcus, we generated deletion mutants for the c-di-AMP phosphodiesterase GdpP (∆gdpP) and for the c-di-AMP regulated transcriptional repressor BusR (∆busR)
For comparative transcritomic analysis, ∆gdpP and ∆busR mutants were generated in two wild-type strains: NEM316 (capsular serotype III, CC-23) and BM110 (capsular serotype III, CC-17)
RNA are purified from exponentialy growing cultures (OD600 = 0.5) in rich media (THY) incubated at 37°C in static condition. Biological triplicate (Replicate 1, 2, and 3) are done on different days.
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| Contributor(s) |
Brissac T, Sismeiro O, Jacquemet E, Legendre R, Firon A |
| Citation(s) |
38993744 |
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| Submission date |
Mar 21, 2024 |
| Last update date |
Aug 08, 2024 |
| Contact name |
Rachel Legendre |
| E-mail(s) |
rachel.legendre@pasteur.fr
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| Organization name |
Institut Pasteur
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| Department |
Research and Resource Center for Scientific Informatics
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| Lab |
Hub of Bioinformatics and Biostatistics
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| Street address |
28, rue du docteur Roux
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| City |
Paris |
| ZIP/Postal code |
75724 |
| Country |
France |
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| Platforms (2) |
| GPL29157 |
Illumina NextSeq 500 (Streptococcus agalactiae) |
| GPL34325 |
Illumina NextSeq 500 (Streptococcus agalactiae NEM316) |
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| Samples (18)
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| Relations |
| BioProject |
PRJNA1090533 |
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