Variations in daptomycin-beta-lactam synergy and enterococcal species
Ontology highlight
ABSTRACT:
PROVIDER: PRJEB31896 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| ERR3342520_1.fastq.gz | Fastqsanger.gz | |||
| ERR3342520_2.fastq.gz | Fastqsanger.gz | |||
| ERR3342521_1.fastq.gz | Fastqsanger.gz | |||
| ERR3342521_2.fastq.gz | Fastqsanger.gz | |||
| ERR3342522_1.fastq.gz | Fastqsanger.gz |
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Project description: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.
2024-04-25 | GSE262190 | GEO
Project description:The transcriptional regulator AmpR controls expression of the AmpC ß-lactamase in P. aeruginosa and other bacteria. Studies have demonstrated that in addition to regulating ampC expression, AmpR also regulates the expression of the sigma factor AlgT/U and the production of some quorum-sensing regulated virulence factors. In order to understand the ampR regulon, we compared the expression profiles of PAO1 and its isogenic ampR mutant, PAO∆ampR in the presence and absence of sub-MIC ß-lactam stress. The analysis demonstrates that the ampR regulon is much more extensive than previously thought, with the deletion of ampR affecting the expression of over 300 genes. Expression of an additional 207 genes are affected by AmpR when the cells are exposed to sub-MIC ß-lactam stress, indicating that the ampR regulon in P. aeruginosa is much more extensive than previously thought. An inframe deletion of ampR was generated in P. aeruginosa PAO1. The wild type and ampR mutant strains were grown to mid-log phase and subjected to sub-MIC ß-lactam exposure. Total RNA was isolated from 2-hour ß-lactam exposed and unexposed cells to monitor changes in gene expression arising due to loss of ampR in the presence and absence of ß-lactam exposure.
2012-03-29 | E-GEOD-33188 | biostudies-arrayexpress
Project description:The transcriptional regulator AmpR controls expression of the AmpC ß-lactamase in P. aeruginosa and other bacteria. Studies have demonstrated that in addition to regulating ampC expression, AmpR also regulates the expression of the sigma factor AlgT/U and the production of some quorum-sensing regulated virulence factors. In order to understand the ampR regulon, we compared the expression profiles of PAO1 and its isogenic ampR mutant, PAO∆ampR in the presence and absence of sub-MIC ß-lactam stress. The analysis demonstrates that the ampR regulon is much more extensive than previously thought, with the deletion of ampR affecting the expression of over 300 genes. Expression of an additional 207 genes are affected by AmpR when the cells are exposed to sub-MIC ß-lactam stress, indicating that the ampR regulon in P. aeruginosa is much more extensive than previously thought.
2012-03-30 | GSE33188 | GEO
Project description:This study investigated the transcriptomic response of rice pathogen Acidovorax avenae subsp. avenae (Aaa) strain RS-1 to ß-lactam antibiotics in particular Ampicillin (Amp) and the result highlights the importance of Amp-induced differentially expressed genes in the virulence of Aaa strain RS-1.
2017-02-10 | GSE68734 | GEO
Project description:Abstract of associated manuscript: Daptomycin is the first of a new class of cyclic lipopeptide antibiotics used against multidrug-resistant Gram-positive pathogens. The proposed mechanism of action involves disruption of the functional integrity of the bacterial membrane in a Ca2+-dependent manner. We have used transcriptional profiling to demonstrate that treatment of Bacillus subtilis with daptomycin strongly induces the lia operon including the autoregulatory LiaRS two-component system (homologous to Staphylococcus aureus VraSR). The lia operon protects against daptomycin and deletion of liaH, encoding a phage shock protein A (PspA)-like protein, leads to 3-fold increased susceptibility. Since daptomycin interacts with the membrane, we tested mutants with altered membrane composition for effects on susceptibility. Deletion mutations of mprF (lacking lysyl-phosphatidylglycerol) or des (lipid desaturase) increased daptomycin susceptibility, whereas overexpression of MprF decreased susceptibility. Conversely, depletion of the cell for the anionic lipid phosphatidylglycerol led to increased resistance. Fluorescently-labeled daptomycin localized to the septa and in a helical pattern around the cell envelope and was delocalized upon depletion of phosphatidylglycerol. Together, these results indicate that the daptomycin-Ca2+ complex interacts preferentially with regions enriched in anionic phospholipids and leads to membrane stresses that can be ameliorated by PspA family proteins.
2008-12-11 | GSE13900 | GEO
Project description:Daptomycin is a lipopeptide antibiotic that has recently been approved for treatment of Gram-positive bacterial infections. The mode of action of daptomycin is not yet entirely clear. To further understand the mechanism transcriptomic analysis of changes in gene expression in daptomycin-treated Staphylococcus aureus was carried out. The expression profile indicated that cell wall stress stimulon member genes (B. J. Wilkinson, A. Muthaiyan, and R. K. Jayaswal. 2005. Curr. Med. Chem. Anti-Infective Agents 4: 259-276) were significantly induced by daptomycin, and by the cell wall-active antibiotics vancomycin and oxacillin. Comparison of the daptomycin response of a two-component cell wall stress stimulon regulator VraSR mutant, S. aureus KVR, to its parent N315 showed diminished expression of the cell wall stress stimulon in the mutant. Daptomycin has been proposed to cause membrane depolarization, and the transcriptional responses to carbonyl cyanide m-chlorophenylhydrazone (CCCP) and nisin were determined. Transcriptional profiles of the responses to these antimicrobial agents showed significantly different patterns compared to those of the cell wall-active antibiotics, including little or no induction of the cell wall stress stimulon. However, there were a significant number of genes induced by both CCCP and daptomycin that were not induced by oxacillin or vancomycin, such that the daptomycin transcriptome was probably reflecting a membrane depolarizing activity of this antimicrobial also. The results indicate that inhibition of peptidoglycan biosynthesis, either directly or indirectly, and membrane depolarization are parts of the mode of action of daptomycin. Keywords: mode of action, transcriptional profiling
2007-12-25 | GSE9494 | GEO
Project description:Abstract of associated manuscript: Daptomycin is the first of a new class of cyclic lipopeptide antibiotics used against multidrug-resistant Gram-positive pathogens. The proposed mechanism of action involves disruption of the functional integrity of the bacterial membrane in a Ca2+-dependent manner. We have used transcriptional profiling to demonstrate that treatment of Bacillus subtilis with daptomycin strongly induces the lia operon including the autoregulatory LiaRS two-component system (homologous to Staphylococcus aureus VraSR). The lia operon protects against daptomycin and deletion of liaH, encoding a phage shock protein A (PspA)-like protein, leads to 3-fold increased susceptibility. Since daptomycin interacts with the membrane, we tested mutants with altered membrane composition for effects on susceptibility. Deletion mutations of mprF (lacking lysyl-phosphatidylglycerol) or des (lipid desaturase) increased daptomycin susceptibility, whereas overexpression of MprF decreased susceptibility. Conversely, depletion of the cell for the anionic lipid phosphatidylglycerol led to increased resistance. Fluorescently-labeled daptomycin localized to the septa and in a helical pattern around the cell envelope and was delocalized upon depletion of phosphatidylglycerol. Together, these results indicate that the daptomycin-Ca2+ complex interacts preferentially with regions enriched in anionic phospholipids and leads to membrane stresses that can be ameliorated by PspA family proteins. Bacillus subtilis W168, WT (+DAP) vs. WT (-DAP). The experiment was conducted in triplicate using three independent total RNA preparations. For WT-rep1 and WT-rep2, daptomycin treated samples were labeled with Alexa Fluor 647 and untreated samples with Alexa Fluor 555. For WT-rep3, the daptomycin treated sample was labeled with Alexa Fluor 555 and the untreated sample with Alexa Fluor 647.
2008-12-10 | E-GEOD-13900 | biostudies-arrayexpress
Project description:Transcriptional response of Bacillus subtilis to daptomycin in wild-type and in a daptomycin resistant mutant.
2011-06-16 | GSE30000 | GEO
Project description:Daptomycin (DAP) is the last-resort treatment for heterogeneous Vancomycin-Intermediate-Staphylococcus aureus (hVISA) and Vancomycin-Intermediate-S.aureus (VISA), and DAP-resistance onset which is also linked to reduced vancomycin susceptibility, is an increasing public health problem. To have more insight into the mechanisms of daptomycin resistance, the comparative transcriptomes of two DAP-R (1C-3B) clinical isogenic isolates vs their DAP-S (1A-3A) counterparts were investigated by Illumina RNA-seq, the Rockhopper tool, computational filtering analyses and bioinformatic tools.
2020-08-07 | GSE121797 | GEO
Project description:The evidence for using combination therapy for the treatment of serious methicillin-resistant Staphylococcus aureus (MRSA) infections is growing. In this study, we investigated the synergistic effect of daptomycin (DAP) combined with piperacillin-tazobactam and ampicillin-sulbactam against MRSA in time-kill experiments. Six of eight strains demonstrated synergy between DAP and the ?-lactam-?-lactamase inhibitor (BLI) combination. In 5/8 strains, the synergy occurred only in the presence of the BLI, highlighting a role for BLIs in peptide-?-lactam synergy.
| S-EPMC5192128 | biostudies-literature