Genomic and Long-Term Transcriptomic Imprints Related to the Daptomycin Mechanism of Action Occurring in Daptomycin- and Methicillin-Resistant Staphylococcus aureus Under Daptomycin Exposure
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ABSTRACT:
ORGANISM(S): Staphylococcus aureus
PROVIDER: GSE121797 | GEO | 2020/08/07
REPOSITORIES: GEO
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Project description:Staphylococcus aureus is a notorious bacterial pathogen that causes a broad range of human diseases, and isolates that are resistant to several antibiotic classes including last resort antibiotics like vancomycin and daptomycin complicate the situation. We characterized S. aureus VC40, a strain that shows full resistance to vancomycin (MIC of 64 M-BM-5g/ml) and daptomycin (MIC of 4 M-BM-5g/ml) as well as a decreased susceptibility to further cell wall active agents. Genome sequencing revealed mutations in genes encoding the histidine kinases WalK and VraS that control cell envelope related processes and gene expression profiling indicated the induction of the respective regulons in strain VC40. Reconstitution of the mutations in walK or vraS into the susceptible S. aureus NCTC 8325 background resulted in a considerably increased resistance to vancomycin and daptomycin with MICs surpassing the clinical breakpoints for these antibiotics, thereby generating vancomycin-intermediate S. aureus (VISA) strains. As observed for S. aureus VC40, the walKwalk and vraS mutations also led to an increased expression of the respective regulons in the NCTC 8325 background. Phenotypic studies showed that S. aureus VC40 as well as the walKwalk and vraS mutants of strain NCTC 8325 were characterized by a significantly thickened cell wall, a decreased growth rate, a reduced autolytic activity and an increased resistance to lysostaphin-induced lysis. These results demonstrate that the WalK and VraS histidine kinases act as major switches which allow S. aureus to rapidly develop vancomycin resistance up to the VISA level via mutation of one single gene locus and concomitantly contribute to cross-resistance to other antibiotics including the last resort antibiotic daptomycin. Microarray was used to evaluate alteration in the transcriptome of mutS mutant and compared to the parental strain VC40
2014-08-18 | E-GEOD-46887 | biostudies-arrayexpress
Project description:Staphylococcus aureus is a notorious bacterial pathogen that causes a broad range of human diseases, and isolates that are resistant to several antibiotic classes including last resort antibiotics like vancomycin and daptomycin complicate the situation. We characterized S. aureus VC40, a strain that shows full resistance to vancomycin (MIC of 64 µg/ml) and daptomycin (MIC of 4 µg/ml) as well as a decreased susceptibility to further cell wall active agents. Genome sequencing revealed mutations in genes encoding the histidine kinases WalK and VraS that control cell envelope related processes and gene expression profiling indicated the induction of the respective regulons in strain VC40. Reconstitution of the mutations in walK or vraS into the susceptible S. aureus NCTC 8325 background resulted in a considerably increased resistance to vancomycin and daptomycin with MICs surpassing the clinical breakpoints for these antibiotics, thereby generating vancomycin-intermediate S. aureus (VISA) strains. As observed for S. aureus VC40, the walKwalk and vraS mutations also led to an increased expression of the respective regulons in the NCTC 8325 background. Phenotypic studies showed that S. aureus VC40 as well as the walKwalk and vraS mutants of strain NCTC 8325 were characterized by a significantly thickened cell wall, a decreased growth rate, a reduced autolytic activity and an increased resistance to lysostaphin-induced lysis. These results demonstrate that the WalK and VraS histidine kinases act as major switches which allow S. aureus to rapidly develop vancomycin resistance up to the VISA level via mutation of one single gene locus and concomitantly contribute to cross-resistance to other antibiotics including the last resort antibiotic daptomycin.
2014-08-18 | GSE46887 | GEO
Project description:Transcriptional response of Bacillus subtilis to daptomycin in wild-type and in a daptomycin resistant mutant. Bacillus subtilis 168, WT (-DAP) vs. DapR1 (-DAP), WT (+DAP) vs. DapR1 (+DAP), DapR1 (+DAP) vs. DapR1 (-DAP). Each experiment was conducted at least twice using two independent total RNA preparations. For daptomycin untreated comparison between 168 WT and DapR1 mutant, DapR1 was labeled with Alexa Fluor 647 and WT was labeled with Alexa Fluor 555. For daptomycin treated experiments between WT and DapR1, DapR1 was labeled with Alexa Fluor 647 and WT with Alexa Fluor 555. For treated vs. untreated DapR1, the DAP treated samples were labeled with Alexa Fluor 647 and the untreated with Alexa Fluor 555. For dye swap, untreated DapR1 was labeled with Alexa Fluor 647 and DAP treated with Alexa Fluor 555.
2011-06-16 | E-GEOD-30000 | biostudies-arrayexpress
Project description:Investigation of baseline transcription activity of two different clinical isolates of Staphylococcus aureus with two different susceptibility levels to the antibiotics Vancomycin and Daptomycin. Two different strains of Staphylococcus aureus, one that is fully Vancomycin and Daptomycin Sensitive and one with decreased Vancomycin and Daptomycin Sensitivity - grown to mid-log phase in rich broth.
2012-08-03 | E-GEOD-39868 | biostudies-arrayexpress
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:Investigation of baseline transcription activity of two different clinical isolates of Staphylococcus aureus with two different susceptibility levels to the antibiotics Vancomycin and Daptomycin.
2012-08-03 | GSE39868 | GEO
Project description:Several groups have shown that through evolution experiments, tolerance and resistance evolved rapidly under cyclic antibiotic treatment. In other words, intermittent antibiotic exposure performed in a typical adaptive laboratory evolution (ALE) experiments will “train” the bacteria to become tolerant/resistant to the drug. Using this experimental strategy, we performed in vitro laboratory evolution in MRSA using daptomycin, and mine novel daptomycin tolerance and resistance mutants, which were isolated at specific time points during the evolution experiments. Three daptomycin-tolerant isolates with different tolerance level were generated from our laboratory evolution (TOL2 and TOL5 with a mild-tolerance phenotype, and TOL6 with a high-tolerance phenotype). They all bear mutations at different genes, and have no increase in MIC towards daptomycin. Besides, we also isolated three daptomycin-resistant isolates (RES1, RES2, RES3) that have a single point mutation in the same gene, mprF, but at different locations, leading to an increased MIC towards daptomycin. Through proteomics, we uncovered the differential adaptation strategies of these daptomycin tolerant and resistant MRSA strains, and how they respond differently to antibiotics compared to the ancestral wild-type.
2022-07-14 | PXD026741 | Pride
Project description:The production of daptomycin (DAP) is precisely regulated by a complex regulatory network in Streptomyces roseosporus (S. roseosporus). Although the most biosynthetic pathway of DAP has been elucidated, the regulatory mechanism of its biosynthesis at transcriptional level is not fully understood. In the present study, a transcriptional regulator DhyR has been identified based on our previous quantification proteomics identification in S. roseosporus, and further the dhyR gene deletion mutant has been carried out to reveal DhyR function through transcriptome sequencing and loss-of function validation, which demonstrates DhyR positively regulates DAP biosynthesis in S. rosesporus. In-frame gene deletion of dhyR results in the significant downregulation of the transcription levels of all structural genes in DAP biosynthetic gene cluster and significantly decreases production of DAP. In contrast, overexpression of dhyR enhances transcription levels of DAP biosynthetic gene cluster and leads to a 23% increase of DAP yield. Moreover, the deletion of dhyR resultes in the significant down-regulation of transcription levels of another three regulatory genes, including atrA, depR1 and ssig-05090, which have been demonstrated to be closely associated with the DAP biosynthesis. Transcriptome analyses also support that DhyR modulates carbohydrate metabolism, amino acid metabolism and synthesis and transport pathways of siderophore in S. roseosporus. In summary, our findings indicate that DhyR functions as a pleiotropic regulator of primary and secondary metabolism to involve in DAP biosynthetic regulation of S. roseosporus.
2024-01-01 | GSE251775 | GEO
Project description:Daptomycin is an important, last-resort antimicrobial therapeutic for the treatment of infections caused by Staphylococcus aureus that has acquired beta-lactam nonsusceptibility or reduced vancomycin susceptibility. The mechanism of action of daptomycin involves disruption of the cell membrane rather than cell wall synthesis, as with beta-lactams and vancomycin. In the rare event of failed daptomycin therapy, the source of resistance is often attributable to single-nucleotide polymorphisms directly within the membrane phospholipid biosynthetic pathway of S. aureus or in the regulatory systems that control cell envelope response and membrane homeostasis. Here we describe the structural changes to the cell envelope in a daptomycin-resistant strain selected from methicillin-resistant S. aureus (MRSA) N315 with mutations in the most commonly reported SNPs associated with daptomycin-resistance: mprF, yycG, and pgsA. In addition to the decreased phosphatidylglycerol (PG) levels that are the hallmark of daptomycin-resistance, the mutant with high-level daptomycin resistance had increased branched-chain fatty acids (BCFAs) in its membrane lipids, increased membrane fluidity, and increased cell wall thickness relative to its parental strain. Despite the enrichment of BCFAs, we found that the daptomycin-resistant strain successfully utilized isotope-labeled straight-chain fatty acids (SCFAs) in the synthesis of membrane lipids and that supplementation of the culture broth with SCFAs restored membrane fluidity in the daptomycin-resistant strain to the state of its parental strain. These results demonstrate that exogenous fatty acids can mitigate, in part, the phenotypes associated with daptomycin resistance when it is driven by mutations in yycG and pgsA.
2023-04-12 | MSV000091690 | MassIVE