Induction kinetics of the Staphylococcus aureus cell wall stress stimulon in response to different cell wall active antibiotics

Dengler, Vanina; Meier, Patricia Stutzmann; Heusser, Ronald; Berger‐Bächi, Brigitte; McCallum, Nadine

doi:10.1186/1471-2180-11-16

Cited by 84 publications

(85 citation statements)

References 47 publications

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“…5). D-Cycloserine and fosfomycin inhibit different steps in the intracellular pathway leading to the biosynthesis of lipid II, the bacterial cell wall precursor (53). In addition, sublethal doses of the glycopeptide antibiotic vancomycin have previously been shown to induce eDNA-dependent biofilm in several vancomycin-susceptible and vancomycin-resistant MRSA strains (44,(54)(55)(56).…”

Section: Discussionmentioning

confidence: 99%

Effects of Low-Dose Amoxicillin on Staphylococcus aureus USA300 Biofilms

Mlynek

Callahan

Shimkevitch

et al. 2016

Antimicrob Agents Chemother

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cPrevious studies showed that sub-MIC levels of ␤-lactam antibiotics stimulate biofilm formation in most methicillin-resistant Staphylococcus aureus (MRSA) strains. Here, we investigated this process by measuring the effects of sub-MIC amoxicillin on biofilm formation by the epidemic community-associated MRSA strain USA300. We found that sub-MIC amoxicillin increased the ability of USA300 cells to attach to surfaces and form biofilms under both static and flow conditions. We also found that USA300 biofilms cultured in sub-MIC amoxicillin were thicker, contained more pillar and channel structures, and were less porous than biofilms cultured without antibiotic. Biofilm formation in sub-MIC amoxicillin correlated with the production of extracellular DNA (eDNA). However, eDNA released by amoxicillin-induced cell lysis alone was evidently not sufficient to stimulate biofilm. Sub-MIC levels of two other cell wall-active agents with different mechanisms of action-D-cycloserine and fosfomycin-also stimulated eDNA-dependent biofilm, suggesting that biofilm formation may be a mechanistic adaptation to cell wall stress. Screening a USA300 mariner transposon library for mutants deficient in biofilm formation in sub-MIC amoxicillin identified numerous known mediators of S. aureus ␤-lactam resistance and biofilm formation, as well as novel genes not previously associated with these phenotypes. Our results link cell wall stress and biofilm formation in MRSA and suggest that eDNA-dependent biofilm formation by strain USA300 in low-dose amoxicillin is an inducible phenotype that can be used to identify novel genes impacting MRSA ␤-lactam resistance and biofilm formation.

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Section: Discussionmentioning

confidence: 99%

Effects of Low-Dose Amoxicillin on Staphylococcus aureus USA300 Biofilms

Mlynek

Callahan

Shimkevitch

et al. 2016

Antimicrob Agents Chemother

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“…We also found higher expression levels of genes involved in cell envelope synthesis and stress response. It could be that the ΔxdrA strain induces the cell wall stress stimulon, as evidenced by higher vraX levels (27,28), which in turn contributes to increased cell envelope strength and reduced lysis and, hence, reduced eDNA.…”

Section: Discussionmentioning

confidence: 99%

“…26), steT, ilvA, and ald, were reduced in the ΔxdrA mutant. Conversely, transcripts found in increased abundance in the deletion mutant included those encoded by the gene for δ-hemolysin (hld/RNA III); genes for the β-phenol soluble modulins (PSMβs); a putative cold shock gene, cspB; vraX, which encodes a protein that has not been well characterized but shown to be highly up-regulated during cell wall stress (27,28); and genes for two hypothetical proteins, SAOUHSC_00560 and SAOUHSC_00141.…”

Section: Mutants Of Genes Underrepresented For Transposon Insertions mentioning

confidence: 99%

Genome-wide screen for genes involved in eDNA release during biofilm formation by Staphylococcus aureus

DeFrancesco

Masloboeva

Syed

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

103

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Staphylococcus aureus is a leading cause of both nosocomial and community-acquired infection. Biofilm formation at the site of infection reduces antimicrobial susceptibility and can lead to chronic infection. During biofilm formation, a subset of cells liberate cytoplasmic proteins and DNA, which are repurposed to form the extracellular matrix that binds the remaining cells together in large clusters. Using a strain that forms robust biofilms in vitro during growth under glucose supplementation, we carried out a genome-wide screen for genes involved in the release of extracellular DNA (eDNA). A high-density transposon insertion library was grown under biofilm-inducing conditions, and the relative frequency of insertions was compared between genomic DNA (gDNA) collected from cells in the biofilm and eDNA from the matrix. Transposon insertions into genes encoding functions necessary for eDNA release were identified by reduced representation in the eDNA. On direct testing, mutants of some of these genes exhibited markedly reduced levels of eDNA and a concomitant reduction in cell clustering. Among the genes with robust mutant phenotypes were gdpP, which encodes a phosphodiesterase that degrades the second messenger cyclic-di-AMP, and xdrA, the gene for a transcription factor that, as revealed by RNA-sequencing analysis, influences the expression of multiple genes, including many involved in cell wall homeostasis. Finally, we report that growth in biofilm-inducing medium lowers cyclicdi-AMP levels and does so in a manner that depends on the gdpP phosphodiesterase gene.Staphylococcus aureus | biofilm | eDNA | cyclic-di-AMP

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“…Interestingly, an even higher magnitude of upregulation was induced in S. aureus challenged with SI doses of antimicrobial peptides, specifically in three genes/operons-vraDE, SA0205, and SAS016 -encoding an ABC transporter, a putative membrane-bound lysostaphinlike peptidase, and a small functionally unknown protein, respectively (32). Construction of a plasmid carrying a luciferase reporter gene fused to sas016 enabled monitoring of the kinetics and detection of very subtle differences in expression of the cell wall stress signal (8). Here we show that EGCG induces this system in the same manner as cell-wall-active antibiotics, albeit at a lower magnitude than that with oxacillin.…”

Section: Discussionmentioning

confidence: 99%

Epigallocatechin Gallate Induces Upregulation of the Two-Component VraSR System by Evoking a Cell Wall Stress Response in Staphylococcus aureus

Levinger

Bikels-Goshen

Landau

et al. 2012

Appl Environ Microbiol

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We previously found that a short exposure of Staphylococcus aureus to subinhibitory (SI) doses of epigallocatechin gallate (EGCG) results in increased cell wall thickness, adaptation, and enhanced tolerance to cell-wall-targeted antibiotics. In this study, the response to EGCG of sigB and vraSR transcription factor mutants was characterized. We show that in contrast to the results observed for wild-type (WT) strains, an S. aureus 315 vraSR null mutant exposed to SI doses of EGCG did not exhibit increased tolerance to EGCG and oxacillin. A diminished increase in tolerance to ampicillin (from 16-fold to 4-fold) and no change in the magnitude of resistance to vancomycin were observed. Preexposure to EGCG enhanced the tolerance of wild-type and sigB null mutant cells to lysostaphin, but this enhancement was much weaker in the vraSR null mutant. Marked upregulation (about 60-fold) of vraR and upregulation of the peptidoglycan biosynthesis-associated genes murA, murF, and pbp2 (2-, 5-, and 6-fold, respectively) in response to SI doses of EGCG were determined by quantitative reverse transcription-PCR (qRT-PCR). EGCG also induced the promoter of sas016 (encoding a cell wall stress protein of unknown function which is not induced in vraSR null mutants) in a concentration-dependent manner, showing kinetics comparable to those of cell-wall-targeting antibiotics. Taken together, our results suggest that the two-component VraSR system is involved in modulating the cell response to SI doses of EGCG.

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Induction kinetics of the Staphylococcus aureus cell wall stress stimulon in response to different cell wall active antibiotics

Cited by 84 publications

References 47 publications

Effects of Low-Dose Amoxicillin on Staphylococcus aureus USA300 Biofilms

Effects of Low-Dose Amoxicillin on Staphylococcus aureus USA300 Biofilms

Genome-wide screen for genes involved in eDNA release during biofilm formation by Staphylococcus aureus

Epigallocatechin Gallate Induces Upregulation of the Two-Component VraSR System by Evoking a Cell Wall Stress Response in Staphylococcus aureus

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