Mutation in the C-Di-AMP Cyclase dacA Affects Fitness and Resistance of Methicillin Resistant Staphylococcus aureus

Dengler, Vanina; McCallum, Nadine; Kiefer, Patrick; Christen, Philipp; Patrignani, Andrea; Vorholt, Julia A.; Berger‐Bächi, Brigitte; Senn, Maria M.

doi:10.1371/journal.pone.0073512

Cited by 84 publications

(102 citation statements)

References 66 publications

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“…Besides the declining adenylate energy charge after 20 min of antibiotic treatment (as discussed above), the intracellular c-di-AMP level also significantly decreased. This is reasonable, since this second messenger is thought to be essential for S. aureus (49), and a very low c-di-AMP level is assumed to be involved in a reduced growth rate (50). Interestingly, no significant alteration in the c-di-AMP level was detected under any other antibiotic stress, although this metabolite is assumed to be involved in sensing envelope stress (49).…”

Section: Resultsmentioning

confidence: 88%

Impact of Antibiotics with Various Target Sites on the Metabolome of Staphylococcus aureus

Dörries

Schlueter

Lalk

2014

Antimicrob Agents Chemother

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In this study, global intra-and extracellular metabolic profiles were exploited to investigate the impact of antibiotic compounds with different cellular targets on the metabolome of Staphylococcus aureus HG001. Primary metabolism was largely covered, yet uncommon staphylococcal metabolites were detected in the cytosol of S. aureus, including sedoheptulose-1,7-bisphosphate and the UDP-MurNAc-pentapeptide with an alanine-seryl residue. By comparing the metabolic profiles of unstressed and stressed staphylococcal cells in a time-dependent manner, we found far-ranging effects within the metabolome. For each antibiotic compound, accumulation as well as depletion of metabolites was detected, often comprising whole biosynthetic pathways, such as central carbon and amino acid metabolism and peptidoglycan, purine, and pyrimidine synthesis. Ciprofloxacin altered the pool of (deoxy)nucleotides as well as peptidoglycan precursors, thus linking stalled DNA and cell wall synthesis. Erythromycin tended to increase the amounts of intermediates of the pentose phosphate pathway and lysine. Fosfomycin inhibited the first enzymatic step of peptidoglycan synthesis, which was followed by decreased levels of peptidoglycan precursors but enhanced levels of substrates such as UDP-GlcNAc and alanine-alanine. In contrast, vancomycin and ampicillin inhibited the last stage of peptidoglycan construction on the outer cell surface. As a result, the amounts of UDP-MurNAc-peptides drastically increased, resulting in morphological alterations in the septal region and in an overall decrease in central metabolite levels. Moreover, each antibiotic affected intracellular levels of tricarboxylic acid cycle intermediates.

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Section: Resultsmentioning

confidence: 88%

Impact of Antibiotics with Various Target Sites on the Metabolome of Staphylococcus aureus

Dörries

Schlueter

Lalk

2014

Antimicrob Agents Chemother

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“…A single nucleotide polymorphism in the dacA (diadenylate cyclase) gene, which synthesizes the second messenger cyclic di-AMP (c-di-AMP), was detected in the more sensitive cells. Thus, decreasing c-di-AMP levels resulted in reduced autolysis, increased salt tolerance, and reduced basal expression of the cell wall stress stimulon (132). Interestingly, Eagle-type heteroresistance was explained based on reduced repression of mecA transcription and penicillin-binding protein 2= production at a high concentration (128 g/ml) of methicillin, which did not occur at lower concentrations (1 and 8 g/ml).…”

Section: Heteroresistance To ␤-Lactamsmentioning

confidence: 99%

Antimicrobial Heteroresistance: an Emerging Field in Need of Clarity

2015

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SUMMARY “Heteroresistance” describes a phenomenon where subpopulations of seemingly isogenic bacteria exhibit a range of susceptibilities to a particular antibiotic. Unfortunately, a lack of standard methods to determine heteroresistance has led to inappropriate use of this term. Heteroresistance has been recognized since at least 1947 and occurs in Gram-positive and Gram-negative bacteria. Its clinical relevance may be considerable, since more resistant subpopulations may be selected during antimicrobial therapy. However, the use of nonstandard methods to define heteroresistance, which are costly and involve considerable labor and resources, precludes evaluating the clinical magnitude and severity of this phenomenon. We review the available literature on antibiotic heteroresistance and propose recommendations for definitions and determination criteria for heteroresistant bacteria. This will help in assessing the global clinical impact of heteroresistance and developing uniform guidelines for improved therapeutic outcomes.

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“…Several studies revealed that c-di-AMP is involved in cell wall homeostasis (9,13,30), which may affect the cell shape. Hence, we investigated the morphology of cdaA and cdaR mutant strains by microscopy.…”

Section: Cdar Does Not Affect Synthesis and Membrane Localization Ofmentioning

confidence: 99%

“…Indeed, both depletion and overexpression of cdaA were shown to severely affect the integrity of the cell wall in several Gram-positive bacteria (6,27). Moreover, alterations in the intracellular c-di-AMP pool affect the resistance to cell wall-targeting antibiotics (9,27,28,29,30). The underlying mechanism, explaining how c-di-AMP synthesis is linked to the cell wall integrity, remains to be elucidated.…”

mentioning

confidence: 99%

Phenotypes Associated with the Essential Diadenylate Cyclase CdaA and Its Potential Regulator CdaR in the Human Pathogen Listeria monocytogenes

et al. 2016

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Cyclic diadenylate monophosphate (c-di-AMP) is a second messenger utilized by diverse bacteria. In many species, including the Gram-positive human pathogen Listeria monocytogenes, c-di-AMP is essential for growth. Here we show that the single diadenylate cyclase of L. monocytogenes, CdaA, is an integral membrane protein that interacts with its potential regulatory protein, CdaR, via the transmembrane protein domain. The presence of the CdaR protein is not required for the membrane localization and abundance of CdaA. We have also found that CdaR negatively influences CdaA activity in L. monocytogenes and that the role of CdaR is most evident at a high growth temperature. Interestingly, a cdaR mutant strain is less susceptible to lysozyme. Moreover, CdaA contributes to cell division, and cells depleted of CdaA are prone to lysis. The observation that the growth defect of a CdaA depletion strain can be partially restored by increasing the osmolarity of the growth medium suggests that c-di-AMP is important for maintaining the integrity of the protective cell envelope. Overall, this work provides new insights into the relationship between CdaA and CdaR. IMPORTANCE Cyclic diadenylate monophosphate (c-di-AMP) is a recently identified second messenger that is utilized by the Gram-positive human pathogen Listeria monocytogenes.Here we show that the single diadenylate cyclase of L. monocytogenes, CdaA, is an integral membrane protein that interacts with CdaR, its potential regulatory protein. We show that CdaR is not required for membrane localization or abundance of the diadenylate cyclase, but modulates its activity. Moreover, CdaA seems to contribute to cell division. Overall, this work provides new insights into the relationship between CdaA and CdaR and their involvement in cell growth. Bacteria from diverse phyla produce the cyclic dinucleotide cyclic diadenylate monophosphate (c-di-AMP) that is synthesized and degraded by specific diadenylate cyclases and phosphodiesterases, respectively (1). The DNA integrity scanning protein DisA from Thermotoga maritima was the first diadenylate cyclase structurally and biochemically characterized (2), and its characterization led to the discovery of c-di-AMP. Many bacteria possess only a single, DisA-type, diadenylate cyclase (1), which is involved in the maintenance of DNA integrity (3, 4, 5). The cyclase activity of DisA is modulated by unusual DNA recombination intermediates (2), but it is presently unclear how c-di-AMP signals the cell that the chromosome integrity is affected.In addition to DisA, two diadenylate cyclases, CdaA and CdaS, are synthesized in the Gram-positive model bacterium Bacillus subtilis (6). While cdaA is expressed during vegetative growth, the cdaS gene is expressed during sporulation or germination of spores (7). The cdaS inactivation decreases the germination efficiency of spores, indicating a germination-specific function for this enzyme (8). Recently, it has been shown that c-di-AMP is essential for the growth of B. subtilis (6, 9, 10). c-d...

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Mutation in the C-Di-AMP Cyclase dacA Affects Fitness and Resistance of Methicillin Resistant Staphylococcus aureus

Cited by 84 publications

References 66 publications

Impact of Antibiotics with Various Target Sites on the Metabolome of Staphylococcus aureus

Impact of Antibiotics with Various Target Sites on the Metabolome of Staphylococcus aureus

Antimicrobial Heteroresistance: an Emerging Field in Need of Clarity

Phenotypes Associated with the Essential Diadenylate Cyclase CdaA and Its Potential Regulator CdaR in the Human Pathogen Listeria monocytogenes

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