Prophylactic Efficacy of Topical Temporin A and RNAIII-Inhibiting Peptide in a Subcutaneous Rat Pouch Model of Graft Infection Attributable to Staphylococci With Intermediate Resistance to Glycopeptides

Cirioni, Oscar; Giacometti, Andrea; Ghiselli, Roberto; Dell'Acqua, Giorgio; Gov, Yael; Kamysz, Wojciech; Łukasiak, Jerzy; Mocchegiani, Federico; Orlando, Fiorenza; D'Amato, Giuseppina; Balaban, Naomi; Saba, Vittorio; Scalise, Giorgio

doi:10.1161/01.cir.0000083717.85060.16

Cited by 76 publications

(53 citation statements)

References 37 publications

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“…Cells containing TRAP that is defective in expression or phosphorylation adhere less to plastic polymers and to host cells in vitro and do not form a biofilm in vivo (1,3,6,(9)(10)(11)(12)(15)(16)(17). Indeed, in the absence of TRAP expression or phosphorylation, although agr is suppressed as shown here (see below), no substantial upregulation of adhesion molecules is observed.…”

Section: Discussionmentioning

confidence: 64%

Transcriptional Profiling of Target of RNAIII-Activating Protein, a Master Regulator of Staphylococcal Virulence

et al. 2005

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Staphylococcus aureus is a gram-positive bacterium that is part of the normal healthy flora but that can become virulent and cause infections by producing biofilms and toxins. The production of virulence factors is regulated by cell-cell communication (quorum sensing) through the histidine phosphorylation of target of RNAIII-activating protein (TRAP), which is a 21-kDa protein that is highly conserved among staphylococci. Using microarray analysis, we show here that the expression and phosphorylation of TRAP upregulate the expression of most, if not all, toxins known to date, as well as their global regulator agr. In addition, we show here that the expression and phosphorylation of TRAP are also necessary for the expression of genes known to be necessary for the survival of the bacteria in a biofilm, like arc, pyr, and ure. TRAP is thus demonstrated to be a master regulator of staphylococcal pathogenesis.Staphylococcus aureus is a gram-positive bacterium that is part of the normal flora of the skin, but it can become pathogenic and cause fatal diseases once it forms a biofilm and/or produces toxins (18,25). Biofilm formation and toxin production are regulated by a quorum-sensing mechanism, where molecules produced and secreted by the bacteria (autoinducers) reach a threshold concentration and activate signal transduction pathways, leading to activation of the genes that encode virulence factors (22,27,32,35,37).To date, two staphylococcal quorum-sensing systems (SQS) have been described. SQS 1 consists of the autoinducer RNAIII-activating protein (RAP) and its target molecule, target of RNAIII-activating protein (TRAP) (4,5,20,21). SQS 2 consists of the molecules encoded by agr (28, 29). The bacteria secrete RAP, a 33-kDa protein, as they multiply (23); when RAP reaches a threshold concentration (in the mid-exponential phase of growth), RAP induces the histidine phosphorylation of its target molecule TRAP (5, 20). The phosphorylation of TRAP leads, in an as-yet-unknown mechanism, to the synthesis of SQS 2, which is composed of the products of the agr system. agr encodes two divergently transcribed transcripts, RNAII and RNAIII (28,29). RNAII encodes AgrA, AgrC, AgrD, and AgrB, where AgrD is a propeptide that yields an autoinducing peptide (AIP) that is processed and secreted with the aid of AgrB. Once agr is activated and AIP is secreted, AIP induces the phosphorylation of its receptor AgrC, leading to the production of the regulatory RNA molecule termed RNAIII (28). RNAIII upregulates the production of numerous secreted toxins (28). SQS 1 and SQS 2 interact with one another because once AIP is made in the mid-exponential phase of growth, it indirectly downregulates the phosphorylation of TRAP (5). The interplay between the phosphorylation of TRAP and AgrC by their respective autoinducers, RAP or AIP, regulates the expression of adhesion molecules or toxins Like typical sensors of classical two component systems, TRAP is histidine phosphorylated in the presence of RAP (5, 20); immunoelectron microscopy and West...

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Section: Discussionmentioning

confidence: 64%

Transcriptional Profiling of Target of RNAIII-Activating Protein, a Master Regulator of Staphylococcal Virulence

et al. 2005

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“…Site-directed Mutagenesis-TRAP has been shown to be histidine-phosphorylated (5), and phosphorylation has been demonstrated to be important for its activity (23)(24)(25)(26). All known TRAP protein sequences in S. aureus and S. epidermidis have three conserved histidine residues (His-66, His-79, and His-154) (Fig.…”

Section: (Cat To Gct)mentioning

confidence: 99%

“…Indeed RIP, which inhibits staphylococcal pathogenesis, acts by inhibiting TRAP phosphorylation. The synthetic amide form of RIP (YSPWTNF-NH 2 ) has already been shown to prevent numerous types of S. aureus and S. epidermidis infections in vivo, including medical device-associated infections (tested against MRSA, MRSE, VISA, and VISE) (23)(24)(25)(26). These findings indicate that RIP can suppress virulence of any staphylococcal strain, which is not surprising considering the fact that the signaling molecule it targets (TRAP) is highly conserved across strains and species.…”

Section: (Cat To Gct)mentioning

confidence: 99%

Quorum Sensing in Staphylococci Is Regulated via Phosphorylation of Three Conserved Histidine Residues

Gov

Borovok

Korem

et al. 2004

Journal of Biological Chemistry

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Staphylococcus aureus cause infections by producing toxins, a process regulated by cell-cell communication (quorum sensing) through the histidine-phosphorylation of the target of RNAIII-activating protein (TRAP). We show here that TRAP is highly conserved in staphylococci and contains three completely conserved histidine residues (His-66, His-79, His-154) that are phosphorylated and essential for its activity. This was tested by constructing a TRAP ؊ strain with each of the conserved histidine residues changed to alanine by site-directed mutagenesis. All mutants were tested for pathogenesis in vitro (expression of RNAIII and hemolytic activity) and in vivo (murine cellulitis model). Results show that RNAIII is not expressed in the TRAP ؊ strain, that it is non hemolytic, and that it does not cause disease in vivo. These pathogenic phenotypes could be rescued in the strain containing the recovered traP, confirming the importance of TRAP in S. aureus pathogenesis. The phosphorylation of TRAP mutated in any of the conserved histidine residues was significantly reduced, and mutants defective in any one of these residues were non-pathogenic in vitro or in vivo, whereas those mutated in a non-conserved histidine residue (His-124) were as pathogenic as the wild type. These results confirm the importance of the three conserved histidine residues in TRAP activity. The phosphorylation pattern, structure, and gene organization of TRAP deviates from signaling molecules known to date, suggesting that TRAP belongs to a novel class of signal transducers.

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“…In recent years research efforts in the field of new biomaterials have aimed at the discovery of new devices refractory to the microbial adhesion (6)(7).…”

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confidence: 99%

Comparison of Anti-Bacterial Prophylactic Properties of Two Different Vascular Grafts: Action of Anti-Bacterial Graft Coating and Systemic Antibiotic Treatment

Artini¹,

Scoarughi²,

Papa³

et al. 2010

Int J Immunopathol Pharmacol

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M.A. and G.L.S. contributed equally to this researchThe main problem associated with artificial vascular devices is the risk of bacterial infections, mostly sustained by coagulase negative staphylococci or Staphylococcus aureus. Many efforts have been made to identify materials refractory to bacterial adhesion. The aim of our study is to verify the antimicrobial properties of two kinds of vascular prosthesis to prevent early onset infections and the efficacy of the concomitant action of a systemic antibiotic treatment. Adult male Wistar rats were used. We subcutaneously implanted in four groups a silver-coated prosthesis fragment, and a rifampicin-soaked prosthesis fragment in the remaining four groups. We inoculated in the site of implant a high bacterial burden of S. aureus in four groups and a low burden in the remaining groups. Systemic levofloxacin was administered for seven days in four groups representing the two kinds of prosthesis; after 21 days the rats were sacrificed, prosthesis fragments were sonicated and the corresponding supernatants were plated for bacterial counts. The rifampicin-soaked prostheses explanted from rats treated with levofloxacin were sterile, regardless of the bacterial inoculum. In other groups some prostheses were colonized. In the experimental rat model used, the action of local and systemic antibiotic treatment was able to reduce colonisation of artificial prostheses.Vascular grafts are made with highly biocompatible polymeric materials. The main problem associated with their use is related to infections due to colonization of the graft by biofilm forming bacteria, even in the very early phases after graft implant. The consequence is graft failure and removal (1-2).Gram-positive bacteria, especially staphylococci, are the prevalentpathogens involved in approximately 80% of all cases (3-5). In arterial graft infections S.aureus is the most common organism isolated from infected synthetic grafts, accounting for 24% to 36% of isolates, but coagulase-negative staphylococci are isolated in 4% to 21% of infections. In recent years research efforts in the field of new biomaterials have aimed at the discovery of new devices refractory to the microbial adhesion (6-7).The aim of our study is to verify the susceptibility

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Prophylactic Efficacy of Topical Temporin A and RNAIII-Inhibiting Peptide in a Subcutaneous Rat Pouch Model of Graft Infection Attributable to Staphylococci With Intermediate Resistance to Glycopeptides

Cited by 76 publications

References 37 publications

Transcriptional Profiling of Target of RNAIII-Activating Protein, a Master Regulator of Staphylococcal Virulence

Transcriptional Profiling of Target of RNAIII-Activating Protein, a Master Regulator of Staphylococcal Virulence

Quorum Sensing in Staphylococci Is Regulated via Phosphorylation of Three Conserved Histidine Residues

Comparison of Anti-Bacterial Prophylactic Properties of Two Different Vascular Grafts: Action of Anti-Bacterial Graft Coating and Systemic Antibiotic Treatment

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