Targeted delivery of flagellin by nebulization offers optimized respiratory immunity and defense against pneumococcal pneumonia.

Novel therapeutic strategies are urgently needed to combat pneumonia caused by strains resistant to standard-of-care antibiotics. Previous studies have shown that targeted stimulation of lung innate immune defenses through intranasal administration of the Toll-like receptor 5 agonist flagellin improves the treatment of pneumonia when combined with antibiotics. To promote translation to the clinic application, this study assessed the direct delivery of flagellin to the airways through nebulization using a vibrating mesh nebulizer in mice.

Triggering Toll-Like Receptor 5 Signaling During Pneumococcal Superinfection Prevents the Selection of Antibiotic Resistance.

Toll-like receptor 5 (TLR5) signaling plays a key role in antibacterial defenses. We previously showed that respiratory administration of flagellin, a potent TLR5 agonist, in combination with amoxicillin (AMX) improves the treatment of primary pneumonia or superinfection caused by AMX-sensitive or AMX-resistant Streptococcus pneumoniae. Here, the impact of adjunct flagellin therapy on antibiotic dose/regimen and the selection of antibiotic-resistant S.

Competence remodels the pneumococcal cell wall exposing key surface virulence factors that mediate increased host adherence.

Competence development in the human pathogen Streptococcus pneumoniae controls several features such as genetic transformation, biofilm formation, and virulence. Competent bacteria produce so-called "fratricins" such as CbpD that kill noncompetent siblings by cleaving peptidoglycan (PGN). CbpD is a choline-binding protein (CBP) that binds to phosphorylcholine residues found on wall and lipoteichoic acids (WTA and LTA) that together with PGN are major constituents of the pneumococcal cell wall.

Amoxicillin-resistant can be resensitized by targeting the mevalonate pathway as indicated by sCRilecs-seq.

Antibiotic resistance in the important opportunistic human pathogen is on the rise. This is particularly problematic in the case of the β-lactam antibiotic amoxicillin, which is the first-line therapy. It is therefore crucial to uncover targets that would kill or resensitize amoxicillin-resistant pneumococci.

Soluble C-Type Lectin-Receptor Ligands Stimulate ROS Production in Dendritic Cells and Potentiate Killing of MRSA as Well as the MRSA Induced IL-12 Production.

Methicillin resistant (MRSA) has developed resistance to most β-lactam antibiotics leaving few treatment options against infections with MRSA. Through mannose receptors, mannan potentiates IL-12 production induced by Gram-positive bacteria, a cytokine crucial in the clearance of infection. We investigated the IL-12 potentiating effect of mannan pre-treatment of bone marrow-derived dendritic cells prior to stimulation with clinical MRSA strains.

The Use of Translational Modelling and Simulation to Develop Immunomodulatory Therapy as an Adjunct to Antibiotic Treatment in the Context of Pneumonia.

The treatment of respiratory tract infections is threatened by the emergence of bacterial resistance. Immunomodulatory drugs, which enhance airway innate immune defenses, may improve therapeutic outcome. In this concept paper, we aim to highlight the utility of pharmacometrics and Bayesian inference in the development of immunomodulatory therapeutic agents as an adjunct to antibiotics in the context of pneumonia.

Phenol-Soluble Modulins Modulate Persister Cell Formation in .

is a human pathogen that can cause chronic and recurrent infections and is recalcitrant to antibiotic chemotherapy. This trait is partly attributed to its ability to form persister cells, which are subpopulations of cells that are tolerant to lethal concentrations of antibiotics. Recently, we showed that the phenol-soluble modulins (PSMs) expressed by reduce persister cell formation.

Effect of Co-inhabiting Coagulase Negative Staphylococci on Quorum Sensing, Host Factor Binding, and Biofilm Formation.

is a commensal colonizer of both humans and animals, but also an opportunistic pathogen responsible for a multitude of diseases. In recent years, colonization of pigs by methicillin resistant has become a problem with increasing numbers of humans being infected by livestock strains. In colonization and virulence factor expression is controlled by the quorum sensing system, which responds to and is activated by self-generated, autoinducing peptides (AIPs).

Identification of autoinducing thiodepsipeptides from staphylococci enabled by native chemical ligation.

Staphylococci secrete autoinducing peptides (AIPs) as signalling molecules to regulate population-wide behaviour. AIPs from non-Staphylococcus aureus staphylococci have received attention as potential antivirulence agents to inhibit quorum sensing and virulence gene expression in the human pathogen Staphylococcus aureus. However, only a limited number of AIP structures from non-S.

Punica granatum sarcotesta lectin (PgTeL) impairs growth, structure, viability, aggregation, and biofilm formation ability of Staphylococcus aureus clinical isolates.

In this work, we evaluated the ability of Punica granatum sarcotesta lectin (PgTeL) to impair the growth and viability of the Staphylococcus aureus clinical isolates 8325-4 (non-resistant) and LAC USA300 (MRSA strain). The effects of this lectin on aggregating, hemolytic activity, biofilm-forming ability, and expression of virulence genes (hla, rnaIII, and spa) were also investigated. PgTeL showed antibacterial activity against 8325-4 and LAC USA300 strains by interfering with both the growth (MIC of 6.

Lactam hybrid analogues of solonamide B and autoinducing peptides as potent S. aureus AgrC antagonists.

Emergence of antibiotic-resistant bacteria constitutes an increasing threat to human health. For example, treatment options for Staphylococcus aureus infections is declining with the worldwide spreading of highly virulent community-associated methicillin-resistant S. aureus (CA-MRSA) strains.

Application of an agr-Specific Antivirulence Compound as Therapy for Staphylococcus aureus-Induced Inflammatory Skin Disease.

Atopic dermatitis (AD) is a chronic inflammatory skin disease where more than 90% of patients affected are colonized with Staphylococcus aureus. In AD, S. aureus δ-toxin is a major virulence factor causing cutaneous inflammation via mast cell degranulation.

Linear peptidomimetics as potent antagonists of Staphylococcus aureus agr quorum sensing.

Staphylococcus aureus is an important pathogen causing infections in humans and animals. Increasing problems with antimicrobial resistance has prompted the development of alternative treatment strategies, including antivirulence approaches targeting virulence regulation such as the agr quorum sensing system. agr is naturally induced by cyclic auto-inducing peptides (AIPs) binding to the AgrC receptor and cyclic peptide inhibitors have been identified competing with AIP binding to AgrC.

Corrigendum: Cross-Talk between and Other Staphylococcal Species via the Quorum Sensing System.

[This corrects the article on p. 1733 in vol. 7, PMID: 27877157.

Corrigendum: Cross-Talk between and Other Staphylococcal Species via the Quorum Sensing System.

[This corrects the article on p. 1733 in vol. 7, PMID: 27877157.

Protocols for Screening Antimicrobial Peptides That Influence Virulence Gene Expression in Staphylococcus aureus.

Compounds that inhibit virulence gene expression in bacterial pathogens have received increasing interest as possible alternatives to the traditional antibiotic treatment of infections. For the human pathogen Staphylococcus aureus, we have developed two simple assays based on reporter gene fusions to central virulence genes that are easily applicable for screening various sources of natural and synthetic peptides for anti-virulence effects. The plate assay is qualitative but simultaneously assesses the effect of gradient concentrations of the investigated compound, whereas the liquid assay is quantitative and can be employed to address whether a compound is acting on the central quorum sensing regulatory system, agr, that controls a large number of virulence genes in S.

Norlichexanthone Reduces Virulence Gene Expression and Biofilm Formation in Staphylococcus aureus.

Staphylococcus aureus is a serious human pathogen and antibiotic resistant, community-associated strains, such as the methicillin resistant S. aureus (MRSA) strain USA300, continue to spread. To avoid resistance, anti-virulence therapy has been proposed where toxicity is targeted rather than viability.

Cross-Talk between and Other Staphylococcal Species via the Quorum Sensing System.

Staphylococci are associated with both humans and animals. While most are non-pathogenic colonizers, is an opportunistic pathogen capable of causing severe infections. virulence is controlled by the quorum sensing system responding to secreted auto-inducing peptides (AIPs) sensed by AgrC, a two component histidine kinase.

The agr Inhibitors Solonamide B and Analogues Alter Immune Responses to Staphylococccus aureus but Do Not Exhibit Adverse Effects on Immune Cell Functions.

Staphylococcus aureus infections are becoming increasingly difficult to treat due to antibiotic resistance with the community-associated methicillin-resistant S. aureus (CA-MRSA) strains such as USA300 being of particular concern. The inhibition of bacterial virulence has been proposed as an alternative approach to treat multi-drug resistant pathogens.

Maggot excretions/secretions inhibit multiple neutrophil pro-inflammatory responses.

There is renewed interest in the use of maggots (Lucilia sericata) to aid in healing of chronic wounds. In such wounds neutrophils precipitate tissue damage rather than contribute to healing. As the molecules responsible for the beneficial actions of maggots are contained in their excretions/secretions (ES), we assessed the effects of ES on functional activities of human neutrophils.