Intranasal exposure to commensal bacterium Rothia mucilaginosa protects against influenza A virus infection.

The respiratory tract hosts a diverse microbial community whose composition varies with anatomical location and throughout life. Rothia mucilaginosa, a common commensal of the upper respiratory tract and oral cavity, has recently been recognized for its ability to inhibit bacteria-triggered pro-inflammatory responses. However, its role in modulating the immune response to viral infections such as influenza A virus (IAV) pneumonia, remains unknown.

Recreating chronic respiratory infections using physiologically relevant models.

Despite the need for effective treatments against chronic respiratory infections (often caused by pathogenic biofilms), only a few new antimicrobials have been introduced to the market in recent decades. Although different factors impede the successful advancement of antimicrobial candidates from the bench to the clinic, a major driver is the use of poorly predictive model systems in preclinical research. To bridge this translational gap, significant efforts have been made to develop physiologically relevant models capable of recapitulating the key aspects of the airway microenvironment that are known to influence infection dynamics and antimicrobial activity In this review, we provide an overview of state-of-the-art cell culture platforms and models that have been used to model chronic (biofilm-associated) airway infections, including air-liquid interfaces, three-dimensional cultures obtained with rotating-wall vessel bioreactors, lung-on-a-chips and pig lungs.

Antibiofilm activity of species from the cystic fibrosis lung microbiota against .

It is increasingly recognized that interspecies interactions may modulate the pathogenicity of during chronic lung infections. Nevertheless, while the interaction between and pathogenic microorganisms co-infecting the lungs has been widely investigated, little is known about the influence of other members of the lung microbiota on the infection process. In this study, we focused on investigating the impact of species isolated from the sputum of people with cystic fibrosis (pwCF) on biofilm formation and virulence factor production by .

Genome-scale model of predicts gene essentialities and reveals metabolic capabilities.

Cystic fibrosis (CF), an inherited genetic disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator gene, results in sticky and thick mucosal fluids. This environment facilitates the colonization of various microorganisms, some of which can cause acute and chronic lung infections, while others may positively impact the disease. , an oral commensal, is relatively abundant in the lungs of CF patients.

Selective Replacement of Cholesterol with Cationic Amphiphilic Drugs Enables the Design of Lipid Nanoparticles with Improved RNA Delivery.

The delivery of RNA across biological barriers can be achieved by encapsulation in lipid nanoparticles (LNPs). Cationic amphiphilic drugs (CADs) are pharmacologically diverse compounds with ionizable lipid-like features. In this work, we applied CADs as a fifth component of state-of-the-art LNPs via microfluidic mixing.

Pooling isolates to address the diversity in antimicrobial susceptibility of in cystic fibrosis.

People with cystic fibrosis (pwCF) often suffer from chronic lung infections with . While antibiotics are still commonly used to treat infections, there is a high discordance between and antibiotic efficacy, which contributes to suboptimal antibiotic therapy. In the present study, we found that isolates from the same sputum sample had highly diverse antibiotic resistance profiles [based on the minimal inhibitory concentration (MIC)], which may explain the reported discrepancy between and antibiotic efficacy.

Effect of malate on the activity of ciprofloxacin against in different and -like infection models.

The clinical significance of infections and the tolerance of this opportunistic pathogen to antibiotic therapy makes the development of novel antimicrobial strategies an urgent need. We previously found that D,L-malic acid potentiates the activity of ciprofloxacin against biofilms grown in a synthetic cystic fibrosis sputum medium by increasing metabolic activity and tricarboxylic acid cycle activity. This suggested a potential new strategy to improve antibiotic therapy in infections.

Combining phages and antibiotic to enhance antibiofilm efficacy against an dual species wound biofilm.

Chronic wound management is extremely challenging because of the persistence of biofilm-forming pathogens, such as and , which are the prevailing bacterial species that co-infect chronic wounds. Phage therapy has gained an increased interest to treat biofilm-associated infections, namely when combined with antibiotics. Here, we tested the effect of gentamicin as a co-adjuvant of phages in a dual species-biofilm wound model formed on artificial dermis.

The development and characterization of in vivo-like three-dimensional models of bronchial epithelial cell lines.

In vitro models of differentiated respiratory epithelium that allow high-throughput screening are an important tool to explore new therapeutics for chronic respiratory diseases. In the present study, we developed in vivo-like three-dimensional (3-D) models of bronchial epithelial cell lines that are commonly used to study chronic lung disease (16HBE14o, CFBE41o and CFBE41o 6.2 WT-CFTR).

Commensal bacteria of the lung microbiota synergistically inhibit inflammation in a three-dimensional epithelial cell model.

Patients with chronic lung disease suffer from persistent inflammation and are typically colonized by pro-inflammatory pathogenic bacteria. Besides these pathogens, a wide variety of commensal species is present in the lower airways but their role in inflammation is unclear. Here, we show that the lung microbiota contains several species able to inhibit activation of the pro-inflammatory NF-κB pathway and production of interleukin 8 (IL-8), triggered by lipopolysaccharide (LPS) or HO, in a physiologically relevant three-dimensional (3D) lung epithelial cell model.

High throughput determination of the biofilm prevention concentration for biofilms using a synthetic cystic fibrosis sputum medium.

The presence of biofilms in cystic fibrosis (CF) patients suffering from chronic lung infections contributes to the failure of antimicrobial therapy. Conventionally, the minimal inhibitory concentration (MIC) is determined to assess the antimicrobial susceptibility of a pathogen, however this parameter fails to predict success in treating biofilm-associated infections. In the present study we developed a high throughput method to determine the antimicrobial concentration required to prevent biofilm formation, using a synthetic cystic fibrosis sputum medium (SCFM2).

Direct lysis of 3D cell cultures for RT-qPCR gene expression quantification.

In vitro cell culture experiments are widely used to study cellular behavior in most biological research fields. Except for suspension cells, most human cell types are cultured as adherent monolayers on a plastic surface. While technically convenient, monolayer cultures can suffer from limitations in terms of physiological relevance, as their resemblance to complex in vivo tissue structures is limited.

Microbial diversity and antimicrobial susceptibility in endotracheal tube biofilms recovered from mechanically ventilated COVID-19 patients.

In patients with acute respiratory failure, mechanical ventilation through an endotracheal tube (ET) may be required to correct hypoxemia and hypercarbia. However, biofilm formation on these ETs is a risk factor for infections in intubated patients, as the ET can act as a reservoir of microorganisms that can cause infections in the lungs. As severely ill COVID-19 patients often need to be intubated, a better knowledge of the composition of ET biofilms in this population is important.

is an anti-inflammatory bacterium in the respiratory tract of patients with chronic lung disease.

Background: Chronic airway inflammation is the main driver of pathogenesis in respiratory diseases such as severe asthma, chronic obstructive pulmonary disease, cystic fibrosis (CF) and bronchiectasis. While the role of common pathogens in airway inflammation is widely recognised, the influence of other microbiota members is still poorly understood.

Methods: We hypothesised that the lung microbiota contains bacteria with immunomodulatory activity which modulate net levels of immune activation by key respiratory pathogens.

Model Systems to Study the Chronic, Polymicrobial Infections in Cystic Fibrosis: Current Approaches and Exploring Future Directions.

A recent workshop titled "Developing Models to Study Polymicrobial Infections," sponsored by the Dartmouth Cystic Fibrosis Center (DartCF), explored the development of new models to study the polymicrobial infections associated with the airways of persons with cystic fibrosis (CF). The workshop gathered 35+ investigators over two virtual sessions. Here, we present the findings of this workshop, summarize some of the challenges involved with developing such models, and suggest three frameworks to tackle this complex problem.

The cystic fibrosis lung microenvironment alters antibiotic activity: causes and effects.

Chronic airway colonisation by , a hallmark of cystic fibrosis (CF) lung disease, is associated with increased morbidity and mortality and despite aggressive antibiotic treatment, is able to persist in CF airways. antibiotic susceptibility assays are poor predictors of antibiotic efficacy to treat respiratory tract infections in the CF patient population and the selection of the antibiotic(s) is often made on an empirical base. In the current review, we discuss the factors that are responsible for the discrepancies between antibiotic activity and clinical efficacy We describe how the CF lung microenvironment, shaped by host factors (such as iron, mucus, immune mediators and oxygen availability) and the microbiota, influences antibiotic activity and varies widely between patients.

Porphyrins produced by acneic strains activate the inflammasome by inducing K leakage.

Some subgroups dominate on healthy skin, whereas others are frequently acne associated. Here we provide mechanistic insights into this difference, using an anaerobic keratinocyte-sebocyte- co-culture model. An acneic strain as well as its porphyrins activates NRLP3 inflammasome assembly, whereas this was not observed with a non-acneic strain.

Model system parameters influence the sodium hypochlorite susceptibility of endodontic biofilms.

Aim: To evaluate in a laboratory setting the influence of several model system parameters on the sodium hypochlorite (NaOCl) susceptibility of endodontic biofilms. Based on these findings, a relevant in vitro endodontic biofilm model is proposed.

Methodology: In vitro biofilms were cultured, varying the following experimental model parameters: biofilm composition (monospecies Enterococcus faecalis and a multispecies biofilm including E.

The Quorum-Sensing Inhibitor Furanone C-30 Rapidly Loses Its Tobramycin-Potentiating Activity against Pseudomonas aeruginosa Biofilms during Experimental Evolution.

The use of quorum-sensing inhibitors (QSI) has been proposed as an alternative strategy to combat antibiotic resistance. QSI reduce the virulence of a pathogen without killing it and it is claimed that resistance to such compounds is less likely to develop, although there is a lack of experimental data supporting this hypothesis. Additionally, such studies are often carried out in conditions that do not mimic the situation.

Antibiotic susceptibility of cystic fibrosis lung microbiome members in a multispecies biofilm.

The lungs of cystic fibrosis (CF) patients are often chronically colonized by multiple microbial species that can form biofilms, including the major CF pathogen . Herewith, lower microbial diversity in CF airways is typically associated with worse health outcomes. In an attempt to treat CF lung infections patients are frequently exposed to antibiotics, which may affect microbial diversity.

Phylotype I and II Strains Interact Differently With Human Skin Cells.

Acne vulgaris is one of the most common skin disorders and affects the pilosebaceous units. Although the exact pathogenesis of acne is still unknown, (formerly known as ) is considered one of the key contributing factors. In fact, a significant association exists between strains belonging to phylotype I and acne.