Airway Infection Research Articles

P-21. Comparison of Three RSV Vaccine Lower Respiratory Tract Disease Primary Endpoint Definitions for Adult Vaccine

Abstract Background Despite their public health importance, a consensus definition for lower respiratory tract disease (LRTD), or illness (LRTI) is lacking. Clinical trials of three respiratory syncytial virus (RSV) vaccines for older adults used different LRTI/LRTD definitions for vaccine efficacy (VE). We hypothesize differences between definitions could bias product comparisons.Table 1.Variation of signs or symptoms included in criteria to meet case definition of LRTI or LRTD in three RSV vaccine clinical trials Methods We reviewed case definitions for LRTI/LRTD in RSV vaccine clinical trials conducted in older adults.Table 2.Specified values for symptoms/signs included in LRTI/LRTD criteria definitions for three RSV vaccine clinical trials Results Two of three published RSV vaccine clinical trials from Pfizer and Moderna used two outcomes (LRTI/LRTD with ≥2 signs/symptoms or ≥3 signs/symptoms) to measure VE, while the third trial from GlaxoSmithKline (GSK) used one (combining ≥2 and ≥3 signs/symptoms) (Table 1). The Pfizer trial included 5 signs/symptoms as components of LRTI; three of these (tachypnea, wheezing, shortness of breath) suggest lower airway involvement and two (cough and self-reported sputum production) could also result from upper airway infection. At interim analysis, 29 of 45 cases had only 2 symptoms (64.4%). Of these 29, 25 had only cough and sputum production (86.2%). The GSK trial, by contrast, required all LRTD cases to include at least one sign, all of which indicated lower airway involvement (Table 2). The Moderna trial included 10 signs/symptoms, including the potential for subjects to have only cough and sputum production. Even within signs/symptoms, definitions differed (e.g., tachypnea cutoff ranged from 20 to 25 breaths per minute; Table 2). When using comparable definitions, full season 1 VEs for Pfizer and GSK products were similar while the point estimate for the Pfizer product was higher during season 2 (Table 3).Table 3.Vaccine efficacy for three RSV vaccine clinical trials using study LRTI/LRTD definitions Conclusion Lack of standard case definitions limit ability to compare results across trials. Some ≥2 LRTI events for Pfizer and Moderna may not have involved the lower respiratory tract but rather the upper respiratory tract only. The most comparable case definitions likely are ≥3 signs/symptoms LRTI in the Pfizer and Moderna trials, and LRTD in the GSK trial. Disclosures Sarah E. Williams, MD, MPH, Pfizer, Inc: Salary|Pfizer, Inc: Stocks/Bonds (Private Company) Elizabeth Begier, MD, M.P.H., Pfizer Vaccines: Employee|Pfizer Vaccines: Stocks/Bonds (Private Company) Kumar Ilangovan, MD, MSPH, MMCi, Pfizer, Inc.: salary|Pfizer, Inc.: Stocks/Bonds (Public Company) Cassandra Hall-Murray, PharmD, Pfizer, Inc.: employee|Pfizer, Inc.: Stocks/Bonds (Public Company) Bradford D. Gessner, M.D., M.P.H., Pfizer: Employee|Pfizer: Stocks/Bonds (Public Company)

Silver Nanoparticles as Antimicrobial Agents in Veterinary Medicine: Current Applications and Future Perspectives

Silver nanoparticles (AgNPs) have gained significant attention in veterinary medicine due to their antimicrobial properties and potential therapeutic applications. Silver has long been recognized for its ability to combat a wide range of pathogens, and when engineered at the nanoscale, silver’s surface area and reactivity are greatly enhanced, making it highly effective against bacteria, viruses, and fungi. This narrative review aimed to summarize the evidence on the antimicrobial properties of AgNPs and their current and potential clinical applications in veterinary medicine. The antimicrobial action of AgNPs involves several mechanisms, including, among others, the release of silver ions, disruption of cell membranes and envelopes, induction of oxidative stress, inhibition of pathogens’ replication, and DNA damage. Their size, shape, surface charge, and concentration influence their efficacy against bacteria, viruses, and fungi. As a result, the use of AgNPs has been explored in animals for infection prevention and treatment in some areas, such as wound care, coating of surgical implants, animal reproduction, and airway infections. They have also shown promise in preventing biofilm formation, a major challenge in treating chronic bacterial infections. Additionally, AgNPs have been studied for their potential use in animal feed as a supplement to enhance animal health and growth. Research suggested that AgNPs could stimulate immune responses and improve the gut microbiota of livestock, potentially reducing the need for antibiotics in animal husbandry. Despite their promising applications, further research is necessary to fully understand the safety, efficacy, and long-term effects of AgNPs on animals, humans, and the environment.

Passive infusion of an S2-Stem broadly neutralizing antibody protects against SARS-CoV-2 infection and lower airway inflammation in rhesus macaques.

The continued evolution of SARS-CoV-2 variants capable of subverting vaccine and infection-induced immunity suggests the advantage of a broadly protective vaccine against betacoronaviruses (β-CoVs). Recent studies have isolated monoclonal antibodies (mAbs) from SARS-CoV-2 recovered-vaccinated donors capable of neutralizing many variants of SARS-CoV-2 and other β-CoVs. Many of these mAbs target the conserved S2 stem region of the SARS-CoV-2 spike protein, rather than the receptor binding domain contained within S1 primarily targeted by current SARS-CoV-2 vaccines. One of these S2-directed mAbs, CC40.8, has demonstrated protective efficacy in small animal models against SARS-CoV-2 challenge. As the next step in the pre-clinical testing of S2-directed antibodies as a strategy to protect from SARS-CoV-2 infection, we evaluated the in vivo efficacy of CC40.8 in a clinically relevant non-human primate model by conducting passive antibody transfer to rhesus macaques (RM) followed by SARS-CoV-2 challenge. CC40.8 mAb was intravenously infused at 10mg/kg, 1mg/kg, or 0.1 mg/kg into groups (n = 6) of RM, alongside one group that received a control antibody (PGT121). Viral loads in the lower airway were significantly reduced in animals receiving higher doses of CC40.8. We observed a significant reduction in inflammatory cytokines and macrophages within the lower airway of animals infused with 10mg/kg and 1mg/kg doses of CC40.8. Viral genome sequencing demonstrated a lack of escape mutations in the CC40.8 epitope. Collectively, these data demonstrate the protective efficiency of broadly neutralizing S2-targeting antibodies against SARS-CoV-2 infection within the lower airway while providing critical preclinical work necessary for the development of pan-β-CoV vaccines.

Dual RNA sequencing of a co-culture model of Pseudomonas aeruginosa and human 2D upper airway organoids

Pseudomonas aeruginosa is a Gram-negative bacterium that is notorious for airway infections in cystic fibrosis (CF) subjects. Bacterial quorum sensing (QS) coordinates virulence factor expression and biofilm formation at population level. Better understanding of QS in the bacterium-host interaction is required. Here, we set up a new P. aeruginosa infection model, using 2D upper airway nasal organoids that were derived from 3D organoids. Using dual RNA-sequencing, we dissected the interaction between organoid epithelial cells and WT or QS-mutant P. aeruginosa strains. Since only a single healthy individual and a single CF subject were used as donors for the organoids, conclusions about CF-specific effects could not be deduced. However, P. aeruginosa induced epithelial inflammation, whereas QS signaling did not affect the epithelial airway cells. Conversely, the epithelium influenced infection-related processes of P. aeruginosa, including QS-mediated regulation. Comparison of our model with samples from the airways of CF subjects indicated that our model recapitulates important aspects of infection in vivo. Hence, the 2D airway organoid infection model is relevant and may help to reduce the future burden of P. aeruginosa infections in CF.

Pseudomonas superinfection drives Pf phage transmission within airway infections in patients with cystic fibrosis.

Pf bacteriophages, lysogenic viruses that infect Pseudomonas aeruginosa (Pa), are implicated in the pathogenesis of chronic Pa infections; phage-infected (Pf+) strains are known to predominate in people with cystic fibrosis (pwCF) who are older and have more severe disease. However, the transmission patterns of Pf underlying the progressive dominance of Pf+ strains are unclear. In particular, it is unknown whether phage transmission commonly occurs horizontally between bacteria within the airway via viral particles or if Pf+ bacteria are mostly acquired via new Pseudomonas infections. Here, we have studied Pa genomic sequences from 3 patient cohorts totaling 663 clinical isolates from 105 pwCF. We identify Pf+ isolates and analyze transmission patterns of Pf within patients between genetically similar groups of bacteria called "clone types". We find that Pf is predominantly passed down vertically within Pa lineages and rarely via horizontal transfer between clone types within the airway. Conversely, we find extensive evidence of Pa superinfection by a new, genetically distinct Pa that is Pf+. Finally, we find that clinical isolates show reduced activity of the type IV pilus and reduced susceptibility to Pf in vitro. These results cast new light on the transmission of virulence-associated phages in the clinical setting.

Efficacy of melatonin treatment in a cystic fibrosis mouse model of airway infection

Approaches to mitigate the severity of infections and of immune responses are still needed for the treatment of cystic fibrosis (CF) even with the success of highly effective modulator therapies. Previous studies identified reduced levels of melatonin in a CF mouse model related to circadian rhythm dysregulation. Melatonin is known to have immunomodulatory properties and it was hypothesized that treatment with melatonin would improve responses to bacterial infection in CF mice. Data demonstrate that CF mice (G542X/G542X) treated with melatonin (10 µg/mL) in drinking water for 10 weeks had improved responses to airway infection with a clinical isolate of Pseudomonas aeruginosa. Melatonin-treated mice exhibited improved bacterial clearance, reduced inflammatory markers. Mice treated in drinking water for 1 week had improved bacterial clearance but no improvement in inflammation. Wild type (WT) control mice showed no response to melatonin treatment suggesting melatonin is eliciting a CF-specific response in this model. The efficacy of direct melatonin (1 µM) treatment to the airways was also tested and found to be ineffective. In conclusion, long-term systemic treatment with melatonin is an effective therapy in a CF mouse model that normalizes the response to airway infection to a WT pattern.

Temporal Trends in Respiratory Infection Epidemics Among Pediatric Inpatients Throughout the Course of the COVID-19 Pandemic From 2018 to 2023 in Fukushima Prefecture, Japan.

Nonpharmaceutical interventions for coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2, during the pandemic altered the epidemiology of respiratory viruses. This study aimed to determine the changes in respiratory viruses among children hospitalized from 2018 to 2023. Nasopharyngeal specimens were collected from children aged under 15 years with fever and/or respiratory symptoms admitted to a medical institution in Fukushima Prefecture between January 2018 and December 2023. Eighteen respiratory viruses were detected using real-time reverse transcription-polymerase chain reaction. Overall, 1933 patients were included. Viruses were detected in 1377 (71.2%); of these, a single virus was detected in 906 (46.9%) and multiple viruses in 471 (24.3%). Among the viruses whose epidemics were temporarily suppressed, the epidemics of respiratory syncytial virus A and human parainfluenza virus type 3 (HPIV3) started earlier, and the epidemics of human metapneumovirus, HPIV1, and influenza A and C viruses resumed as behavioral restrictions for preventing COVID-19 eased. The median age of children with airway infection was significantly higher in the postpandemic group than in the prepandemic group (18.0 months vs. 21.0 months, p < 0.01). The median age of children infected with HPIV3 and human rhinovirus was significantly higher in the postpandemic group than in the prepandemic group. Strengthening of nonpharmaceutical interventions changed the epidemic dynamics of pediatric infectious diseases, with a trend toward older hospitalized children. Continuous monitoring of pediatric infectious disease outbreaks in hospitalized children can help prepare for the emergence of future viruses and pandemics.

Long-term sublingual bacterial immunotherapy prevents ear, nose and throat infections: A real-life study.

Bacterial extracts have been used for many years to prevent airway infections. Recent findings suggest that immunity can be trained by inducing an immunological memory in both the innate and acquired immune response. This real-life observational study investigated the potential of sublingual bacterial immunotherapy in the prevention of ear, nose, and throat infections. Patients received sublingual bacterial immunotherapy for 12 months and were followed for 24 months. The number of ear, nose, and throat infection episodes from the previous year was recorded during the initial visit based on the patient's clinical history. Patients were then followed up with visits every 2 months, and the occurrence of ear, nose, and throat infection episodes was documented at 6, 12, 18, and 24 months after the start of the study. The results demonstrated a strong potential for preventing ear, nose, and throat infections, with a reduction in the number of episodes by 75.68%, 82.27%, 82.78%, and 89.88% at 6, 12, 18, and 24 months, respectively. No adverse effects related to sublingual bacterial immunotherapy administration were reported. The results suggested that long-term sublingual bacterial immunotherapy is safe and effectively prevents ear, nose, and throat infections, even after treatment ends.

Azithromycin Prevents Subglottic Stenosis in Mice.

Pediatric subglottic stenosis (SGS) is characterized by subglottic narrowing which occurs when pathological fibroblasts deposit extracellular matrix that reduces airway patency. Recent clinical observations have suggested that azithromycin may have favorable impacts on SGS reduction while treating airway infections; furthermore, our recent work in mice demonstrated that the airway microbiome influences SGS. In this work, we characterize the protective effect of azithromycin as an immunomodulatory and antibacterial therapeutic against subglottic stenosis. Immunomodulatory and antifibrotic effects of azithromycin were assessed on TGF-β1-stimulated airway fibroblasts at 10 μg/mL for 5 days. Changes in gene expression were quantified by RT-qPCR and myofibroblast differentiation by α-SMA immunostaining. Murine airways were pretreated (2-weeks) with intranasal azithromycin before SGS injury by a twisted wire brush. Disease severity and immune response were characterized by histology and immunostaining for immune cells. In vitro, azithromycin treatment of TGF-β1-stimulated fibroblasts exhibited strong reductions in extracellular matrix (COL1A1, LOX) and myofibroblast-related gene expression (ACTA2). Notably, there was a significant reduction in pro-fibrotic expression, which was observed with 10 μg/mL azithromycin. Immunostaining of fibroblasts for α-SMA revealed strong reductions in the number of positive-staining cells and the intensity of each positive cell. In vivo, azithromycin exhibited a significant decrease in lamina propria thickness indicative of reduced stenosis with associated changes in T-cell infiltration. Overall, we show azithromycin prevents pro-fibrotic gene expression and myofibroblast differentiation and can help protect mice from developing SGS. This introduces azithromycin as a potential treatment for SGS. NA Laryngoscope, 135:409-415, 2025.

Aqueous extracts of Moringa oleifera and Cinnamomum cassia as promising sources of antibiofilm compounds against mucoid and small colony variants of Pseudomonas aeruginosa and Staphylococcus aureus.

Bacterial biofilms formed by Staphylococcus aureus and Pseudomonas aeruginosa pose significant challenges in treating cystic fibrosis (CF) airway infections due to their resistance to antibiotics. New therapeutic approaches are urgently needed to treat these chronic infections. This study aimed to investigate the antibiofilm potential of various plant extracts, specifically targeting mucoid and small colony variants of P. aeruginosa and S. aureus and strains. Moreover, it aimed to gain insights into the mechanisms of action and the potential phytochemicals responsible for antibiofilm activity. Solid-liquid extractions were performed on seven biomasses using water and ethanol (70 and 96%) under controlled conditions, resulting in 21 distinct plant extracts. These extracts were evaluated for extraction yield, antioxidant activity, phenolic content, chemical composition by HPLC-TOF-MS, and antibiofilm activity using a 96-well plate assay, followed by crystal violet staining, bacterial adhesion assessment, and brightfield microscopy. Our findings revealed that aqueous extracts exhibited the highest inhibition of biofilm formation, with cinnamon bark and moringa seeds showing strong antibiofilm activity against both bacterial species. Brightfield microscopy confirmed that these extracts effectively inhibited biofilm formation. Chemical analysis identified key bioactive compounds, including moringin, benzaldehyde, coumarin, and quinic acid, which likely contribute to the observed antibiofilm effects. Recognizing that the antibiofilm properties of moringin, a common compound in both moringa seed and cinnamon bark extracts, remain underexplored, we conducted potential target identification via PharmMapper and molecular docking analyses to provide a foundation for future research. Computational analyses indicated that moringin might inhibit aspartate-semialdehyde dehydrogenase in P. aeruginosa and potentially interact with an unknown target in S. aureus. In conclusion, moringa seed and cinnamon bark extracts demonstrated significant potential for developing new therapies targeting biofilm-associated infections in CF. Further studies are needed to validate the computational predictions, identify the bacterial targets, and elucidate the precise mechanisms behind moringin's antibiofilm activity, which is likely the potential key contributor to the observed activity of the moringa and cinnamon bark extracts.

Immunomodulatory effects of supercritical CO2 extracted oils from Portulaca oleracea and Perilla frutescens (PPCE) in healthy individuals: a randomized double-blind clinical trial.

The human immune system plays a crucial role in defending the body against various infections, viruses, and external substances, contributing to overall well-being. However, an imbalance in the immune system can lead to increased susceptibility to infections, impacting overall health. Preclinical investigations suggest the potential application of Portulaca oleracea L. and Perilla frutescens var. japonica Hara seed complex extract (PPCE) as a potent biological response modifier in terms of immunity. However, the safety and efficacy of PPCE in boosting immune function have not been investigated clinically. The present study aims to evaluate the safety and efficacy of PPCE on the immune system in healthy adults. An 8-week randomized, double-blinded, placebo-controlled cross-over clinical trial was adopted for the study. Study participants were administered either 1080 mg day-1 of a PPCE supplement or a placebo. The study assessed the Natural Killer (NK) cell activity as the primary outcome measure. Serum concentrations of cytokines (IL-6, IL-12, IFN-γ, TNF-α) and a questionnaire-based assessment of upper airway infection were the secondary outcomes. At the end of the 8 weeks, NK cell activity significantly improved in the PPCE group compared to the placebo group (p < 0.05). Similarly, the concentrations of IFN-γ and IL-12 significantly increased (p < 0.05). However, there were no significant differences between the two groups in the cytokines IL-6 and TNF-α. Additionally, no adverse effects were observed during the trial. These findings suggest that PPCE supplementation is safe and potentially benefits immune stimulation by enhancing NK cell activity and inducing the production of Th-1 type cell-stimulating cytokines like IL-12 in healthy individuals.

Clinical Implications of the Obstructive Pattern on Chest Radiography in Children Aged 3-59 Months With Severe Lower Respiratory Tract Infections.

To investigate the clinical implications of the obstructive pattern on plain chest radiography, defined as peribronchial cuffing or hyperinflation, in young children with severe lower respiratory tract infections (LRTIs). We reviewed all children aged 3‒59 months with LRTIs who underwent radiography and polymerase chain reaction in a Korean emergency department from 2016 through 2020. The radiographs were read as consolidation, peribronchial cuffing, or hyperinflation, with each interrater reliability computed. As per the obstructive pattern, we compared their clinical features, therapeutic interventions, outcomes, and microbiology. Among 599 children with LRTIs, 465 were enrolled, of whom 98 (21.1%) had consolidation (κ = 0.60; 95% confidence interval, 0.50‒0.70), and 367 (78.9%) had peribronchial cuffing (0.55; 0.46‒0.65) or hyperinflation (0.59; 0.52‒0.67). The obstructive pattern was significantly associated with more frequent wheezing (obstructive, 28.6% vs. consolidation, 10.2%) and the use of inhaled albuterol or systemic steroids (39.0% vs. 23.5%), and lower median values or frequencies of age (22.0 vs. 35.0 months), crackle or diminished breath sound (42.0% vs. 61.2%), C-reactive protein (1.4 vs. 2.9 mg/dL), antibiotic therapy (72.2% vs. 93.9%), length of hospital stay (4.0 vs 5.0 days), fever lasting 3 days or longer (7.9% vs. 29.6%), and complications (0.5% vs. 9.2%). Microbiologically, viruses, such as respiratory syncytial virus, were more frequently detected in children with the obstructive pattern or at a younger age. This study confirms an association of the obstructive pattern on radiography with viral infection and inflammatory airway obstruction-relieving therapy in young children with severe LRTIs.

Human airway epithelium controls Pseudomonas aeruginosa infection via inducible nitric oxide synthase.

Airway epithelial cells play a central role in the innate immune response to invading bacteria, yet adequate human infection models are lacking. We utilized mucociliary-differentiated human airway organoids with direct access to the apical side of epithelial cells to model the initial phase of Pseudomonas aeruginosa respiratory tract infection. Immunofluorescence of infected organoids revealed that Pseudomonas aeruginosa invades the epithelial barrier and subsequently proliferates within the epithelial space. RNA sequencing analysis demonstrated that Pseudomonas infection stimulated innate antimicrobial immune responses, but specifically enhanced the expression of genes of the nitric oxide metabolic pathway. We demonstrated that activation of inducible nitric oxide synthase (iNOS) in airway organoids exposed bacteria to nitrosative stress, effectively inhibiting intra-epithelial pathogen proliferation. Pharmacological inhibition of iNOS resulted in expansion of bacterial proliferation whereas a NO producing drug reduced bacterial numbers. iNOS expression was mainly localized to ciliated epithelial cells of infected airway organoids, which was confirmed in primary human lung tissue during Pseudomonas pneumonia. Our findings highlight the critical role of epithelial-derived iNOS in host defence against Pseudomonas aeruginosa infection. Furthermore, we describe a human tissue model that accurately mimics the airway epithelium, providing a valuable framework for systemically studying host-pathogen interactions in respiratory infections.

Characterization of the ciliary beating efficiency in primary diffuse chronic rhinosinusitis.

Ciliary dysfunction may result in chronic airway inflammation and infection causing injury and structural changes to the airway epithelium, leading to a variety of diseases, like bronchiectasis and primary diffuse chronic rhinosinusitis (CRS). Currently, ciliary beating analysis has mainly been studied through the measure of the ciliary beating frequency (CBF) by high-speed digital video microscopy (HSDV). However, a normal CBF has been described in different forms of primary and acquired ciliary dyskinesia.

Reporte de caso: Síndrome de Kartagener completo diagnosticado en la edad adulta

We present the case of a 48-year-old patient with a clinical picture of recurrent upper airway infections of the chronic sinusitis type and acute otitis media, in addition to clinical diagnoses of pneumonia in childhood that required hospital admission for intravenous antibiotic therapy. In addition, the patient had tried to become pregnant several years ago without success. She consulted the pulmonologist for this condition, reaching a diagnosis of bilateral bronchiectasis, chronic sinusitis and situs inversus, diagnosis of complete Kartagener syndrome. The diagnosis, treatment and prognosis of the disease are discussed.

Congenital Tracheal Stenosis: Two Case Reports and Literature Review

Background: Congenital tracheal stenosis is defined as the narrowing of the airway lumen due to the abnormal formation of complete tracheal cartilage rings. It may present with different clinical pictures, depending on the range and extent of stenosis. We present two cases of congenital tracheal stenosis, with a different range of severity and, consequently, different treatment approaches. Case Presentation: We describe the case of a 3-month-old infant with breathing noise that worsened particularly when crying and after nutrition. He presented a congenital funnel-shaped tracheal stenosis with an associated tracheal bronchus, which was treated endoscopically with an endobronchial stent. The second presented case is of a newborn who presented severe respiratory distress and inspiratory stridor in the first hours of life. A congenital cylindrical tracheal stenosis was diagnosed and it was treated surgically through slide tracheoplasty. Discussion: These two cases showed us that congenital tracheal stenosis can present with a very variable clinical picture. Thus, according to clinical presentation, different treatments can be considered. Conclusion: We underline the importance of considering congenital tracheal stenosis in the differential diagnosis of prolonged wheezing and recurrent airway infections.

Immunomodulatory activity of omadacycline in vitro and in a murine model of acute lung injury.

Cystic fibrosis (CF) is characterized by chronic airway obstruction, infection, and inflammation leading to progressive loss of lung function and eventual respiratory failure. Omadacycline, a tetracycline antibiotic, demonstrates in vitro activity against key CF pathogens, substantial lung penetration, and increasing clinical evidence for the treatment of lung infections in people with CF (PwCF). Preliminary in vitro data demonstrate that omadacycline exhibits anti-inflammatory activity. This study aims to determine the anti-inflammatory effects of omadacycline in vitro and in a murine model of lipopolysaccharide (LPS)-induced lung neutrophilia. In vitro, THP-1-derived macrophages were treated with omadacycline (20-100 µg/mL) 30 minutes prior to LPS stimulation. Pro-inflammatory cytokine (TNF-α, IL-1β/6), chemokine (CXCL-1/2), and MMP-9 levels were analyzed after 24 hours by ELISA. Omadacycline's effects on IL-8-induced human neutrophil chemotaxis were also investigated. In vivo, omadacycline (2.5-30 mg/kg), comparators dexamethasone (1 mg/kg), and azithromycin (30 mg/kg) were administered 1 hour before and 6 hours after intranasal LPS challenge, respectively. Leukocyte counts and differentials in bronchoalveolar lavage fluid (BALF), inflammatory mediator levels in BALF and lung homogenates, pulmonary edema markers, and the severity of lung injury were evaluated 24 hours or 48 hours post-challenge. Treatment with omadacycline in vitro resulted in significant, dose-dependent reductions in IL-6, CXCL-1, and MMP-9 expression and inhibition of IL-8-induced neutrophil chemotaxis. In vivo, omadacycline yielded protective and therapeutic effects by reducing the production of proinflammatory cytokines and chemokines and neutrophil infiltration into the lungs, along with modestly improving lung injury severity. These preclinical results suggest that omadacycline may provide dual anti-bacterial and anti-inflammatory activities relevant to chronic lung infection treatment in PwCF.IMPORTANCENontuberculous mycobacteria, particularly Mycobacterium abscessus complex (MABSC), are a major concern for people with cystic fibrosis (PwCF) due to their association with deteriorating lung function. A substantial barrier to effective treatment is the limited number of safe and effective antibiotics. Omadacycline offers a potential advancement in managing MABSC infections in cystic fibrosis due to its activity, effective penetration into pulmonary secretions, improved tolerability, and good oral bioavailability as shown in healthy volunteers. Our study is the first to explore omadacycline's effects in a model of sterile lung inflammation and acute lung injury. We found that omadacycline not only has potent anti-bacterial properties but also exhibits anti-inflammatory effects, reducing lung inflammation and injury in our preclinical models. These findings underscore omadacycline's potential as a dual-action therapy for lung infections in PwCF, indicating significant potential to improve patient outcomes and guide more effective antimicrobial therapy decisions.

Clinical epidemiology and impact of Haemophilus influenzae airway infections in adults with cystic fibrosis

BackgroundHaemophilus influenzae is prevalent within the airways of persons with cystic fibrosis (pwCF). H. influenzae is often associated with pulmonary exacerbations (PEx) in pediatric cohorts, but in adults, studies have yielded conflicting reports around the impact(s) on clinical outcomes such as lung function decline. Accordingly, we sought to discern the prevalence, natural history, and clinical impact of H. influenzae in adult pwCF.MethodsThis single-centre retrospective cohort study reviewed all adult pwCF with H. influenzae sputum cultures between 2002 and 2016. From this cohort, persistently infected subjects (defined as: ≥2 samples with the same pulsotype and > 50% sputum culture-positive for H. influenzae in each year) were matched (1:2) to controls without H. influenzae. Demographic and clinical status (baseline health or during periods of PEx) were obtained at each visit that H. influenzae was cultured. Yearly biobank isolates were typed using pulsed-field gel electrophoresis (PFGE) to assess relatedness.ResultsOver the study period, 30% (n = 70/240) of pwCF were culture positive for H. influenzae, of which 38 (54%) were culture-positive on multiple occasions and 12 (17%) had persistent infection. One hundred and thirty-seven isolates underwent PFGE, with 94 unique pulsotypes identified. Two (1.5%) were serotype f with the rest non-typeable (98.5%). H. influenzae isolation was associated with an increased risk of PEx (RR = 1.61 [1.14–2.27], p = 0.006), however, this association was lost when we excluded those who irregularly produced sputum (i.e. only during a PEx). Annual lung function decline did not differ across cohorts.ConclusionsIsolation of H. influenzae was common amongst adult pwCF but often transient. H. influenzae infection was not associated with acute PEx or chronic lung function decline.

Solid-state NMR compositional analysis of sputum from people with cystic fibrosis

People with the genetic disease cystic fibrosis (CF) often have chronic airway infections and produce airway secretions called sputum. A better understanding of sputum composition is desired in order to track changes in response to CF therapeutics and to improve laboratory models for the study of CF airway infections. The glycosylated protein mucin is a primary component. Along with extracellular DNA, mucin gives rise to the high viscoelasticity of sputum, which inhibits airway clearance and is thought to promote chronic airway infections in people with CF. Past studies of sputum composition identified additional biomolecular components of sputum including other proteins, both glycosylated and not glycosylated, free amino acids, and lipids. Typically, studies of sputum, as well as other complex biological materials, have focused on soluble or isolated components. Solid-state NMR is not limited to the study of soluble components. Instead, it can provide molecular-level information about insoluble biological samples. Additionally, solid-state NMR can provide information about sample composition without requiring any processing of the sample, eliminating the possibility of misestimating certain components due to insolubility or potential sample loss in isolation steps. In this study, we used both 13C and 31P CPMAS to investigate the total composition of sputum samples obtained from six people with CF. We compared these spectra to those of commercially available mucin, DNA, and phospholipid samples. Lastly, we performed complementary biochemical analyses to identify specific proteins present in the sputum samples. Overall, our findings provide insight into the composition of unprocessed sputum samples from people with CF, which can be used as a benchmark for future investigations of CF and infections in the airways of people with CF. Further, this study provides opportunities to expand the solid-state NMR approach to include dynamic nuclear polarization (DNP) to obtain high-resolution information of sputum and similar biological samples that are not feasible to isotopically enrich.

Pseudomonas aeruginosa faces a fitness trade-off between mucosal colonization and antibiotic tolerance during airway infection.

Pseudomonas aeruginosa frequently causes antibiotic-recalcitrant pneumonia, but the mechanisms driving its adaptation during human infections remain unclear. To reveal the selective pressures and adaptation strategies at the mucosal surface, here we investigated P. aeruginosa growth and antibiotic tolerance in tissue-engineered airways by transposon insertion sequencing (Tn-seq). Metabolic modelling based on Tn-seq data revealed the nutritional requirements for P. aeruginosa growth, highlighting reliance on glucose and lactate and varying requirements for amino acid biosynthesis. Tn-seq also revealed selection against biofilm formation during mucosal growth in the absence of antibiotics. Live imaging in engineered organoids showed that biofilm-dwelling cells remained sessile while colonizing the mucosal surface, limiting nutrient foraging and reduced growth. Conversely, biofilm formation increased antibiotic tolerance at the mucosal surface. Moreover, mutants with exacerbated biofilm phenotypes protected less tolerant but more cytotoxic strains, contributing to phenotypic heterogeneity. P. aeruginosa must therefore navigate conflicting physical and biological selective pressures to establish chronic infections.