Genetic liability of gut microbiota for idiopathic pulmonary fibrosis and lung function: a two-sample Mendelian randomization study.

Background: The microbiota-gut-lung axis has elucidated a potential association between gut microbiota and idiopathic pulmonary fibrosis (IPF). However, there is a paucity of population-level studies with providing robust evidence for establishing causality. This two-sample Mendelian randomization (MR) analysis aimed to investigate the causal relationship between the gut microbiota and IPF as well as lung function. Materials and methods: Adhering to Mendel's principle of inheritance, this MR analysis utilized summary-level data from respective genome-wide association studies (GWAS) involving 211 gut microbial taxa, IPF, and lung function indicators such as FEV1, FVC, and FEV1/FVC. A bidirectional two-sample MR design was employed, utilizing multiple MR analysis methods, including inverse variance-weighted (IVW), weighted median, MR-Egger, and weighted mode. Multivariable MR (MVMR) was used to uncover mediating factors connecting the exposure and outcome. Additionally, comprehensive sensitivity analyses were conducted to ensure the robustness of the results. Results: The MR results confirmed four taxa were found causally associated with the risk of IPF. Order Bifidobacteriales (OR=0.773, 95% CI: 0.610-0.979, p=0.033), Family Bifidobacteriaceae (OR=0.773, 95% CI: 0.610-0.979, p=0.033), and Genus RuminococcaceaeUCG009 (OR=0.793, 95% CI: 0.652-0.965, p=0.020) exerted protective effects on IPF, while Genus Coprococcus2 (OR=1.349, 95% CI: 1.021-1.783, p=0.035) promote the development of IPF. Several taxa were causally associated with lung function, with those in Class Deltaproteobacteria, Order Desulfovibrionales, Family Desulfovibrionaceae, Class Verrucomicrobiae, Order Verrucomicrobiales and Family Verrucomicrobiaceae being the most prominent beneficial microbiota, while those in Family Lachnospiraceae, Genus Oscillospira, and Genus Parasutterella were associated with impaired lung function. As for the reverse analysis, MR results confirmed the effects of FEV1 and FVC on the increased abundance of six taxa (Phylum Actinobacteria, Class Actinobacteria, Order Bifidobacteriales, Family Bifidobacteriaceae, Genus Bifidobacterium, and Genus Ruminiclostridium9) with a boosted level of evidence. MVMR suggested monounsaturated fatty acids, total fatty acids, saturated fatty acids, and ratio of omega-6 fatty acids to total fatty acids as potential mediating factors in the genetic association between gut microbiota and IPF. Conclusion: The current study suggested the casual effects of the specific gut microbes on the risk of IPF and lung function. In turn, lung function also exerted a positive role in some gut microbes. A reasonable dietary intake of lipid substances has a certain protective effect against the occurrence and progression of IPF. This study provides novel insights into the potential role of gut microbiota in IPF and indicates a possible gut microbiota-mediated mechanism for the prevention of IPF.

Cryptococcus neoformans trehalose-6-phosphate synthase (tps1) promotes organ-specific virulence and fungal protection against multiple lines of host defenses.

Trehalose-6-phosphate synthase (TPS1) was identified as a virulence factor for Cryptococcus neoformans and a promising therapeutic target. This study reveals previously unknown roles of TPS1 in evasion of host defenses during pulmonary and disseminated phases of infection. In the pulmonary infection model, TPS1-deleted (tps1Δ) Cryptococci are rapidly cleared by mouse lungs whereas TPS1-sufficent WT (H99) and revertant (tps1Δ:TPS1) strains expand in the lungs and disseminate, causing 100% mortality. Rapid pulmonary clearance of tps1Δ mutant is T-cell independent and relies on its susceptibility to lung resident factors and innate immune factors, exemplified by tps1Δ but not H99 inhibition in a coculture with dispersed lung cells and its rapid clearance coinciding with innate leukocyte infiltration. In the disseminated model of infection, which bypasses initial lung-fungus interactions, tps1Δ strain remains highly attenuated. Specifically, tps1Δ mutant is unable to colonize the lungs from the bloodstream or expand in spleens but is capable of crossing into the brain, where it remains controlled even in the absence of T cells. In contrast, strains H99 and tps1Δ:TPS1 rapidly expand in all studied organs, leading to rapid death of the infected mice. Since the rapid pulmonary clearance of tps1Δ mutant resembles a response to acapsular strains, the effect of tps1 deletion on capsule formation in vitro and in vivo was examined. Tps1Δ cryptococci form capsules but with a substantially reduced size. In conclusion, TPS1 is an important virulence factor, allowing C. neoformans evasion of resident pulmonary and innate defense mechanisms, most likely via its role in cryptococcal capsule formation.

Longitudinal multicompartment characterization of host-microbiota interactions in patients with acute respiratory failure.

Critical illness can significantly alter the composition and function of the human microbiome, but few studies have examined these changes over time. Here, we conduct a comprehensive analysis of the oral, lung, and gut microbiota in 479 mechanically ventilated patients (223 females, 256 males) with acute respiratory failure. We use advanced DNA sequencing technologies, including Illumina amplicon sequencing (utilizing 16S and ITS rRNA genes for bacteria and fungi, respectively, in all sample types) and Nanopore metagenomics for lung microbiota. Our results reveal a progressive dysbiosis in all three body compartments, characterized by a reduction in microbial diversity, a decrease in beneficial anaerobes, and an increase in pathogens. We find that clinical factors, such as chronic obstructive pulmonary disease, immunosuppression, and antibiotic exposure, are associated with specific patterns of dysbiosis. Interestingly, unsupervised clustering of lung microbiota diversity and composition by 16S independently predicted survival and performed better than traditional clinical and host-response predictors. These observations are validated in two separate cohorts of COVID-19 patients, highlighting the potential of lung microbiota as valuable prognostic biomarkers in critical care. Understanding these microbiome changes during critical illness points to new opportunities for microbiota-targeted precision medicine interventions.

Exploratory Research for New Diagnostic Markers of Mucormycosis.

Mucormycosis is a fungal infectious disease caused by Rhizopus oryzae and other members of the order Mucorales, and it is known as one of the most lethal fungal infections. Early diagnosis of mucormycosis improves prognosis because of limited effective treatments and the rapid progression of the disease. On the other hand, the lack of characteristic clinical findings in mucormycosis and the challenge of early definitive diagnosis make early treatment difficult. Our goal was to establish a serodiagnostic method to detect Rhizopus specific antigen (RSA), and we have developed a diagnostic kit by Enzyme-linked immuno-sorbent assay (ELISA) using a monoclonal antibody against this antigen. RSA increased over time in the serum and alveolar lavage fluid of R. oryzae-infected mice. RSA was also detected in serum and alveolar fluid, even at an early stage (Day 1), when the tissue invasion of R. oryzae mycelium was not histopathologically detectable in the lungs of R. oryzae-infected mice. Further evaluation is needed to determine the feasibility of using this assay in clinical practice.

COVID-19 PBMCs are doubly harmful, through LDN-mediated lung epithelial damage and monocytic impaired responsiveness to live Pseudomonas aeruginosa exposure.

Introduction: Although many studies have underscored the importance of T cells, phenotypically and functionally, fewer have studied the functions of myeloid cells in COVID disease. In particular, the potential role of myeloid cells such as monocytes and low-density neutrophils (LDNs) in innate responses and particular in the defense against secondary bacterial infections has been much less documented. Methods: Here, we compared, in a longitudinal study, healthy subjects, idiopathic fibrosis patients, COVID patients who were either hospitalized/moderate (M-) or admitted to ICU (COV-ICU) and patients in ICU hospitalized for other reasons (non-COV-ICU). Results: We show that COVID patients have an increased proportion of low-density neutrophils (LDNs), which produce high levels of proteases (particularly, NE, MMP-8 and MMP-9) (unlike non-COV-ICU patients), which are partly responsible for causing type II alveolar cell damage in co-culture experiments. In addition, we showed that M- and ICU-COVID monocytes had reduced responsiveness towards further live Pseudomonas aeruginosa (PAO1 strain) infection, an important pathogen colonizing COVID patients in ICU, as assessed by an impaired secretion of myeloid cytokines (IL-1, TNF, IL-8,…). By contrast, lymphoid cytokines (in particular type 2/type 3) levels remained high, both basally and post PAO1 infection, as reflected by the unimpaired capacity of T cells to proliferate, when stimulated with anti-CD3/CD28 beads. Discussion: Overall, our results demonstrate that COVID circulatory T cells have a biased type 2/3 phenotype, unconducive to proper anti-viral responses and that myeloid cells have a dual deleterious phenotype, through their LDN-mediated damaging effect on alveolar cells and their impaired responsiveness (monocyte-mediated) towards bacterial pathogens such as P. aeruginosa.

Role of the intestinal microbiota in host defense against respiratory viral infections.

Viral infections, including those affecting the respiratory tract, can alter the composition of the intestinal microbiota, which, in turn, can significantly influence both innate and adaptive immune responses, resulting in either enhanced pathogen clearance or exacerbation of the infection, possibly leading to inflammatory complications. A deeper understanding of the interplay between the intestinal microbiota and host immune responses in the context of respiratory viral infections (i.e. the gut-lung axis) is necessary to develop new treatments. This review highlights key mechanisms by which the intestinal microbiota, including its metabolites, can act locally or at distant organs to combat respiratory viruses. Therapeutics aimed at harnessing the microbiota to prevent and/or help treat respiratory viral infections represent a promising avenue for future investigation.

Sialic Acid-Siglec-E Interactions Regulate the Response of Neonatal Macrophages to Group B Streptococcus.

The mammalian Siglec receptor sialoadhesin (Siglec1, CD169) confers innate immunity against the encapsulated pathogen group B Streptococcus (GBS). Newborn lung macrophages have lower expression levels of sialoadhesin at birth compared with the postnatal period, increasing their susceptibility to GBS infection. In this study, we investigate the mechanisms regulating sialoadhesin expression in the newborn mouse lung. In both neonatal and adult mice, GBS lung infection reduced Siglec1 expression, potentially delaying acquisition of immunity in neonates. Suppression of Siglec1 expression required interactions between sialic acid on the GBS capsule and the inhibitory host receptor Siglec-E. The Siglec1 gene contains multiple STAT binding motifs, which could regulate expression of sialoadhesin downstream of innate immune signals. Although GBS infection reduced STAT1 expression in the lungs of wild-type newborn mice, we observed increased numbers of STAT1+ cells in Siglece-/- lungs. To test if innate immune activation could increase sialoadhesin at birth, we first demonstrated that treatment of neonatal lung macrophages ex vivo with inflammatory activators increased sialoadhesin expression. However, overcoming the low sialoadhesin expression at birth using in vivo prenatal exposures or treatments with inflammatory stimuli were not successful. The suppression of sialoadhesin expression by GBS-Siglec-E engagement may therefore contribute to disease pathogenesis in newborns and represent a challenging but potentially appealing therapeutic opportunity to augment immunity at birth.

The imbalance of pulmonary Th17/Treg cells in BALB/c suckling mice infected with respiratory syncytial virus-mediated intestinal immune damage and gut microbiota changes.

The immune response induced by respiratory syncytial virus (RSV) infection is closely related to changes in the composition and function of gastrointestinal microorganisms. However, the specific mechanism remains unknown and the pulmonary-intestinal axis deserves further study. In this study, the mRNA levels of ROR-γt and Foxp3 in the lung and intestine increased first and then decreased. IL-17 and IL-22 reached the maximum on the third day after infection in the lung, and on the second day after infection in the small intestine and colon, respectively. RegⅢγ in intestinal tissue reached the maximum on the third day after RSV infection. Moreover, the genus enriched in the RSV group was Aggregatibacter, and Proteus was reduced. RSV infection not only causes Th17/Treg cell imbalance in the lungs of mice but also leads to the release of excessive IL-22 from the lungs through blood circulation which binds to IL-22 receptors on the intestinal surface, inducing RegⅢγ overexpression, impaired intestinal Th17/Treg development, and altered gut microbiota composition. Our research reveals a significant link between the pulmonary and intestinal axis after RSV infection. IMPORTANCE: RSV is the most common pathogen causing acute lower respiratory tract infections in infants and young children, but the complex interactions between the immune system and gut microbiota induced by RSV infection still requires further research. In this study, it was suggested that RSV infection in 7-day-old BALB/c suckling mice caused lung inflammation and disruption of Th17/Treg cells development, and altered the composition of gut microbiota through IL-22 induced overexpression of RegⅢγ, leading to intestinal immune injury and disruption of gut microbiota. This research reveals that IL-22 may be the link between the lung and gut. This study may provide a new insight into the intestinal symptoms caused by RSV and other respiratory viruses and the connection between the lung and gut axis, as well as new therapeutic ideas for the treatment of RSV-infected children.

Comparison of the upper and lower airway microbiome in early postoperative lung transplant recipients.

The upper and lower respiratory tract may share microbiome because they are directly continuous, and the nasal microbiome contributes partially to the composition of the lung microbiome. But little is known about the upper and lower airway microbiome of early postoperative lung transplant recipients (LTRs). Using 16S rRNA gene sequencing, we compared paired nasal swab (NS) and bronchoalveolar lavage fluid (BALF) microbiome from 17 early postoperative LTRs. The microbiome between the two compartments were significantly different in Shannon diversity and beta diversity. Four and eight core NS-associated and BALF-associated microbiome were identified, respectively. NS samples harbored more Corynebacterium, Acinetobacter, and Pseudomonas, while BALF contained more Ralstonia, Stenotrophomonas, Enterococcus, and Pedobacter. The within-subject dissimilarity was higher than the between-subject dissimilarity, indicating a greater impact of sampling sites than sampling individuals on microbial difference. There were both difference and homogeneity between NS and BALF microbiome in early postoperative LTRs. High levels of pathogens were detected in both samples, suggesting that both of them can reflect the diseases characteristics of transplanted lung. The differences between upper and lower airway microbiome mainly come from sampling sites instead of sampling individuals. IMPORTANCE: Lung transplantation is the only therapeutic option for patients with end-stage lung disease, but its outcome is much worse than other solid organ transplants. Little is known about the NS and BALF microbiome of early postoperative LTRs. Here, we compared paired samples of the nasal and lung microbiome from 17 early postoperative LTRs and showed both difference and homogeneity between the two samples. Most of the "core" microbiome in both NS and BALF samples were recognized respiratory pathogens, suggesting that both samples can reflect the diseases characteristics of transplanted lung. We also found that the differences between upper and lower airway microbiome in early postoperative LTRs mainly come from sampling sites instead of sampling individuals.

Dual neutrophil subsets exacerbate or suppress inflammation in tuberculosis via IL-1ß or PD-L1.

Neutrophils can be beneficial or deleterious during tuberculosis (TB). Based on the expression of MHC-II and programmed death ligand 1 (PD-L1), we distinguished two functionally and transcriptionally distinct neutrophil subsets in the lungs of mice infected with mycobacteria. Inflammatory [MHC-II-, PD-L1lo] neutrophils produced inflammasome-dependent IL-1ß in the lungs in response to virulent mycobacteria and "accelerated" deleterious inflammation, which was highly exacerbated in IFN-γR-/- mice. Regulatory [MHC-II+, PD-L1hi] neutrophils "brake" inflammation by suppressing T-cell proliferation and IFN-γ production. Such beneficial regulation, which depends on PD-L1, is controlled by IFN-γR signaling in neutrophils. The hypervirulent HN878 strain from the Beijing genotype curbed PD-L1 expression by regulatory neutrophils, abolishing the braking function and driving deleterious hyperinflammation in the lungs. These findings add a layer of complexity to the roles played by neutrophils in TB and may explain the reactivation of this disease observed in cancer patients treated with anti-PD-L1.

Lactobacillus plantarum GUANKE modulate anti-viral function of dendritic cells in mice.

GUANKE is a Lactobacillus plantarum isolated from the feces of healthy volunteer. We have previously shown that GUANKE enhances the efficacy of the SARS-CoV-2 vaccine and prolongs the duration of vaccine protection by upregulating the IFN pathway and T and B lymphocyte functions of the host. The purpose of this study was to evaluate the protective effects and mechanism of oral administration of Lactobacillus plantarum GUANKE in the influenza (A virus A/Puerto Rico/8/34) infection mouse model. In our experiment, oral administration of GUANKE significantly decreased viral load and increased tight junction proteins expression in lung tissues of influenza-infected mice. After GUANKE was co-cultured with mBMDCs in vitro, mBMDCs' maturity and antiviral ability were enhanced, and matured mBMDCs induced polarization of naïve CD4+ T cells into T helper (Th) 1 cells. Adoptive transfer of GUANKE-treated mBMDCs could protect mice from influenza infections. This study suggests that oral administration of Lactobacillus plantarum GUANKE could provide protection against influenza infection in mice, and this protective effect may be mediated, at least in part, by dendritic cells.

Exploring the role of the ocular surface in the lung-eye axis: Insights into respiratory disease pathogenesis.

Chronic respiratory diseases (CRDs) represent a significant proportion of global health burden, with a wide spectrum of varying, heterogenic conditions largely affecting the pulmonary system. Recent advances in immunology and respiratory biology have highlighted the systemic impact of these diseases, notably through the elucidation of the lung-eye axis. The current review focusses on understanding the pivotal role of the lung-eye axis in the pathogenesis and progression of chronic respiratory infections and diseases. Existing literature published on the immunological crosstalk between the eye and the lung has been reviewed. The various roles of the ocular microbiome in lung health are also explored, examining the eye as a gateway for respiratory virus transmission, and assessing the impact of environmental irritants on both ocular and respiratory systems. This novel concept emphasizes a bidirectional relationship between respiratory and ocular health, suggesting that respiratory diseases may influence ocular conditions and vice versa, whereby this conception provides a comprehensive framework for understanding the intricate axis connecting both respiratory and ocular health. These aspects underscore the need for an integrative approach in the management of chronic respiratory diseases. Future research should further elucidate the in-depth molecular mechanisms affecting this axis which would pave the path for novel diagnostics and effective therapeutic strategies.

Antimycobacterial and healing effects of Pranlukast against MTB infection and pathogenesis in a preclinical mouse model of tuberculosis.

It is essential to understand the interactions and relationships between Mycobacterium tuberculosis (Mtb) and macrophages during the infection in order to design host-directed, immunomodulation-dependent therapeutics to control Mtb. We had reported previously that ornithine acetyltransferase (MtArgJ), a crucial enzyme of the arginine biosynthesis pathway of Mtb, is allosterically inhibited by pranlukast (PRK), which significantly reduces bacterial growth. The present investigation is centered on the immunomodulation in the host by PRK particularly the activation of the host's immune response to counteract bacterial survival and pathogenicity. Here, we show that PRK decreased the bacterial burden in the lungs by upregulating the population of pro-inflammatory interstitial macrophages (IMs) and reducing the population of Mtb susceptible alveolar macrophages (AMs), dendritic cells (DCs), and monocytes (MO). Additionally, we deduce that PRK causes the host macrophages to change their metabolic pathway from fatty acid metabolism to glycolytic metabolism around the log phage of bacterial multiplication. Further, we report that PRK reduced tissue injury by downregulating the Ly6C-positive population of monocytes. Interestingly, PRK treatment improved tissue repair and inflammation resolution by increasing the populations of arginase 1 (Arg-1) and Ym1+Ym2 (chitinase 3-like 3) positive macrophages. In summary, our study found that PRK is useful not only for reducing the tubercular burden but also for promoting the healing of the diseased tissue.

Isolation, identification and characteristics of Bibersteinia trehalosi from goat.

A conditionally pathogenic bacterium called Bibersteinia trehalosi inhabits the upper respiratory tract of ruminants and is becoming a significant cause of pneumonia, especially in goats. In this study, we identified a gram-negative bacteria strain isolated from dead goat's lungs, which was named M01. By integrating the outcomes of its morphological and biochemical characterization with the investigation of the 16S rRNA gene sequence analysis, the isolate was identified as B. trehalosi. Based on antibiotic susceptibility tests, the isolate was shown to be resistant to ß-lactams, tetracyclines, and amphenicols. Its genome was discovered to comprise 2115 encoded genes and a circular chromosome measuring 2,345,568 bp using whole genome sequencing. Annotation of the VFBD database revealed that isolate M01 had four virulence genes encoding three virulence factors. The CARD database revealed that its genome has two antibiotic-resistance genes. Based on pathogenicity testing, isolate M01 was highly pathogenic to mice, primarily causing pneumonia, with an LD50 of 1.31 × 107 CFU/ml. Moreover, histopathology showed loss of alveolar structure and infiltration of lung inflammatory cells. Hence, the current study could provide sufficient information for prevention and control strategies for future epidemics of B. trehalosi in goat species.

Dry powder inhalation containing muco-inert ciprofloxacin and colistin co-loaded liposomes for pulmonary P. Aeruginosa biofilm eradication.

Pseudomonas aeruginosa (PA), a predominant pathogen in lung infections, poses significant challenges due to its biofilm formation, which is the primary cause of chronic and recalcitrant pulmonary infections. Bacteria within these biofilms exhibit heightened resistance to antibiotics compared to their planktonic counterparts, and their secreted toxins exacerbate lung infections. Diverging from traditional antibacterial therapy for biofilm eradication, this study introduces a novel dry powder inhalation containing muco-inert ciprofloxacin and colistin co-encapsulated liposomes (Cipro-Col-Lips) prepared using ultrasonic spray freeze drying (USFD) technique. This USFD dry powder is designed to efficiently deliver muco-inert Cipro-Col-Lips to the lungs. Once deposited, the liposomes rapidly diffuse into the airway mucus, reaching the biofilm sites. The muco-inert Cipro-Col-Lips neutralize the biofilm-secreted toxins and simultaneously trigger the release of their therapeutic payload, exerting a synergistic antibiofilm effect. Our results demonstrated that the optimal USFD liposomal dry powder formulation exhibited satisfactory in vitro aerosol performance in terms of fine particle fraction (FPF) of 44.44 ± 0.78 %, mass median aerodynamic diameter (MMAD) of 4.27 ± 0.21 µm, and emitted dose (ED) of 99.31 ± 3.31 %. The muco-inert Cipro-Col-Lips effectively penetrate the airway mucus and accumulate at the biofilm site, neutralizing toxins and safeguarding lung cells. The triggered release of ciprofloxacin and colistin works synergistically to reduce the biofilm's antibiotic resistance, impede the development of antibiotic resistance, and eliminate 99.99 % of biofilm-embedded bacteria, including persister bacteria. Using a PA-beads induced biofilm-associated lung infection mouse model, the in vivo efficacy of this liposomal dry powder aerosol was tested, and the results demonstrated that this liposomal dry powder aerosol achieved a 99.7 % reduction in bacterial colonization, and significantly mitigated inflammation and pulmonary fibrosis. The USFD dry powder inhalation containing muco-inert Cipro-Col-Lips emerges as a promising therapeutic strategy for treating PA biofilm-associated lung infections.

HDAC6 inhibitor promotes reactive oxygen species-meditated clearance of Staphylococcus aureus in macrophage.

Staphylococcus aureus (S. aureus) pneumonia has become an increasingly important public health problem. Recent evidence suggests that epigenetic modifications are critical in the host immune defence against pathogen infection. In this study, we found that S. aureus infection induces the expression of histone deacetylase 6 (HDAC6) in a dose-dependent manner. Furthermore, by using a S. aureus pneumonia mouse model, we showed that the HDAC6 inhibitor, tubastatin A, demonstrates a protective effect in S. aureus pneumonia, decreasing the mortality and destruction of lung architecture, reducing the bacterial burden in the lungs and inhibiting inflammatory responses. Mechanistic studies in primary bone marrow-derived macrophages demonstrated that the HDAC6 inhibitors, tubastatin A and tubacin, reduced the intracellular bacterial load by promoting bacterial clearance rather than regulating phagocytosis. Finally, N-acetyl-L- cysteine, a widely used reactive oxygen species (ROS) scavenger, antagonized ROS production and significantly inhibited tubastatin A-induced S. aureus clearance. These findings demonstrate that HDAC6 inhibitors promote the bactericidal activity of macrophages by inducing ROS, an important host factor for S. aureus clearance and production. Our study identified HDAC6 as a suitable epigenetic modification target for preventing S. aureus infection, and tubastatin A as a useful compound in treating S. aureus pneumonia.

Scutellaria baicalensis water decoction ameliorates lower respiratory tract infection by modulating respiratory microbiota.

BACKGROUND: The pathogenesis of lower respiratory tract infections (LRTIs) has been demonstrated to be strongly associated with dysbiosis of respiratory microbiota. Scutellaria baicalensis, a traditional Chinese medicine, is widely used to treat respiratory infections. However, whether the therapeutic effect of S. baicalensis on LRTIs depends upon respiratory microbiota regulation is largely unclear. PURPOSE: To investigate the potential effect and mechanism of S. baicalensis on the respiratory microbiota of LRTI mice. METHODS: A mouse model of LRTI was established using Klebsiella pneumoniae or Streptococcus pneumoniae. Antibiotic treatment was administered, and transplantation of respiratory microbiota was performed to deplete the respiratory microbiota of mice and recover the destroyed microbial community, respectively. High-performance liquid chromatography (HPLC) was used to determine and quantify the chemical components of S. baicalensis water decoction (SBWD). Pathological changes in lung tissues and the expressions of serum inflammatory cytokines, including interleukin-17A (IL-17A), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), were determined by hematoxylin and eosin (H&E) staining and enzyme-linked immunosorbent assay (ELISA), respectively. Quantitative real-time PCR (qRT-PCR) analysis was performed to detect the mRNA expression of GM-CSF. Metagenomic sequencing was performed to evaluate the effect of SBWD on the composition and function of the respiratory microbiota in LRTI mice. RESULTS: Seven main components, including scutellarin, baicalin, oroxylin A-7-O-ß-d-glucuronide, wogonoside, baicalein, wogonin, and oroxylin A, were identified and their levels in SBWD were quantified. SBWD ameliorated pulmonary pathological injury and inflammatory responses in K. pneumoniae and S. pneumoniae-induced LRTI mice, as evidenced by the dose-dependent reductions in the levels of serum inflammatory cytokines, IL-6 and TNF-α. SBWD may exert a bidirectional regulatory effect on the host innate immune responses in LRTI mice and regulate the expressions of IL-17A and GM-CSF in a microbiota-dependent manner. K. pneumoniae infection but not S. pneumoniae infection led to dysbiosis in the respiratory microbiota, evident through disturbances in the taxonomic composition characterized by bacterial enrichment, including Proteobacteria, Enterobacteriaceae, and Klebsiella. K. pneumoniae and S. pneumoniae infection altered the bacterial functional profile of the respiratory microbiota, as indicated by increases in lipopolysaccharide biosynthesis, metabolic pathways, and carbohydrate metabolism. SBWD had a certain trend on the regulation of compositional disorders in the respiratory flora and modulated partial microbial functions embracing carbohydrate metabolism in K. pneumoniae-induced LRTI mice. CONCLUSION: SBWD may exert an anti-infection effect on LRTI by targeting IL-17A and GM-CSF through respiratory microbiota regulation. The mechanism of S. baicalensis action on respiratory microbiota in LRTI treatment merits further investigation.

The effect of focused lung ultrasonography on antibiotic prescribing in patients with acute lower respiratory tract infections in Danish general practice: study protocol for a pragmatic randomized controlled trial (PLUS-FLUS).

BACKGROUND: The use of antibiotics is a key driver of antimicrobial resistance and is considered a major threat to global health. In Denmark, approximately 75% of antibiotic prescriptions are issued in general practice, with acute lower respiratory tract infections (LRTIs) being one of the most common indications. Adults who present to general practice with symptoms of acute LRTI often suffer from self-limiting viral infections. However, some patients have bacterial community-acquired pneumonia (CAP), a potential life-threatening infection, that requires immediate antibiotic treatment. Importantly, no single symptom or specific point-of-care test can be used to discriminate the various diagnoses, and diagnostic uncertainty often leads to (over)use of antibiotics. At present, general practitioners (GPs) lack tools to better identify those patients who will benefit from antibiotic treatment. The primary aim of the PLUS-FLUS trial is to determine whether adults who present with symptoms of an acute LRTI in general practice and who have FLUS performed in addition to usual care are treated less frequently with antibiotics than those who only receive usual care. METHODS: Adults (≥ 18 years) presenting to general practice with acute cough (< 21 days) and at least one other symptom of acute LRTI, where the GP suspects a bacterial CAP, will be invited to participate in this pragmatic randomized controlled trial. All participants will receive usual care. Subsequently, participants will be randomized to either the control group (usual care) or to an additional focused lung ultrasonography performed by the GP (+ FLUS). The primary outcome is the proportion of participants with antibiotics prescribed at the index consultation (day 0). Secondary outcomes include comparisons of the clinical course for participants in groups. DISCUSSION: We will examine whether adults who present with symptoms of acute LRTI in general practice, who have FLUS performed in addition to usual care, have antibiotics prescribed less frequently than those given usual care alone. It is highly important that a possible reduction in antibiotic prescriptions does not compromise patients' recovery or clinical course, which we will assess closely. TRIAL REGISTRATION: ClinicalTrials.gov NCT06210282. Registered on January 17, 2024.

Helicobacter pylori infection in infant rhesus macaque monkeys is associated with an altered lung and oral microbiome.

It is estimated that more than half of the world population has been infected with Helicobacter pylori. Most newly acquired H. pylori infections occur in children before 10 years of age. We hypothesized that early life H. pylori infection could influence the composition of the microbiome at mucosal sites distant to the stomach. To test this hypothesis, we utilized the infant rhesus macaque monkey as an animal model of natural H. pylori colonization to determine the impact of infection on the lung and oral microbiome during a window of postnatal development. From a cohort of 4-7 month-old monkeys, gastric biopsy cultures identified 44% of animals infected by H. pylori. 16S ribosomal RNA gene sequencing of lung washes and buccal swabs from animals showed distinct profiles for the lung and oral microbiome, independent of H. pylori infection. In order of relative abundance, the lung microbiome was dominated by the phyla Proteobacteria, Firmicutes, Bacteroidota, Fusobacteriota, Campilobacterota and Actinobacteriota while the oral microbiome was dominated by Proteobacteria, Firmicutes, Bacteroidota, and Fusobacteriota. In comparison to the oral cavity, the lung was composed of more genera and species that significantly differed by H. pylori status, with a total of 6 genera and species that were increased in H. pylori negative infant monkey lungs. Lung, but not plasma IL-8 concentration was also associated with gastric H. pylori load and lung microbial composition. We found the infant rhesus macaque monkey lung harbors a microbiome signature that is distinct from that of the oral cavity during postnatal development. Gastric H. pylori colonization and IL-8 protein were linked to the composition of microbial communities in the lung and oral cavity. Collectively, these findings provide insight into how H. pylori infection might contribute to the gut-lung axis during early childhood and modulate future respiratory health.