Lipidation of pneumococcal proteins enables activation of human antigen-presenting cells and initiation of an adaptive immune response.

Streptococcus pneumoniae remains a significant global threat, with existing vaccines having important limitations such as restricted serotype coverage and high manufacturing costs. Pneumococcal lipoproteins are emerging as promising vaccine candidates due to their surface exposure and conservation across various serotypes. While prior studies have explored their potential in mice, data in a human context and insights into the impact of the lipid moiety remain limited. In the present study, we examined the immunogenicity of two pneumococcal lipoproteins, DacB and MetQ, both in lipidated and non-lipidated versions, by stimulation of primary human immune cells. Immune responses were assessed by the expression of common surface markers for activation and maturation as well as cytokines released into the supernatant. Our findings indicate that in the case of MetQ lipidation was crucial for activation of human antigen-presenting cells such as dendritic cells and macrophages, while non-lipidated DacB demonstrated an intrinsic potential to induce an innate immune response. Nevertheless, immune responses to both proteins were enhanced by lipidation. Interestingly, following stimulation of dendritic cells with DacB, LipDacB and LipMetQ, cytokine levels of IL-6 and IL-23 were significantly increased, which are implicated in triggering potentially important Th17 cell responses. Furthermore, LipDacB and LipMetQ were able to induce proliferation of CD4+ T cells indicating their potential to induce an adaptive immune response. These findings contribute valuable insights into the immunogenic properties of pneumococcal lipoproteins, emphasizing their potential role in vaccine development against pneumococcal infections.

B cells in the pneumococcus-infected lung are heterogeneous and require CD4+ T cell help including CD40L to become resident memory B cells.

Recovery from respiratory pneumococcal infections generates lung-localized protection against heterotypic bacteria, mediated by resident memory lymphocytes. Optimal protection in mice requires re-exposure to pneumococcus within days of initial infection. Serial surface marker phenotyping of B cell populations in a model of pneumococcal heterotypic immunity revealed that bacterial re-exposure stimulates the immediate accumulation of dynamic and heterogeneous populations of B cells in the lung, and is essential for the establishment of lung resident memory B (BRM) cells. The B cells in the early wave were activated, proliferating locally, and associated with both CD4+ T cells and CXCL13. Antagonist- and antibody-mediated interventions were implemented during this early timeframe to demonstrate that lymphocyte recirculation, CD4+ cells, and CD40 ligand (CD40L) signaling were all needed for lung BRM cell establishment, whereas CXCL13 signaling was not. While most prominent as aggregates in the loose connective tissue of bronchovascular bundles, morphometry and live lung imaging analyses showed that lung BRM cells were equally numerous as single cells dispersed throughout the alveolar septae. We propose that CD40L signaling from antigen-stimulated CD4+ T cells in the infected lung is critical to establishment of local BRM cells, which subsequently protect the airways and parenchyma against future potential infections.

Respiratory pathogen and clinical features of hospitalized patients in acute exacerbation of chronic obstructive pulmonary disease after COVID 19 pandemic.

Respiratory infections are common causes of acute exacerbation of chronic obstructive lung disease (AECOPD). We explored whether the pathogens causing AECOPD and clinical features changed from before to after the coronavirus disease 2019 (COVID-19) outbreak. We reviewed the medical records of patients hospitalized with AECOPD at four university hospitals between January 2017 and December 2018 and between January 2021 and December. We evaluated 1180 patients with AECOPD for whom medication histories were available. After the outbreak, the number of patients hospitalized with AECOPD was almost 44% lower compared with before the outbreak. Patients hospitalized with AECOPD after the outbreak were younger (75 vs. 77 years, p = 0.003) and more often stayed at home (96.6% vs. 88.6%, p < 0.001) than patients of AECOPD before the outbreak. Hospital stay was longer after the outbreak than before the outbreak (10 vs. 8 days. p < 0.001). After the COVID-19 outbreak, the identification rates of S. pneumoniae (15.3 vs. 6.2%, p < 0.001) and Hemophilus influenzae (6.4 vs. 2.4%, p = 0.002) decreased, whereas the identification rates of P. aeruginosa (9.4 vs. 13.7%, p = 0.023), Klebsiella pneumoniae (5.3 vs. 9.8%, p = 0.004), and methicillin-resistant Staphylococcus aureus (1.0 vs. 2.8%, p = 0.023) increased. After the outbreak, the identification rate of influenza A decreased (10.4 vs. 1.0%, p = 0.023). After the outbreak, the number of patients hospitalized with AECOPD was lower and the identification rates of community-transmitted pathogens tended to decrease, whereas the rates of pathogens capable of chronic colonization tended to increase. During the period of large-scale viral outbreaks that require quarantine, patients with AECOPD might be given more consideration for treatment against strains that can colonize chronic respiratory disease rather than community acquired pathogens.

Impaired upper respiratory tract barrier function during postnatal development predisposes to invasive pneumococcal disease.

Infants are highly susceptible to invasive respiratory and gastrointestinal infections. To elucidate the age-dependent mechanism(s) that drive bacterial spread from the mucosa, we developed an infant mouse model using the prevalent pediatric respiratory pathogen, Streptococcus pneumoniae (Spn). Despite similar upper respiratory tract (URT) colonization levels, the survival rate of Spn-infected infant mice was significantly decreased compared to adults and corresponded with Spn dissemination to the bloodstream. An increased rate of pneumococcal bacteremia in early life beyond the newborn period was attributed to increased bacterial translocation across the URT barrier. Bacterial dissemination in infant mice was independent of URT monocyte or neutrophil infiltration, phagocyte-derived ROS or RNS, inflammation mediated by toll-like receptor 2 or interleukin 1 receptor signaling, or the pore-forming toxin pneumolysin. Using molecular barcoding of Spn, we found that only a minority of bacterial clones in the nasopharynx disseminated to the blood in infant mice, indicating the absence of robust URT barrier breakdown. Rather, transcriptional profiling of the URT epithelium revealed a failure of infant mice to upregulate genes involved in the tight junction pathway. Expression of many such genes was also decreased in early life in humans. Infant mice also showed increased URT barrier permeability and delayed mucociliary clearance during the first two weeks of life, which corresponded with tighter attachment of bacteria to the respiratory epithelium. Together, these results demonstrate a window of vulnerability during postnatal development when altered mucosal barrier function facilitates bacterial dissemination.

IL-10-Mediated Regulation of Microglial Inflammation in Brain Meningitis: Novel Insights and Therapeutic Potential.

BACKGROUND: Inflammation is a key pathological process in bacterial meningitis, and the transforming growth factor-beta-activated kinase 1 (TAK1)/nuclear factor-kappa B (NF-κB) pathway is implicated in the activation of microglia and the production of inflammatory factors. Interleukin (IL)-10 is an anti-inflammatory cytokine acting in an autocrine fashion in macrophages to limit inflammatory responses by decreasing the production of pro-inflammatory cytokines. This paper investigates how IL-10 can inhibit microglia activation and reduce the inflammatory response of nervous system diseases. METHODS: This study used a pneumococcal-induced in Pneumococcal meningitis (PM) C57BL/6 mice and BV-2 cells model of microglial activation, assessing the effects of IL-10 on the TAK1/NF-κB pathway. The impact of IL-10 on microglial autophagy was investigated through western blot and immunofluorescence. The effects of IL-10 were evaluated by examining cellular activation markers and the activity of molecular signaling pathways (such as phosphorylation levels of TAK1 and NF-κB). RESULTS: Pneumococcus induced the activation of microglia and reduced IL-10. IL-10 inhibited the TAK1/NF-κB pathway, reducing the pneumococcal-induced inflammatory response in microglia. IL-10 ameliorated pneumococcal infection-induced microglial injury by inhibiting autophagy. Animal experiment results also showed that IL-10 inhibited inflammation and autophagy during Pneumococcal meningitis in mice. CONCLUSION: Our study demonstrates that IL-10 reduces the inflammatory response of microglia by inhibiting the TAK1/NF-κB pathway. Additionally, IL-10 ameliorates pneumococcal infection-induced microglial injury by inhibiting the process of autophagy. These results provide a new theoretical basis and offer new insights for developing strategies to treat bacterial meningitis.

Biological effects of corticosteroids on pneumococcal pneumonia in Mice-translational significance.

BACKGROUND: Streptococcus pneumoniae is the most common bacterial cause of community acquired pneumonia and the acute respiratory distress syndrome (ARDS). Some clinical trials have demonstrated a beneficial effect of corticosteroid therapy in community acquired pneumonia, COVID-19, and ARDS, but the mechanisms of this benefit remain unclear. The primary objective of this study was to investigate the effects of corticosteroids on the pulmonary biology of pneumococcal pneumonia in a mouse model. A secondary objective was to identify shared transcriptomic features of pneumococcal pneumonia and steroid treatment in the mouse model and clinical samples. METHODS: We carried out comprehensive physiologic, biochemical, and histological analyses in mice to identify the mechanisms of lung injury in Streptococcus pneumoniae with and without adjunctive steroid therapy. We also studied lower respiratory tract gene expression from a cohort of 15 mechanically ventilated patients (10 with Streptococcus pneumoniae and 5 controls) to compare with the transcriptional studies in the mice. RESULTS: In mice with pneumonia, dexamethasone in combination with ceftriaxone reduced (1) pulmonary edema formation, (2) alveolar protein permeability, (3) proinflammatory cytokine release, (4) histopathologic lung injury score, and (5) hypoxemia but did not increase bacterial burden. Transcriptomic analyses identified effects of steroid therapy in mice that were also observed in the clinical samples. CONCLUSIONS: In combination with appropriate antibiotic therapy in mice, treatment of pneumococcal pneumonia with steroid therapy reduced hypoxemia, pulmonary edema, lung permeability, and histologic criteria of lung injury, and also altered inflammatory responses at the protein and gene expression level. The transcriptional studies in patients suggest that the mouse model replicates some of the features of pneumonia in patients with Streptococcus pneumoniae and steroid treatment. Overall, these studies provide evidence for the mechanisms that may explain the beneficial effects of glucocorticoid therapy in patients with community acquired pneumonia from Streptococcus Pneumoniae.

Transcriptional regulation of TacL-mediated lipoteichoic acids biosynthesis by ComE during competence impacts pneumococcal transformation.

Competence development is essential for bacterial transformation since it enables bacteria to take up free DNA from the surrounding environment. The regulation of teichoic acid biosynthesis is tightly controlled during pneumococcal competence; however, the mechanism governing this regulation and its impact on transformation remains poorly understood. We demonstrated that a defect in lipoteichoic acid ligase (TacL)-mediated lipoteichoic acids (LTAs) biosynthesis was associated with impaired pneumococcal transformation. Using a fragment of tacL regulatory probe as bait in a DNA pulldown assay, we successfully identified several regulatory proteins, including ComE. Electrophoretic mobility shift assays revealed that phosphomimetic ComE, but not wild-type ComE, exhibited specific binding to the probe. DNase I footprinting assays revealed the specific binding sequences encompassing around 30 base pairs located 31 base pairs upstream from the start codon of tacL. Expression of tacL was found to be upregulated in the ΔcomE strain, and the addition of exogenous competence-stimulating peptide repressed the tacL transcription in the wild-type strain but not the ΔcomE mutant, indicating that ComE exerted a negative regulatory effect on the transcription of tacL. Mutation in the JH2 region of tacL upstream regulatory sequence led to increased LTAs abundance and displayed higher transformation efficiency. Collectively, our work identified the regulatory mechanisms that control LTAs biosynthesis during competence and thereby unveiled a repression mechanism underlying pneumococcal transformation.

IL-33 controls IL-22-dependent antibacterial defense by modulating the microbiota.

IL-22 plays a critical role in defending against mucosal infections, but how IL-22 production is regulated is incompletely understood. Here, we show that mice lacking IL-33 or its receptor ST2 (IL-1RL1) were more resistant to Streptococcus pneumoniae lung infection than wild-type animals and that single-nucleotide polymorphisms in IL33 and IL1RL1 were associated with pneumococcal pneumonia in humans. The effect of IL-33 on S. pneumoniae infection was mediated by negative regulation of IL-22 production in innate lymphoid cells (ILCs) but independent of ILC2s as well as IL-4 and IL-13 signaling. Moreover, IL-33's influence on IL-22-dependent antibacterial defense was dependent on housing conditions of the mice and mediated by IL-33's modulatory effect on the gut microbiota. Collectively, we provide insight into the bidirectional crosstalk between the innate immune system and the microbiota. We conclude that both genetic and environmental factors influence the gut microbiota, thereby impacting the efficacy of antibacterial immune defense and susceptibility to pneumonia.

Exploring Zingiber officinale bioactive compounds for inhibitory effects on Streptococcus pneumoniae capsular polysaccharide biosynthesis proteins: In silico study.

The capsule is a major virulence factor for Streptococcus pneumoniae which causes global morbidity and mortality. It is already known that there are few conserved genes in the capsular biosynthesis pathway, which are common among all known serotypes, called CpsA, CpsB, CpsC and CpsD. Inhibiting capsular synthesis can render S. pneumoniae defenseless and vulnerable to phagocytosis. The Inhibitory potential of active Zingiber officinale compounds was investigated against the 3D (3-dimensional) structural products of Cps genes using in silico techniques. A 3D compound repository was created and screened for drug-likeness and the qualified compounds were used for molecular docking and dynamic simulation-based experiments using gallic acid for outcome comparison. Cavity-based docking revealed five different cavities in the CpsA, CpsB and CpsD proteins, with gallic acid and selected compounds of Zingiber in a binding affinity range of -6.8 to -8.8 kcal/mol. Gingerenone A, gingerenone B, isogingerenone B and gingerenone C showed the highest binding affinities for CpsA, CpsB and CpsD, respectively. Through the Molegro Virtual Docker re-docking strategy, the highest binding energies (-126.5 kcal/mol) were computed for CpsB with gingerenone A and CpsD with gingerenone B. These findings suggest that gingerenone A, B and C are potential inhibitors of S. pneumoniae-conserved capsule-synthesizing proteins.

Follow-Up Study of Effectiveness of 23-Valent Pneumococcal Polysaccharide Vaccine Against All-Type and Serotype-Specific Invasive Pneumococcal Disease, Denmark.

As a follow-up to a previous study, we investigated vaccine effectiveness (VE) of 23-valent pneumococcal polysaccharide vaccine (PPSV23) against invasive pneumococcal disease (IPD) among 1,254,498 persons >65 years of age as part of a vaccination program in Denmark during April 2020-January 2023. We assessed VE by using a Cox regression model and adjusted for age, sex, and underlying conditions. Using nationwide data, we estimated a VE of PPSV23 against all-type IPD of 32% and against PPSV23-serotype IPD of 41%. Because this follow-up study had more statistical power than the original study, we also estimated VE against IPD caused by PPSV23-serotypes excluding serotype 3; serotype 3; serotype 8; serotype 22F; PPSV23 non-PCV15 serotypes; PPSV23 non-PCV20 serotypes; and IPD over time. Our findings suggest PPSV23 vaccination can protect persons >65 years of age against IPD caused by all serotypes or serotype groupings, except serotype 3.

Post-resolution macrophages shape long-term tissue immunity and integrity in a mouse model of pneumococcal pneumonia.

Resolving inflammation is thought to return the affected tissue back to homoeostasis but recent evidence supports a non-linear model of resolution involving a phase of prolonged immune activity. Here we show that within days following resolution of Streptococcus pneumoniae-triggered lung inflammation, there is an influx of antigen specific lymphocytes with a memory and tissue-resident phenotype as well as macrophages bearing alveolar or interstitial phenotype. The transcriptome of these macrophages shows enrichment of genes associated with prostaglandin biosynthesis and genes that drive T cell chemotaxis and differentiation. Therapeutic depletion of post-resolution macrophages, inhibition of prostaglandin E2 (PGE2) synthesis or treatment with an EP4 antagonist, MF498, reduce numbers of lung CD4+/CD44+/CD62L+ and CD4+/CD44+/CD62L-/CD27+ T cells as well as their expression of the α-integrin, CD103. The T cells fail to reappear and reactivate upon secondary challenge for up to six weeks following primary infection. Concomitantly, EP4 antagonism through MF498 causes accumulation of lung macrophages and marked tissue fibrosis. Our study thus shows that PGE2 signalling, predominantly via EP4, plays an important role during the second wave of immune activity following resolution of inflammation. This secondary immune activation drives local tissue-resident T cell development while limiting tissue injury.

Respiratory Syncytial Virus and Influenza Infections in Children in Ulaanbaatar, Mongolia, 2015-2021.

BACKGROUND: Data available for RSV and influenza infections among children < 2 years in Mongolia are limited. We present data from four districts of Ulaanbaatar from April 2015 to June 2021. METHODS: This study was nested in an enhanced surveillance project evaluating pneumococcal conjugate vaccine (PCV13) impact on the incidence of hospitalized lower respiratory tract infections (LRTIs). Our study was restricted to children aged < 2 years with arterial O2 saturation < 93% and children with radiological pneumonia. Nasopharyngeal (NP) swabs collected at admission were tested for RSV and influenza using qRT-PCR. NP swabs of all patients with radiological pneumonia and of a subset of randomly selected NP swabs were tested for S. pneumoniae (S.p.) by qPCR and for serotypes by culture and DNA microarray. RESULTS: Among 5705 patients, 2113 (37.0%) and 386 (6.8%) had RSV and influenza infections, respectively. Children aged 2-6 months had a higher percentage of very severe RSV infection compared to those older than 6 months (42.2% versus 31.4%, p-value Fisher's exact = 0.001). S.p. carriage was detected in 1073/2281 (47.0%) patients. Among S.p. carriage cases, 363/1073 (33.8%) had S.p. and RSV codetection, and 82/1073 (7.6%) had S.p. and influenza codetection. S.p. codetection with RSV/influenza was not associated with more severe LRTIs, compared to only RSV/influenza cases. CONCLUSION: In Mongolia, RSV is an important pathogen causing more severe LRTI in children under 6 months of age. Codetection of RSV or influenza virus and S.p. was not associated with increased severity.

Evaluation of Acute and Convalescent Antibody Concentration Against Pneumococcal Capsular Polysaccharides for the Diagnosis of Pneumococcal Infection in Children with Community-Acquired Pneumonia.

We evaluated whether the quantification of IgG to pneumococcal capsular polysaccharides is an accurate diagnostic test for pneumococcal infection in children with pneumonia in Nepal. Children with pneumococcal pneumonia did not have higher convalescent, or higher fold change, IgG to pneumococcal polysaccharides than children with other causes of pneumonia. Caution is needed in interpreting antibody responses in pneumococcal infections.

Nasopharyngeal carriage of Streptococcus pneumoniae in Latin America and the Caribbean: A systematic review and meta-analysis.

BACKGROUND: Streptococcus pneumoniae is a leading cause of morbidity and mortality globally, causing bacteremic pneumonia, meningitis, sepsis, and other invasive pneumococcal diseases. Evidence supports nasopharyngeal pneumococcal carriage as a reservoir for transmission and precursor of pneumococcal disease. OBJECTIVES: To estimate the pneumococcal nasopharyngeal burden in all age groups in Latin America and the Caribbean (LAC) before, during, and after the introduction of pneumococcal vaccine conjugate (PVC). METHODS: Systematic literature review of international, regional, and country-published and unpublished data, together with reports including data from serotype distribution in nasopharyngeal carriage in children and adults from LAC countries following Cochrane methods. The protocol was registered in PROSPERO database (ID: CRD42023392097). RESULTS: We included 54 studies with data on nasopharyngeal pneumococcal carriage and serotypes from 31,803 patients. In children under five years old, carriage was found in 41% and in adults over 65, it was 26%. During the study period, children under five showed a colonization proportion of 34% with PCV10 serotypes and 45% with PCV13 serotypes. When we analyze the carriage prevalence of PCV serotypes in all age groups between 1995 and 2019, serotypes included in PCV10 and those included in PCV13, both showed a decreasing trend along analysis by lustrum. CONCLUSION: The data presented in this study highlights the need to establish national surveillance programs to monitor pneumococcal nasopharyngeal carriage to monitor serotype prevalence and replacement before and after including new pneumococcal vaccines in the region. In addition, to analyze differences in the prevalence of serotypes between countries, emphasize the importance of approaches to local realities to reduce IPD effectively.

Inhaled antibiotics: A promising drug delivery strategies for efficient treatment of lower respiratory tract infections (LRTIs) associated with antibiotic resistant biofilm-dwelling and intracellular bacterial pathogens.

Antibiotic-resistant bacteria associated with LRTIs are frequently associated with inefficient treatment outcomes. Antibiotic-resistant Streptococcus pneumoniae, Haemophilus influenzae, Pseudomonas aeruginosa, and Staphylococcus aureus, infections are strongly associated with pulmonary exacerbations and require frequent hospital admissions, usually following failed management in the community. These bacteria are difficult to treat as they demonstrate multiple adaptational mechanisms including biofilm formation to resist antibiotic threats. Currently, many patients with the genetic disease cystic fibrosis (CF), non-CF bronchiectasis (NCFB) and chronic obstructive pulmonary disease (COPD) experience exacerbations of their lung disease and require high doses of systemically administered antibiotics to achieve meaningful clinical effects, but even with high systemic doses penetration of antibiotic into the site of infection within the lung is suboptimal. Pulmonary drug delivery technology that reliably deliver antibacterials directly into the infected cells of the lungs and penetrate bacterial biofilms to provide therapeutic doses with a greatly reduced risk of systemic adverse effects. Inhaled liposomal-packaged antibiotic with biofilm-dissolving drugs offer the opportunity for targeted, and highly effective antibacterial therapeutics in the lungs. Although the challenges with development of some inhaled antibiotics and their clinicals trials have been studied; however, only few inhaled products are available on market. This review addresses the current treatment challenges of antibiotic-resistant bacteria in the lung with some clinical outcomes and provides future directions with innovative ideas on new inhaled formulations and delivery technology that promise enhanced killing of antibiotic-resistant biofilm-dwelling bacteria.

Serotype epidemiology and antibiotic resistance of pneumococcal isolates colonizing infants in Botswana (2016-2019).

BACKGROUND: In 2012, Botswana introduced 13-valent pneumococcal conjugate vaccine (PCV-13) to its childhood immunization program in a 3+0 schedule, achieving coverage rates of above 90% by 2014. In other settings, PCV introduction has been followed by an increase in carriage or disease caused by non-vaccine serotypes, including some serotypes with a high prevalence of antibiotic resistance. METHODS: We characterized the serotype epidemiology and antibiotic resistance of pneumococcal isolates cultured from nasopharyngeal samples collected from infants (≤12 months) in southeastern Botswana between 2016 and 2019. Capsular serotyping was performed using the Quellung reaction. E-tests were used to determine minimum inhibitory concentrations for common antibiotics. RESULTS: We cultured 264 pneumococcal isolates from samples collected from 150 infants. At the time of sample collection, 81% of infants had received at least one dose of PCV-13 and 53% had completed the three-dose series. PCV-13 serotypes accounted for 27% of isolates, with the most prevalent vaccine serotypes being 19F (n = 20, 8%), 19A (n = 16, 6%), and 6A (n = 10, 4%). The most frequently identified non-vaccine serotypes were 23B (n = 29, 11%), 21 (n = 12, 5%), and 16F (n = 11, 4%). Only three (1%) pneumococcal isolates were resistant to amoxicillin; however, we observed an increasing prevalence of penicillin resistance using the meningitis breakpoint (2016: 41%, 2019: 71%; Cochran-Armitage test for trend, p = 0.0003) and non-susceptibility to trimethoprim-sulfamethoxazole (2016: 55%, 2019: 79%; p = 0.04). Three (1%) isolates were multi-drug resistant. CONCLUSIONS: PCV-13 serotypes accounted for a substantial proportion of isolates colonizing infants in Botswana during a four-year period starting four years after vaccine introduction. A low prevalence of amoxicillin resistance supports its continued use as the first-line agent for non-meningeal pneumococcal infections. The observed increase in penicillin resistance at the meningitis breakpoint and the low prevalence of resistance to ceftriaxone supports use of third-generation cephalosporins for empirical treatment of suspected bacterial meningitis.

Effectiveness of 13-valent pneumococcal conjugate vaccine for prevention of invasive pneumococcal disease among children in the United States between 2010 and 2019: An indirect cohort study.

BACKGROUND: A U.S. case-control study (2010-2014) demonstrated vaccine effectiveness (VE) for ≥ 1 dose of the thirteen-valent pneumococcal conjugate vaccine (PCV13) against vaccine-type (VT) invasive pneumococcal disease (IPD) at 86 %; however, it lacked statistical power to examine VE by number of doses and against individual serotypes. METHODS: We used the indirect cohort method to estimate PCV13 VE against VT-IPD among children aged < 5 years in the United States from May 1, 2010 through December 31, 2019 using cases from CDC's Active Bacterial Core surveillance, including cases enrolled in a matched case-control study (2010-2014). Cases and controls were defined as individuals with VT-IPD and non-PCV13-type-IPD (NVT-IPD), respectively. We estimated absolute VE using the adjusted odds ratio of prior PCV13 receipt (1-aOR x 100 %). RESULTS: Among 1,161 IPD cases, 223 (19.2 %) were VT cases and 938 (80.8 %) were NVT controls. Of those, 108 cases (48.4 %; 108/223) and 600 controls (64.0 %; 600/938) had received > 3 PCV13 doses; 23 cases (17.6 %) and 15 controls (2.4 %) had received no PCV doses. VE ≥ 3 PCV13 doses against VT-IPD was 90.2 % (95 % Confidence Interval75.4-96.1 %), respectively. Among the most commonly circulating VT-IPD serotypes, VE of ≥ 3 PCV13 doses was 86.8 % (73.7-93.3 %), 50.2 % (28.4-80.5 %), and 93.8 % (69.8-98.8 %) against serotypes 19A, 3, and 19F, respectively. CONCLUSIONS: At least three doses of PCV13 continue to be effective in preventing VT-IPD among children aged < 5 years in the US. PCV13 was protective against serotypes 19A and 19F IPD; protection against serotype 3 IPD did not reach statistical significance.

Xiaoer-Feire-Qing granules alleviate pyretic pulmonary syndrome induced by Streptococcus pneumoniae in young rats by affecting the lungs and intestines: An in vivo study based on network pharmacology.

ETHNOPHARMACOLOGICAL RELEVANCE: The traditional Chinese medicine (TCM) Xiaoer-Feire-Qing granules (XEFRQ) has been used to treat pyretic pulmonary syndrome (PPS) in children for many years. The function of the lungs is considered to be closely related to the large intestine in TCM. PURPOSE: We aimed to investigate the effects of XEFRQ on PPS and the underlying mechanisms via network pharmacology and animal experiments. METHODS: The TCMSP platform was used to identify the ingredients and potential targets of XEFRQ. The GeneCards, OMIM, and TTD databases were used to predict PPS-associated targets. Cytoscape 3.9.1 was employed to construct the protein-protein interaction network, and target prediction was performed by GO and KEGG analyses. For the animal experiment, a PPS model was constructed by three cycles of nasal drip of Streptococcus pneumoniae (STP; 0.5 mL/kg). The animals were randomly divided into the following four groups according to their weight (n = 10 rats per group): the blank group, the model group, the XEFRQ-L (16.3 g/kg) group, and the XEFRQ-H (56.6 g/kg) group. Rats in the blank group and the model group were given 0.5% CMC-Na by gavage. The general conditions of the rats were observed, and their food-intake, body weight, and body temperature were recorded for 14 days. After the intervention of 14 days, serum was collected to detect inflammatory cytokines (TNF-α, IL-1ß, and PGE2) and neurotransmitters (5-HT, SP, and VIP). H&E staining was used to observe the pathological morphology of lung and colon tissue. AQP3 expression was detected by Western blot. In addition, the gut microbiota in cecal content samples were analyzed by 16S rDNA high-throughput sequencing. RESULTS: Our network analysis revealed that XEFRQ may alleviate PPS injury by affecting the levels of inflammatory cytokines and neurotransmitters and mitigating STP-induced PPS.In vivo validation experiments revealed that XEFRQ improved STP-induced PPS and reduced the expression of inflammatory cytokines and neurotransmitters. Notably, XEFRQ significantly decreased the protein expression levels of AQP3, which was associated with dry stool. Our gut microbiota analysis revealed that the relative abundance of [Eubacterium]_ruminantium_group, Colidextribacter, Romboutsia, and Oscillibacter was decreased, which means XEFRQ exerts therapeutic effects against PPS associated with these bacteria. CONCLUSION: Our results demonstrate that XEFRQ alleviates PPS by affecting the lungs and intestines, further guiding its clinical application.

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.