Corynebacterium species as one of the major causative pathogens of bacterial pneumonia

Recent advances using molecular methods, matrix-assisted laser desorption ionization time of flightmass spectrometry, and next-generation sequencers enable rapid and precise detection of bacterial species in the clinical samples, revealing bacterial diversities in the human body. Corynebacterium species are Gram-positive bacilli, which can cause pneumonia and have been reported as causative pathogens of lower respiratory tract infections since the 1970's. However, Corynebacterium spp. may be recognized and sorted as part of normal respiratory flora on Gram staining and culture, resulting in clinical under-recognition as pathogenic bacteria.The results of the clone library method using bacterial 16S ribosomal RNA gene sequence analysis in Japanese patients with hospital-acquired pneumonia revealed that bronchoalveolar lavage fluid obtained from the lung lesions contained 11.8% Corynebacterium spp., which was the second most predominant bacterial phylotype. Additionally, among patients in whom Corynebacterium spp. were detected, C. simulans was most commonly detected followed by C. striatum. In addition, almost half of the patients in whom C. simulans was detected was monophylotypic infection and/or co-detection of C. simulansand C. striatum. Further clinical information is expected on corynebacteria as pathogens of lower respiratory tract infection.     

Relationship between gut microbiota composition and sensitization to inhaled allergens

BackgroundAn imbalance in gut microbiota is implicated in several pathological conditions, including allergic diseases. This study investigates the association between gut microbiota composition and sensitization to two inhaled antigens.MethodsThe study comprised 1109 local residents who had participated in the Iwaki Health Promotion Project in 2016. Blood samples were analyzed for levels of antigen-specific IgE against Japanese cedar pollen (JCP) and house dust (HD1). Fecal samples were analyzed for bacterial 16S rRNA (ribosomal ribonucleic acid) using next generation sequencing. The percent composition of gut microbes was compared between patients sensitized and unsensitized group for JCP and HD1 to determine whether the rate of sensitization to inhaled antigens associates with specific bacterial orders composing the gut microbiota.ResultsIn participants aged 20–49 years, the percent composition of Bacteroidales was significantly higher among participants sensitized to JCP than in those unsensitized. The percent composition of Lactobacillales was significantly higher in participants unsensitized to HD group than in those sensitized to that antigen. In addition, participants with low Bacteroidales and high Bifidobacteriales or Lactobacillales has low sensitization rates to HD compared with high Bacteroidales and low Bifidobacteriales or Lactobacillales.ConclusionsThe presence of bacteria of order Lactobacillales, Bifidobacteriales, and Bacteroidales in the gut microbiota may affect sensitization to inhaled allergens.     

Effect of gut microbial composition and diversity on major inhaled allergen sensitization and onset of allergic rhinitis

BackgroundDecreased gut microbiota diversity is associated with gut dysbiosis and causes various diseases, including allergic diseases. We investigated the relationship between gut microbial diversity and sensitization to major inhaled allergens. Furthermore, the relationship of allergic symptom onset with bacterial composition in sensitized individuals was investigated.MethodsThis study included 1092 local residents who had participated in the Iwaki Health Promotion Project in 2016. Blood samples were analyzed to ascertain specific IgE levels against major inhaled allergens (JCP, HD1, Grass-mix, Weed-mix). Nasal symptoms were estimated by questionnaires. Fecal samples were analyzed for bacterial 16S rRNA using next generation sequencing. The diversity index (α-diversity, β-diversity) and the composition of gut microbes in phylum/order levels were compared between patients sensitized or unsensitized to allergen, and symptomatic and asymptomatic groups.ResultsSome α-diversity metrics were significantly decreased in patients who were sensitized to any/all four allergens compared with the unsensitized group. β-diversity differed significantly between those unsensitized and sensitized to all allergens (aged 20–49 years), and between those unsensitized and sensitized to any/all four allergens (aged ≥50 years). The relative abundance of Bacteroidales was significantly lower in the unsensitized than in the sensitized group. The composition and diversity of gut microbiota were similar between the symptomatic and asymptomatic groups.ConclusionsOur results suggest that lack of diversity in gut microbiota has an effect on sensitization to allergens. Bacteroidales in order level may affect sensitization; however, the onset of allergy symptoms was not significantly associated with bacterial composition and diversity.     

A novel deep intronic SERPING1 variant as a cause of hereditary angioedema due to C1-inhibitor deficiency

BackgroundIn about 5% of patients with hereditary angioedema due to C1-inhibitor deficiency (C1-INH-HAE) no mutation in the SERPING1 gene is detected.MethodsC1-INH-HAE cases with no mutation in the coding region of SERPING1 after conventional genotyping were examined for defects in the intronic or untranslated regions of the gene. Using a next-generation sequencing (NGS) platform targeting the entire SERPING1, 14 unrelated C1-INH-HAE patients with no detectable mutations in the coding region of the gene were sequenced. Detected variants with a global minor allele frequency lower than the frequency of C1-INH-HAE (0.002%), were submitted to in silico analysis using ten different bioinformatics tools. Pedigree analysis and examination of their pathogenic effect on the RNA level were performed for filtered in variants.ResultsIn two unrelated patients, the novel mutation c.-22-155G > T was detected in intron 1 of the SERPING1 gene by the use NGS and confirmed by Sanger sequencing. All bioinformatics tools predicted that the variant causes a deleterious effect on the gene and pedigree analysis showed its co-segregation with the disease. Degradation of the mutated allele was demonstrated by the loss of heterozygosity on the cDNA level. According to the American College of Medical Genetics and Genomics 2015 guidelines the c.-22-155G > T was curated as pathogenic.ConclusionsFor the first time, a deep intronic mutation that was detected by NGS in the SERPING1 gene, was proven pathogenic for C1-INH-HAE. Therefore, advanced DNA sequencing methods should be performed in cases of C1-INH-HAE where standard approaches fail to uncover the genetic alteration.     

Incidence and Risk Factors for Infectious Complications of EBUS-TBNA: Prospective Multicenter Study

The aim of our study was to describe the incidence of infectious complications of endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA) and to analyze the potential risk factors in a prospective cohort of patients.MethodsWe conducted a prospective multicenter study, with all consecutive patients referred for an EBUS-TBNA with patients at risk of developing an infectious complication (considering > 10 nodal samplings, known immunosuppression, bronchial colonization and cavitated or necrotic lesions) and a second group without any risk factor.ResultsThree hundred seventy patients were included: 245 with risk factors and 125 without risk factors (as the control group). Overall, 15 patients (4.05%) presented an acute infectious complication: fourteen in cases (5.7%) and 1 in controls (0.8%). Of these, 4 patients presented pneumonia, 1 mediastinitis, 4 obstructive pneumonitis and 6 mild complications (respiratory tract infection that resolved with antibiotic). Also 7 (1.9%) patients had self-limited fever. One-month follow-up showed 1 mediastinitis at sixteenth day post-EBUS, which required surgical treatment, and 3 pneumonias and 3 respiratory tract infections at nineteenth day (1.9%). All patients had a good evolution and there were no deaths related with infectious complication. We observed an increased risk of complication in patients with risk factors and in patients with necrosis (p = 0.018).ConclusionsThe incidence of infectious complications in a subgroup of patients with risk factors was higher than in patients without risk factors. Nevertheless, it remains low, and no fatal complication occurred, which reinforces the idea that EBUS-TBNA is a safe technique for the assessment of the mediastinum. Necrotic lesions are a risk factor of post-EBUS infection, and their puncture should be avoided.     

Alterations in the Duodenal Fluid Microbiome of Patients With Pancreatic Cancer

Background & AimsThe tumor microbiome of patients with pancreas ductal adenocarcinoma (PDAC) includes bacteria normally present in the upper gastrointestinal tract. If the predominant source of intratumoral bacteria in patients with PDAC is retrograde migration from the duodenum, duodenal fluid could be a representative biospecimen for determining microbiome profiles of patients with PDAC or at risk of developing PDAC.MethodsWe performed a case-control study comparing bacterial and fungal (16S and 18S rRNA) profiles of secretin-stimulated duodenal fluid collections from 308 patients undergoing duodenal endoscopy including 134 normal pancreas control subjects, 98 patients with pancreatic cyst(s) and 74 patients with PDAC.ResultsAlterations in duodenal fluid microbiomes with diminished alpha diversity were significantly associated with age >70 and proton pump inhibitor use. Patients with PDAC had significantly decreased duodenal microbial alpha diversity compared with age-matched control subjects with normal pancreata and those with pancreatic cyst(s). There was evidence of enrichment of Bifidobacterium genera in the duodenal fluid of patients with PDAC compared with control subjects and those with pancreatic cyst(s). There were also enrichment of duodenal fluid Fusobacteria and Rothia bacteria among patients with PDAC with short-term survival. Duodenal fluid microbiome profiles were not significantly different between control subjects and patients with pancreatic cyst(s).ConclusionPatients with PDAC have alterations in their duodenal fluid microbiome profiles compared with patients with pancreatic cysts and those with normal pancreata. ClinicalTrials.gov, Number: NCT02000089     

Gut microbiota and allergic diseases in children

The gut microbiota resides in the human gastrointestinal tract, where it plays an important role in maintaining host health. The human gut microbiota is established by the age of 3 years. Studies have revealed that an imbalance in the gut microbiota, termed dysbiosis, occurs due to factors such as cesarean delivery and antibiotic use before the age of 3 years and that dysbiosis is associated with a higher risk of future onset of allergic diseases. Recent advancements in next-generation sequencing methods have revealed the presence of dysbiosis in patients with allergic diseases, which increases attention on the relationship between dysbiosis and the development of allergic diseases. However, there is no unified perspective on the characteristics on dysbiosis or the mechanistic link between dysbiosis and the onset of allergic diseases. Here, we introduce the latest studies on the gut microbiota in children with allergic diseases and present the hypothesis that dysbiosis characterized by fewer butyric acid-producing bacteria leads to fewer regulatory T cells, resulting in allergic disease. Further studies on correcting dysbiosis for the prevention and treatment of allergic diseases are warranted.     

The role of viral infections in pulmonary exacerbations of patients with non-cystic fibrosis bronchiectasis: A systematic review

BackgroundBronchiectasis is a cause of increased morbidity of the respiratory system. Exacerbations among patients with non-CF (cystic fibrosis) bronchiectasis result in reduced pulmonary function and poor quality of life. While the role of bacteria in triggering exacerbations in patients with non- CF bronchiectasis has been well studied, little is known about viral infections in these patients. We aimed to review the evidence on the role of respiratory viruses in the exacerbations of non-CF bronchiectasis.MethodsRelevant literature was searched on the MEDLINE/PubMed database. Seven studies satisfied the criteria and were included in this review.ResultsAccording to the included articles, respiratory viruses are often identified in exacerbations of patients with non-CF bronchiectasis with the most frequent being human rhinovirus and influenza viruses. When a virus is isolated during an exacerbation patients have more symptoms from the upper respiratory tract. One study showed that detection of Epstein- Barr virus among patients with non-CF bronchiectasis is correlated with faster reduction of pulmonary function and progression of the disease.ConclusionViruses seem to have a role in the exacerbation of patients with non-CF bronchiectasis. However, the exact nature and importance of this role remain elusive. Viruses are also isolated during the stable period of the disease. Further well-designed studies are necessary to clarify this complex issue.     

Differences in the spectrum of respiratory viruses and detection of human rhinovirus C in exacerbations of adult asthma and chronic obstructive pulmonary disease

BackgroundViral respiratory infections are a common cause of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) and asthma. We conducted a multicenter prospective study to determine the differences in the spectrum of viruses between adults with asthma exacerbations and AECOPD and assessed the prevalence and impact of human rhinovirus (HRV)-C in adults, which is more pathogenic in children with asthma than other HRV species.MethodsNasopharyngeal and serum samples and clinical information were collected from 64 outpatients with adult asthma exacerbations and 44 outpatients with AECOPD between April 2018 and March 2020. Viral pathogens and HRV strains were identified from nasal samples by multiplex PCR and VP4/VP2 nested PCR.ResultsViral pathogens were identified in 31 patients with asthma exacerbations (48.4%) and 17 patients with AECOPD (38.6%). The most commonly detected viruses were HRV/enterovirus followed by human metapneumovirus (hMPV) in patients with asthma exacerbations, and hMPV followed by parainfluenza virus in patients with AECOPD. HRV-C was the HRV species most commonly associated with both asthma exacerbations and AECOPD. Clinical characteristics, baseline lung function, serum inflammatory chemokines, hospitalization, and systemic steroid use did not differ between HRV-C-positive patients and those positive for other HRV species.ConclusionsExacerbation-associated spectrum of viruses differed between adults with asthma exacerbations and AECOPD. HRV-C was the HRV species most often observed in adult asthma exacerbations and AECOPD, although it did not worsen patients’ clinical outcomes relative to those of patients with other HRVs. Underlying disease-specific factors may be responsible for susceptibility to respiratory viruses.Trial registrationUMIN-CTR UMIN000031934.     

Compositional and functional alterations of gut microbiota in patients with stroke

Background and aimsThere is accumulating evidence that gut microbiota plays a key role in cardiovascular diseases. Gut bacteria can transform dietary choline, l-carnitine, and trimethylamine N-oxide (TMAO) into trimethylamine, which can be oxidized into TMAO again in the liver. However, the alterations of the gut microbiota in large artery atherosclerotic (LAA) stroke and cardioembolic (CE) stroke have been less studied.Methods and resultsWe performed a case–control study in patients with LAA and CE types of strokes. We profiled the gut microbiome using Illumina sequencing of the 16S ribosomal RNA gene (V4–V5 regions), and TMAO was determined via liquid chromatography–tandem mass spectrometry. Our results showed that the TMAO levels in the plasma of patients with LAA and CE strokes were significantly higher than those in controls (LAA stroke, 2931 ± 456.4 ng/mL; CE stroke, 4220 ± 577.6 ng/mL; healthy control, 1663 ± 117.8 ng/mL; adjusted p < 0.05). The TMAO level in the plasma of patients with LAA stroke was positively correlated with the carotid plaque area (rho = 0.333, 95% CI = 0.08–0.55, p = 0.0093). Notably, the composition and the function of gut microbiota in the LAA stroke group were significantly different from those in the control group (FDR-adjusted p-value < 0.05). There was no significant association between gut microbiota and CE stroke in our study.ConclusionThis study provides evidence for significant compositional and functional alterations of the gut microbiome in patients with LAA stroke. Gut microbiota might serve as a potential biomarker for patients with LAA stroke.     

Sustained coronavirus disease 2019-related organizing pneumonia successfully treated with corticosteroid

A 70-year-old Japanese man contracted severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and required oxygen to maintain oxygen saturation (>90%), 5 weeks after onset of coronavirus disease 2019 (COVID-19) symptoms. Transbronchial lung cryobiopsy revealed pathological features of organizing pneumonia with alveolar epithelial injury, and prednisolone administration led to alleviation of respiratory symptoms and recovery of respiratory function. This case report is the first to demonstrate the use of corticosteroids to successfully treat post-COVID-19 respiratory failure in a patient with biopsy-proven organizing pneumonia. We propose that steroid treatment be considered for patients with persistent respiratory dysfunction as COVID-19 pneumonia sequelae.     

Prevalence of viral infection in acute exacerbation of interstitial lung diseases in Japan

BackgroundFatal acute exacerbation of interstitial lung diseases is often accompanied by indicators of infection such as fever, cough, and sputum. Although viral infection can contribute to acute exacerbation of interstitial lung diseases, few studies have identified a relationship between acute exacerbations and viral infections. The present study aimed to prospectively clarify the role of viral infection in patients showing acute exacerbation of interstitial lung disease in Japan.MethodsNasopharyngeal swab specimens were collected from patients with acute exacerbation of interstitial lung disease between May 2017 and February 2019. Respiratory viruses were detected by the Luminex xTAG Respiratory Viral Panel FAST v2 RUO kit and the BioFire FilmArray Respiratory Panel assay.ResultsThree of 29 patients demonstrated respiratory viral infection during acute exacerbation of interstitial lung diseases. The infectious agents were identified as respiratory syncytial virus, respiratory syncytial virus and influenza A virus, and influenza A virus and rhino/enterovirus in the three patients, respectively.ConclusionsThese results suggest that viral infection did not frequently induce acute exacerbation of interstitial lung diseases in Japan.     

Clinical course and prognosis in survivors of acute exacerbations of idiopathic pulmonary fibrosis

BackgroundPatients with idiopathic pulmonary fibrosis (IPF) are at risk of acute exacerbations (AEs) that manifest as respiratory distress. However, the clinical course after AEs of IPF (AE-IPFs) has not been well described. Therefore, we aimed to elucidate the clinical course and prognosis in survivors of AE-IPFs.MethodsConsecutive patients with IPF who presented to our institution with their first AE-IPFs between January 2008 and December 2019 were included in this study. Data were retrospectively collected, and the clinical course, survival, and cause of death were further analyzed.ResultsNinety-seven patients were included in this retrospective study. Among them, 67 (69.1%) were discharged alive, with a median survival time after discharge of 1081 days. AE recurrence and pneumonia were the most common causes of death, each accounting for 22.2% of cases among survivors of AE-IPFs. AEs were the most frequent during the first 3 years after discharge, whereas pneumonia was more common thereafter.ConclusionsSurvivors of AE-IPFs have a relatively favorable long-term prognosis. Among the survivors of first AE-IPFs, AE recurrence and pneumonia were the most common causes of death after discharge. Therefore, preventing AE recurrence and lung infections is crucial for prolonging survival in survivors of AE-IPFs.     

Gut microbiota dysbiosis in stable coronary artery disease combined with type 2 diabetes mellitus influences cardiovascular prognosis

Background and aimsHost–microbiota interactions involving metabolic pathways have been linked to the pathogenesis of atherosclerotic disease and type 2 diabetes. As stable coronary artery disease (SCAD) patients combined with type 2 diabetes have significantly increased risk for cardiac event, we focused on elucidating the role of microbiota affecting cardiometabolic disease development.Methods and resultsWe used multi-omics analyses (metagenomics and metabolomics) of fecal and serum samples from a prospective cohort including stable coronary artery disease combined with diabetes mellitus (SCAD + T2DM, n = 38), SCAD (n = 71), and healthy control (HC, n = 55). We linked microbiome features to disease severity in a three-pronged association analysis and identified prognostic bacterial biomarkers. We identified that bacterial and metabolic signatures varied significantly between SCAD and SCAD + T2DM groups. SCAD + T2DM individuals were characterized by increased levels of aromatic amino acids and carbohydrates, which correlate with a gut microbiome with enriched biosynthetic potential. Our study also addressed how metformin may confound gut dysbiosis and increase the potential for nitrogen metabolism. In addition, we found that specific bacterial taxa Ruminococcus torques [HR: 2.363 (08–4.56), P = 0.03] was predictive of cardiac survival outcomes.ConclusionOverall, our study identified relationships between features of the gut microbiota (GM) and circulating metabolites, providing a new direction for future studies aiming to understand the host–GM interplay in atherosclerotic cardiovascular pathogenesis.     

Risk factors for progression to acute respiratory failure after casirivimab and imdevimab administration: A retrospective study

BackgroundCasirivimab and imdevimab are effective in preventing hospitalization in outpatients with coronavirus disease 2019 (COVID-19); however, disease progression after casirivimab and imdevimab administration has been reported. This study aimed to elucidate the risk factors for disease progression after casirivimab and imdevimab administration.MethodsThis retrospective study included patients with COVID-19 who received casirivimab and imdevimab at Hiroshima City Funairi Citizens Hospital between August 6, 2021, and October 10, 2021. All patients had at least one risk factor for severe disease and were treated on admission. The patients’ background characteristics and test results at the first visit were analyzed. The patients were divided into two groups (progressed and improved) based on whether they progressed to acute respiratory failure during hospitalization.ResultsSixty-seven patients were included: 9 patients in the progressed group (median age, 56 years) and 58 patients in the improved group (median age, 51 years). Age, coexistence rate of diabetes, cycle threshold value of polymerase chain reaction test, rate of detectable pneumonia on chest radiographs or chest computed tomography images, lymphocyte count, and the levels of C-reactive protein, interleukin-6, glucose, and glycated hemoglobin were significantly different between the two groups. Multivariate logistic regression analysis revealed that the coexistence of diabetes and the presence of detectable pneumonia on chest radiographs were independent factors predicting the progression to acute respiratory failure.ConclusionAcute respiratory failure after antibody therapy with casirivimab and imdevimab may develop in patients with diabetes or detectable pneumonia on chest radiographs at the first visit.     

Decrease in hemoglobin level predicts increased risk for severe respiratory failure in COVID-19 patients with pneumonia

BackgroundIn December 2019, the coronavirus disease (COVID-19), caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), emerged in Wuhan, China, and has since spread throughout the world. This study aimed to investigate the association between the change in laboratory markers during the three days after pneumonia diagnosis and severe respiratory failure in COVID-19 patients.MethodsData of 23 COVID-19 patients with pneumonia, admitted to the Kumamoto City Hospital between February and April 2020 were retrospectively analyzed.ResultsAmong the 23 patients, eight patients received mechanical ventilation (MV) (MV group), and the remaining 15 comprised the non-MV group. The levels of hemoglobin (Hb) and albumin (Alb) decreased in the MV group during the three days after pneumonia diagnosis more than in the non-MV group (median Hb: 1.40 vs. ?0.10 g/dL, P = 0.015; median Alb: 0.85 vs. ?0.30 g/dL, P = 0.020). Univariate logistic regression analysis showed that the decrease in Hb was associated with receiving MV care (odds ratio: 0.313, 95% confidence interval: 0.100–0.976, P = 0.045). Receiver operating characteristic curve analyses showed that the optimal cut-off value for the decrease in Hb level was ?1.25 g/dL, with sensitivity and specificity values of 0.867 and 0.750, respectively.ConclusionsThe decrease in Hb level during the short period after pneumonia diagnosis might be a predictor of worsening pneumonia in COVID-19 patients.     

Risk factors for transfer from Respiratory Intermediate Care Unit to Intensive Care Unit in COVID-19

BackgroundPatients hospitalized for COVID-19-related pneumonia often need several degrees of ventilatory support, which are performed between Respiratory Intermediate Care Units (RICUs) and Intensive Care Units (ICUs), and which depend on the severity of acute respiratory distress syndrome. There is no firm consensus on transfer predictors from the RICU to the ICU.MethodsIn this retrospective observational single center study, we evaluated 96 COVID-19 patients referred to the RICU for acute respiratory failure (ARF) according to their transferal to the ICU or their stay at the RICU. We compared demographic data, baseline laboratory profile, and final clinical outcomes to identify early risk factors for transfer.ResultsThe best predictors for transfer to the ICU were elevated C-reactive protein and lymphopenia. The mortality rate was lower in the RICU than in the ICU, where transferred patients who died were mostly younger men and with less comorbidities than those in the RICU.ConclusionsFew inflammatory markers can predict the need for transfer from the RICU to the ICU. Due to the ongoing COVID-19 pandemic, we urge better clinical stratification by early and meaningful profiles in patients admitted to the RICU who are at risk of transferal to the ICU.     

Where is Chlamydophila pneumoniae pneumonia?

BackgroundMolecular diagnostic methods have recently gained widespread use, and consequently, the importance of viral pathogens in community-acquired pneumonia (CAP) has undergone re-evaluation. Under these circumstances, the role of Chlamydophila pneumoniae as a pathogen that causes CAP also needs to be reviewed.MethodsWe reviewed articles that contained data on the frequency of identification of C. pneumoniae pneumonia as a causative pathogen for CAP. The articles were identified by performing a search in PubMed with the keywords “community-acquired pneumonia” and “pathogen”.ResultsSixty-three articles were identified. The reviewed articles demonstrated that the rates of identification of C. pneumoniae as the causative pathogen for CAP were significantly lower in assessments based on polymerase chain reaction (PCR) methods than in those based on serological methods. In some studies, it was possible to compare both serological and PCR methods directly using the same set of samples.ConclusionsThe use of PCR methods, including multiplex PCR assays, has revealed that C. pneumoniae may play a limited role as a pathogen for CAP.     

Anti-inflammatory effects of medications used for viral infection-induced respiratory diseases

Respiratory viruses like rhinovirus, influenza virus, respiratory syncytial virus, and coronavirus cause several respiratory diseases, such as bronchitis, pneumonia, pulmonary fibrosis, and coronavirus disease 2019, and exacerbate bronchial asthma, chronic obstructive pulmonary disease, bronchiectasis, and diffuse panbronchiolitis. The production of inflammatory mediators and mucin and the accumulation of inflammatory cells have been reported in patients with viral infection-induced respiratory diseases. Interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor-α, granulocyte-macrophage colony-stimulating factor, and regulated on activation normal T-cell expressed and secreted are produced in the cells, including human airway and alveolar epithelial cells, partly through the activation of toll-like receptors, nuclear factor kappa B and p44/42 mitogen-activated protein kinase. These mediators are associated with the development of viral infection-induced respiratory diseases through the induction of inflammation and injury in the airway and lung, airway remodeling and hyperresponsiveness, and mucus secretion. Medications used to treat respiratory diseases, including corticosteroids, long-acting β₂-agonists, long-acting muscarinic antagonists, mucolytic agents, antiviral drugs for severe acute respiratory syndrome coronavirus 2 and influenza virus, macrolides, and Kampo medicines, reduce the production of viral infection-induced mediators, including cytokines and mucin, as determined in clinical, in vivo, or in vitro studies. These results suggest that the anti-inflammatory effects of these medications on viral infection-induced respiratory diseases may be associated with clinical benefits, such as improvements in symptoms, quality of life, and mortality rate, and can prevent hospitalization and the exacerbation of chronic obstructive pulmonary disease, bronchial asthma, bronchiectasis, and diffuse panbronchiolitis.