Pneumoniae-induced Pneumonia Research Articles

Therapeutic effects and mechanisms of Modified Ma-Xing-Shi-Gan Decoction on Klebsiella pneumoniae-induced pneumonia in mice assessed by Multi-omics

Ethnopharmacological relevanceModified Ma-Xing-Shi-Gan decoction (MMXSGD), a classic prescription from Treatise on Febrile Disease in China, is commonly used to treat Klebsiella pneumoniae (KP) infections in clinical settings. Materials and methodsThe aim of this study is to assess the efficacy of MMXSGD in the treatment of pneumonia and investigate its underlying mechanism of action. UHPLC-MS/MS was established to identify the main chemical components of serum after intragastric administration with MMXSGD. A mouse model of pneumonia caused by KP was used to evaluate the therapeutic potential of MMXSGD. The macrophage polarization was analyzed by immunohistochemistry. The cytokine profile was assessed using Luminex assay. Lung transcript and metabolite levels were assessed by transcriptomics and non-targeted metabolomics to analyze potential anti-pneumonia mechanisms and targets. Results22 major blood-entry components and 274 MMXSGD-pneumonia-related targets were identified. Compared with the model group, the mortality rate of mice in different dosage groups of MMXSGD was significantly reduced, and pathological lung damage was significantly alleviated. Among them, the low dose of MMXSGD treatment had the best protective effect. Further, MMXSGD treatment could regulates M1/M2 polarization in macrophages and inhibits the production of pro-inflammatory cytokines. The data from transcriptome and metabolome analysis indicate that MMXSGD could regulate inflammation-related pathways (PI3K/AKT, HIF-1, NF-κB pathway) and metabolites to modulate pulmonary inflammation. The results demonstrate that MMXSGD enhances the antibacterial effect in vivo by suppressing inflammation and regulating immunity rather than directly antibacterial effect. ConclusionThese findings provide a further assessment of MMXSGD, suggesting that MMXSGD has good therapeutic efficacy in bacterial infectious diseases.

Effect of SiHuangQingXinWan on Klebsiella pneumoniae-induced pneumonia: mechanistic insights.

Due to the high mortality rate and increasing severity of antibiotic resistance, there is a growing interest in new treatments for Klebsiella pneumoniae (KP)-induced pneumonia. Research has shown that the single herbs of SiHuangQingXinWan (SHQXW) are effective in treating pneumonia caused by KP. The PI3K/AKT signaling pathway has garnered attention for its potential role in the management of bacterial infections. This study aimed to evaluate the anti-pneumonia effect of SHQXW and to investigate its mechanism of action. The potential plant metabolites and molecular targets of SHQXW in the context of pneumonia were determined through ultra-high performance liquid chromatography-tandem mass-spectrometry (UHPLC-MS/MS) and bioinformatics analysis. The therapeutic effect of SHQXW was evaluated in a KP-induced pneumonia murine model with imipenem/cilastatin as a positive control. Transcriptomics and non-targeted metabolomics were carried out to unveil potential mechanisms and targets for anti-pneumonia effects. Additionally, an in-depth exploration on the PI3K/AKT signaling pathway was conducted in this study. A total of 24 potential plant metabolites and 285 SHQXW-pneumonia-related targets selected by Homo sapiens were identified in this study. The tested doses of SHQXW significantly reduced mortality, improved body weight, decreased the lung index, reduced the bacterial load, and alleviated lung pathological damage in the KP-induced pneumonia murine model (p < 0.05). Notably, 1.3g/kg/day of SHQXW provided the most effective protective outcome. Furthermore, SHQXW demonstrated the ability to suppress the production of inflammatory factors such as IL-1α, IL-1β, IL-3, IL-6, IL-12p70, G-CSF, GM-CSF, MCP-1, KC, and TNF-α. Analysis of transcriptomic and metabolomic data revealed that SHQXW could modulate inflammation-related signaling pathways (TNF, HIF-1, NF-κB, and PI3K/AKT) and metabolites to regulate pulmonary inflammation. Additional experiments using RT-qPCR and western blotting indicated that SHQXW may exert anti-inflammatory effects by activating the PI3K/AKT pathway. The findings indicate that SHQXW effectively reduces inflammation in mice with KP-induced pneumonia by modulating inflammatory signaling pathways and metabolites, rather than by directly inhibiting the growth of KP. This study introduces a novel treatment approach for KP-induced pneumonia and presents a new outlook on drug development.

Acute Exacerbation of Chronic Obstructive Pulmonary Disease Due to Carbapenem-Resistant Klebsiella pneumoniae-Induced Pneumonia: Clinical Features and Prognostic Factors.

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is closely related to respiratory tract infection. The aim of this study was to investigate the clinical features and prognostic factors of CRKP-induced pneumonia in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) patients. A single-centre, retrospective case-control study on COPD patients hospitalized for acute exacerbation and CRKP-induced pneumonia was conducted from January 1, 2016, to December 31, 2022. The mortality rate of acute exacerbation due to CRKP-induced pneumonia was investigated. The patients were divided into the CRKP-induced pneumonic acute exacerbation (CRKPpAE) group and the non-CRKP-induced pneumonic acute exacerbation (non-CRKPpAE) group, and the clinical characteristics and prognostic factors were compared using univariate analysis and multivariate analysis. A total of 65 AECOPD patients were included, composed of 26 patients with CRKPpAE and 39 patients with non-CRKPpAE. The mortality rate of CRKPpAE was 57.69%, while non-CRKPpAE was 7.69%. Compared with non-CRKPpAE, a history of acute exacerbation in the last year (OR=8.860, 95% CI: 1.360-57.722, p=0.023), ICU admission (OR=11.736, 95% CI: 2.112-65.207, p=0.005), higher NLR levels (OR=1.187, 95% CI: 1.037-1.359, p=0.013) and higher D-dimer levels (OR=1.385, 95% CI: 1.006-1.905, p=0.046) were independently related with CRKPpAE. CRKP isolates were all MDR strains (26/26, 100%), and MDR strains were also observed in non-CRKP isolates (5/39, 12.82%). Compared with non-CRKPpAE, CRKPpAE affects the COPD patient's condition more seriously and significantly increases the risk of death.

Bio-Responsive Sliver Peroxide-Nanocarrier Serves as Broad-Spectrum Metallo-β-lactamase Inhibitor for Combating Severe Pneumonia.

Metallo-β-lactamases (MBLs) represent a prevalent resistance mechanism in Gram-negative bacteria, rendering last-line carbapenem-related antibiotics ineffective. Here, a bioresponsive sliver peroxide (Ag2 O2 )-based nanovesicle, named Ag2 O2 @BP-MT@MM, is developed as a broad-spectrum MBL inhibitor for combating MBL-producing bacterial pneumonia. Ag2 O2 nanoparticle is first orderly modified with bovine serum albumin and polydopamine to co-load meropenem (MER) and [5-(p-fluorophenyl)-2-ureido]-thiophene-3-carboxamide (TPCA-1) and then encapsulated with macrophage membrane (MM) aimed to target inflammatory lung tissue specifically. The resultant Ag2 O2 @BP-MT@MM effectively abrogates MBL activity by displacing the Zn2+ cofactor in MBLs with Ag+ and displays potent bactericidal and anti-inflammatory properties, specific targeting abilities, and great bioresponsive characteristics. After intravenous injection, the nanoparticles accumulate prominently at infection sites through MM-mediated targeting . Ag+ released from Ag2 O2 decomposition at the infection sites effectively inhibits MBL activity and overcomes the resistance of MBL-producing bacteria to MER, resulting in synergistic elimination of bacteria in conjunction with MER. In two murine infection models of NDM-1+ Klebsiella pneumoniae-induced severe pneumonia and NDM-1+ Escherichia coli-induced sepsis-related bacterial pneumonia, the nanoparticles significantly reduce bacterial loading, pro-inflammatory cytokine levels locally and systemically, and the recruitment and activation of neutrophils and macrophages. This innovative approach presents a promising new strategy for combating infections caused by MBL-producing carbapenem-resistant bacteria.

Anemoside B4 inhibits SARS-CoV-2 replication in vitro and in vivo

ObjectiveAnemoside B4 (AB4), the most abundant triterpenoidal saponin isolated from Pulsatilla chinensis, inhibited influenza virus FM1 or Klebsiella pneumoniae-induced pneumonia. However, the anti-SARS-CoV-2 effect of AB4 has not been unraveled. Therefore, this study aimed to determine the antiviral activity and potential mechanism of AB4 in inhibiting human coronavirus SARS-CoV-2 in vivo and in vitro. MethodsThe cytotoxicity of AB4 was evaluated using the Cell Counting Kit-8 (CCK8) assay. SARS-CoV-2 infected HEK293T, HPAEpiC, and Vero E6 cells were used for in vitro assays. The antiviral effect of AB4 in vivo was evaluated by SARS-CoV-2-infected hACE2-IRES-luc transgenic mouse model. Furthermore, label-free quantitative proteomics and bioinformatic analysis were performed to explore the potential antiviral mechanism of action of AB4. Type I IFN signaling-associated proteins were assessed using Western blotting or immumohistochemical staining. ResultsThe data showed that AB4 reduced the propagation of SARS-CoV-2 along with the decreased Nucleocapsid protein (N), Spike protein (S), and 3C-like protease (3CLpro) in HEK293T cells. In vivo antiviral activity data revealed that AB4 inhibited viral replication and relieved pneumonia in a SARS-CoV-2 infected mouse model. We further disclosed that the antiviral activity of AB4 was associated with the enhanced interferon (IFN)-β response via the activation of retinoic acid-inducible gene I (RIG-1) like receptor (RLP) pathways. Additionally, label-free quantitative proteomic analyses discovered that 17 proteins were significantly altered by AB4 in the SARS-CoV-2 coronavirus infections cells. These proteins mainly clustered in RNA metabolism. ConclusionOur results indicated that AB4 inhibited SARS-CoV-2 replication through the RLR pathways and moderated the RNA metabolism, suggesting that it would be a potential lead compound for the development of anti-SARS-CoV-2 drugs.

Risk Factors for 30-Day Mortality in Patients with Bacteremic Pneumonia Caused by Escherichia coli and Klebsiella pneumoniae: A Retrospective Study.

Escherichia coli and Klebsiella pneumoniae are prevalent Gram-negative microorganisms responsible for pneumonia, as well as the primary Enterobacteriaceae pathogens causing bacteremic pneumonia. The objective of this research is to analyze the risk factors associated with bacteremic pneumonia caused by these pathogens and develop a predictive model. This retrospective investigation encompassed a cohort of 252 patients diagnosed with Escherichia coli or Klebsiella pneumoniae-induced bacteremic pneumonia between 2018 and 2022. The primary endpoint was 30-day mortality, which was analyzed using multifactorial logistic regression, nomogram construction, and Bootstrap validation. Among the 252 patients diagnosed with Escherichia coli and Klebsiella pneumoniae, 65 succumbed to the disease while 187 survived. The overall 30-day mortality was found to be 25.8%. A multifactorial logistic regression analysis revealed that diastolic blood pressure, cerebrovascular diseases/transient ischemic attacks (TIA), immunosuppression, blood urea nitrogen, Pitt score, and CURB-65 score were statistically significant factors. The Nomogram model demonstrated an AUC of 0.954, which closely aligns with the Bootstrap-derived mean AUC of 0.953 (95% CI: 0.952-0.954). In patients with bacteremic pneumonia caused by Escherichia coli and Klebsiella pneumoniae, Low diastolic blood pressure (≤61 mmHg), pre-existing cerebrovascular disease/ transient ischemic attacks (TIA), immunosuppression status, elevated blood urea nitrogen levels (≥8.39 mmol/L), high Pitt score (≥3), and a high CURB-65 score (≥2) are all independent risk factors for Escherichia coli and Klebsiella pneumoniae bacteremic pneumonia, among which the first three warrant particular attention.

Bakuchiol reduces the severity of Mycoplasma pneumoniae-induced pneumonia in mice by attenuating inflammatory responses

BackgroundPneumonia has become a leading cause of death due to its high morbidity rates worldwide. Pneumonia is caused by the bacterium Mycoplasma pneumoniae (MP), which is a prominent airway pathogen. MP infection is usually self-limiting, but an alarming increase in cases has recently developed into refractory, severe, and even fatal pneumonia. ObjectiveThe objective of the current work was to study the anti-inflammatory and antioxidant properties of bakuchiol in ameliorating MP-induced pneumonia in mice. MethodologyBALB/c mice were challenged with MP (100 µl) via nasal drops for 2 days to induce pneumonia, and bakuchiol (25 mg/kg) was given concurrently to the mice for 3 days. Thereafter, measurements of lung weight, MPO, and NO concentrations were done. The corresponding kits were used to analyze the GSH, SOD, and MDA concentrations. The DNA contents of MP were assessed by PCR, and the total cells in BALF were counted. The corresponding kits were used to measure NF-κB levels and examine the inflammatory cytokine levels in the BALF samples. The lung histopathology was assessed to identify the histological changes. ResultsIn pneumonia-induced mice, the lung weight was significantly reduced after treatment with 25 mg/kg of bakuchiol. The bakuchiol treatment exhibited an effective antioxidant and anti-inflammatory properties on the pneumonia mice. Bakuchiol also lowered the NF-κB level and attenuated histological alterations in the lungs of pneumonia-induced mice. Conclusion: In summary, our findings exhibited that bakuchiol significantly reduced inflammation induced by MP in a mouse model of pneumonia. As a result, it has potential as a future salutary agent for the pneumonia treatment.

Multiple Dosing and Preactivation of Mesenchymal Stromal Cells Enhance Efficacy in Established Pneumonia Induced by Antimicrobial-Resistant Klebsiella pneumoniae in Rodents.

Antimicrobial-resistant (AMR) bacteria, such as Klebsiella species, are an increasingly common cause of hospital-acquired pneumonia, resulting in high mortality and morbidity. Harnessing the host immune response to AMR bacterial infection using mesenchymal stem cells (MSCs) is a promising approach to bypass bacterial AMR mechanisms. The administration of single doses of naïve MSCs to ARDS clinical trial patient cohorts has been shown to be safe, although efficacy is unclear. The study tested whether repeated MSC dosing and/or preactivation, would attenuate AMR Klebsiella pneumonia-induced established pneumonia. Rat models of established K. pneumoniae-induced pneumonia were randomised to receive intravenous naïve or cytomix-preactivated umbilical cord MSCs as a single dose at 24 h post pneumonia induction with or without a subsequent dose at 48 h. Physiological indices, bronchoalveolar lavage (BAL), and tissues were obtained at 72 h post pneumonia induction. A single dose of naïve MSCs was largely ineffective, whereas two doses of MSCs were effective in attenuating Klebsiella pneumosepsis, improving lung compliance and oxygenation, while reducing bacteria and injury in the lung. Cytomix-preactivated MSCs were superior to naïve MSCs. BAL neutrophil counts and activation were reduced, and apoptosis increased. MSC therapy reduced cytotoxic BAL T cells, and increased CD4+/CD8+ ratios. Systemically, granulocytes, classical monocytes, and the CD4+/CD8+ ratio were reduced, and nonclassical monocytes were increased. Repeated doses of MSCs-particularly preactivated MSCs-enhance their therapeutic potential in a clinically relevant model of established AMR K. pneumoniae-induced pneumosepsis.

Anti-inflammatory effect of chlorogenic acid in Klebsiella pneumoniae-induced pneumonia by inactivating the p38MAPK pathway

IntroductionPneumonia is an inflammation-related respiratory infection and chlorogenic acid (CGA) possesses a wide variety of bioactive properties, such as anti-inflammation and anti-bacteria. AimThis study explored the anti-inflammatory mechanism of CGA in Klebsiella pneumoniae (Kp)-induced rats with severe pneumonia. MethodsThe pneumonia rat models were established by infection with Kp and treated with CGA. Survival rates, bacterial load, lung water content, and cell numbers in the bronchoalveolar lavage fluid were recorded, lung pathological changes were scored, and levels of inflammatory cytokines were determined by enzyme-linked immunosorbent assay. RLE6TN cells were infected with Kp and treated with CGA. The expression levels of microRNA (miR)-124–3p, p38, and mitogen-activated protein kinase (MAPK)-activated protein kinase 2 (MK2) in lung tissues and RLE6TN cells were quantified by real-time quantitative polymerase chain reaction or Western blotting. The binding of miR-124–3p to p38 was validated by the dual-luciferase and RNA pull-down assays. In vitro, the functional rescue experiments were performed using miR-124–3p inhibitor or p38 agonist. ResultsKp-induced pneumonia rats presented high mortality, increased lung inflammatory infiltration and the release of inflammatory cytokines, and enhanced bacterial load, while CGA treatment improved rat survival rates and the above situations. CGA increased miR-124–3p expression, and miR-124–3p inhibited p38 expression and inactivated the p38MAPK pathway. Inhibition of miR-124–3p or activation of the p38MAPK pathway reversed the alleviative effect of CGA on pneumonia in vitro. ConclusionCGA upregulated miR-124–3p expression and inactivated the p38MAPK pathway to downregulate inflammatory levels, facilitating the recovery of Kp-induced pneumonia rats.

Platelet p110β mediates platelet-leukocyte interaction and curtails bacterial dissemination in pneumococcal pneumonia.

Phosphatidylinositol 3-kinase catalytic subunit p110β is involved in tumorigenesis and hemostasis. However, it remains unclear if p110β also regulates platelet-mediated immune responses, which could have important consequences for immune modulation during anti-cancer treatment with p110β inhibitors. Thus, we investigate how platelet p110β affects inflammation and infection. Using a mouse model of Streptococcus pneumoniae-induced pneumonia, we find that both platelet-specific p110β deficiency and pharmacologic inhibition of p110β with TGX-221 exacerbate disease pathogenesis by preventing platelet-monocyte and neutrophil interactions, diminishing their infiltration and enhancing bacterial dissemination. Platelet p110β mediates neutrophil phagocytosis of S.pneumoniae invitro and curtails bacteremia invivo. Genetic deficiency or inhibition of platelet p110β also impairs macrophage recruitment in an independent model of sterile peritonitis. Our results demonstrate that platelet p110β dysfunction exacerbates pulmonary infection by impeding leukocyte functions. Thereby, our findings provide important insights into the immunomodulatory potential of PI3K inhibitors in bacterial infection.

The Therapeutic Treatment with the GAG-Binding Chemokine Fragment CXCL9(74-103) Attenuates Neutrophilic Inflammation and Lung Dysfunction during Klebsiella pneumoniae Infection in Mice.

Klebsiella pneumoniae is an important pathogen associated with hospital-acquired pneumonia (HAP). Bacterial pneumonia is characterized by a harmful inflammatory response with a massive influx of neutrophils, production of cytokines and chemokines, and consequent tissue damage and dysfunction. Targeted therapies to block neutrophil migration to avoid tissue damage while keeping the antimicrobial properties of tissue remains a challenge in the field. Here we tested the effect of the anti-inflammatory properties of the chemokine fragment CXCL9(74–103) in pneumonia induced by Klebsiella pneumoniae in mice. Mice were infected by intratracheal injection of Klebsiella pneumoniae and 6 h after infection were treated systemically with CXCL9(74–103). The recruitment of leukocytes, levels of cytokines and chemokines, colony-forming units (CFU), and lung function were evaluated. The treatment with CXCL9(74–103) decreased neutrophil migration to the airways and the production of the cytokine interleukin-1β (IL-1β) without affecting bacterial control. In addition, the therapeutic treatment improved lung function in infected mice. Our results indicated that the treatment with CXCL9(74–103) reduced inflammation and improved lung function in Klebsiella pneumoniae-induced pneumonia.

G9a promotes inflammation in Streptococcus pneumoniae induced pneumonia mice by stimulating M1 macrophage polarization and H3K9me2 methylation in FOXP1 promoter region

BackgroundStreptococcus pneumoniae has become a leading cause of pneumonia in recent years. Here, we investigated the mechanism of histone methylase G9a in Streptococcus pneumoniae-induced pneumonia (Spn).MethodsG9a expression in Spn mouse tissue was measured. G9a lentivirus interference vector was injected into Spn mice to evaluate the wet and dry weight of the right upper lobe and the total lung water content (TLW) and wet/dry ratio (W/D). The number of neutrophils, macrophages, and lymphocytes in bronchoalveolar lavage fluid (BALF) was detected, and the levels of interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), and IL-10 in BALF were assessed. The expressions of M1 and M2 macrophage markers were also detected. The enrichment of histone 3 lysine 9 dimethylation (H3K9me2) in the Forkhead Box P1 (FOXP1) promoter was detected by chromatin immunoprecipitation (ChIP) assay, and the transcription level of FOXP1 was detected. Mouse macrophage RAW264.7 was induced by lipopolysaccharide (LPS) following G9a interference.ResultsG9a in the lung tissue of Spn mice was increased. After G9a knockdown, the mouse weight increased, the infiltration of inflammatory cells was decreased, levels of pro-inflammatory cytokines in BALF were decreased, CD86 and inducible nitric oxide synthase (iNOS) were decreased, and CD206 and arginase-1 (Arg-1) were elevated. In LPS-induced RAW264.7, G9a inhibited macrophage polarization to M1 and promoted macrophage polarization to M2. G9a promoted H3K9me2 methylation in the FOXP1 promoter region and inhibited its transcription, while FOXP1 downregulation reversed the inhibition of G9a knockdown on macrophage polarization to M1 and the inflammatory effect on Spn mice.ConclusionsG9a promotes M1 polarization of macrophages by promoting H3K9me2 methylation in the FOXP1 promoter region, promoting an inflammatory response in Spn mice.

Combination Therapy with TCM Preparation Kumu Injection and Azithromycin against Bacterial Infection and Inflammation: In Vitro and In Vivo

Background Azithromycin (AZM) is one of the most common broad-spectrum antibiotics. However, drug resistance is increasing and combination therapy has attracted great attention. AZM is usually combined with traditional Chinese medicine (TCM) preparations with heat-clearing and detoxifying effects, including Kumu injection (KM) made from Picrasma quassioides (D. Don) Benn. Purpose The present study aimed to investigate synergistic antimicrobial and anti-inflammatory activities of KM plus AZM with the aim of understanding the mechanism of clinical efficacy of combination regimens. Methods Seven common bacterial clinical isolates and LPS-induced RAW 264.7 cells were used for assay of in vitro potency. The minimum inhibitory concentration (MIC) was determined for each drug, followed by synergy testing through the checkerboard method and fractional inhibitory concentration index (FICI) for quantifying combined antibacterial effects. The rat model of Klebsiella pneumoniae-induced pneumonia was developed and subjected to various drug treatments, namely, AZM, KM, or AZM plus KM, intravenously administered at 75 mg/kg once a day for one week. The combination effects then were evaluated according to pharmacodynamics and pharmacokinetic assessments. Results KM-AZM combination synergistically inhibits in vitro growth of all the test standard strains except Pseudomonas aeruginosa and also the drug-resistant strains of Staphylococcus aureus, Streptococcus pneumoniae, Shigella dysenteriae, Klebsiella pneumoniae, and Escherichia coli. Despite an additive effect against NO, KM plus AZM at an equal dose could synergistically suppress overrelease of the inflammatory cytokines TNF-α and IL-6 by LPS-induced RAW 264.7 cells. The combination significantly inhibited the proliferation of K. pneumoniae in the rat lungs, mainly by inactivating MAPKs and NF-κB signaling pathways. KM-AZM combination caused a onefold increase in apparent distribution volume of AZM, along with a significant decrease of AZM level in the livers and heart for pharmacokinetics. Conclusion KM-AZM combination displayed synergistic antibacterial and anti-inflammatory effects beneficial to the therapeutic potential against bacterial infection.

Ceftazidime-Avibactam-Based Versus Tigecycline-Based Regimen for the Treatment of Carbapenem-Resistant Klebsiella pneumoniae-Induced Pneumonia in Critically Ill Patients.

IntroductionThe aim of the present study was to assess the safety profile and outcomes of a ceftazidime–avibactam (CAZ-AVI)-based regimen and compare them with those of a tigecycline (TGC)-based regimen in intensive care unit (ICU) for the treatment of carbapenem-resistant Klebsiella pneumoniae (CRKP), which is classified into hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP).MethodsClinical and microbiological cure rates, 28-day survival rates, and safety evaluation findings were compared between patients treated with CAZ-AVI-based regimen and those treated with TGC-based regimen in this retrospective study. Conventional multivariate logistic regression analysis and regression adjustment analysis with propensity score (PS) were performed to control for confounding variables.ResultsA total of 105 cases of critically ill ICU patients with CRKP-induced HAP or VAP were included in the present study from July 2019 to September 2020; 62 patients (59%) received TGC-based regimen and 43 patients (41%) received CAZ-AVI-based regimen. The most common concomitant agent in the CAZ-AVI group and TGC group was carbapenem (44.2% versus 62.9%, P = 0.058), while only a small proportion of the study population received CAZ-AVI and TGC monotherapy (20.9% versus 6.5%, P = 0.027). The clinical and microbiological cure rates of the CAZ-AVI group were superior to those of the TGC group [51.2% versus 29.0% (P = 0.022) and 74.4% versus 33.9% (P < 0.001), respectively]. No significant differences in the 28-day survival rates were identified between the two groups (69.8% versus 66.1%, P = 0.695). Conventional multivariate logistic regression and PS analyses showed that patients who had used CAZ-AVI were more likely to have achieved a clinical cure [4.767 (95%CI 1.694-13.414), P=0.003;3.405 (95%CI 1.304-8.889), P=0.012] and microbiological success [6.664 (95%CI 2.626-16.915), P<0.001;7.778 (95%CI 2.717-22.265), P<0.001] than patients who used TGC. However, the difference in the 28-day survival rates between the two groups was not significant. According to the safety evaluation findings, the CAZ-AVI group exhibited a generally lower incidence of adverse reactions compared with that in the TGC group.ConclusionsCAZ-AVI may be a suitable alternative for TGC in the treatment of critically ill patients with CRKP-induced HAP or VAP. These observations require further confirmation in larger randomized prospective clinical trials.

Mechanism of chlorogenic acid in alveolar macrophage polarization in Klebsiella pneumoniae-induced pneumonia.

Chlorogenic acid (CA) has been discovered to regulate macrophage polarization in pneumonia. This study aims to analyze the functional mechanism of CA in alveolar macrophage (AM) polarization and provide a theoretical basis for treatment of Klebsiella pneumoniae (Kp)-induced pneumonia. Mice were infected with Kp, and treated with CA and silent information regulator 1 (SIRT1) inhibitor (Selisistat). Mouse survival rate was recorded and bacterial burden was detected. AM polarization and pathologic change of lung tissues were evaluated. Expressions of SIRT1 and HMGB1 and cytokine levels were detected. MH-S cells were infected with Kp to establish the pneumonia cell model, followed by transfection of si-SIRT1 and HMGB1 overexpression vector. The HMGB1 expression in the nucleus and cytoplasm was detected. HMGB1 subcellular localization and HMGB1 acetylation level were detected. Kp led to high death rates, SIRT down-regulation and increases in inflammatory factor level and bacterial burden, and promoted M1 polarization. CA treatment improved mouse survival rate and promoted M2 polarization and SIRT1 expression. SIRT1 decreased HMGB1 acetylation level to inhibit nuclear to the cytoplasm translocation. Silencing SIRT1 or HMGB1 overexpression reversed the effect of CA on Kp-induced pneumonia. Overall, CA activated SIRT1 to inhibit HMGB1 acetylation level and nuclear translocation, thereby promoting M2 polarization in AMs and alleviating Kp-induced pneumonia.

IL-17 stimulates neutrophils to release S100A8/A9 to promote lung epithelial cell apoptosis in Mycoplasma pneumoniae–induced pneumonia in children

Mycoplasma pneumoniae-induced pneumonia (MPP) is a common cause of community-acquired respiratory tract infections, increasing risk of morbidity and mortality, in children. However, diagnosing early-stage MPP is difficult owing to the lack of good diagnostic methods. Here, we examined the protein profile of bronchoalveolar lavage fluid (BALF) and found that S100A8/A9 was highly expressed. Enzyme-linked immunosorbent assays used to assess protein levels in serum samples indicated that S100A8/A9 concentrations were also increased in serum obtained from children with MPP, with no change in S100A8/A9 levels in children with viral or bacterial pneumonia. In vitro, S100A8/A9 treatment significantly increased apoptosis in a human alveolar basal epithelial cell line (A549 cells). Bioinformatics analyses indicated that up-regulated S100A8/A9 proteins participated in the interleukin (IL)−17 signaling pathway. The origin of the increased S100A8/A9 was investigated in A549 cells and in neutrophils obtained from children with MPP. Treatment of neutrophils, but not of A549 cells, with IL-17A released S100A8/A9 into the culture medium. In summary, we demonstrated that S100A8/A9, possibly released from neutrophils, is a new potential biomarker for the clinical diagnosis of children MPP and involved in the development of this disease through enhancing apoptosis of alveolar basal epithelial cells.

Ambient NO2 is associated with Streptococcus pneumoniae-induced pneumonia in children and increases the minimum inhibitory concentration of penicillin.

The present study aimed to assess the correlation between ambient air pollutants and Streptococcus pneumoniae (S. pneumoniae)-induced pneumonia in children and retrospectively reviewed the daily data regarding S. pneumoniae from children with pneumonia in a tertiary hospital of Hangzhou City, between January 1st, 2018, and December 31st, 2018. The excess risk (ER) of NO2 with regard to the daily number of S. pneumoniae isolates obtained from the respiratory tract specimens of children with pneumonia was 13.31% (95% confidence interval [CI]: 3.12-24.51%, P = 0.010) in the single-pollutant model. An increase of 10μg/m3 in NO2 exposure was associated with a 23.30% increased risk for the acquisition of S. pneumoniae-induced pneumonia in children (95% CI: 2.02-49.02%; P = 0.031) according to the multi-pollutant model. The ER of NO2 with regard to the daily number of S. pneumoniae isolates (1μg/ml ≤ minimum inhibitory concentration (MIC) to penicillin ≤ 2μg/ml) obtained from the respiratory tract specimens of children with pneumonia was 15.80% (95% CI: 2.02-31.45%; P = 0.024) in the single-pollutant model. According to the multi-pollutant model, the ER of NO2 with regard to the daily number of S. pneumoniae isolates (1μg/ml ≤ MIC to penicillin ≤ 2μg/ml) obtained from the respiratory tract specimens of children with pneumonia was 37.09% (95% CI: 5.70-77.81%; P = 0.018). In conclusion, ambient NO2 is associated with S. pneumoniae-induced pneumonia in children. More importantly, NO2 exposure is associated with the increased MICs of penicillin against S. pneumoniae from children with pneumonia.

Immunological Features of Pediatric Interstitial Pneumonia Due to Mycoplasma pneumoniae.

Background: Inflammatory response, oxidative stress, and immunologic mechanism are involved in the pathogenesis of Mycoplasma pneumoniae pneumonia (MPP). However, the role of immune system of pediatric interstitial pneumonia due to M. pneumoniae infections remains poorly understood. The aim of this study was to analyze the immunologic features of pediatric interstitial pneumonia due to Mycoplasma pneumoniae (M. pneumoniae).Methods: A retrospective study was conducted on a primary cohort of children with MPP. Propensity score analysis was performed to match interstitial pneumonia and pulmonary consolidation children.Results: The clinical characteristics strongly associated with the development of interstitial pneumonia were boys, age >5 years, wheezing history, hydrothorax free, lymphocytes (>3.0 × 109/L), CD19+ (>0.9 × 109/L), CD3+ (>2.5 × 109/L), CD4+ (>1.5 × 109/L), CD8+ (>0.9 × 109/L), interleukin-6 (IL-6, <30 pg/ml), IL-10 (<6 pg/ml), and interferon-γ (IFN-γ, <15 pg/ml). After propensity score analysis, children with interstitial pneumonia showed significantly higher CD19+, CD3+, and CD4+ T cell counts, and lower serum IL-6, IL-10, and IFN-γ levels. The final regression model showed that only CD4+ T cells (>1.5 × 109/L, OR = 2.473), IFN-γ (<15 pg/ml, OR = 2.250), and hydrothorax free (OR = 14.454) were correlated with the development of interstitial pneumonia among children with MPP.Conclusions: The M. pneumoniae-induced interstitial pneumonia showed increased CD4+ T cells and lower serum IFN-γ level. Specific immunologic profiles could be involved in the development of pediatric interstitial pneumonia due to M. pneumoniae infections.

Inhaled Polymyxin in Treatment of Elderly Patients with Severe Community-Acquired Klebsiella pneumoniae-Induced Pneumonia

Background. Inhaled administration of antibacterial drugs (ABD) is a new insufficiently studied area of modern pulmonology. Its feasible advantages comprise a targeted drug delivery to the infection site, amplified antibiotic concentration in tracheobronchial secretion and reduced systemic toxicity risks. The most common inhaled ABDs include aminoglycosides and polymyxin­E (colistin). Aim. A comparison of patient cohorts with severe community­acquired pneumonia induced by Klebsiella pneumoniae receiving and not receiving inhaled colistin. Materials and methods. The study conducted is a retrospective multicentre controlled non­randomised assay. Among the 45 patients included, 20 were and 25 were not receiving colistin inhalation. The endpoint was survival. Data were analysed with Statistica 6.0. Results and discussion . The cohorts differed significantly neither in the main clinical and laboratory values, nor in point scoring of severity and outcome. However, statistical significance was obtained for differences in the ALV ( p = 0.04) and pneumonia resolution ( p = 0.044) times. Conclusion . Inhaled polymyxin­supplemented therapy for severe community­acquired pneumonia induced by Kl. pneumoniae significantly reduces the ALV and pneumonia resolution times in elderly and senile patients but does not affect survival.

Alterations in the Gut Microbiome and Cecal Metabolome During Klebsiella pneumoniae-Induced Pneumosepsis.

Klebsiella (K.) pneumoniae is a common cause of pneumonia-derived sepsis in human and is associated with high morbidity and mortality. The microbiota promotes and maintains host immune homeostasis during bacterial infections. However, the mechanisms by which the gut microbiota affects immune responses in the lung still remain poorly understood. Here, we performed cecal metabolomics sequencing and fecal 16s rRNA sequencing in K. pneumoniae-infected mice and uninfected controls and showed that K. pneumoniae infection led to profound alterations in the gut microbiome and thus the cecal metabolome. We observed that the levels of Lactobacillus reuteri and Bifidobacterium pseudolongum were significantly decreased in K. pneumoniae-infected mice. Spearman correlation analysis showed that alterations in the richness and composition of the gut microbiota were associated with profound changes in host metabolite concentrations. Further, short-chain fatty acids (SCFAs), including acetate, propionate, and butyrate, were detected in cecal contents and serum by gas chromatography-mass spectrometry (GC-MS). We observed that the concentrations of these three SCFAs were all lower in the infected groups than in the untreated controls. Lastly, oral supplementation with these three SCFAs reduced susceptibility to K. pneumoniae infections, as indicated by lower bacterial burdens in the lung and higher survival rates. Our data highlight the protective roles of gut microbiota and certain metabolites in K. pneumoniae-pneumonia and suggests that it is possible to intervene in this bacterial pneumonia by targeting the gut microbiota.