Severe sepsis in community-acquired pneumonia--early recognition and treatment

Clinical application value of simultaneous plasma and bronchoalveolar lavage fluid metagenomic next generation sequencing in patients with pneumonia-derived sepsis

BACKGROUND

Despite the increasing use of metagenomic next-generation sequencing (mNGS) in sepsis, identifying clinically relevant pathogens remains challenging. This study was aimed to evaluate the clinical utility of simultaneous plasma and bronchoalveolar lavage fluid (BALF) detection using mNGS.

METHODS

This retrospective study enrolled 95 patients with pneumonia-derived sepsis (PDS) admitted to the intensive care unit (ICU) between October 2021 and January 2023. Patients were divided into two groups: mNGS group (n = 60) and the non-mNGS group (n = 35), based on whether simultaneous plasma and BALF mNGS were conducted. All patients underwent conventional microbiological tests (CMT), including bacterial/fungal culture of peripheral blood and BALF, as well as sputum culture, detection of 1, 3-beta-D- glucan in BALF and RT-PCR testing. The clinical data of the enrolled patients were collected, and the detection performance and prognosis of plasma mNGS, BALF mNGS and CMT were compared.

RESULTS

The mNGS group exhibited a lower mortality rate than the non-mNGS group (35.0% vs. 57.1%, P = 0.034). Simultaneous detection in dual-sample resulted in a higher proportion of microorganisms identified as definite causes of sepsis alert compared to detection in either plasma or BALF alone (55.6% vs. 20.8% vs. 18.8%, P<0.001). Acinetobacter baumannii, Stenotrophomonas maltophilia, Candida albicans, and human mastadenovirus B were the primary strains responsible for infections in PDS patients. Patients with lower white blood cells and neutrophil indices had a greater consistency in dual-sample mNGS. Patients in the mNGS group had more antibiotic adjustments compared to the non-mNGS group (85.71% vs. 33.33%, P<0.001). The percentage of neutrophils was a risk factor for mortality in PDS patients (P = 0.002).

CONCLUSION

Dual sample mNGS has the advantage of detecting and determining the pathogenicity of more pathogens and has the potential to improve the prognosis of patients with PDS.

Predictive value of risk factors for prognosis of patients with sepsis in intensive care unit

Sepsis has emerged as a major global public health concern due to its elevated mortality and high cost of care. This study aimed to evaluate the risk factors associated with the mortality of sepsis patients in the Intensive Care Unit (ICU), and to intervene in the early stages of sepsis in order to improve patient outcomes and reduce mortality. From January 1st, 2021 to December 31st, 2021, Longhua Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Huashan Hospital Affiliated to Fudan University, and The Seventh People's Hospital Affiliated to Shanghai University of Traditional Chinese Medicine were designated as sentinel hospitals, and sepsis patients in their respective ICU and Emergency ICU were selected as research subjects, and divided into survivors and non-survivors according to their discharge outcomes. The mortality risk of sepsis patients was subsequently analyzed by logistic regression. A total of 176 patients with sepsis were included, of which 130 (73.9%) were survivors and 46 (26.1%) were non-survivors. Factors identified as having an impact on death among sepsis patients included female [Odds Ratio (OR) = 5.135, 95% confidence interval (CI): 1.709, 15.427, P = .004)], cardiovascular disease (OR = 6.272, 95% CI: 1.828, 21.518, P = .004), cerebrovascular disease (OR = 3.133, 95% CI: 1.093, 8.981, P = .034), pulmonary infections (OR = 6.700, 95% CI: 1.744, 25.748, P = .006), use of vasopressors (OR = 34.085, 95% CI: 10.452, 111.155, P < .001), WBC < 3.5 × 109/L (OR = 9.752, 95% CI: 1.386, 68.620, P = .022), ALT < 7 U/L (OR = 7.672, 95% CI: 1.263, 46.594, P = .027), ALT > 40 U/L (OR = 3.343, 95% CI: 1.097, 10.185, P = .034). Gender, cardiovascular disease, cerebrovascular disease, pulmonary infections, the use of vasopressors, WBC, and ALT are important factors in evaluating the prognostic outcome of sepsis patients in the ICU. This suggests that medical professionals should recognize them expeditiously and implement aggressive treatment tactics to diminish the mortality rate and improve outcomes.

Comprehensive clinical evaluation of moxifloxacin: A retrospective study

The objective was to provide a basis for the rational clinical application of moxifloxacin through its comprehensive clinical evaluation, and to serve as a reference for the clinical comprehensive evaluation of relevant drugs in the future. We obtained data from 91 community-acquired pneumonia patients admitted to Weifang people's hospital from April 2020 to November 2021, including 46 in the evaluation group and 45 in the control group. Based on the requirements of the "Guidelines for the Management of Comprehensive Clinical Evaluation of Drugs" (for trial implementation), systematic evaluations are conducted in terms of drug safety, effectiveness, economy, innovation, suitability, and accessibility. The incidence of adverse drug reactions was low, drug quality, safety and stable efficacy; treatment efficiency was 91.3% and 93.3%, respectively (P > .05); the average total cost of the evaluation group was 9765.28RMB and 10250.69RMB, respectively; efficient cost-effectiveness ratio was 104.67 and 112.52 and cost-effectiveness ratio was 242.71. The economy of the evaluation group had a low price and was highly available.

Inception-GAN for Semi-supervised Detection of Pneumonia in Chest X-rays

Recent advances in Deep Learning have led to the development of supervised models to detect anomalies in medical images such as pneumonia in chest X-rays. Automatic detection of such anomalies can help clinicians with faster decision making and treatment planning for patients. Nonetheless, supervised models require complete labeled training data with all possible labels (i.e., positive and negative), which are cumbersome and expensive to obtain. We propose an adversarial learning-based semi-supervised algorithm for anomaly detection, which requires training data only with a single class (positive or negative). We applied our proposed Generative Adversarial Network architecture to detect anomalies and score pneumonia in chest X-rays and achieved statistically significant improvements compared to previous state-of-the-art generative network and one-class classifiers for anomaly detection.

Community-acquired bacterial pneumonia in adults: An update

Community-acquired pneumonia (CAP) is the prominent cause of mortality and morbidity with important clinical impact across the globe. India accounts for 23 per cent of global pneumonia burden with case fatality rates between 14 and 30 per cent, and Streptococcus pneumoniae is considered a major bacterial aetiology. Emerging pathogens like Burkholderia pseudomallei is increasingly recognized as an important cause of CAP in Southeast Asian countries. Initial management in the primary care depends on clinical assessment while the hospitalized patients require combinations of clinical scores, chest radiography and various microbiological and biomarker assays. This comprehensive diagnostic approach together with additional sampling and molecular tests in selected high-risk patients should be practiced. Inappropriate therapy in CAP in hospitalized patients lengthens hospital stay and increases cost and mortality. In addition, emergence of multidrug-resistant organisms poses tough challenges in deciding empirical as well as definitive therapy. Developing local evidence on the cause and management should be a priority to improve health outcomes in CAP.

RANDGAN: Randomized generative adversarial network for detection of COVID-19 in chest X-ray

COVID-19 spread across the globe at an immense rate and has left healthcare systems incapacitated to diagnose and test patients at the needed rate. Studies have shown promising results for detection of COVID-19 from viral bacterial pneumonia in chest X-rays. Automation of COVID-19 testing using medical images can speed up the testing process of patients where health care systems lack sufficient numbers of the reverse-transcription polymerase chain reaction tests. Supervised deep learning models such as convolutional neural networks need enough labeled data for all classes to correctly learn the task of detection. Gathering labeled data is a cumbersome task and requires time and resources which could further strain health care systems and radiologists at the early stages of a pandemic such as COVID-19. In this study, we propose a randomized generative adversarial network (RANDGAN) that detects images of an unknown class (COVID-19) from known and labelled classes (Normal and Viral Pneumonia) without the need for labels and training data from the unknown class of images (COVID-19). We used the largest publicly available COVID-19 chest X-ray dataset, COVIDx, which is comprised of Normal, Pneumonia, and COVID-19 images from multiple public databases. In this work, we use transfer learning to segment the lungs in the COVIDx dataset. Next, we show why segmentation of the region of interest (lungs) is vital to correctly learn the task of classification, specifically in datasets that contain images from different resources as it is the case for the COVIDx dataset. Finally, we show improved results in detection of COVID-19 cases using our generative model (RANDGAN) compared to conventional generative adversarial networks for anomaly detection in medical images, improving the area under the ROC curve from 0.71 to 0.77.

Bacterial Membrane Vesicles in Pneumonia: From Mediators of Virulence to Innovative Vaccine Candidates

Pneumonia due to respiratory infection with most prominently bacteria, but also viruses, fungi, or parasites is the leading cause of death worldwide among all infectious disease in both adults and infants. The introduction of modern antibiotic treatment regimens and vaccine strategies has helped to lower the burden of bacterial pneumonia, yet due to the unavailability or refusal of vaccines and antimicrobials in parts of the global population, the rise of multidrug resistant pathogens, and high fatality rates even in patients treated with appropriate antibiotics pneumonia remains a global threat. As such, a better understanding of pathogen virulence on the one, and the development of innovative vaccine strategies on the other hand are once again in dire need in the perennial fight of men against microbes. Recent data show that the secretome of bacteria consists not only of soluble mediators of virulence but also to a significant proportion of extracellular vesicles-lipid bilayer-delimited particles that form integral mediators of intercellular communication. Extracellular vesicles are released from cells of all kinds of organisms, including both Gram-negative and Gram-positive bacteria in which case they are commonly termed outer membrane vesicles (OMVs) and membrane vesicles (MVs), respectively. (O)MVs can trigger inflammatory responses to specific pathogens including S. pneumonia, P. aeruginosa, and L. pneumophila and as such, mediate bacterial virulence in pneumonia by challenging the host respiratory epithelium and cellular and humoral immunity. In parallel, however, (O)MVs have recently emerged as auspicious vaccine candidates due to their natural antigenicity and favorable biochemical properties. First studies highlight the efficacy of such vaccines in animal models exposed to (O)MVs from B. pertussis, S. pneumoniae, A. baumannii, and K. pneumoniae. An advanced and balanced recognition of both the detrimental effects of (O)MVs and their immunogenic potential could pave the way to novel treatment strategies in pneumonia and effective preventive approaches.

Ventilator for the management of patients with severe pneumonia: A protocol of systematic review

BACKGROUND

This study will assess the efficacy and safety of ventilator for the management of severe pneumonia (SP).

METHODS

This study will search the following electronic databases in MEDLINE, EMBASE, Web of Science, PsycINFO, Cochrane Library, CNKI, and Scopus from the beginning to present without language restrictions. Two authors will screen all records according to the eligibility criteria; assess study quality; and extract all essential data from eligible studies. If sufficient studies are included, we will pool the extracted data and carry out meta-analysis.

RESULTS

This study will summarize published studies to assess the efficacy and safety of ventilator for patients with SP.

CONCLUSION

The results of this study may supply a genuine understanding of perspective from a scientific basis on ventilator for the management of patients with SP.

The activation of IL-17 signaling pathway promotes pyroptosis in pneumonia-induced sepsis

Background

Pyroptosis is closely relevant to sepsis. However, the molecular mechanisms of pyroptosis in pneumonia-induced sepsis are still not fully understood. Thus, this study aimed to find the specific molecular pathways associated with pyroptosis and explore their relationship in pneumonia-induced sepsis.

Methods

First, significant signaling pathways related to pneumonia-induced sepsis were screened by bioinformatics analysis based on GSE48080. The peripheral blood samples from patients with pneumonia-induced sepsis and healthy subjects were collected. Pneumonia-induced sepsis rat models were also established. Then, inflammatory response, pyroptosis, and regulatory T cells (Tregs)/T-helper 17 (Th17), Th1/Th2, and M1/M2 cell ratios in pneumonia-induced sepsis were evaluated.

Results

IL-17 signaling pathway was significantly related to pneumonia-induced sepsis by bioinformatics analysis. Compared with healthy groups, the higher of Th17/Treg, Th1/Th2 and M1/M2 cell radios in the patients and sepsis rat model indicated that pneumonia-induced sepsis caused a severe inflammatory response. This result was confirmed by higher levels of pro-inflammatory factors (IL-6, TNF-α, IL-1β, and IL-18) and an inflammation indicator (LDH), as well as pyroptosis occurrence in sepsis. Additionally, the up-regulation of key molecules (HMGB1, RAGE, IL-17A, TRAF6 and NK-κB) in the IL-17 signaling pathway suggested the IL-17 pathway was activated. Moreover, the release of IL-1β and IL-18 and the levels of the molecules (NLRP3, NLRC4, Cleaved caspase-1, and Cleaved GSDMD) associated with caspase-1-dependent pyroptosis were up-regulated in pneumonia-induced sepsis.

Conclusions

As NK-κB activation can promote the development of caspase-1-dependent pyroptosis, these findings suggested that the activation of the IL-17 signaling pathway could promote pyroptosis in pneumonia-induced sepsis.

Quinolones for sepsis. A protocol for a systematic review of randomised clinical trials with meta-analysis and trial sequential analysis

BACKGROUND

Sepsis is a relatively common and deadly condition that constitutes a major challenge to the modern health care system. Quinolones are sometimes used in combination with beta-lactam antibiotics for sepsis, but no former systematic review has assessed the benefits and harms of quinolones in patients with sepsis.

METHODS

We will perform a systematic review with meta-analysis and trial sequential analysis including randomised clinical trials assessing the effects of quinolones as add on therapy to usual care in children and adults with sepsis. For the assessment of harms, we will also include quasi-randomised studies and observational studies identified during our searches for randomised clinical trials.

DISCUSSION

This systematic review will clarify if there is evidence to support quinolones being part of the standard treatment for sepsis.

An increase in mean platelet volume during admission can predict the prognoses of patients with pneumonia in the intensive care unit: A retrospective study

Platelets play an important role in hemostasis, inflammation, and immunity. Mean platelet volume (MPV), considered a marker of platelet function and activation, is associated with increased morbidity and mortality in sepsis, coronary artery disease, and chronic inflammatory disease. However, the clinical characteristics and prognostic significance of MPV changes for patients with pneumonia in the intensive care unit (ICU) have not been investigated. This retrospective study was conducted using data from an operational database of patients admitted to a medical ICU between October 2010 and October 2017. Of 235 adult patients with pneumonia admitted to the ICU, clinical characteristics and in-hospital mortality values were compared according to MPV, ΔMPV_day1–2, ΔMPV_day1–3, ΔMPV_day1–4, and ΔMPV_{day1–Discharge} between those who survived and those who did not. The MPV increased during the first four days for both non-survivors and survivors (P < 0.001). However, repeated measures analysis of variance revealed a significantly higher MPV rate over the first four days in non-survivors than in survivors. Additionally, the ΔMPV_day1–2, ΔMPV_day1–3, ΔMPV_day1–4, and ΔMPV_{day1–Discharge} values were significantly greater in non-survivors than in survivors. For in-hospital mortality, the optimal ΔMPV values were >0.9 fL, P = 0.020; >0.9 fL, P < 0.001; >0.8 fL, P < 0.001; and >1.3 fL, P < 0.001 on day 2, day 3, day 4, and at discharge, respectively. In conclusion, our findings demonstrate that ΔMPV during ICU admission may be used as a prognostic marker of mortality in ICU patients with pneumonia. Repeated MPV measurements throughout hospitalization may improve risk stratification for these patients, which could aid in improving patient outcomes.

High HMGB1 levels in sputum are related to pneumococcal bacteraemia but not to disease severity in community-acquired pneumonia

During bacterial infections, damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs) activate immune cells. Here, we investigated whether plasma and sputum levels of High Mobility Group Box 1 (HMGB1), a prototypic DAMP, are associated with disease severity and aetiology in community-acquired pneumonia (CAP). In addition, in patients with pneumococcal CAP, the impact of the level of sputum lytA DNA load, a PAMP, was investigated. We studied patients hospitalised for bacterial CAP (n = 111), and samples were collected at admission. HMGB1 was determined by enzyme-linked immunosorbent assays, and pneumococcal lytA DNA load was determined by quantitative polymerase chain reaction. Plasma and sputum HMGB1 levels did not correlate to disease severity (pneumonia severity index or presence of sepsis), but high sputum HMGB1 level was correlated to pneumococcal aetiology (p = 0.002). In pneumococcal pneumonia, high sputum lytA DNA load was associated with respiratory failure (low PaO2/FiO2 ratio; p = 0.019), and high sputum HMGB1 level was associated with bacteraemia (p = 0.006). To conclude, high sputum HMGB1 was not associated with severe disease, but with pneumococcal bacteraemia, indicating a potential role for HMGB1 in bacterial dissemination. High sputum lytA was associated with severe disease.

Footprints of Sepsis Framed Within Community Acquired Pneumonia in the Blood Transcriptome

We analyzed the blood transcriptome of sepsis framed within community-acquired pneumonia (CAP) and characterized its molecular and cellular heterogeneity in terms of functional modules of co-regulated genes with impact for the underlying pathophysiological mechanisms. Our results showed that CAP severity is associated with immune suppression owing to T-cell exhaustion and HLA and chemokine receptor deactivation, endotoxin tolerance, macrophage polarization, and metabolic conversion from oxidative phosphorylation to glycolysis. We also found footprints of host's response to viruses and bacteria, altered levels of mRNA from erythrocytes and platelets indicating coagulopathy that parallel severity of sepsis and survival. Finally, our data demonstrated chromatin re-modeling associated with extensive transcriptional deregulation of chromatin modifying enzymes, which suggests the extensive changes of DNA methylation with potential impact for marker selection and functional characterization. Based on the molecular footprints identified, we propose a novel stratification of CAP cases into six groups differing in the transcriptomic scores of CAP severity, interferon response, and erythrocyte mRNA expression with impact for prognosis. Our analysis increases the resolution of transcriptomic footprints of CAP and reveals opportunities for selecting sets of transcriptomic markers with impact for translation of omics research in terms of patient stratification schemes and sets of signature genes.

An Argument for the Use of Aminoglycosides in the Empiric Treatment of Ventilator-Associated Pneumonia

BACKGROUND

Appropriate empiric antibiotic therapy for ventilator-associated pneumonia improves outcomes. Controversy exists regarding the inclusion of aminoglycosides in empiric therapeutic regimens.

METHODS

The Ovid and Cochrane databases were searched for relevant literature regarding the use of aminoglycosides in combination therapy for ventilator-associated pneumonia. The data supporting the use of aminoglycosides in certain populations and strategies to limit toxicity are summarized.

RESULTS

In patients at high risk of infection with antibiotic-resistant gram-negative bacilli and in those with severe illness, aminoglycosides improve clinical outcomes. In critically ill populations, short-duration therapy and high-dose extended-interval dosing of aminoglycosides can improve therapeutic efficacy while limiting nephrotoxicity.

CONCLUSIONS

In selected populations using appropriate dosing strategies, aminoglycosides should be considered for empiric treatment of ventilator-associated pneumonia.

Performance of pro-adrenomedullin for identifying adverse outcomes in community-acquired pneumonia

BACKGROUND

We sought to evaluate the usefulness of biomarkers-procalcitonin (PCT), C-reactive protein (CRP) and proadrenomedullin (pro-ADM)-combined with prognostic scales (PSI, CURB-65 and SCAP score) for identifying adverse outcomes in patients with community-acquired pneumonia (CAP) attending at an Emergency Department (ED).

METHODS

Prospective observational study in a teaching hospital among patients with CAP. In addition to collecting data for the prognostic scales, samples were taken at the ED for assessing PCT, CRP and pro-ADM levels. We compared the prognostic accuracy of these biomarkers with severity scores to predict pneumonia related complications, using the area under the receiver operating characteristics curves (AUC), which evaluates how well the model discriminate between patients who had a pneumonia related complication or not.

RESULTS

A total of 491 patients with CAP were enrolled, 256 being admitted to the hospital and 235 treated as outpatients. Admitted patients had higher biomarker levels than outpatients (p < 0.001). The SCAP score and pro-ADM level had the best AUCs for predicting pneumonia related complications (0.83 and 0.84, respectively). Considering SCAP score plus pro-ADM level, the AUC increased significantly to 0.88. SCAP score class 0 or 1 with a pro-ADM level <0.5 ng/mL was the best indicator for selecting patients for outpatient care.

CONCLUSIONS

A new risk score combining SCAP score with pro-ADM level is useful to classify severity risk in CAP patients and hence supporting decision-making on hospital admission.

Azithromycin suppresses CD4(+) T-cell activation by direct modulation of mTOR activity

Advanced macrolides, such as azithromycin (AZM) or clarithromycin (CLM), are antibiotics with immunomodulatory properties. Here we have sought to evaluate their in vitro influence on the activation of CD4(+) T-cells. Isolated CD4(+) T-cells were stimulated with agonistic anti-CD3/anti-CD28 monoclonal antibodies in the presence of 0.6 mg/L, 2.5 mg/L, 10 mg/L or 40 mg/L AZM or CLM. Cell proliferation, cytokine level in supernatants and cell viability was assessed. Intracellular signaling pathways were evaluated using reporter cell lines, FACS analysis, immunoblotting and in vitro kinase assays. AZM inhibited cell proliferation rate and cytokine secretion of CD4(+) T-cells in a dose-dependent manner. Similarly, high concentrations of CLM (40 mg/L) also suppressed these T-cell functions. Analysis of molecular signaling pathways revealed that exposure to AZM reduced the phosphorylation of the S6 ribosomal protein, a downstream target of mTOR. This effect was also observed at 40 mg/L CLM. In vitro kinase studies using recombinant mTOR showed that AZM inhibited mTOR activity. In contrast to rapamycin, this inhibition was independent of FKBP12. We show for the first time that AZM and to a lesser extent CLM act as immunosuppressive agents on CD4(+) T-cells by inhibiting mTOR activity. Our results might have implications for the clinical use of macrolides.

Diagnosis of infection in critical care

Sepsis is the primary cause of death in the intensive care unit. The prevention of sepsis complications requires an early and accurate diagnosis as well as the appropriate mon itoring. A deep knowledge of the immunologic basis of sepsis is essential to better understand the scope of incorporating a new marker into clinical practice. Besides revising this theoretical aspect, the current available tools for bacterial iden tification have been briefly reviewed as well as a variety of new markers showing either well-recognized or potential usefulness for diagnosis and prognosis of infections in crit ically ill patients. Particular conditions such as community acquired pneumonia, pedi atric sepsis, or liver transplantation, among others, have been separately treated, since the optimal approaches and markers might be different in these special cases.

Community-acquired pneumonia

PURPOSE OF REVIEW

Community-acquired pneumonia (CAP) contributes significantly to morbidity and mortality, especially in the elderly. Recent advances aimed at improving outcomes and reducing CAP disease burden are summarized.

RECENT FINDINGS

Emerging data suggests that newer CAP risk stratification indices based on disease severity hold promise in predicting intensive care need. Additional evidence supports a role of procalcitonin and pro-adrenomedullin as biomarkers of disease severity and for guiding antimicrobial therapy. New diagnostic tools have greatly contributed to early diagnosis and better-targeted therapy. There is increasing recognition of the role of coinfections in CAP. In patients with severe disease, therefore, current guidelines advise against monotherapy. Although inclusion of coverage for atypical pathogens in nonsevere CAP has been challenged, evidence suggests that such coverage is beneficial in patients with severe disease. Use of steroids as adjunctive therapy for CAP, however, is associated with complications and prolonged hospitalization. Updated prevention strategies include approval of pneumococcal conjugate vaccine (PCV13) for adults at risk.

SUMMARY

Despite these developments research aimed at further reducing CAP-related morbidity and mortality is required. Increasing global life expectancy is likely to expand the at-risk population; therefore, research directed at CAP prevention in view of changing demography is essential.