Influenza Infections and Emergent Viral Infections in Intensive Care Unit

Investigate the potential impact of Hemagglutinin from the H1N1 strain on severe pneumonia

The most prevalent glycoprotein on the influenza virus envelope is called hemagglutinin (HA), yet little is known about its involvement in the pathophysiology and etiology of severe influenza pneumonia. Here, after stimulating human bronchial epithelial cells (16-HBE) and mice with HA of H1N1 for 12 h, we investigated the proliferation, migration, inflammatory cytokines expression, and apoptosis in 16-HBE and the pathological damage in mouse lung tissue. The expression of inflammatory cytokines plasminogen activator inhibitor 1(PAI-1), urokinase-type (uPA) and tissue-type (tPA) plasminogen activators, and apoptosis were all enhanced by HA, which also prevented the proliferation and migration of bronchial epithelial cells. HA enhanced up-regulated PAI-1, uPA, and tPA protein expression within mouse lung tissue and caused lung injury. In conclusion, HA alone, but not the whole H1N1 virus, induces lung tissue injury by inhibiting cell proliferation and migration, while promoting the expression of inflammatory cytokines and apoptosis.

Development and validation of nomogram for predicting the risk of transferring to the ICU for children with influenza

OBJECTIVE

Development of a nomogram model for predicting the magnitude of risk of transferring hospitalized children with influenza to the ICU.

METHODS

In a single-center retrospective study, 318 children with influenza who were hospitalized in our hospital from January 2018 to August 2023 were collected as study subjects. Children with influenza were randomly assigned to the training set and validation set in a ratio of 4:1. In the training set, risk factors were identified using univariate and multivariate logistic regression analyses, and a nomogram model was created on this basis. The validation set was used to evaluate the predictive power of the model.

RESULTS

Multifactorial logistic regression analysis revealed six independent risk factors for transfer to the ICU in hospitalized children with influenza, including elevated peripheral white blood cell counts, elevated large platelet ratios, reduced mean platelet width, reduced complement C3, elevated serum globulin levels, and reduced total immunoglobulin M levels. Using these six metrics as predictors to construct a nomogram graphical model, the C-index was 0.970 (95% Cl: 0.953-0.988). The areas under the curve for the training and validation sets were 0.966 (95%Cl 0.947-0.985) and 0.919 (95%Cl 0.851-0.986), respectively.

CONCLUSION

A nomogram for predicting the risk of transferring to the ICU for children with influenza was developed and validated, which demonstrates good calibration and clinical benefits.

Early predictors of Epstein-Barr virus infection in patients with severe fever with thrombocytopenia syndrome

BACKGROUND

Epstein-Barr virus (EBV) can be reactivated and proliferated with fatal outcome in immuno-compromised people, but the clinical consequences of EBV infection in patients with severe fever with thrombocytopenia syndrome (SFTS) remain uncertain. In this study, we investigated the infection rate, the influence and the early predictors of EBV infection in SFTS patients.

METHODS

In this retrospective study, SFTS patients who were treated in the First Affiliated Hospital of Nanjing Medical University from May 2011 to August 2021 were enrolled and divided into infected and non-infected groups. We compared the demographic characteristics, clinical manifestations and signs, laboratory tests and prognosis, and explored the risk factors of EBV infection by receiver operating characteristic (ROC) curve and logistic regression.

RESULTS

A total of 120 hospitalized SFTS patients with EBV-DNA testing were enrolled in this study. Patients with EBV infection had statistically significant higher mortality rate (32.0% vs. 11.43%, P = 0.005). Compared with the non-infected group, the EBV-infected group had higher levels of C-reactive protein (CRP), creatine-kinase (CK), fasting blood glucose (FBG), blood urea nitrogen (BUN), D-dimer, and CD56+ cell counts, lower levels of immunoglobulin G (IgG), IgM, complement 3 (C3), and C4. The proportion of patients with age ≥ 60 years and ferritin > 1500.0 ng/ml in the EBV-infected group was significantly higher than that in the non-infected group. The results of ROC analysis showed that the cut-off values of CRP, IgG, C3, C4, and CD56+ cell counts to predict EBV infection were 13.2 mg/l, 12.5 g/l, 1.1 g/l, 0.6 g/l, 0.3 g/l, and 94.0 cells/µl. Multivariable logistic analysis showed that age ≥ 60 years old, CRP > 13.2 mg/l, BUN > 5.4 mmol/l, ferritin > 1500.0 ng/ml, IgG < 12.5 g/l, IgM < 1.1 g/l, C4 < 0.3 g/l, and CD56+ cell counts > 94.0 cells/µl were the independent risk factors of EBV infection in SFTS patients.

CONCLUSIONS

SFTS combined with EBV infection is associated with high morbidity and mortality. It is necessary to strengthen screening for EBV infection and its early predictive markers after admission in SFTS patients.

Enhancing pathogen description and antibiotic regimen selection in community-acquired pneumonia through RT-qPCR assays

Background

Adults with community-acquired pneumonia (CAP) in China suffer high morbidity. CAP is caused by a multitude of pathogens; however, pathogen-directed clinical symptoms are often lacking. Therefore, patients lacking an accurate microbiological diagnosis are administered with empirical antimicrobials.

Methods

We collected bronchoalveolar lavage fluid, as well as clinical and laboratory data from 650 adult patients with CAP admitted to three hospitals in Hubei, Sichuan, and Zhejiang provinces in China. Specimens were cultured and tested using real-time reverse transcription qPCR (RT-qPCR) assays for the presence of 42 respiratory bacteria and viruses. CAP was investigated with respect to regions, genders, and age and patterns of infections or co-infections. Employing clinical guidelines adapted for diagnosis, we assessed retrospectively the appropriate pathogen-directed therapy and compared it with the initial empirical therapies.

Results

Our study identified that 21.38% (139/650) of the patients were classified as having Severe CAP (S-CAP), with a higher prevalence among males, older adults, and during the warm season. Bacterial pathogens were detected in 35.53% (231/650) of cases. K. pneumoniae, H. influenzae, and S. aureus were the most prevalent bacteria across different demographics and regions. Viral pathogens were found in 48.76% (317/650) of patients Epstein-Barr, Human rhinovirus, and Cytomegalovirus were the most common viruses. Co-infections were present in 24.31% (158/650) of cases, with viral-bacterial co-infections being the most frequent. The RT-qPCR demonstrated significantly higher detection rates for key pathogens compared to standard culture methods. It showed potential in optimizing antimicrobial prescriptions by allowing for de-escalation in 18.30% (95/518) of patients, among which reducing the number of excessive antibiotics mainly comprised decreasing the use of 2nd or 3rd generation cephalosporins (5.79%, 30/518) and β-lactamase inhibitor combinations.

Conclusion

The study highlights the significant burden of S-CAP, particularly among specific demographics and seasons. The prevalence of bacterial and viral pathogens, along with the high rate of co-infections, emphasizes the need for comprehensive diagnostic approaches. The RT-qPCR assays emerge as a superior diagnostic tool, offering enhanced pathogen detection capabilities and facilitating more precise antimicrobial therapy. This could lead to improved patient outcomes and contribute to the rational use of antimicrobials, addressing the growing concern of antibiotic resistance.

Hussein S, Abdalhabib EK, Nabi SU. The critical impacts of cytokine storms in respiratory disorders

Cytokine storm (CS) refers to the spontaneous dysregulated and hyper-activated inflammatory reaction occurring in various clinical conditions, ranging from microbial infection to end-stage organ failure. Recently the novel coronavirus involved in COVID-19 (Coronavirus disease-19) caused by SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) has been associated with the pathological phenomenon of CS in critically ill patients. Furthermore, critically ill patients suffering from CS are likely to have a grave prognosis and a higher case fatality rate. Pathologically CS is manifested as hyper-immune activation and is clinically manifested as multiple organ failure. An in-depth understanding of the etiology of CS will enable the discovery of not just disease risk factors of CS but also therapeutic approaches to modulate the immune response and improve outcomes in patients with respiratory diseases having CS in the pathogenic pathway. Owing to the grave consequences of CS in various diseases, this phenomenon has attracted the attention of researchers and clinicians throughout the globe. So in the present manuscript, we have attempted to discuss CS and its ramifications in COVID-19 and other respiratory diseases, as well as prospective treatment approaches and biomarkers of the cytokine storm. Furthermore, we have attempted to provide in-depth insight into CS from both a prophylactic and therapeutic point of view. In addition, we have included recent findings of CS in respiratory diseases reported from different parts of the world, which are based on expert opinion, clinical case-control research, experimental research, and a case-controlled cohort approach.

Exploring the immune-inflammatory mechanism of Maxing Shigan Decoction in treating influenza virus A-induced pneumonia based on an integrated strategy of single-cell transcriptomics and systems biology

BACKGROUND

Influenza is an acute respiratory infection caused by influenza virus. Maxing Shigan Decoction (MXSGD) is a commonly used traditional Chinese medicine prescription for the prevention and treatment of influenza. However, its mechanism remains unclear.

METHOD

The mice model of influenza A virus pneumonia was established by nasal inoculation. After 3 days of intervention, the lung index was calculated, and the pathological changes of lung tissue were detected by HE staining. Firstly, transcriptomics technology was used to analyze the differential genes and important pathways in mouse lung tissue regulated by MXSGD. Then, real-time fluorescent quantitative PCR (RT-PCR) was used to verify the changes in mRNA expression in lung tissues. Finally, intestinal microbiome and intestinal metabolomics were performed to explore the effect of MXSGD on gut microbiota.

RESULTS

The lung inflammatory cell infiltration in the MXSGD group was significantly reduced (p < 0.05). The results of bioinformatics analysis for transcriptomics results show that these genes are mainly involved in inflammatory factors and inflammation-related signal pathways mediated inflammation biological modules, etc. Intestinal microbiome showed that the intestinal flora Actinobacteriota level and Desulfobacterota level increased in MXSGD group, while Planctomycetota in MXSGD group decreased. Metabolites were mainly involved in primary bile acid biosynthesis, thiamine metabolism, etc. This suggests that MXSGD has a microbial-gut-lung axis regulation effect on mice with influenza A virus pneumonia.

CONCLUSION

MXSGD may play an anti-inflammatory and immunoregulatory role by regulating intestinal microbiome and intestinal metabolic small molecules, and ultimately play a role in the treatment of influenza A virus pneumonia.

AMPK protects endothelial cells against HSV-1 replication via inhibition of mTORC1 and ACC1

Herpes simplex virus type 1 (HSV-1) is a widespread contagious pathogen, mostly causing mild symptoms on the mucosal entry side. However, systemic distribution, in particular upon reactivation of the virus in immunocompromised patients, may trigger an innate immune response and induce damage of organs. In these conditions, HSV-1 may infect vascular endothelial cells, but little is known about the regulation of HSV-1 replication and possible defense mechanisms in these cells. The current study addresses the question of whether the host cell protein AMP-activated protein kinase (AMPK), an important metabolic sensor, can control HSV-1 replication in endothelial cells. We show that downregulation of the catalytic subunits AMPKα1 and/or AMPKα2 increased HSV-1 replication as monitored by TCID50 titrations, while a potent AMPK agonist, MK-8722, strongly inhibited it. MK-8722 induced a persistent phosphorylation of the AMPK downstream targets acetyl-CoA carboxylase (ACC) and the rapamycin-sensitive adaptor protein of mTOR (Raptor) and, related to this, impairment of ACC1-mediated lipid synthesis and the mechanistic target of the rapamycin complex-1 (mTORC1) pathway. Since blockade of mTOR by Torin-2 as well as downregulation of ACC1 by siRNA also decreased HSV-1 replication, MK-8722 is likely to exert its anti-viral effect via mTORC1 and ACC1 inhibition. Importantly, MK-8722 was able to reduce virus replication even when added after HSV-1. Together, our data highlight the importance of endothelial cells as host cells for HSV-1 replication upon systemic infection and identify AMPK, a metabolic host cell protein, as a potential target for antiviral strategies against HSV-1 infection and its severe consequences. IMPORTANCE Herpes simplex virus type 1 (HSV-1) is a common pathogen that causes blisters or cold sores in humans. It remains latent in infected individuals and can be reactivated multiple times. In adverse conditions, for instance, in immunocompromised patients, HSV-1 can lead to serious complications such as encephalitis, meningitis, or blindness. In these situations, infection of endothelial cells lining the surface of blood vessels may contribute to the manifestation of disease. Here, we describe the role of AMP-activated protein kinase (AMPK), a potent regulator of cellular energy metabolism, in HSV-1 replication in endothelial cells. While downregulation of AMPK potentiates HSV-1 replication, pharmacological AMPK activation inhibits it by limiting the availability of required host cell macromolecules such as proteins or fatty acids. These data highlight the role of metabolic host cell proteins as antiviral targets and reveal activation of endothelial AMPK as a potential strategy to protect from severe consequences of HSV-1 infection.

Cytokine Storm in Acute Viral Respiratory Injury: Role of Qing-Fei-Pai-Du Decoction in Inhibiting the Infiltration of Neutrophils and Macrophages through TAK1/IKK/NF-[Formula: see text]B Pathway

COVID-19 has posed unprecedented challenges to global public health since its outbreak. The Qing-Fei-Pai-Du decoction (QFPDD), a Chinese herbal formula, is widely used in China to treat COVID-19. It exerts an impressive therapeutic effect by inhibiting the progression from mild to critical disease in the clinic. However, the underlying mechanisms remain obscure. Both SARS-CoV-2 and influenza viruses elicit similar pathological processes. Their severe manifestations, such as acute respiratory distress syndrome (ARDS), multiple organ failure (MOF), and viral sepsis, are correlated with the cytokine storm. During flu infection, QFPDD reduced the lung indexes and downregulated the expressions of MCP-1, TNF-[Formula: see text], IL-6, and IL-1[Formula: see text] in broncho-alveolar lavage fluid (BALF), lungs, or serum samples. The infiltration of neutrophils and inflammatory monocytes in lungs was decreased dramatically, and lung injury was ameliorated in QFPDD-treated flu mice. In addition, QFPDD also inhibited the polarization of M1 macrophages and downregulated the expressions of IL-6, TNF-[Formula: see text], MIP-2, MCP-1, and IP-10, while also upregulating the IL-10 expression. The phosphorylated TAK1, IKK[Formula: see text]/[Formula: see text], and I[Formula: see text]B[Formula: see text] and the subsequent translocation of phosphorylated p65 into the nuclei were decreased by QFPDD. These findings indicated that QFPDD reduces the intensity of the cytokine storm by inhibiting the NF-[Formula: see text]B signaling pathway during severe viral infections, thereby providing theoretical and experimental support for its clinical application in respiratory viral infections.

Metagenomic-based pathogen surveillance for children with severe pneumonia in pediatric intensive care unit

Background

Pneumonia is a significant cause of morbidity and mortality in children. Metagenomic next-generation sequencing (mNGS) has the potential to assess the landscape of pathogens responsible for severe pulmonary infection.

Methods

Bronchoalveolar lavage fluid (BALF) samples of 262 children with suspected pulmonary infections were collected from April 2019 to October 2021 in the Pediatric Intensive Care Unit (PICU) of Guangdong Women and Children Hospital. Both mNGS and conventional tests were utilized for pathogen detection.

Results

A total of 80 underlying pathogens were identified using both mNGS and conventional tests. Respiratory syncytial virus (RSV), Staphylococcus aureus and rhinovirus were the most frequently detected pathogens in this cohort. The incidence rate of co-infection was high (58.96%, 148/251), with bacterial-viral agents most co-detected. RSV was the main pathogen in children younger than 6 months of age, and was also commonly found in older pediatric patients. Rhinovirus was prevalent in children older than 6 months. Adenovirus and Mycoplasma pneumoniae were more prevalent in children older than 3 years than in other age groups. Pneumocystis jirovecii was detected in nearly 15% of children younger than 6 months. Besides, influenza virus and adenovirus were rarely found in 2020 and 2021.

Conclusions

Our study highlights the importance of using advanced diagnostic techniques like mNGS to improve our understanding of the microbial epidemiology of severe pneumonia in pediatric patients.

Viral infections in critical care: a narrative review

Viral infections form a substantial part of the intensive care workload, even before the recent and ongoing COVID-19 pandemic. The growing availability of molecular diagnostics for viral infections has led to increased recognition of these pathogens. This additional information, however, provides new challenges for interpretation and management. As the SARS-CoV-2 pandemic has amply demonstrated, the emergence and global spread of novel viruses are likely to provide continued challenges for critical care physicians into the future. This article will provide an overview of viral infections relevant to the critical care physician, discussing the diagnosis and management of respiratory viral infections, blood borne and enteric viruses. We will also discuss herpesviridae complications, commonly seen due to reactivation of latent infections. Further, we explore some rarer and emerging viruses, including recognition of viral haemorrhagic fevers, and briefly discuss post-viral syndromes which may present to the intensive care unit. Finally, we will discuss infection control and its importance in preventing nosocomial viral transmission.

Effect of Cytomegalovirus Reactivation on Inflammatory Status and Mortality of Older COVID-19 Patients

Herpesviridae reactivation such as cytomegalovirus (CMV) has been described in severe COVID-19 (COronaVIrusDisease-2019). This study aimed to understand if CMV reactivation in older COVID-19 patients is associated with increased inflammation and in-hospital mortality. In an observational single-center cohort study, 156 geriatric COVID-19 patients were screened for CMV reactivation by RT-PCR. Participants underwent a comprehensive clinical investigation that included medical history, functional evaluation, laboratory tests and cytokine assays (TNF-α, IFN-α, IL-6, IL-10) at hospital admission. In 19 (12.2%) of 156 COVID-19 patients, CMV reactivation was detected. Multivariate Cox regression models showed that in-hospital mortality significantly increased among CMV positive patients younger than 87 years (HR: 9.94, 95% CI: 1.66–59.50). Other factors associated with in-hospital mortality were C-reactive protein (HR: 1.17, 95% CI: 1.05–1.30), neutrophil count (HR: 1.20, 95% CI: 1.01–1.42) and clinical frailty scale (HR:1.54, 95% CI: 1.04–2.28). In patients older than 87 years, neutrophil count (HR: 1.13, 95% CI: 1.05–1.21) and age (HR: 1.15, 95% CI: 1.01–1.31) were independently associated with in-hospital mortality. CMV reactivation was also correlated with increased IFN-α and TNF-α serum levels, but not with IL-6 and IL-10 serum changes. In conclusion, CMV reactivation was an independent risk factor for in-hospital mortality in COVID-19 patients younger than 87 years old, but not in nonagenarians.

Outcomes Associated With Intensive Care and Organ Support Among Patients With COVID-19: A Systematic Review and Meta-Analysis

BACKGROUND

Accurate accounting of coronavirus disease 2019 (COVID-19) critical care outcomes has important implications for health care delivery.

RESEARCH QUESTION

We aimed to determine critical care and organ support outcomes of intensive care unit (ICU) COVID-19 patients and whether they varied depending on the completeness of study follow-up or admission time period.

STUDY DESIGN AND METHODS

We conducted a systematic review and meta-analysis of reports describing ICU, mechanical ventilation (MV), renal replacement therapy (RRT), and extracorporeal membrane oxygenation (ECMO) mortality. A search was conducted using PubMed, Embase, and Cochrane databases.We included English language observational studies of COVID-19 patients, reporting ICU admission, MV, and ICU case fatality, published from December 1, 2019 to December 31, 2020. We excluded reports of less than 5 ICU patients and pediatric populations. Study characteristics, patient demographics, and outcomes were extracted from each article. Subgroup meta-analyses were performed based on the admission end date and the completeness of data.

RESULTS

Of 6,778 generated articles, 145 were retained for inclusion (n = 60,357 patients). Case fatality rates across all studies were 34.0% (95% CI = 30.7%, 37.5%, P < 0.001) for ICU deaths, 47.9% (95% CI = 41.6%, 54.2%, P < 0.001) for MV deaths, 58.7% (95% CI = 50.0%, 67.2%, P < 0.001) for RRT deaths, and 43.3% (95% CI = 31.4%, 55.4%, P < 0.001) for extracorporeal membrane oxygenation deaths. There was no statistically significant difference in ICU and organ support outcomes between studies with complete follow-up versus studies without complete follow-up. Case fatality rates for ICU, MV, and RRT deaths were significantly higher in studies with patients admitted before April 31st 2020.

INTERPRETATION

Coronavirus disease 2019 critical care outcomes have significantly improved since the start of the pandemic. Intensive care unit outcomes should be evaluated contextually (study quality, data completeness, and time) for the most accurate reporting and to effectively guide mortality predictions.

Metagenomic next-generation sequencing of bronchoalveolar lavage fluid from children with severe pneumonia in pediatric intensive care unit

Background

Severe pneumonia due to lower respiratory tract infections (LRTIs) is a significant cause of morbidity and mortality in children. Noninfectious respiratory syndromes resembling LRTIs can complicate the diagnosis and may also make targeted therapy difficult because of the difficulty of identifying LRTI pathogens. In the present study, a highly sensitive metagenomic next-generation sequencing (mNGS) approach was used to characterize the microbiome of bronchoalveolar lavage fluid (BALF) in children with severe lower pneumonia and identify pathogenic microorganisms that may cause severe pneumonia. The purpose of this study was to use mNGS to explore the potential microbiomes of children with severe pneumonia in a PICU.

Methods

We enrolled patients meeting diagnostic criteria for severe pneumonia admitted at PICU of the Children’s Hospital of Fudan University, China, from February 2018 to February 2020. In total, 126 BALF samples were collected, and mNGS was performed at the DNA and/or RNA level. The pathogenic microorganisms in BALF were identified and correlated with serological inflammatory indicators, lymphocyte subtypes, and clinical symptoms.

Results

mNGS of BALF identified potentially pathogenic bacteria in children with severe pneumonia in the PICU. An increased BALF bacterial diversity index was positively correlated with serum inflammatory indicators and lymphocyte subtypes. Children with severe pneumonia in the PICU had the potential for coinfection with viruses including Epstein–Barr virus, Cytomegalovirus, and Human betaherpesvirus 6B, the abundance of which was positively correlated with immunodeficiency and pneumonia severity, suggesting that the virus may be reactivated in children in the PICU. There was also the potential for coinfection with fungal pathogens including Pneumocystis jirovecii and Aspergillus fumigatus in children with severe pneumonia in the PICU, and an increase in potentially pathogenic eukaryotic diversity in BALF was positively associated with the occurrence of death and sepsis.

Conclusions

mNGS can be used for clinical microbiological testing of BALF samples from children in the PICU. Bacterial combined with viral or fungal infections may be present in the BALF of patients with severe pneumonia in the PICU. Viral or fungal infections are associated with greater disease severity and death.

Leflunomide: Traditional immunosuppressant with concurrent antiviral effects

Leflunomide is a classic disease-modifying anti-rheumatic drug that is widely used to treat autoimmune diseases. Studies also show its antiviral effects in in vitro and/or in vivo experiments. Considering glucocorticoids, immunosuppressants and newly emerged antibodies commonly used in autoimmune diseases and autoinflammatory disorders bring risk of infection such as viral infection, leflunomide with combination of anti-viral and immunosuppressive features to maintain the balance between infection and anti-inflammation are attractive. Here we summarize the actions and mechanisms of leflunomide in immunoregulatory and antiviral effects.

Protein kinase C isoforms mediate the formation of neutrophil extracellular traps

Neutrophils release extracellular traps (NETs) in response to numerous pathogenic microbes as the last suicidal resource (NETosis) in the fight against infection. Apart from the host defense function, NETs play an essential role in the pathogenesis of various autoimmune, inflammatory and malignant diseases. Therefore, understanding the molecular mechanisms of NETosis is important for regulating the aberrant or excessive NET release. Protein kinase C (PKC) is a serine/threonine kinase which is involved in various neutrophil functions, however, little is known about its implication in NETosis activated by various physiological and pharmacological stimuli. Since there are conventional, novel and atypical PKC isoforms (α, βI, βII, δ, and ζ) found in human neutrophils, we investigated their impact in NETosis, oxidative burst and spreading applying pharmacological approach. Using specific inhibitors of PKC isoforms, we showed that PKCβ, PKCδ, and PKCζ are involved in the oxidative burst, spreading and NETosis activated by calcium ionophore A23187, while only PKCβ is implicated in these functions activated by phorbol 12-myristate 13-acetate (PMA). The data obtained in our study might help in the development of new drugs useful for the treatment of autoimmune and inflammatory diseases associated with NETs.

Updates in the management of respiratory virus infections in ICU patients: revisiting the non-SARS-CoV-2 pathogens

INTRODUCTION

Although viruses are an underestimated cause of community-acquired pneumonias (CAP) and hospital-acquired pneumonias (HAP)/ventilator-associated pneumonias (VAP) in intensive care unit (ICU) patients, they have an impact on morbidity and mortality.

AREAS COVERED

In this perspective article, we discuss the available data regarding the management of severe influenza CAP and herpesviridae HAP/VAP. We review diagnostic and therapeutic strategies in order to give clear messages and address unsolved questions.

EXPERT OPINION

Influenza CAP affects yearly thousands of people; however, robust data regarding antiviral treatment in the most critical forms are scarce. While efficacy of oseltamivir has been investigated in randomized controlled trials (RCT) in uncomplicated influenza, only observational data are available in ICU patients. Herpesviridae are an underestimated cause of HAP/VAP in ICU patients. Whilst incidence of herpesviridae identification in samples from lower respiratory tract of ICU patients is relatively high (from 20% to 50%), efforts should be made to differentiate local reactivation from true lung infection. Only few randomized controlled trials evaluated the efficacy of antiviral treatment in herpesviridae reactivation/infection in ICU patients and all were exploratory or negative. Further studies are needed to evaluate the impact of such treatment in specific populations.

Case report: Disseminated herpes simplex virus 1 infection and hemophagocytic lymphohistiocytosis after immunomodulatory therapy in a patient with coronavirus disease 2019

Corticosteroids and immunomodulatory therapies are widely used to treat patients with severe coronavirus disease 2019 (COVID-19). Janus kinase (JAK) inhibitors such as tofacitinib have been recently studied as adjuvants in the treatment of COVID-19. Although immunomodulatory therapies may be linked to decreased mortality rates in the acute phase, subsequent severe infectious complications may result from them. We describe a case of a multiorgan system failure secondary to disseminated primary herpes simplex virus 1 (HSV-1) infection and hemophagocytic lymphohistiocytosis (HLH) following treatment with tofacitinib and high-dose dexamethasone therapy for severe COVID-19. Early diagnosis and treatment of these life-threatening conditions may have a significant impact on COVID-19 patients' outcomes.

Herpesviridae lung reactivation and infection in patients with severe COVID-19 or influenza virus pneumonia: a comparative study

Background

Lung reactivations of Herpesviridae, herpes simplex virus (HSV) and cytomegalovirus (CMV) have been reported in COVID-19 patients. Whether or not those viral reactivations are more frequent than in other patients is not known.

Methods

Retrospective monocentric cohort study of 145 patients with severe COVID-19 pneumonia requiring invasive mechanical ventilation and who were tested for HSV and CMV in bronchoalveolar lavage performed during fiberoptic bronchoscopy for ventilator-associated pneumonia suspicion. Rates of HSV and CMV lung reactivations, and HSV bronchopneumonitis were assessed and compared with an historical cohort of 89 patients with severe influenza pneumonia requiring invasive mechanical ventilation.

Results

Among the 145 COVID-19 patients included, 50% and 42% had HSV and CMV lung reactivations, respectively, whereas among the 89 influenza patients, 63% and 28% had HSV and CMV lung reactivations, respectively. Cumulative incidence of HSV lung reactivation (taking into account extubation and death as competing events) was higher in influenza than in COVID-19 patients (p = 0.03), whereas the rate of HSV bronchopneumonitis was similar in both groups (31% and 25%, respectively). Cumulative incidence of CMV lung reactivation (taking into account extubation and death as competing events) was similar in COVID-19 and influenza patients (p = 0.07). Outcomes of patients with HSV or CMV lung reactivations were similar to that of patients without, whatever the underlying conditions, i.e., in COVID-19 patients, in influenza patients, or when all patients were grouped.

Conclusions

HSV and CMV lung reactivations are frequent in COVID-19 patients, but not more frequent than in patients with influenza-associated severe pneumonia, despite a higher severity of illness at intensive care unit admission of the latter and a longer duration of mechanical ventilation of the former. Although no impact on outcome of HSV and CMV lung reactivations was detected, the effect of antiviral treatment against these Herpesviridae remains to be determined in these patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01062-0.

[Epstein-Barr viral infection is a global epidemiological problem]

The number of studies devoted to Epstein-Barr viral infection (EBV infection) has been growing in recent years. However, they all relate to the clinical aspects of this problem. Epidemiology issues remain practically unexplored. A review of domestic and foreign publications has shown that at the present stage there is a high intensity of the epidemic process of EBV infection both in Russia and abroad. The main indicators of unfavorable epidemiological situation are the ubiquitous spread of the pathogen and the increase in the incidence of infectious mononucleosis in recent years. The deterioration of the epidemic situation of EBV infection is influenced by changes in the immunological reactivity of various population groups due to the spread of HIV, HBV, HCV, the causative agent of tuberculosis and SARS-CoV-2. The above makes it possible to classify the problem as a global one and determines the need for the rapid implementation of the system of epidemiological surveillance of EBV infection and optimization of the complex of preventive and anti-epidemic measures. Reducing the burden of EBV is possible only with the consolidated participation of specialists of various profiles.

Clinical Characteristics and Risk Factors for Pulmonary Infection in Emergency ICU Patients

Background

Pulmonary infection in the emergency ICUs increases patient morbidity, hospital stay, treatment costs, and the risk of related adverse events.

Methods

This study included 695 patients admitted to our emergency ICU between December 2019 and March 2021. Medical records of emergency ICU patients were reviewed to collect their clinical data, including antibiotic use, history of tracheostomy, history of mechanical ventilation, presence or absence of underlying disease, history of smoking, alcohol consumption, age, gender, and history of shock. Bacterial cultures were performed. The incidence, main clinical features, main pathogens, and risk factors of pulmonary infection in emergency ICU were analyzed.

Results

In this study, 69 of the 695 emergency ICU patients (9.93%) developed pulmonary infection. The main clinical features of patients with pulmonary infection included cough and expectoration (97.10%), shortness of breath and chest tightness (95.65%), leukocyte elevation (69.57%), confusion (31.88%), drowsiness (28.99%), persistent fever (27.54%), and nausea and vomiting (10.14%). The main pathogenic bacteria in those with pulmonary infection included Klebsiella pneumoniae (62.32%), Pseudomonas aeruginosa (49.28%), Streptococcus pneumoniae (21.74%), Staphylococcus aureus (39.13%), Candida albicans (7.25%), Pneumococcus pneumoniae (15.95%), Pseudomonas aeruginosa (24.64%), and lung diplococcus inflammatory (13.04%). Univariate analysis showed that there were no significant differences in the occurrence of pulmonary infection with regard to sex, smoking, and alcohol consumption, but there were significant differences with regard to age, basic disease, invasive surgery, and shock. Logistic regression analysis confirmed that age ≥ 80 years, invasive surgery, shock, and basic diseases ≥ 2 were important risk factors for pulmonary infection in emergency ICU patients.

Conclusion

Considering the clinical features and risk factors for pulmonary infection in the emergency ICU, preventive and control measures are required to minimize its occurrence and ensure good outcomes.

Emergent Virus Reactivation in SARS-CoV-2-Negative Community Acquired Pneumonia Patients During the COVID-19 Pandemic

Emergent viruses (namely, HSV-1, CMV, and EBV) reactivation were common in critically ill patients and/or immunosuppressed patients. This study aimed to understand the clinical manifestations and reactivation of the emergent viruses in SARS-CoV-2-Negative community acquired pneumonia (CAP) patients during the COVID-19 pandemic. We retrospectively reviewed the medical records of CAP patients from January to March 2020, in our university hospital in China. The patients were divided into two groups based on the presence or absence of emergent viruses. In all patients, the positive rates of EBV, HSV, and CMV were 23.43% (15/64), 22.06% (15/68), and 12.50% (8/64), respectively. The most common presenting symptoms were fever (98, 57.99%) and dry cough (55, 32.54%). The levels of albumin, hemoglobin, lymphocyte count, and CD4 + T lymphocyte count in emergent viruses positive group were lower than those of viruses negative group (P < 0.05). The initial chest CT features of these patients were diverse. The most common manifestations were ground-glass opacity (91/169, 53.85%) and pulmonary nodule (88/169, 52.07%). More emergent viruses positive patients have bilateral upper lobes involvement than emergent viruses negative patients (P < 0.05). A total of 80.47% patients (136/169) received empirical antimicrobial treatment. The most commonly used antibiotic regimen was fluoroquinolone monotherapy (80/169, 47.34%). The emergent viruses positive patients have poorer clinical outcome (P < 0.05). In conclusion, emergent viruses reactivation was common in SARS-CoV-2-Negative CAP patients. Emergent viruses positive patients have poorer cellular immune function, more severer conditions and poorer prognosis. Fluoroquinolones may be a therapeutic option for CAP patients.

Preemptive acyclovir to prevent herpes simplex virus bronchopneumonitis in mechanically ventilated patients with herpes simplex virus oropharyngeal reactivation: An ancillary study of the preemptive treatment for herpesviridae trial

Background

To evaluate the impact of preemptive acyclovir treatment on herpes simplex virus (HSV) bronchopneumonitis in mechanically ventilated patients with HSV oropharyngeal reactivation.

Methods

Ancillary study of the Preemptive Treatment for Herpesviridae (PTH) clinical trial. Patients included in that trial from one centre (Pitié-Salpêtrière Hospital) and in whom at least one bronchoalveolar lavage (BAL) was performed for ventilator-associated pneumonia suspicion were included in the present study. Rate of HSV bronchopneumonitis, defined as clinical symptoms suggesting of pneumonia and presence of HSV in BAL fluid ≥105 copies of HSV/106 cells, were compared in patients who received either acyclovir or placebo.

Results

Eighty-three patients were included; 40 having received preemptive acyclovir and 43 having received a placebo, without differences between groups at admission or at randomization. The number of patients who developed HSV bronchopneumonitis was lower among acyclovir-treated patients than among placebo-treated patients (40% vs. 72%, respectively, p = .003). Results were similar when restricted to patients without HSV detected in the lower respiratory tract at randomization (31% vs. 61%, respectively, p = .03).

Conclusions

Preemptive acyclovir treatment in mechanically ventilated patients with HSV oropharyngeal reactivation reduces HSV bronchopneumonitis rate.

Flu-IV score: a predictive tool for assessing the risk of invasive mechanical ventilation in patients with influenza-related pneumonia

Background

The need for invasive mechanical ventilation (IMV) is linked to significant morbidity and mortality in patients with influenza-related pneumonia (Flu-p). We aimed to develop an assessment tool to predict IMV among Flu-p patients within 14 days of admission.

Methods

In total, 1107 Flu-p patients from five teaching hospitals were retrospectively enrolled from January 2012 to December 2019, including 895 patients in the derivation cohort and 212 patients in the validation cohort. The predictive model was established based on independent risk factors for IMV in the Flu-p patients from the derivation cohort.

Results

Overall, 10.6% (117/1107) of patients underwent IMV within 14 days of admission. Multivariate regression analyses revealed that the following factors were associated with IMV: early neuraminidase inhibitor use (− 3 points), lymphocytes < 0.8 × 10⁹/L (1 point), multi-lobar infiltrates (1 point), systemic corticosteroid use (1 point), age ≥ 65 years old (1 points), PaO₂/FiO₂ < 300 mmHg (2 points), respiratory rate ≥ 30 breaths/min (3 points), and arterial PH < 7.35 (4 points). A total score of five points was used to identify patients at risk of IMV. This model had a sensitivity of 85.5%, a specificity of 88.8%, and exhibited better predictive performance than the ROX index (AUROC = 0.909 vs. 0.594, p = 0.004), modified ROX index (AUROC = 0.909 vs. 0.633, p = 0.012), and HACOR scale (AUROC = 0.909 vs. 0.622, p < 0.001) using the validation cohort.

Conclusions

Flu-IV score is a valuable prediction rule for 14-day IMV rates in Flu-p patients. However, it should be validated in a prospective study before implementation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01833-2.

Herpesviruses in Critically Ill Patients With ARDS

Reactivation of herpsviruses, mainly HSV, CMV and EBV, are frequent among critically ill patients. Although they are not immunocompromised from a classical point of view, these patients often present an alteration of their immune system favoring viral reactivation. Seropositive patients with sepsis and under mechanical ventilation are particularly at risk. Herpesviruses have a pulmonary tropism and can be responsible for non-resolving forms of acute respiratory distress syndrome with high mortality. However, the direct causality between herpesviruses reactivation and impaired outcomes among severely ill patients remains under debate.

Viral Respiratory Infections: New Tools for a Rapid Diagnosis

Respiratory tract infection is one of the most common diseases in human worldwide. Many viruses are implicated in these infections, including emerging viruses, such as the novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Identification of the causative viral pathogens of respiratory tract infections is important to select a correct management of patients, choose an appropriate treatment, and avoid unnecessary antibiotics use. Different diagnostic approaches present variable performance in terms of accuracy, sensitivity, specificity, and time-to-result, that have to be acknowledged to be able to choose the right diagnostic test at the right time, in the right patient. This review describes currently available rapid diagnostic strategies and syndromic approaches for the detection of viruses commonly responsible for respiratory diseases.

Management of Severe Influenza

Influenza infection causes severe illness in 3 to 5 million people annually, with up to an estimated 650,000 deaths per annum. As such, it represents an ongoing burden to health care systems and human health. Severe acute respiratory infection can occur, resulting in respiratory failure requiring intensive care support. Herein we discuss diagnostic approaches, including development of CLIA-waived point of care tests that allow rapid diagnosis and treatment of influenza. Bacterial and fungal coinfections in severe influenza pneumonia are associated with worse outcomes, and we summarize the approach and treatment options for diagnosis and treatment of bacterial and Aspergillus coinfection. We discuss the available drug options for the treatment of severe influenza, and treatments which are no longer supported by the evidence base. Finally, we describe the supportive management and ventilatory approach to patients with respiratory failure as a result of severe influenza in the intensive care unit.

The Pfizer-BNT162b2 mRNA-based vaccine against SARS-CoV-2 may be responsible for awakening the latency of herpes varicella-zoster virus

BACKGROUND

To prevent the invasion and transmission of SARS-CoV-2, mRNA-based vaccines, non-replicating viral vector vaccines, and inactivated vaccines have been developed. The European Medicines Agency (EMA) authorized the use of the anti-SARS-CoV-2 vaccine in January 2021, the date on which the vaccination program began in Spain and across Europe. The aim of this study is to monitor the safety of anti-SARS-CoV-2 vaccines and report any cases of undesirable effects that have occurred, that are not included in the health profile of mRNA-based vaccines for commercialisation in humans. Furthermore, a brief review is given of the mechanism of action of the anti-SARS-CoV-2 vaccine on the host's immune system in triggering the reactivation of the herpes varicella-zoster infection.

METHODS

Follow-up of patients under the care of the southern health district of Seville of the SAS (Andalusian Health Service) during the Spanish state of alarm over the COVID-19 pandemic.

RESULTS

Two patients, a 79-year-old man and a 56-year-old woman, are reported who, after 4 and 16 days respectively of receiving the Pfizer-BNT162b2 vaccine against SARS-CoV-2, presented a state of reactivation of herpes varicella-zoster virus (VZV).

DISCUSSION

The immunosenescence of the reported patients, together with the immunomodulation generated by administering the anti-SARS-CoV-2 vaccines, that depress certain cell subpopulations, could explain the awakening of VZV latency.

The viral distribution and pathological characteristics of BALB/c mice infected with highly pathogenic Influenza H7N9 virus

Background

The highly pathogenic Influenza H7N9 virus is believed to cause multiple organ infections. However, there have been few systematic animal experiments demonstrating the virus distribution after H7N9 virus infection. The present study was carried out to investigate the viral distribution and pathological changes in the main organs of mice after experimental infection with highly pathogenic H7N9 virus.

Methods

Infection of mice with A/Guangdong/GZ8H002/2017(H7N9) virus was achieved via nasal inoculation. Mice were killed at 2, 3, and 7 days post infection. The other mice were used to observe their illness status and weight changes. Reverse transcription polymerase chain reaction and viral isolation were used to analyse the characteristics of viral invasion. The pathological changes of the main organs were observed using haematoxylin and eosin staining and immunohistochemistry.

Results

The weight of H7N9 virus-infected mice increased slightly in the first two days. However, the weight of the mice decreased sharply in the following days, by up to 20%. All the mice had died by the 8th day post infection and showed multiple organ injury. The emergence of viremia in mice was synchronous with lung infection. On the third day post infection, except in the brain, the virus could be isolated from all organs (lung, heart, kidney, liver, and spleen). On the seventh day post infection, the virus could be detected in all six organs. Brain infection was detected in all mice, and the viral titre in the heart, kidney, and spleen infection was high.

Conclusion

Acute diffuse lung injury was the initial pathogenesis in highly pathogenic H7N9 virus infection. In addition to lung infection and viremia, the highly pathogenic H7N9 virus could cause multiple organ infection and injury.

The Contribution of Human Herpes Viruses to γδ T Cell Mobilisation in Co-Infections

γδ T cells are activated in viral, bacterial and parasitic infections. Among viruses that promote γδ T cell mobilisation in humans, herpes viruses (HHVs) occupy a particular place since they infect the majority of the human population and persist indefinitely in the organism in a latent state. Thus, other infections should, in most instances, be considered co-infections, and the reactivation of HHV is a serious confounding factor in attributing γδ T cell alterations to a particular pathogen in human diseases. We review here the literature data on γδ T cell mobilisation in HHV infections and co-infections, and discuss the possible contribution of HHVs to γδ alterations observed in various infectious settings. As multiple infections seemingly mobilise overlapping γδ subsets, we also address the concept of possible cross-protection.

Association of bleeding symptoms during influenza infection and administered drugs

On March 1, 2019, the Ministry of Health, Labour and Welfare added bleeding symptoms to adverse reaction package inserts as a possible adverse event for a new anti-influenza drug, baloxavir marboxil, because 13 patients with bleeding symptoms were identified among influenza patients taking the drug. Nevertheless, aspects of the epidemiology of bleeding symptoms among influenza patients remain unclear. This study elucidated bleeding symptoms among influenza patients and hospitalized patients as severe cases. A survey was administered to all physicians in Japan during the 2019-2020 season for reporting of bleeding symptoms in influenza patients. The survey elicited information about outcomes, assuming associated underlying diseases and drugs in addition to administered drugs including acetaminophen and anti-influenza (antiviral) drugs. We received reports of 63 cases with bleeding symptoms, including 5 cases of hospitalized patients. Among all patients, 54% had been administered oseltamivir; 10% had been administered baloxavir marboxil. Among hospitalized patients, all had been administered acetaminophen; 40% of them had been administered oseltamivir, and one patient had been administered baloxavir marboxil. Accumulation of bleeding symptom cases is expected to be necessary to evaluate the association.

Herpes DNAemia and TTV Viraemia in Intensive Care Unit Critically Ill Patients: A Single-Centre Prospective Longitudinal Study

Introduction

We analysed blood DNAemia of TTV and four herpesviruses (CMV, EBV, HHV6, and HSV-1) in the REAnimation Low Immune Status Marker (REALISM) cohort of critically ill patients who had presented with either sepsis, burns, severe trauma, or major surgery. The aim was to identify common features related to virus and injury-associated pathologies and specific features linking one or several viruses to a particular pathological context.

Methods

Overall and individual viral DNAemia were measured over a month using quantitative PCR assays from the 377 patients in the REALISM cohort. These patients were characterised by clinical outcomes [severity scores, mortality, Intensive Care Unit (ICU)-acquired infection (IAI)] and 48 parameters defining their host response after injury (cell populations, immune functional assays, and biomarkers). Association between viraemic event and clinical outcomes or immune markers was assessed using χ²-test or exact Fisher’s test for qualitative variables and Wilcoxon test for continuous variables.

Results

The cumulative incidence of viral DNAemia increased from below 4% at ICU admission to 35% for each herpesvirus during the first month. EBV, HSV1, HHV6, and CMV were detected in 18%, 12%, 10%, and 9% of patients, respectively. The incidence of high TTV viraemia (>10,000 copies/ml) increased from 11% to 15% during the same period. Herpesvirus viraemia was associated with severity at admission; CMV and HHV6 viraemia correlated with mortality during the first week and over the month. The presence of individual herpesvirus during the first month was significantly associated (p < 0.001) with the occurrence of IAI, whilst herpesvirus DNAemia coupled with high TTV viraemia during the very first week was associated with IAI. Herpesvirus viraemia was associated with a lasting exacerbated host immune response, with concurrent profound immune suppression and hyper inflammation, and delayed return to immune homeostasis. The percentage of patients presenting with herpesvirus DNAemia was significantly higher in sepsis than in all other groups. Primary infection in the hospital and high IL10 levels might favour EBV and CMV reactivation.

Conclusion

In this cohort of ICU patients, phenotypic differences were observed between TTV and herpesviruses DNAemia. The higher prevalence of herpesvirus DNAemia in sepsis hints at further studies that may enable a better in vivo understanding of host determinants of herpesvirus viral reactivation. Furthermore, our data suggest that EBV and TTV may be useful as additional markers to predict clinical deterioration in ICU patients.

The Potential Role of Cytokine Storm Pathway in the Clinical Course of Viral Respiratory Pandemic

The "cytokine storm" (CS) consists of a spectrum of different immune dysregulation disorders characterized by constitutional symptoms, systemic inflammation and multiorgan dysfunction triggered by an uncontrolled immune response. Particularly in respiratory virus infections, the cytokine storm plays a primary role in the pathogenesis of respiratory disease and the clinical outcome of respiratory diseases, leading to complications such as alveolar edema and hypoxia. In this review, we wanted to analyze the different pathogenetic mechanisms involved in the various respiratory viral pandemics (COVID-19; SARS; MERS; H1N1 influenza A and Spanish flu) which have affected humans in this and last century, with particular attention to the phenomenon of the "cytokine storm" which determines the clinical severity of the respiratory disease and consequently its lethality.

Hypercoagulability of COVID-19 and Neurological Complications: A Review

The SARS-CoV-2 virus, which causes Coronavirus disease 2019 (COVID-19), has resulted in millions of worldwide deaths. When the SARS-CoV-2 virus emerged from Wuhan, China in December 2019, reports of patients with COVID-19 revealed that hospitalized patients had acute changes in mental status, cognition, and encephalopathy. Neurologic complications can be a consequence from overall severity of the systemic infection, direct viral invasion of the SARS-CoV-2 virus in the central nervous system, and possible immune mediated mechanisms. We will examine the landscape regarding this topic in this review in addition to current understandings of COVID-19 and hemostasis, treatment, and prevention, as well as vaccination.

Metagenomic Next-Generation Sequencing in the Diagnosis of HHV-1 Reactivation in a Critically Ill COVID-19 Patient: A Case Report

Background: Secondary infections pose tremendous challenges in Coronavirus disease 2019 (COVID-19) treatment and are associated with higher mortality rates. Clinicians face of the challenge of diagnosing viral infections because of low sensitivity of available laboratory tests.

Case Presentation: A 66-year-old woman initially manifested fever and shortness of breath. She was diagnosed as critically ill with COVID-19 using quantitative reverse transcription PCR (RT-qPCR) and treated with antiviral therapy, ventilator and extracorporeal membrane oxygenation (ECMO). However, after the condition was relatively stabled for a few days, the patient deteriorated with fever, frequent cough, increased airway secretions, and increased exudative lesions in the lower right lung on chest X-rays, showing the possibility of a newly acquired infection, though sputum bacterial and fungal cultures and smears showed negative results. Using metagenomic next-generation sequencing (mNGS), we identified a reactivation of latent human herpes virus type 1 (HHV-1) in the respiratory tract, blood and gastrointestinal tract, resulting in a worsened clinical course in a critically ill COVID-19 patient on ECMO. Anti-HHV-1 therapy guided by these sequencing results effectively decreased HHV-1 levels, and improved the patient's clinical condition. After 49 days on ECMO and 67 days on the ventilator, the 66-year-old patient recovered and was discharged.

Conclusions: This case report demonstrates the potential value of mNGS for evidence-based treatment, and suggests that potential reactivation of latent viruses should be considered in critically ill COVID-19 patients.

Failure mode and effects analysis on the control effect of multi-drug-resistant bacteria in ICU patients

OBJECTIVE

The failure mode and effect analysis of the prevention and control in intensive care unit (ICU) patients with multi-drug-resistant (MDR) bacterial infection were explored and analyzed in this research.

METHODS

A total of 251 critically ill patients who were hospitalized in the ICU from June to December 2019 were selected as the control group, and another 258 patients who were hospitalized in the ICU from January to June 2020 were set as the observation group. The control-group patients received conventional ICU care, the observation group was treated by the failure mode and effects analysis (FMEA), and then the prevention and control effect of the two nursing modes on multi-drug-resistant bacteria infection in the two groups were compared accordingly.

RESULTS

The RPN values of the five highest-level factors in the nursing process were critically lower after the improved interventions than before the improvement. The infection rate of MDR bacteria in the observation group was obviously lower than that in the control group (14.73%, 26.69%, χ² =11.1233, P=0.0009). In addition, the mortality rate of patients with MDR in the observation group was remarkably lower than that in the control group, and the difference was statistically significant (5.26%, 22.39%, χ² =5.2405, P=0.0221). The satisfaction of the observation group with the ICU treatment was critically higher than that of the control group, and the difference was statistically significant (89.53%, 76.49%, χ² =15.4094, P=0.0001).

CONCLUSION

Through the application of FMEA to prevent MDR bacterial infection in ICU patients, nursing staff can accurately pay attention to the keynotes in nursing process, and as such reduce the proportion and mortality of MDR infection in ICU patients and promote the patients' satisfaction with nursing, which are all worthy of clinical application.

The severity and risk factors for mortality in immunocompromised adult patients hospitalized with influenza-related pneumonia

Objective

To explore disease severity and risk factors for 30-day mortality of adult immunocompromised (IC) patients hospitalized with influenza-related pneumonia (Flu-p).

Method

A total of 122 IC and 1191 immunocompetent patients hospitalized with Flu-p from January 2012 to December 2018 were recruited retrospectively from five teaching hospitals in China.

Results

After controlling for confounders, multivariate logistic regression analysis showed that immunosuppression was associated with increased risks for invasive ventilation [odds ratio: (OR) 2.475, 95% confidence interval (CI): 1.511–4.053, p < 0.001], admittance to the intensive care unit (OR: 3.247, 95% CI 2.064–5.106, p < 0.001), and 30-day mortality (OR: 3.206, 95% CI 1.926–5.335, p < 0.001) in patients with Flu-p. Another multivariate logistic regression model revealed that baseline lymphocyte counts (OR: 0.993, 95% CI 0.990–0.996, p < 0.001), coinfection (OR: 5.450, 95% CI 1.638–18.167, p = 0.006), early neuraminidase inhibitor therapy (OR 0.401, 95% CI 0.127–0.878, p = 0.001), and systemic corticosteroid use at admission (OR: 6.414, 95% CI 1.348–30.512, p = 0.020) were independently related to 30-day mortality in IC patients with Flu-p. Based on analysis of the receiver operating characteristic curve (ROC), the optimal cutoff for lymphocyte counts was 0.6 × 10⁹/L [area under the ROC (AUROC) = 0.824, 95% CI 0.744—0.887], sensitivity: 97.8%, specificity: 73.7%].

Conclusions

IC conditions are associated with more severe outcomes in patients with Flu-p. The predictors for mortality that we identified may be valuable for the management of Flu-p among IC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12941-021-00462-7.

Novel insights into the pathogenesis of virus-induced ARDS: review on the central role of the epithelial-endothelial barrier

Introduction: Respiratory viruses can directly or indirectly damage the pulmonary defense barrier, potentially contributing to acute respiratory distress syndrome (ARDS). Despite developments in the understanding of the pathogenesis of ARDS, the underlying pathophysiology still needs to be elucidated.Areas covered: The PubMed database was reviewed for relevant papers published up to 2021. This review summarizes the currently immunological and clinical studies to provide a systemic overview of the epithelial-endothelial barrier, given the recently published immunological profiles upon viral pneumonia, and the potentially detrimental contribution to respiratory function caused by damage to this barrier.Expert opinion: The biophysical structure of host pulmonary defense is intrinsically linked with the ability of alveolar epithelial and capillary endothelial cells, known as the epithelial-endothelial barrier, to respond to, and instruct the delicate immune system to protect the lungs from infections and injuries. Recently published immunological profiles upon viral infection, and its contributions to the damage of respiratory function, suggest a central role for the pulmonary epithelial and endothelial barrier in the pathogenesis of ARDS. We suggest a central role and common pathways by which the epithelial-endothelial barrier contributes to the pathogenesis of ARDS.

Overview of Viral Pneumonia Associated With Influenza Virus, Respiratory Syncytial Virus, and Coronavirus, and Therapeutics Based on Natural Products of Medicinal Plants

Viral pneumonia has been a serious threat to global health, especially now we have dramatic challenges such as the COVID-19 pandemic. Approximately six million cases of community-acquired pneumonia occur every year, and over 20% of which need hospital admission. Influenza virus, respiratory virus, and coronavirus are the noteworthy causative agents to be investigated based on recent clinical research. Currently, anaphylactic reaction and inflammation induced by antiviral immunity can be incriminated as causative factors for clinicopathological symptoms of viral pneumonia. In this article, we illustrate the structure and related infection mechanisms of these viruses and the current status of antiviral therapies. Owing to a set of antiviral regiments with unsatisfactory clinical effects resulting from side effects, genetic mutation, and growing incidence of resistance, much attention has been paid on medicinal plants as a natural source of antiviral agents. Previous research mainly referred to herbal medicines and plant extracts with curative effects on viral infection models of influenza virus, respiratory virus, and coronavirus. This review summarizes the results of antiviral activities of various medicinal plants and their isolated substances, exclusively focusing on natural products for the treatment of the three types of pathogens that elicit pneumonia. Furthermore, we have introduced several useful screening tools to develop antiviral lead compounds.

Viral Respiratory Pathogens and Lung Injury

Several viruses target the human respiratory tract, causing different clinical manifestations spanning from mild upper airway involvement to life-threatening acute respiratory distress syndrome (ARDS). As dramatically evident in the ongoing SARS-CoV-2 pandemic, the clinical picture is not always easily predictable due to the combined effect of direct viral and indirect patient-specific immune-mediated damage. In this review, we discuss the main RNA (orthomyxoviruses, paramyxoviruses, and coronaviruses) and DNA (adenoviruses, herpesviruses, and bocaviruses) viruses with respiratory tropism and their mechanisms of direct and indirect cell damage. We analyze the thin line existing between a protective immune response, capable of limiting viral replication, and an unbalanced, dysregulated immune activation often leading to the most severe complication. Our comprehension of the molecular mechanisms involved is increasing and this should pave the way for the development and clinical use of new tailored immune-based antiviral strategies.

Post-COVID-19 Pulmonary Fibrosis: Novel Sequelae of the Current Pandemic

Since the initial identification of the novel coronavirus SARS-CoV-2 in December 2019, the COVID-19 pandemic has become a leading cause of morbidity and mortality worldwide. As effective vaccines and treatments begin to emerge, it will become increasingly important to identify and proactively manage the long-term respiratory complications of severe disease. The patterns of imaging abnormalities coupled with data from prior coronavirus outbreaks suggest that patients with severe COVID-19 pneumonia are likely at an increased risk of progression to interstitial lung disease (ILD) and chronic pulmonary vascular disease. In this paper, we briefly review the definition, classification, and underlying pathophysiology of interstitial lung disease (ILD). We then review the current literature on the proposed mechanisms of lung injury in severe COVID-19 infection, and outline potential viral- and immune-mediated processes implicated in the development of post-COVID-19 pulmonary fibrosis (PCPF). Finally, we address patient-specific and iatrogenic risk factors that could lead to PCPF and discuss strategies for reducing risk of pulmonary complications/sequelae.

Asymptomatic Transmission and the Infection Fatality Risk for COVID-19: Implications for School Reopening

Asymptomatic infection occurs for numerous respiratory viral diseases, including influenza and coronavirus disease 2019 (COVID-19). We seek to clarify confusion in 3 areas: age-specific risks of transmission and/or disease; various definitions for the COVID-19 "mortality rate," each useful for specific purposes; and implications for student return strategies from preschool through university settings.

Prognosis of severe lower respiratory tract infected patients with virus detected: a retrospective observational study

OBJECTIVES

To compare the prognosis of severe lower respiratory tract infected patients with virus detected and patients with virus undetected by using metagenomic sequencing technology and a series of traditional serological tests.

METHODS

A total of 51 consecutive lower respiratory tract infected patients were enrolled in this study and samples were obtained to perform metagenomic next-generation sequencing (mNGS) and other traditional tests for virus detection. According to the results, patients were divided into a virus-detected (VD) group and a virus-undetected (VUD) group. Meanwhile, patients' demographic information, relevant baseline indicators and outcome indicators were also collected.

RESULTS

There were 27 patients in the VD group and 24 patients in the VUD group. Patients in the VD group had a longer mechanical ventilation (MV) supporting time [528.0 h (216.0, 997.0) vs 235.5 h (119.3, 421.3), p = .003], a higher tracheotomy rate [(63.0 vs. 29.2%), p = .016] and red blood cell (RBC) transfusion rate [(66.7 vs. 33.3%), p = .017] compared to the VUD group. The two groups had no significant difference in mortality rate, hospital length of stay (HLOS) or ICU length of stay (ICULOS).

CONCLUSIONS

Virus detected in patients with severe lower respiratory tract infection (LRTI) was not related to a poorer prognosis, but patients in the VD group did need more clinical resources, such as more MV support and RBC transfusion.

What Do Influenza and COVID-19 Represent for Patients With Inflammatory Bowel Disease?

BACKGROUND

Inflammatory bowel diseases (IBD) are a group of immune and inflammatory diseases; and patients seem to be more vulnerable to influenza and coronavirus disease 2019 (COVID-19). These conditions are characterized by the augmented release of inflammatory cytokines that have been suggested as potential triggers for the acute respiratory distress syndrome, which may favor severe and even fatal outcomes. For these reasons, this review aims to evaluate what influenza and COVID-19 may represent for patients with IBD.

METHODS

The search was performed in MEDLINE/PubMed, EMBASE, and Cochrane databases. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to build the review.

RESULTS

The conventional therapies used by IBD patients may also interfere in the outcomes of influenza and COVID-19. Immune-suppressors agents are associated with a higher risk of infections due to the inhibition of intracellular signals necessary to the host act against pathogens. On the other hand, drugs related to the suppression of the production of cytokines in IBD could bring benefits to reduce mucosal inflammation, and for preventing pneumonia. Moreover, coronaviruses can bind to the target cells through angiotensin-converting enzyme 2 (ACE-2) receptor that is expressed in epithelial cells of the lung and largely the colon and the terminal ileum suggesting that human intestinal tract could be an alternative route for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

CONCLUSIONS

Once the cytokine storm observed in influenza and COVID-19 is similar to the cytokine pattern observed in IBD patients during the disease flares, the advice is that avoiding the infections is still an optimal option for IBD subjects.

The Artificial-Liver Blood-Purification System Can Effectively Improve Hypercytokinemia for COVID-19

Since the December 2019 outbreak of coronavirus disease 2019 (COVID-19) in Wuhan, the infection has spread locally and globally resulting in a pandemic. As the numbers of confirmed diagnoses and deaths continue to rise, COVID-19 has become the focus of international public health. COVID-19 is highly contagious, and there is no effective treatment yet. New treatment strategies are urgently needed to improve the treatment success rate of severe and critically ill patients. Increasing evidence has shown that a cytokine storm plays an important role in the progression of COVID-19. The artificial-liver blood-purification system (ALS) is expected to improve the outcome of the cytokine storm. In the present study, the levels of cytokines were detected in 12 COVID-19 patients pre- and post-ALS with promising results. The present study shows promising evidence that ALS can block the cytokine storm, rapidly remove the inflammatory mediators, and hopefully, suppress the progression of the disease, thereby providing a new strategy for the clinical treatment of COVID-19.

EBV DNA increase in COVID-19 patients with impaired lymphocyte subpopulation count

Objectives

The immunologic profile and opportunistic viral DNA increase were monitored in Italian patients with COVID-19 in order to identify markers of disease severity.

Methods

A total of 104 patients infected with SARS-CoV-2 were evaluated in the study. Of them, 42/104 (40.4%) were hospitalized in an intensive care unit (ICU) and 62/104(59.6%) in a sub-intensive care unit (SICU). Human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV), Parvovirus B19 and Human Herpesvirus 6 virus reactivations were determined by real-time PCR, and lymphocyte subpopulation counts were determined by flow cytometry.

Results

Among opportunistic viruses, only EBV was consistently detected. EBV DNA was observed in 40/42 (95.2%) of the ICU patients and in 51/61 (83.6%) of the SICU patients. Comparing the two groups of patients, the EBV DNA median level among ICU patients was significantly higher than that observed in SICU patients. In parallel, a significant reduction of CD8 T cell and NK count in ICU patients as compared with SICU patients was observed (p < 0.05). In contrast, B cell count was significantly increased in ICU patients (p = 0.0172).

Conclusions

A correlation between reduced CD8⁺ T cells and NK counts, EBV DNA levels and COVID-19 severity was observed. Other opportunistic viral infections were not observed. The relationship between EBV load and COVID-19 severity should be further evaluated in longitudinal studies.