Intubated patients developing tracheobronchitis or pneumonia have distinctive complement system gene expression signatures in the pre-infection period: a pilot study.

INTRODUCTION: It remains unknown why some intubated patients remain infection-free while others develop tracheobronchitis (VAT) or pneumonia (VAP). OBJECTIVE: To identify and compare VAP/VAT gene expression "signatures" using genome-wide oligonucleotide microarrays. MATERIAL AND METHODS: A prospective translational study of gene expression profiles of VAP and VAT groups was carried out, establishing comparisons in both pre-infection and infection phases. Pathway and functional analyses were performed with Ingenuity Pathway Analysis (IPA). Data analysis and hierarchical clustering of the genes involved in the signalling pathways expressed differentially in the two groups were performed with GeneSpring GX 11.0. RESULTS: Eight patients developing respiratory infections (3 VAP and 5 VAT) after 4 days of mechanical ventilation were assessed. Comparison of gene expression profiles in the pre-infection period revealed 5595 genes expressed differentially between VAP and VAT (p<0.01, fold change >2). Comparative IPA analysis identified a significant depression of the complement system signalling pathway in the VAP group, affecting the classical pathway along with the final common pathway (p<0.05). In addition, the cAMP and calcium signalling pathways were also significantly depressed in the VAP group during the pre-infection phase also. CONCLUSION: Intubated patients complicated with pneumonia developed immune impairment in the pre-infection period, manifesting as a relatively lower expression of genes involved in the complement system that differed from patients developing tracheobronchitis. These findings suggest that a significant proportion of VAP episodes cannot be prevented, but might be treatable through pre-emptive therapy.

Prior influenza vaccine is not a risk factor for bacterial coinfection in patients admitted to the ICU due to severe influenza.

OBJECTIVE: To determine whether the prior usage of the flu vaccine is a risk factor for bacterial co-infection in patients with severe influenza. DESIGN: This was a retrospective observational cohort study of subjects admitted to the ICU. A propensity score matching, and logistic regression adjusted for potential confounders were carried out to evaluate the association between prior influenza vaccination and bacterial co-infection. SETTINGS: 184 ICUs in Spain due to severe influenza. PATIENTS: Patients included in the Spanish prospective flu registry. INTERVENTIONS: Flu vaccine prior to the hospital admission. RESULTS: A total of 4175 subjects were included in the study. 489 (11.7%) received the flu vaccine prior to develop influenza infection. Prior vaccinated patients were older 71 [61-78], and predominantly male 65.4%, with at least one comorbid condition 88.5%. Prior vaccination was not associated with bacterial co-infection in the logistic regression model (OR: 1.017; 95%CI 0.803-1.288; p=0.885). After matching, the average treatment effect of prior influenza vaccine on bacterial co-infection was not statistically significant when assessed by propensity score matching (p=0.87), nearest neighbor matching (p=0.59) and inverse probability weighting (p=0.99). CONCLUSIONS: No association was identified between prior influenza vaccine and bacterial coinfection in patients admitted to the ICU due to severe influenza. Post influenza vaccination studies are necessary to continue evaluating the possible benefits.

Impact of Aspergillus spp. isolation in the first 24 hours of admission in critically ill patients with severe influenza virus pneumonia.

OBJECTIVE: To determine the incidence and impact of Aspergillus spp. isolation (AI) on ICU mortality in critically ill patients with severe influenza pneumonia during the first 24h of admission. DESIGN: Secondary analysis of an observational and prospective cohort study. SETTING: ICUs voluntary participating in the Spanish severe Influenza pneumonia registry, between June 2009 and June 2019. PATIENTS: Consecutive patients admitted to the ICU with diagnosis of severe influenza pneumonia, confirmed by real-time polymerase chain reaction. INTERVENTIONS: None. MAIN VARIABLES OF INTEREST: Incidence of AI in respiratory samples. Demographic variables, comorbidities, need for mechanical ventilation and the presence of shock according at admission. Acute Physiology and Chronic Health Evaluation II (APACHE II) scale calculated on ICU admission. RESULTS: 3702 patients were analyzed in this study. AI incidence was 1.13% (n=42). Hematological malignancies (OR 4.39, 95% CI 1.92-10.04); HIV (OR 3.83, 95% CI 1.08-13.63), and other immunosuppression situations (OR 4.87, 95% CI 1.99-11.87) were factors independently associated with the presence of Aspergillus spp. The automatic CHAID decision tree showed that hematologic disease with an incidence of 3.3% was the most closely AI related variable. Hematological disease (OR 2.62 95% CI 1.95-3.51), immunosuppression (OR 2.05 95% CI 1.46-2.88) and AI (OR 3.24, 95% CI 1.60-6.53) were variables independently associated with ICU mortality. CONCLUSIONS: Empirical antifungal treatment in our population may only be justified in immunocompromised patients. In moderate-high risk cases, active search for Aspergillus spp. should be implemented.

Prior influenza vaccine is not a risk factor for bacterial coinfection in patients admitted to the ICU due to severe influenza.

OBJECTIVE: To determine whether the prior usage of the flu vaccine is a risk factor for bacterial co-infection in patients with severe influenza. DESIGN: This was a retrospective observational cohort study of subjects admitted to the ICU. A propensity score matching, and logistic regression adjusted for potential confounders were carried out to evaluate the association between prior influenza vaccination and bacterial co-infection. SETTINGS: 184 ICUs in Spain due to severe influenza. PATIENTS: Patients included in the Spanish prospective flu registry. INTERVENTIONS: Flu vaccine prior to the hospital admission. RESULTS: A total of 4175 subjects were included in the study. 489 (11.7%) received the flu vaccine prior to develop influenza infection. Prior vaccinated patients were older 71 [61-78], and predominantly male 65.4%, with at least one comorbid condition 88.5%. Prior vaccination was not associated with bacterial co-infection in the logistic regression model (OR: 1.017; 95%CI 0.803-1.288; p=0.885). After matching, the average treatment effect of prior influenza vaccine on bacterial co-infection was not statistically significant when assessed by propensity score matching (p=0.87), nearest neighbor matching (p=0.59) and inverse probability weighting (p=0.99). CONCLUSIONS: No association was identified between prior influenza vaccine and bacterial coinfection in patients admitted to the ICU due to severe influenza. Post influenza vaccination studies are necessary to continue evaluating the possible benefits.

Intubated patients developing tracheobronchitis or pneumonia have distinctive complement system gene expression signatures in the pre-infection period: A pilot study

Introduction: It remains unknown why some intubated patients remain infection-free while others develop tracheobronchitis (VAT) or pneumonia (VAP). Objective: To identify and compare VAP/VAT gene expression "signatures" using genome-wide oligonucleotide microarrays. Material and methods: A prospective translational study of gene expression profiles of VAP and VAT groups was carried out, establishing comparisons in both pre-infection and infection phases. Pathway and functional analyses were performed with Ingenuity Pathway Analysis (IPA). Data analysis and hierarchical clustering of the genes involved in the signalling pathways expressed differentially in the two groups were performed with GeneSpring GX 11.0. Results: Eight patients developing respiratory infections (3 VAP and 5 VAT) after 4 days of mechanical ventilation were assessed. Comparison of gene expression profiles in the pre-infection period revealed 5595 genes expressed differentially between VAP and VAT (p<0.01, fold change >2). Comparative IPA analysis identified a significant depression of the complement system signalling pathway in the VAP group, affecting the classical pathway along with the final common pathway (p<0.05). In addition, the cAMP and calcium signalling pathways were also significantly depressed in the VAP group during the pre-infection phase also. Conclusion: Intubated patients complicated with pneumonia developed immune impairment in the pre-infection period, manifesting as a relatively lower expression of genes involved in the complement system that differed from patients developing tracheobronchitis. These findings suggest that a significant proportion of VAP episodes cannot be prevented, but might be treatable through pre-emptive therapy (AU)

Introducción: Seguimos sin saber por qué algunos pacientes intubados no sufren infecciones mientras que otros presentan traqueobronquitis (TAV) o neumonía (NAV). Objetivo: Identificar y comparar los patrones de la expresión genética de la NAV/TAV usando micromatrices multigénicas oligonucleotídicas. Material y métodos: Se realizó un estudio aplicado prospectivo de los patrones de la expresión genética de los grupos con NAV y TAV, estableciendo comparaciones tanto en la fase previa a la infección como en la fase infecciosa. Se realizaron análisis de vías y funcionales con Ingenuity Pathway (IPA). Los análisis de datos y el agrupamiento jerárquico de los genes implicados en las vías de señalización expresados de forma diferenciada en ambos grupos se realizaron con GeneSpring GX 11.0. Resultados: Se evaluaron ocho pacientes que presentaron infecciones respiratorias (3 NAV y 5 TAV) después de 4 días con la ventilación mecánica. La comparación de los perfiles de la expresión genética durante el período previo a la infección reveló 5.595 genes expresados de forma diferenciada entre la NAV y la TAV (p<0,01, cambio múltiplo>2). Los análisis comparativos de los IPA identificaron una depresión importante de la vía de señalización del sistema del complemento en el grupo con NAV, que afectó a la vía clásica además de a la vía común final (p<0,05). Por otra parte, el monofosfato cíclico de adenosina y las vías de señalización del calcio también se vieron muy deprimidos en el grupo (..)(AU)