Risk factors for nosocomial infection among hospitalised severe influenza A(H1N1)pdm09 patients.

BACKGROUND AND OBJECTIVE: Nosocomial infections following influenza are important causes of death, requiring early implementation of preventive measures, but predictors for nosocomial infection in the early stage remained undetermined. We aimed to determine risk factors that can help clinicians identify patients with high risk of nosocomial infection following influenza on admission. METHOD: Using a database prospectively collected through a Chinese national network for hospitalised severe influenza A(H1N1)pdm09 patients, we compared the characteristics on admission between patients with and without nosocomial infection. RESULT: A total of 2146 patients were enrolled in the final analysis with a median age of 36.0 years, male patients comprising 50.2% of the sample and 232 (10.8%) patients complicated with nosocomial infection. Acinetobacter baumannii, Pseudomonas aeruginosa, Stenotrophomonas maltophilia and Staphylococcus aureus were the leading pathogens, and invasive fungal infection was found in 30 cases (12.9%). The in-hospital mortality was much higher in patients with nosocomial infection than those without (45.7% vs 11.8%, P < 0.001). Need for mechanical ventilation (OR: 3.336; 95% CI 2.362-4.712), sepsis (OR: 2.125; 95% CI 1.236-3.651), ICU admission on first day (OR: 2.074; 95% CI 1.425-3.019), lymphocytopenia (OR: 1.906; 95% CI 1.361-2.671), age > 65 years (OR: 1.83; 95% CI 1.04-3.21) and anaemia (OR: 1.39; 95% CI 1.39-2.79) were independently associated with nosocomial infection. CONCLUSION: Need for mechanical ventilation, sepsis, ICU admission on first day, lymphocytopenia, older age and anaemia were independent risk factors that can help clinicians identify severe influenza A(H1N1)pdm09 patients at high risk of nosocomial infection.

Differences in inflammatory marker patterns for adult community-acquired pneumonia patients induced by different pathogens.

INTRODUCTION: The inflammatory marker patterns of community-acquired Pneumonia (CAP) induced by different microorganisms in adult patients remained unclear. OBJECTIVES: We aim to explore the inflammatory marker patterns of adult CAP patients induced by different pathogens. METHODS: Adult CAP patients with definite etiologies were enrolled from September 2010 to June 2012. They were divided into three groups according to the causative pathogens: typical bacteria, Mycoplasma pneumoniae (MP), and viruses. Twenty-seven cytokines and bactericidal/permeability-increasing protein (BPI) levels of serum collected within 7 days onset in these groups were compared. RESULTS: One hundred twenty-four cases were enrolled for serum detection and analysis, including 10 typical bacterial pneumonia patients, 56 cases with MP pneumonia and 58 with viral pneumonia. Three kinds (PDGF-BB, IP-10, RANTES) of 27 cytokines and BPI levels were significantly elevated in patients with acute pneumonia than healthy controls. Distinct inflammatory marker patterns were released by different pathogens: typical bacterial pneumonia patients had highest levels of BPI, IL-6, IL-8, IL-1rα; while patients caused by MP presented higher levels of PDGF-BB, IL-17A, G-CSF than those caused by viruses. Rhinovirus owned a higher inflammatory response level than the other viruses. The area under the curve (AUC) of PDGF-BB to differentiate MP and virus infection was biggest, which was 0.708. CONCLUSION: Distinct inflammatory marker patterns were released by different pathogens during acute pneumonia. Significantly increased level of PDGF-BB was observed in acute pneumonia for the first time. It showed a better ability to differentiate MP and virus infection.

Effect of low-to-moderate-dose corticosteroids on mortality of hospitalized adolescents and adults with influenza A(H1N1)pdm09 viral pneumonia.

BACKGROUND: The effect of corticosteroids on influenza A(H1N1)pdm09 viral pneumonia patients remains controversial, and the impact of dosage has never been studied. METHODS: Using data of hospitalized adolescent and adult patients with influenza A(H1N1)pdm09 viral pneumonia, prospectively collected from 407 hospitals in mainland China, the effects of low-to-moderate-dose (25-150 mg d-1 ) and high-dose (>150 mg d-1 ) corticosteroids on 30-day mortality, 60-day mortality, and nosocomial infection were assessed with multivariate Cox regression and propensity score-matched case-control analysis. RESULTS: In total, 2141 patients (median age: 34 years; morality rate: 15.9%) were included. Among them, 1160 (54.2%) had PaO2 /FiO2 <300 mm Hg on admission, and 1055 (49.3%) received corticosteroids therapy. Corticosteroids, without consideration of dose, did not influence either 30-day or 60-day mortality. Further analysis revealed that, as compared with the no-corticosteroid group, low-to-moderate-dose corticosteroids were related to reduced 30-day mortality (adjusted hazard ratio [aHR] 0.64 [95% CI 0.43-0.96, P=.033]). In the subgroup analysis among patients with PaO2 /FiO2 <300 mm Hg, low-to-moderate-dose corticosteroid treatment significantly reduced both 30-day mortality (aHR 0.49 [95% CI 0.32-0.77]) and 60-day mortality (aHR 0.51 [95% CI 0.33-0.78]), while high-dose corticosteroid therapy yielded no difference. For patients with PaO2 /FiO2 ≥300 mm Hg, corticosteroids (irrespective of dose) showed no benefit and even increased 60-day mortality (aHR 3.02 [95% CI 1.06-8.58]). Results were similar in the propensity model analysis. CONCLUSIONS: Low-to-moderate-dose corticosteroids might reduce mortality of influenza A(H1N1)pdm09 viral pneumonia patients with PaO2 /FiO2 <300 mm Hg. Mild patients with PaO2 /FiO2 ≥300 mm Hg could not benefit from corticosteroid therapy.