Clinical aspects and cytokine response in severe H1N1 influenza A virus infection.

INTRODUCTION: The immune responses in patients with novel A(H1N1) virus infection (nvA(H1N1)) are incompletely characterized. We investigated the profile of Th1 and Th17 mediators and interferon-inducible protein-10 (IP-10) in groups with severe and mild nvA(H1N1) disease and correlated them with clinical aspects. METHODS: Thirty-two patients hospitalized with confirmed nvA(H1N1) infection were enrolled in the study: 21 patients with nvA(H1N1)-acute respiratory distress syndrome (ARDS) and 11 patients with mild disease. One group of 20 patients with bacterial sepsis-ARDS and another group of 15 healthy volunteers were added to compare their cytokine levels with pandemic influenza groups. In the nvA(H1N1)-ARDS group, the serum cytokine samples were obtained on admission and 3 days later. The clinical aspects were recorded prospectively. RESULTS: In the nvA(H1N1)-ARDS group, obesity and lymphocytopenia were more common and IP-10, interleukin (IL)-12, IL-15, tumor necrosis factor (TNF)α, IL-6, IL-8 and IL-9 were significantly increased versus control. When comparing mild with severe nvA(H1N1) groups, IL-6, IL-8, IL-15 and TNFα were significantly higher in the severe group. In nonsurvivors versus survivors, IL-6 and IL-15 were increased on admission and remained higher 3 days later. A positive correlation of IL-6, IL-8 and IL-15 levels with C-reactive protein and with > 5-day interval between symptom onset and admission, and a negative correlation with the PaO(2):FiO(2) ratio, were found in nvA(H1N1) groups. In obese patients with influenza disease, a significant increased level of IL-8 was found. When comparing viral ARDS with bacterial ARDS, the level of IL-8, IL-17 and TNFα was significantly higher in bacterial ARDS and IL-12 was increased only in viral ARDS. CONCLUSIONS: In our critically ill patients with novel influenza A(H1N1) virus infection, the hallmarks of the severity of disease were IL-6, IL-15, IL-8 and TNFα. These cytokines, except TNFα, had a positive correlation with the admission delay and C-reactive protein, and a negative correlation with the PaO(2):FiO(2) ratio. Obese patients with nvA(H1N1) disease have a significant level of IL-8. There are significant differences in the level of cytokines when comparing viral ARDS with bacterial ARDS.

Central venous catheter colonization and catheter-related bloodstream infections in critically ill patients: a comparison between standard and silver-integrated catheters.

BACKGROUND AND OBJECTIVE: Catheter-related bloodstream infections are one of the main complications affecting patients in intensive care units. This prospective, randomized, unblinded, controlled study investigated colonization and infection rates of standard central venous catheters in comparison with the rates for silver-integrated catheters in the intensive care unit. METHODS: Complete data were evaluated for 272 catheters inserted into 230 patients (141 standard and 131 silver-integrated central venous catheters). Patient and catheter characteristics were documented for all patients. Positive catheters were detected by semi-quantitative and quantitative microbiologic techniques. Peripheral blood cultures were obtained at the time of catheter removal. RESULTS: There was no significant difference in the colonization rates and the colonization per 1000 catheter days between the standard and silver-integrated catheters. Using the Kaplan-Meier curves (long-rank test), there was a significant difference in the incidence of colonization and infections over time between standard and silver-integrated catheters (P<0.01 and P<0.05, respectively). Whereas standard catheters were first colonized 3 days after the insertion, silver-integrated catheters were first colonized 5 days after insertion. CONCLUSION: Silver-integrated central venous catheters did not prevent catheter colonization and infections in critically ill patients, but there might be a significant difference in the incidence of colonization and infections over time between standard polyurethane and silver-integrated catheters.