Monica Gordon

Th1 and Th17 hypercytokinemia as early host response signature in severe pandemic influenza.

IntroductionHuman host immune response following infection with the new variant of A/H1N1 pandemic influenza virus (nvH1N1) is poorly understood. We utilize here systemic cytokine and antibody levels in evaluating differences in early immune response in both mild and severe patients infected with nvH1N1.MethodsWe profiled 29 cytokines and chemokines and evaluated the haemagglutination inhibition activity as quantitative and qualitative measurements of host immune responses in serum obtained during the first five days after symptoms onset, in two cohorts of nvH1N1 infected patients. Severe patients required hospitalization (n = 20), due to respiratory insufficiency (10 of them were admitted to the intensive care unit), while mild patients had exclusively flu-like symptoms (n = 15). A group of healthy donors was included as control (n = 15). Differences in levels of mediators between groups were assessed by using the non parametric U-Mann Whitney test. Association between variables was determined by calculating the Spearman correlation coefficient. Viral load was performed in serum by using real-time PCR targeting the neuraminidase gene.ResultsIncreased levels of innate-immunity mediators (IP-10, MCP-1, MIP-1β), and the absence of anti-nvH1N1 antibodies, characterized the early response to nvH1N1 infection in both hospitalized and mild patients. High systemic levels of type-II interferon (IFN-γ) and also of a group of mediators involved in the development of T-helper 17 (IL-8, IL-9, IL-17, IL-6) and T-helper 1 (TNF-α, IL-15, IL-12p70) responses were exclusively found in hospitalized patients. IL-15, IL-12p70, IL-6 constituted a hallmark of critical illness in our study. A significant inverse association was found between IL-6, IL-8 and PaO2 in critical patients.ConclusionsWhile infection with the nvH1N1 induces a typical innate response in both mild and severe patients, severe disease with respiratory involvement is characterized by early secretion of Th17 and Th1 cytokines usually associated with cell mediated immunity but also commonly linked to the pathogenesis of autoimmune/inflammatory diseases. The exact role of Th1 and Th17 mediators in the evolution of nvH1N1 mild and severe disease merits further investigation as to the detrimental or beneficial role these cytokines play in severe illness.

Host adaptive immunity deficiency in severe pandemic influenza

IntroductionPandemic A/H1N1/2009 influenza causes severe lower respiratory complications in rare cases. The association between host immune responses and clinical outcome in severe cases is unknown.MethodsWe utilized gene expression, cytokine profiles and generation of antibody responses following hospitalization in 19 critically ill patients with primary pandemic A/H1N1/2009 influenza pneumonia for identifying host immune responses associated with clinical outcome. Ingenuity pathway analysis 8.5 (IPA) (Ingenuity Systems, Redwood City, CA) was used to select, annotate and visualize genes by function and pathway (gene ontology). IPA analysis identified those canonical pathways differentially expressed (P < 0.05) between comparison groups. Hierarchical clustering of those genes differentially expressed between groups by IPA analysis was performed using BRB-Array Tools v.3.8.1.ResultsThe majority of patients were characterized by the presence of comorbidities and the absence of immunosuppressive conditions. pH1N1 specific antibody production was observed around day 9 from disease onset and defined an early period of innate immune response and a late period of adaptive immune response to the virus. The most severe patients (n = 12) showed persistence of viral secretion. Seven of the most severe patients died. During the late phase, the most severe patient group had impaired expression of a number of genes participating in adaptive immune responses when compared to less severe patients. These genes were involved in antigen presentation, B-cell development, T-helper cell differentiation, CD28, granzyme B signaling, apoptosis and protein ubiquitination. Patients with the poorest outcomes were characterized by proinflammatory hypercytokinemia, along with elevated levels of immunosuppressory cytokines (interleukin (IL)-10 and IL-1ra) in serum.ConclusionsOur findings suggest an impaired development of adaptive immunity in the most severe cases of pandemic influenza, leading to an unremitting cycle of viral replication and innate cytokine-chemokine release. Interruption of this deleterious cycle may improve disease outcome.

Direct association between pharyngeal viral secretion and host cytokine response in severe pandemic influenza

BackgroundSevere disease caused by 2009 pandemic influenza A/H1N1virus is characterized by the presence of hypercytokinemia. The origin of the exacerbated cytokine response is unclear. As observed previously, uncontrolled influenza virus replication could strongly influence cytokine production. The objective of the present study was to evaluate the relationship between host cytokine responses and viral levels in pandemic influenza critically ill patients.MethodsTwenty three patients admitted to the ICU with primary viral pneumonia were included in this study. A quantitative PCR based method targeting the M1 influenza gene was developed to quantify pharyngeal viral load. In addition, by using a multiplex based assay, we systematically evaluated host cytokine responses to the viral infection at admission to the ICU. Correlation studies between cytokine levels and viral load were done by calculating the Spearman correlation coefficient.ResultsFifteen patients needed of intubation and ventilation, while eight did not need of mechanical ventilation during ICU hospitalization. Viral load in pharyngeal swabs was 300 fold higher in the group of patients with the worst respiratory condition at admission to the ICU. Pharyngeal viral load directly correlated with plasma levels of the pro-inflammatory cytokines IL-6, IL-12p70, IFN-γ, the chemotactic factors MIP-1β, GM-CSF, the angiogenic mediator VEGF and also of the immuno-modulatory cytokine IL-1ra (p < 0.05). Correlation studies demonstrated also the existence of a significant positive association between the levels of these mediators, evidencing that they are simultaneously regulated in response to the virus.ConclusionsSevere respiratory disease caused by the 2009 pandemic influenza virus is characterized by the existence of a direct association between viral replication and host cytokine response, revealing a potential pathogenic link with the severe disease caused by other influenza subtypes such as H5N1.

IgM levels in plasma predict outcome in severe pandemic influenza

BACKGROUND Little is known on the participation of immunoglobulin isotypes and subclasses in the pathogenesis of the severe disease caused by the pandemic influenza virus (influenza A(H1N1)pdm09). OBJECTIVES (1) To evaluate the association between plasma levels of IgG1, IgG2, IgG3, IgG4, IgA, IgM, IgE and outcome in patients with severe pandemic influenza. (2) To evaluate the association between immunoglobulin and cytokine levels in these patients. STUDY DESIGN 40 critically ill patients with community acquired pneumonia and influenza A(H1N1)pdm09 infection were recruited from November 2010 to February 2011. Plasma samples were collected during the first 24h following admission to the ICU. Immunoglobulins and 17 major cytokines were profiled in plasma. RESULTS 15 patients died (37.5%). When the association between clinical variables and prognosis was assessed, prior immunosuppression, APACHE II score, levels of IgG2 and levels of IgM were associated with outcome in a univariate Cox regression analysis. Kaplan Meier analysis showed that patients with levels of IgG2 and IgM < 59 and<58 mg/dl respectively died earlier. Multivariate Cox regression analysis showed that APACHE II score and levels of IgM were the best predictors of outcome, being levels of IgM a protective factor against mortality. IgM was the immunoglobulin showing the largest number of negative correlations with cytokine levels. CONCLUSIONS Our results support a central role of IgM in preventing uncontrolled inflammatory response and mortality in severe pandemic influenza. Early assessment of IgM could contribute to guide clinical decisions in these patients.

Blood culture contamination rate in an intensive care setting: Effectiveness of an education-based intervention

BACKGROUND Blood culture (BC) contamination rate is an indicator of quality of care scarcely explored in intensive care units (ICUs). We analyzed the BC contamination rate in our ICU to assess the effectiveness of an education-based intervention. METHODS We conducted an interventional study with concurrent controls. Consecutive BCs drawn during a 6-month period were included. An education-based intervention was presented to case nurses (optimal technique). The remaining nurses comprised the control group (standard technique). Two independent observers assessed clinical significance of saprophytic skin bacteria isolated in BCs. RESULTS Six hundred fifty-six BCs were obtained: 308 (47%) via optimal technique and 348 (53%) via standard technique (47%). One hundred eighty-seven BCs were positive for saprophytic microorganisms; 127 (89%) were considered unrelated to infection. Coagulase-negative staphylococci isolation was lower in the optimal technique group (14% vs 26%; P < .001), as well as contamination due to coagulase-negative staphylococci (12% vs 21%; P = .002) or Acinetobacter baumannii (0.3% vs 2%; P = .013). BC contamination rate was 13% in the optimal technique group versus 23% in the standard group (P < .005). In the optimal technique group, BC contamination rate was higher in BCs drawn through the catheter (17% vs 7%; P = .028). CONCLUSIONS An education-based intervention significantly reduced the BC contamination rate in our ICU. It seems necessary to design a tool to extract BCs through the catheter to minimize the risk of contamination.

Utilidad de la procalcitonina para el diagnóstico de infección en el paciente crítico con cirrosis hepática

OBJECTIVE To evaluate the usefulness of procalcitonin (PCT) for diagnosing infection in patients with liver cirrhosis admitted to an Intensive Care Unit. DESIGN A retrospective study was carried out. SCOPE Intensive Care Unit. Versatile, twenty-four beds. Participants Patients with liver cirrhosis admitted to our Intensive Care Unit in the last four years with suspected infection and measurement of PCT. RESULTS Among the 255 patients with cirrhosis admitted to our unit, PCT was determined for the differential diagnosis of infection in 69 cases (27%). Three patients were excluded from analysis due to a lack of clinical data. The average stay was 10.6 ± 9.2 days, with a mortality rate of 65%. The origin of cirrhosis was mainly viral (57%) or alcoholic (37%). The Child-Pugh and MELD scores were 9.5 ± 2 and 23 ± 8, respectively. Infection was diagnosed in 54 patients (82%). The most common infection was pneumonia (72%), followed by intraabdominal infections (18%) and bacteremia (5%). In patients without infection, the median PCT concentration was 0.57 ng/ml (range 0.28 to 1.14) versus 2.99 (1.31 to 9.4) in those with infection (p<.001). Diagnostic capacity was maintained in patients with intraabdominal infections. The diagnostic cutoff point was set at 0.8 ng/ml (sensitivity 83%, specificity 75%, AUC 0.82 [0.702-0.93]). CONCLUSIONS In patients with liver cirrhosis, PCT is useful for identifying bacterial infections, including intraabdominal processes.

Diagnosing external ventricular drain-related ventriculitis by means of local inflammatory response: soluble triggering receptor expressed on myeloid cells-1

IntroductionExternal ventricular drainage (EVD)-related ventriculitis is one of the most severe complications associated with the use of EVDs. Establishing an early and certain diagnosis can be difficult in critically ill patients. We performed this prospective study to evaluate the usefulness of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) determination in cerebrospinal fluid (CSF) in the diagnosis of ventriculitis.MethodsA prospective observational study was conducted of 73 consecutive patients with EVD. Samples of CSF for culture, cytobiochemical analysis and sTREM-1 determination were extracted three times a week. Ventriculitis diagnosis required a combination of microbiological, cytobiochemical and clinical criteria.ResultsSeventy-three consecutive patients were included. EVD-related ventriculitis was diagnosed in six patients and EVD-colonization in ten patients. Patients without clinical or microbiological findings were considered controls. The median CSF sTREM-1 was 4,320 pg/ml (interquartile range (IQR): 2,987 to 4,886) versus 266 pg/ml (118 to 689); P <0.001. There were no differences when comparing colonized-patients and controls. The best cut-off sTREM-1 value for the diagnosis of ventriculitis was 2,388.79 pg/ml (sensitivity 100%, specificity 98.5%, positive predictive value 85.71%, negative predictive value 100%). CSF proteins, glucose and the ratio CSF/serum glucose were also significantly different (P = 0.001). Serum biomarkers were not useful to diagnose EVD-related infection. These results were confirmed by a case°Control study with ventriculitis patients (cases) and non-ventriculitis (control subjects) matched by age, comorbidities, severity scales and EVD duration (P = 0.004).ConclusionsCSF sTREM-1 was useful in the diagnosis of ventriculitis, in a similar measure to classical CSF parameters. Furthermore, CSF sTREM-1 could prove the diagnosis in uncertain cases and discriminate between EVD-colonization and infection.

Determination of meropenem in endotracheal tubes by in-tube solid phase microextraction coupled to capillary liquid chromatography with diode array detection

Graphical abstract Figure. No caption available. HighlightsIn‐tube SPME‐CapLC‐DAD has been evaluated to determine meropenem in ETTs.The analytical performance has been successfully demonstrated.Meropenem was found at concentrations of ng/mL.The proposed procedure is a sustainable and operational efficient methodology. ABSTRACT Meropenem is a widely used antimicrobial for the treatment of infections associated with the use of invasive medical devices in intensive care unit patients. These treatments are not always effective, in fact, in‐vitro studies have demonstrated the difficulty of antimicrobials to penetrate into the biofilm, however in‐vivo studies of the effect of these compounds is a trend, mostly because of the complexity of pulmonary samples extracted from ETTs. Therefore, the objective of this study was to evaluate in‐tube solid phase microextraction (in‐tube SPME) coupled to capillary liquid chromatography (CapLC) with DAD to determine meropenem in ETTs in order to estimate the penetration capability into the biofilm. Firstly, different parameter affecting in‐tube SPME, such as processed sample volume, capillary length, flow and capillary coating were studied. The best analytical response was achieved by processing 500 &mgr;L of standards/samples at 9 &mgr;L/seg with a 60‐cm capillary column coated with 35%‐diphenyl 65%‐polydimethylsiloxane. Under these conditions, the analytical performance of in‐tube SPME‐CapLC‐DAD, using acetonitrile‐water in gradient mode as mobile phase, showed satisfactory results for estimation of meropenem in terms of sensitivity (LOD = 3 &mgr;g/L) and precision (RSD < 10%). Once the experimental conditions were stablished for in‐tube SPME, the extraction of meropenem from the ETTs was studied. Liquid extraction, vortex‐assisted liquid extraction (VALE) and ultrasound‐extraction (UAE) extraction were tested. The results indicated that meropenem could be quantitatively extracted (91 ± 6%) from ETTs, for its subsequent determination by in‐tube SPME‐CapLC‐DAD using water as extraction solvent and 1 min as extraction time. Finally, samples from ETTs used for critically ill patients with different antimicrobial treatments were analysed with successful results.

Utilización del oxigenador de membrana extracorpórea en la miocarditis con shock cardiogénico refractario: resultados iniciales de una experiencia pionera en España

Un pequeño porcentaje de pacientes diagnosticados de miocarditis cursan con disfunción ventricular grave y shock cardiogénico, en ocasiones refractario al tratamiento con fármacos vasoactivos. En estos pacientes se ha planteado el uso de dispositivos de asistencia circulatoria mecánica como puente a la recuperación o al trasplante cardı́aco (TC). Estudios recientes propugnan la elección del extracorporeal membrane oxygenation (ECMO, «oxigenador de membrana extracorpórea»), y aunque la

Initial experience of use of tolvaptan in critically ill patients with fluid overload

Positive volume balance is related with high mortality in critically ill patients. We describe our experience in the use of tolvaptan in patients with fluid overload.