Epidemiology and clinical outcome of virus-positive respiratory samples in ventilated patients: a prospective cohort study

INTRODUCTION: Respiratory viruses are a major cause of respiratory tract infections. The prevalence of a virus-positive respiratory sample and its significance in patients requiring mechanical ventilation remain unknown. METHODS: We conducted a cohort study in all consecutive adults ventilated for more than 48 hours admitted to a 22-bed medical intensive care unit during a 12-month period. Respiratory samples at the time of intubation were assessed by culture, by indirect immunofluorescence assay or by molecular methods in systematic tracheobronchial aspirates. Patients with a virus-negative respiratory sample at the time of intubation were considered unexposed and served as the control group. RESULTS: Forty-five viruses were isolated in 41/187 (22%) patients. Rhinovirus was the most commonly isolated virus (42%), followed byherpes simplex virus type 1 (22%) and virus influenza A (16%). In multivariate analysis controlling for the Acute Pathophysiology and Chronic Health Evaluation II score, patients with respiratory disorder at admission (adjusted odds ratio, 2.1; 95% confidence interval, 0.8–5.1; P = 0.12), with chronic obstructive pulmonary disease/asthma patients (adjusted odds ratio, 3.0; 95% confidence interval, 1.3–6.7; P = 0.01) and with admission between 21 November and 21 March (adjusted odds ratio, 2.8; 95% confidence interval, 1.3–5.9; P = 0.008) were independently associated with a virus-positive sample. Among the 122 patients admitted with respiratory disorder, a tracheobronchial aspirate positive for respiratory viruses at the time of intubation (adjusted hazard ratio, 0.273; 95% confidence interval, 0.096–0.777; P < 0.006) was independently associated with better survival, controlling for the Simplified Acute Physiology Score II and admission for cardiogenic shock or cardiac arrest. Among the remaining 65 patients, a virus-positive sample on intubation did not predict survival. CONCLUSION: We confirmed the pathogenic role of respiratory viruses in the intensive care unit, particularly rhinovirus. We suggest, however, that the prognostic value of virus-associated respiratory disorder is better than that of other causes of respiratory disorder

Global Genetic Diversity of Human Metapneumovirus Fusion Gene

We analyzed 64 human metapneumovirus strains from eight countries. Phylogenetic analysis identified two groups (A and B, amino acid identity 93%–96%) and four subgroups. Although group A strains predominated, accounting for 69% of all strains, as many B as A strains were found in persons >3 years of age

Procalcitonin levels in acute exacerbation of COPD admitted in ICU: a prospective cohort study

<p>Abstract</p> <p>Background</p> <p>Antibiotics are recommended for severe acute exacerbation of chronic obstructive pulmonary disease (AECOPD) admitted to intensive care units (ICU). Serum procalcitonin (PCT) could be a useful tool for selecting patients with a lower probability of developing bacterial infection, but its measurement has not been investigated in this population.</p> <p>Methods</p> <p>We conducted a single center prospective cohort study in consecutive COPD patients admitted to the ICU for AECOPD between September 2005 and September 2006. Sputum samples or tracheal aspirates were tested for the presence of bacteria and viruses. PCT levels were measured at the time of admittance, six hours, and 24 hours using a sensitive immunoassay.</p> <p>Results</p> <p>Thirty nine AECOPD patients were included, 31 of which (79%) required a ventilator support at admission. The median [25%–75% interquartile range] PCT level, assessed in 35/39 patients, was: 0.096 μg/L [IQR, 0.065 to 0.178] at the time of admission, 0.113 μg/L [IQR, 0.074 to 0.548] at six hours, and 0.137 μg/L [IQR, 0.088 to 0.252] at 24 hours. The highest PCT (PCTmax) levels were less than 0.1 μg/L in 14/35 (40%) patients and more than 0.25 μg/L in 10/35 (29%) patients, suggesting low and high probability of bacterial infection, respectively. Five species of bacteria and nine species of viruses were detected in 12/39 (31%) patients. Among the four patients positive for <it>Pseudomonas aeruginosa</it>, one had a PCTmax less than 0.25 μg/L and three had a PCTmax less than 0.1 μg/L. The one patient positive for <it>Haemophilus influenzae </it>had a PCTmax more than 0.25 μg/L. The presence or absence of viruses did not influence PCT at time of admission (0.068 vs 0.098 μg/L respectively, <it>P </it>= 0.80).</p> <p>Conclusion</p> <p>The likelihood of bacterial infection is low among COPD patients admitted to ICU for AECOPD (40% with PCT < 0.1 μg/L) suggesting a possible inappropriate use of antibiotics. Further studies are necessary to assess the impact of a procalcitonin-based therapeutic strategy in critically ill COPD patients.</p

Apports des outils de génétique moléculaire à la connaissance de deux infections virales du cheval (herpèsvirus équin 1 et artérite virale équine)

CAEN-BU Médecine pharmacie (141182102) / SudocSudocFranceF

L'infection à rotavirus du groupe C (mise au point d'une technique sérologique utilisant une protéine recombinante VP6)

CAEN-BU Médecine pharmacie (141182102) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Intérêt de l'étude moléculaire du gène de la protéine M pour la caractérisation du métapneumovirus humain et des virus influenza équins

Le métapneumovirus humain (hMPV) et les virus influenza de type A équins (EIV), sous-type H3N8, appartiennent respectivement à la famille des Paramyxoviridae et à celle des Orthomyxoviridae. Le travail présenté est une évaluation de l intérêt des gènes M et M1 codant les protéines de matrice des virions 1/ pour la détection des ARN viraux par les techniques de génétique moléculaire 2/ pour l analyse phylogénique des souches. Pour le hMPV, les outils de détection ont été mis au point dans le gène M suite à une étude décrivant pour la première fois le hMPV en France qui a été réalisée à l aide d un test RT-PCR développé dans le gène N. Ce premier test validé dans le gène N n ayant pas permis la mise en évidence de l ensemble des groupes de hMPV, une nouvelle RT-PCR suivie d une PCR nichée ont été développées dans le gène M et ont été utilisés pour les études phylogénétiques du hMPV en Normandie sur la période de 2002 à 2005. L ensemble des différents groupes et sous-groupes du hMPV (A1, A2, B1 et B2) ont pu être détectés. Par la suite, ces techniques ont été adaptées à un système réalisé en multiplex permettant une détection simultanée du hMPV, du virus respiratoire syncytial humain et des virus influenza A et B. Pour le virus influenza équin, une RT-PCR en temps réel a été développée dans le gène M1 et utilisée pour la recherche de l EIV circulant en France de 2005 à 2010. Une analyse phylogénétique a également été réalisée mais non ciblée sur le gène M1, ce dernier présentant un nombre trop faible de variations. Le gène H3, codant la principale protéine de surface de l EIV, a constitué la cible pour déterminer les différents variants. Cette étude a révélé, pour la première fois en France, la présence d EIV de lignage américain, cluster Florida. Les techniques de génétique moléculaires développées dans les gènes M et M1 ont donc permis la détection des deux virus étudiés, mais seul le gène M des Paramyxoviridae semble être adapté à une étude de la variabilité des virus. Pour l analyse des différentes souches d EIV, le gène H3 reste le plus approprié.The human metapneumovirus and equine influenza viruses, H3N8 subtypes, belong to the Paramyxoviridae and Orthomyxoviridae Family, respectively. The reported work evaluates the relevance of the M and M1 genes, coding for matrix protein, 1/ in detecting viral RNA by molecular genetic tools 2/ for phylogenetic purposes. For the hMPV, molecular genetic tools have been developed against the M gene because a study, the first detection of hMPV in France, was carried out using RT-PCR targeting the N gene. Since the tests being developed against the N gene did not allow the identification of all group of hMPV, a rRT-PCR following by a nested PCR were set up in the M gene and used to perform a phylogenetic characterization of hMPV strains circulating in Normandy between 2002 and 2005. All groups and subgroups of hMPV (A1, A2, B1 and B2) were detected. Subsequently, these methods were adapted to a multiplex detection tool, also including human respiratory syncytial virus and influenza virus A and B. Considering EIV, a real-time RT-PCR was developed in the M1 gene, which was used to detect EIV circulating in France between 2005 and 2010. Phylogenic analyses were also conducted even not in the M1 gene, which was insufficiently variable. H3 gene, encoding the major EIV surface protein, was used to determine the different variants. This study revealed for the first time in France the presence of an EIV American lineage, cluster Florida. Molecular genetic tools developed in M and M1 genes thus allowed the detection of both viruses. While Paramyxoviridae M gene only seems suitable for studying viral variability, H3 gene remains the most appropriate for EIV for this purpose.CAEN-BU Médecine pharmacie (141182102) / SudocSudocFranceF

Etude de la diversité génétique des VRS A et B

CAEN-BU Médecine pharmacie (141182102) / SudocSudocFranceF

Comparaison de trois techniques d'amplification génique par PCR aux méthodes traditionnelles de diagnostic pour la recherche des virus influenza A

CAEN-BU Médecine pharmacie (141182102) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Expression de l'interleukine 4 et de l'interféron gamma dans les sécrétions nasales d'enfants au cours d'une infection par le Virus Respiratoire Syncytial

CAEN-BU Médecine pharmacie (141182102) / SudocLYON1-BU Santé (693882101) / SudocSudocFranceF