Brain MRI findings in neurologically asymptomatic patients with infective endocarditis.

BACKGROUND AND PURPOSE: Neurologic complications in infective endocarditis are frequent and affect patient prognosis negatively. Additionally, detection of asymptomatic lesions by MR imaging could help early management of this condition. The objective of our study was to describe MR imaging characteristics of cerebral lesions in a neurologically asymptomatic population with infective endocarditis. MATERIALS AND METHODS: One hundred nine patients at the acute phase of a definite or possible infective endocarditis according to the Duke modified criteria and without neurologic manifestations according to the NIHSS were prospectively included. Each patient underwent cerebral MR imaging and MRA within 7 days of admission. RESULTS: MR imaging showed abnormalities in 78 patients (71.5%). Acute ischemic lesions (40 patients, 37%) and cerebral microbleeds (62 patients, 57%) were the most frequent lesions. Eight patients had an acute SAH, 3 patients had brain microabscesses, 3 had a small cortical hemorrhage, and 3 had a mycotic aneurysm. Acute ischemic lesions mostly appeared as multiple small infarcts disseminated in watershed territories (25/40, 62.5%) and as lesions of different ages (21/40, 52.5%). Cerebral microbleeds were preferentially distributed in cortical areas (362/539 cerebral microbleeds, 67%). No significant correlation was found among lesions, in particular between acute ischemia and cerebral microbleeds. CONCLUSIONS: Occult cerebral lesions, in particular cerebral microbleeds and acute ischemic lesions, are frequent in infective endocarditis. The MR imaging pattern of acute small infarcts of different ages predominating in watershed territories and cortical cerebral microbleeds may represent a surrogate imaging marker of infective endocarditis.

Factors associated with clinical and virological response in patients treated with oseltamivir or zanamivir for influenza A during the 2008-2009 winter.

Oseltamivir or zanamivir are effective in outpatients with seasonal influenza; however, factors associated with response have been incompletely described. During the 2008/2009 epidemic, in a randomized trial for influenza A-infected outpatients, clinical (time to alleviation of flu-related symptoms) and virological (rate of patients with day 2 nasal viral load <200 cgeq/µL) responses to oseltamivir or zanamivir were assessed and associated factors were determined using multivariate analysis. For oseltamivir (141 patients) and zanamivir (149 patients) median times to alleviation of symptoms were 3 and 4 days, respectively; 59% and 34% had virological response. For oseltamivir, a lower clinical response was associated with female gender (HR, 0.53; 95% CI, 0.36-0.79), baseline symptoms score >14 (HR, 0.47; 0.32-0.70), viral load ≥5 log cgeq/µL (HR, 0.63; 0.43-0.93), and initiation of antibiotics (HR, 0.30; 0.12-0.76); a lower virological response was associated with female gender (OR, 0.45; 0.21-0.96), baseline viral load ≥5 log cgeq/µL (OR, 0.40; 0.20-0.84) and days 0-2 incomplete compliance (OR, 0.31; 0.10-0.98). For zanamivir, virological response was associated with age ≥50 years (OR, 0.29; 0.10-0.85) and initiation of antibiotics at baseline (OR, 4.24; 1.07-17.50). Factors associated with lower response to neuraminidase inhibitors in outpatients appeared to be easily identifiable during routine clinical examination and, when appropriate, by nasal sampling at baseline. The unknown association between gender and response to oseltamivir was not explained by compliance.

Bacteraemia caused by third-generation cephalosporin-resistant Escherichia coli in France: prevalence, molecular epidemiology and clinical features.

Escherichia coli is one of the major pathogens responsible for bactaeremia. Empirical antibiotherapy of these infections usually relies on third-generation cephalosporins (3GCs). Thus, the occurrence and epidemiology of 3GC-resistant strains have to be monitored. The French prospective multicentre study COLIBAFI collected 1081 strains of E. coli responsible for bacteraemia in 2005. In the present work, the prevalence of resistance to 3GCs was evaluated, and the implicated molecular mechanisms were characterized by specific PCR and sequencing. Phylogenetic grouping, O-typing, pulsed-field gel electrophoresis and virulence factor analysis were used to investigate the genetic background of the 3GC-resistant (3GC-R) strains. Clinical features of the patients with documented data (n = 1051) were analysed. Decreased susceptibility to 3GCs was observed in 41 strains (3.8%): 19, 18 and four had extended-spectrum ß-lactamase (ESBL), AmpC cephalosporinase and OXA-type penicillinase phenotypes, respectively. Pulsed-field gel electrophoresis revealed that the 3GC-R strains constitute a diverse population. All but one of the strains with an ESBL phenotype produced a CTX-M-type enzyme, and six of them belonged to the widespread intercontinental clone O25b:H4-ST131. AmpC phenotype strains harboured various chromosomal ampC promoter and coding region mutations and/or the bla(CMY-2) plasmidic gene. 3GC-R strains carried fewer virulence factors and were more co-resistant to other antibiotics than 3GC-susceptible (3GC-S) strains. Infections with 3GC-R strains were mostly community-acquired and, as compared with those caused by their 3GC-S counterparts, were more severe. Underlying chronic disease and prior use of antibiotics were independent risk factors for development of a 3GC-R strain bacteraemia. The fact that the molecular support of 3GC resistance is mainly plasmid-mediated represents a potentially epidemic threat.