Typing of vancomycin-resistant enterococci with MALDI-TOF mass spectrometry in a nosocomial outbreak setting.

OBJECTIVES: To investigate the usefulness of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) typing as a first-line epidemiological tool in a nosocomial outbreak of vancomycin-resistant Enterococcus faecium (VREfm). METHODS: Fifty-five VREfm isolates, previously characterized by whole-genome sequencing (WGS), were included and analysed by MALDI-TOF MS. To take peak reproducibility into account, ethanol/formic acid extraction and other steps of the protocol were conducted in triplicate. Twenty-seven spectra were generated per isolate, and spectra were visually inspected to determine discriminatory peaks. The presence or absence of these was recorded in a peak scheme. RESULTS: Nine discriminatory peaks were identified. A characteristic pattern of these could distinguish between the three major WGS groups: WGS I, WGS II and WGS III. Only one of 38 isolates belonging to WGS I, WGS II or WGS III was misclassified. However, ten of the 17 isolates not belonging to WGS I, II or III displayed peak patterns indistinguishable from those of the outbreak strain. CONCLUSIONS: Using visual inspection of spectra, MALDI-TOF MS typing proved to be useful in differentiating three VREfm outbreak clones from each other. However, as non-outbreak isolates could not be reliably differentiated from outbreak clones, the practical value of this typing method for VREfm outbreak management was limited in our setting.

Incidence, clinical characteristics and 30-day mortality of enterococcal bacteraemia in Denmark 2006-2009: a population-based cohort study.

Enterococci currently account for approximately 10% of all bacteraemias, reflecting remarkable changes in their epidemiology. However, population-based data of enterococcal bacteraemia are scarce. A population-based cohort study comprised all patients with a first episode of Enterococcus faecalis or Enterococcus faecium bacteraemia in two Danish regions during 2006-2009. We used data collected prospectively during clinical microbiological counselling and hospital registry data. We determined the incidence of mono- and polymicrobial bacteraemia and assessed clinical and microbiological characteristics as predictors of 30-day mortality in monomicrobial bacteraemia by logistic regression analysis. We identified 1145 bacteraemic patients, 700 (61%) of whom had monomicrobial bacteraemia. The incidence was 19.6/100 000 person-years (13.0/100 000 person-years for E. faecalis and 6.6/100 000 person-years for E. faecium). The majority of bacteraemias were hospital-acquired (E. faecalis, 45.7%; E. faecium, 85.2%). Urinary tract and intra-abdominal infections were the predominant foci for the two species, respectively. Infective endocarditis (IE) accounted for 25% of patients with community-acquired E. faecalis bacteraemia. Thirty-day mortality was 21.4% in patients with E. faecalis and 34.6% in patients with E. faecium. Predictors of 30-day mortality included age, co-morbidity and hospital-acquired bacteraemia. In addition, intra-abdominal infection, unknown focus and high-level gentamicin resistance were predictors of mortality in E. faecalis patients. E. faecium was associated with increased risk of mortality compared with E. faecalis. The study emphasizes the importance of enterococci both in terms of incidence and prognosis. The frequency of IE in patients with E. faecalis bacteraemia emphasizes the importance of echocardiography, especially in community-acquired cases.

The association between apolipoprotein E and multiple sclerosis.

The article is a complete literature study that investigates the association between apolipoprotein E (Apo E) and multiple sclerosis (MS). Apo E is an important factor in transport, uptake, and redistribution of cholesterol, which is significant to remodelling and repair of nerve tissue. Apo E is involved in neurodegenerative diseases and the most well known association is between Apo epsilon4 and Alzheimer's disease. Only one study found that homozygosity for Apo epsilon4 does cause an increased risk of developing MS. No results indicate that heterozygosity for Apo epsilon4 causes a greater risk of developing MS. No association between the Apo epsilon4 allele and MS subgroups, age of onset, and gender has been found. The association between Apo epsilon4 and relapse rate is contradictory. Most results confirm the hypothesis about an association between the Apo epsilon4 allele and increased disease progression. Two longitudinal studies found an association between Apo epsilon4 and increased disease progression. Half of the cross-sectional studies found the same association. Four of seven published studies examining the association between Apo epsilon4 and increased disease progression using magnetic resonance imaging (MRI) found a significant association. Apo epsilon4 appears to be a predisposing factor to a faster disease progression in MS.

Apo E in multiple sclerosis and optic neuritis: the apo E-epsilon4 allele is associated with progression of multiple sclerosis.

OBJECTIVE: To investigate the association between apolipoprotein E (Apo E) genotype in multiple sclerosis (MS) and acute monosymptomatic optic neuritis (ON) in a genetically homogeneous population with a high frequency of the Apo epsilon4 allele. BACKGROUND: The association between heterozygosity of Apo epsilon4 and the development of MS is thoroughly investigated, while the association between homozygosity of Apo epsilon4 and the development of MS is insufficiently studied. The association between Apo E genotype and disease progression remains controversial. METHODS: 475 patients were included, 385 with MS and 90 with ON, consecutively seen in the MS clinic in the County of Copenhagen. Clinical data were obtained from medical records and degree of disability was determined prospectively using the Kurtzke expanded disability status scale (EDSS). Blood samples were used for Apo E genotyping. Disease progression was evaluated by the progression index (PI = EDSS/disease duration). Apo E genotype distribution was compared with 361 healthy controls. RESULTS: The Apo epsilon genotype distribution in the MS and ON groups was similar to the controls. The rate of disease progression in the group of MS patients with a disease duration of 10 years or less was significantly faster in the Apo epsilon4 positive group (heterozygosity and homozygosity for Apo epsilon4) (PI = 1.41) compared to the Apo epsilon4 negative group (PI =0.92) (P =0.009). Observing the MS subgroups, we found that the group of patients with RRMS had a faster rate of disease progression in the Apo epsilon4 positive group (PI =1.12) compared to the Apo epsilon4 negative group (P =0.77) (P =0.024). CONCLUSIONS: Apo E genotypes do not influence the development of MS and ON. The Apo epsilon4 allele seems to predispose carriers with MS to a faster progression of disease.