Multilocus Sequence Typing Confirms Wild Birds as the Source of a Campylobacter Outbreak Associated with the Consumption of Raw Peas

From August to September 2008, the Centers for Disease Control and Prevention (CDC) assisted the Alaska Division of Public Health with an outbreak investigation of campylobacteriosis occurring among the residents of Southcentral Alaska. During the investigation, pulsed-field gel electrophoresis (PFGE) of Campylobacter jejuni isolates from human, raw pea, and wild bird fecal samples confirmed the epidemiologic link between illness and the consumption of raw peas contaminated by sandhill cranes for 15 of 43 epidemiologically linked human isolates. However, an association between the remaining epidemiologically linked human infections and the pea and wild bird isolates was not established. To better understand the molecular epidemiology of the outbreak, C. jejuni isolates (n = 130; 59 from humans, 40 from peas, and 31 from wild birds) were further characterized by multilocus sequence typing (MLST). Here we present the molecular evidence to demonstrate the association of many more human C. jejuni infections associated with the outbreak with raw peas and wild bird feces. Among all sequence types (STs) identified, 26 of 39 (67%) were novel and exclusive to the outbreak. Five clusters of overlapping STs (n = 32 isolates; 17 from humans, 2 from peas, and 13 from wild birds) were identified. In particular, cluster E (n = 7 isolates; ST-5049) consisted of isolates from humans, peas, and wild birds. Novel STs clustered closely with isolates typically associated with wild birds and the environment but distinct from lineages commonly seen in human infections. Novel STs and alleles recovered from human outbreak isolates allowed additional infections caused by these rare genotypes to be attributed to the contaminated raw peas.     

Volatile Compounds of Viola odorata Absolutes: Identification of Odorant Active Markers to Distinguish Plants Originating from France and Egypt

Absolutes isolated from Viola odorata leaves, valuable materials for the flavor and fragrance industry, were studied. Violets are mainly cultivated in France and Egypt and extracted locally. The absolutes of the two origins showed different olfactory profiles both in top and heart notes, as evidenced by sensory analysis. The aims of this study were i) to characterize the volatile compounds, ii) to determine the odorant‐active ones, and iii) to identify some markers of the plant origin. Two complementary analytical methods were used for these purposes, i.e., headspace solid‐phase microextraction (HS‐SPME) using different fiber coatings followed by GC/MS analysis and gas chromatography – olfactometry/mass spectrometry (GC‐O/MS) applied to violet leaf extracts. From a total of 70 identified compounds, 61 have never been reported so far for this species, 17 compounds were characterized by both techniques (with seven among them known from the literature), 23 compounds were solely identified by HS‐SPME GC/MS (among them only two being already mentioned as components of violet absolutes in the literature), and, finally, 30 compounds were only identified by GC‐O/MS. According to the HS‐SPME GC/MS analyses, ethyl hexanoate and (2E,6Z)‐nona‐2,6‐dienol were specific volatile compounds of the sample with French origin, while (E,E)‐hepta‐2,4‐dienal, hexanoic acid, limonene, tridecane, and eugenol were specific of the samples with Egyptian origin. Additional compounds that were not detected by HS‐SPME GC/MS analysis were revealed by GC‐O analyses, some of them being markers of origin. Pent‐1‐en‐3‐ol, 3‐methylbut‐2‐enal, 2‐methoxy‐3‐(1‐methylethyl)pyrazine, 4‐ethylbenzaldehyde, β‐phenethyl formate, and 2‐methoxy‐3‐(2‐methylpropyl)pyrazine revealed to be odorant markers of the French sample, whereas cis‐rose oxide, trans‐rose oxide, and 3,5,5‐trimethylcyclohex‐2‐enone were odorant markers of the Egyptian samples.     

Exploring the Structure-Function Loop Adaptability of a (β/α)(8)-Barrel Enzyme through Loop Swapping and Hinge Variability

Cellulosomes are large extracellular multi-enzyme complexes that exhibit elevated activity on plant cell-wall polysaccharides. In the present study, the relationships between the conformational flexibility and efficacy of cellulosomes, and the inter-modules linkers of their scaffold protein were investigated. For this purpose, the length of the intrinsically disordered Ser/Thr-rich 50-residue linker connecting a Clostridium thermocellum and a Clostridium cellulolyticum cohesin in a hybrid scaffoldin (Scaf4) was changed by sequences ranging from 4 to 128 residues. The composition was also modified and new linkers composed of series of N, S or repeats of the EPPV motif were generated. Two model cellulases (Cel48F and Cel9G) appended with appropriate dockerins were subsequently bound to the engineered scaffoldins. All the resulting minicomplexes displayed the same activity on crystalline cellulose as the complex based on the initial Scaf4, and were found to be 2-fold more active than Cel48F and Cel9G bound to separate cohesins. Small-angle X-ray scattering assays of the engineered scaffoldins confirmed, however, that the size and the conformational flexibility of some of the new inter-cohesins linkers differed significantly from that of the initial 50 residue linker displayed by the parental Scaf4. Our data suggest that the synergy induced by proximity does not require a specific inter-cohesins sequence or distance. The present study reveals that complexation onto the hybrid scaffoldins modifies the type of soluble sugars released from crystalline cellulose by the selected cellulases, compared to the free enzyme system.     

Determining a low disease activity threshold for decision to maintain disease-modifying antirheumatic drug treatment unchanged in rheumatoid arthritis patients

Introduction

The aim of this study was to determine a low disease activity threshold - a 28-joint disease activity score (DAS28) value - for the decision to maintain unchanged disease-modifying antirheumatic drug (DMARD) treatment in rheumatoid arthritis patients, based on expert opinion.

Methods

Nine hundred and sixty-seven case scenarios with various levels for each component of the DAS28 (resulting in a disease activity score between 2 and 3.2) were presented to 44 panelists. For each scenario, panelists had to decide whether or not DMARD treatment (excluding steroids) could be maintained unchanged. In each scenario, for decision, the participants were given the DAS28 parameters, without knowledge of the resultant DAS28. The relationship between panelists' decision, DAS28 value, and components of the score were analysed by multiple logistic regression analysis. Each panelist analysed 160 randomised scenarios. Intra-rater and inter-rater reproducibility were assessed.

Results

Forty-four panelists participated in the study. Inter-panelist agreement was good (κ = 0.63; 95% confidence interval = 0.61 to 0.65). Intra-panelist agreement was excellent (κ = 0.87; 95% confidence interval = 0.82 to 0.92). Quasi-perfect agreement was observed for DAS28 ≤ 2.4, less pronounced between 2.5 and 2.9, and almost no agreement for DAS28 > 3.0. For values below 2.5, panelists agreed to maintain unchanged DMARDs; for values above 2.5, discrepancies occurred more frequently as the DAS28 value increased. Multivariate analysis confirmed the relationship between panelist's decision, DAS28 value and components of the DAS28. Between DAS28 of 2.4 and 3.2, a major determinant for panelists' decision was swollen joint count. Female and public practice physicians decided more often to maintain treatment unchanged.

Conclusions

As a conclusion, panelists suggested that in clinical practice there is no need to change DMARD treatment in rheumatoid arthritis patients with DAS28 ≤ 2.4.     

Pandemic influenza due to pH1N1/2009 virus: estimation of infection burden in Reunion Island through a prospective serosurvey, austral winter 2009

Background

To date, there is little information that reflects the true extent of spread of the pH1N1/2009v influenza pandemic at the community level as infection often results in mild or no clinical symptoms. This study aimed at assessing through a prospective study, the attack rate of pH1N1/2009 virus in Reunion Island and risk factors of infection, during the 2009 season.

Methodology/Principal Findings

A serosurvey was conducted during the 2009 austral winter, in the frame of a prospective population study. Pairs of sera were collected from 1687 individuals belonging to 772 households, during and after passage of the pandemic wave. Antibodies to pH1N1/2009v were titered using the hemagglutination inhibition assay (HIA) with titers ≥1/40 being considered positive. Seroprevalence during the first two weeks of detection of pH1N1/2009v in Reunion Island was 29.8% in people under 20 years of age, 35.6% in adults (20–59 years) and 73.3% in the elderly (≥60 years) (P<0.0001). Baseline corrected cumulative incidence rates, were 42.9%, 13.9% and 0% in these age groups respectively (P<0.0001). A significant decline in antibody titers occurred soon after the passage of the epidemic wave. Seroconversion rates to pH1N1/2009 correlated negatively with age: 63.2%, 39.4% and 16.7%, in each age group respectively (P<0.0001). Seroconversion occurred in 65.2% of individuals who were seronegative at inclusion compared to 6.8% in those who were initially seropositive.

Conclusions

Seroincidence of pH1N1/2009v infection was three times that estimated from clinical surveillance, indicating that almost two thirds of infections occurring at the community level have escaped medical detection. People under 20 years of age were the most affected group. Pre-epidemic titers ≥1/40 prevented seroconversion and are likely protective against infection. A concern was raised about the long term stability of the antibody responses.     

Ambient Air Pollution and the Progression of Atherosclerosis in Adults

Background

Cross-sectional studies suggest an association between exposure to ambient air pollution and atherosclerosis. We investigated the association between outdoor air quality and progression of subclinical atherosclerosis (common carotid artery intima-media thickness, CIMT).

Methodology/Principal Findings

We examined data from five double-blind randomized trials that assessed effects of various treatments on the change in CIMT. The trials were conducted in the Los Angeles area. Spatial models and land-use data were used to estimate the home outdoor mean concentration of particulate matter up to 2.5 micrometer in diameter (PM2.5), and to classify residence by proximity to traffic-related pollution (within 100 m of highways). PM2.5 and traffic proximity were positively associated with CIMT progression. Adjusted coefficients were larger than crude associations, not sensitive to modelling specifications, and statistically significant for highway proximity while of borderline significance for PM2.5 (P = 0.08). Annual CIMT progression among those living within 100 m of a highway was accelerated (5.5 micrometers/yr [95%CI: 0.13–10.79; p = 0.04]) or more than twice the population mean progression. For PM2.5, coefficients were positive as well, reaching statistical significance in the socially disadvantaged; in subjects reporting lipid lowering treatment at baseline; among participants receiving on-trial treatments; and among the pool of four out of the five trials.

Conclusion

Consistent with cross-sectional findings and animal studies, this is the first study to report an association between exposure to air pollution and the progression of atherosclerosis – indicated with CIMT change – in humans. Ostensibly, our results suggest that air pollution may contribute to the acceleration of cardiovascular disease development – the main causes of morbidity and mortality in many countries. However, the heterogeneity of the volunteering populations across the five trials, the limited sample size within trials and other relevant subgroups, and the fact that some key findings reached statistical significance in subgroups rather than the sample precludes generalizations to the general population.     

Short/branched-chain acyl-CoA dehydrogenase deficiency due to an IVS3+3A>G mutation that causes exon skipping

Short/branched-chain acyl-CoA dehydrogenase deficiency (SBCADD) is an autosomal recessive disorder of l-isoleucine catabolism. Little is known about the clinical presentation associated with this enzyme defect, as it has been reported in only a limited number of patients. Because the presence of C5-carnitine in blood may indicate SBCADD, the disorder may be detected by MS/MS-based routine newborn screening. It is, therefore, important to gain more knowledge about the clinical presentation and the mutational spectrum of SBCADD. In the present study, we have studied two unrelated families with SBCADD, both with seizures and psychomotor delay as the main clinical features. One family illustrates the fact that affected individuals may also remain asymptomatic. In addition, the normal level of newborn blood spot C5-acylcarnitine in one patient underscores the fact that newborn screening by MS/MS currently lacks sensitivity in detecting SBCADD. Until now, seven mutations in the SBCAD gene have been reported, but only three have been tested experimentally. Here, we identify and characterize an IVS3+3A>G mutation (c.303+3A>G) in the SBCAD gene, and provide evidence that this mutation is disease-causing in both families. Using a minigene approach, we show that the IVS3+3A>G mutation causes exon 3 skipping, despite the fact that it does not appear to disrupt the consensus sequence of the 5′ splice site. Based on these results and numerous literature examples, we suggest that this type of mutation (IVS+3A>G) induces missplicing only when in the context of non-consensus (weak) 5′ splice sites. Statistical analysis of the sequences shows that the wild-type versions of 5′ splice sites in which +3A>G mutations cause exon skipping and disease are weaker on average than a random set of 5′ splice sites. This finding is relevant to the interpretation of the functional consequences of this type of mutation in other disease genes.     

Non‐fire induced seed release ina weakly serotinous pine: climatic factors,maintenance costs or both?

The advantages of canopy seed retention (serotiny) for plants inhabiting fire‐prone ecosystems are well documented. However, very few species are completely serotinous and non‐fire induced opening of serotinous fruits is commonly observed (weak serotiny). Two non‐mutually exclusive causes are envisaged to contribute to this process: mechanical changes in serotinous fruits mediated by climatic conditions (e.g. drought) or the costs of maintenance for the plant of these long‐lasting structures. However, their relative contribution to the spontaneous opening of serotinous fruits remains elusive as well as the consequences for the build‐up of the canopy seed bank and inter‐individual differences in serotiny. In this study we monitored the dynamics of cone production and cone opening in the weakly serotinous Pinus halepensis for five years (2004–2008), including two severe drought episodes (2005, 2006). Drought decreased the production of conelets, increased the abortion of immature cones, reduced the seed quality in the cohorts of cones produced during these years, and increased the opening of serotinous cones. During the first drought episode, a higher proportion of serotinous cones opened in those pines bearing a larger crop of younger cones. This suggests that not only passive changes induced by drought but also competition among cones for resources (e.g. water) might be involved in this process. The opening of serotinous cones in pines bearing more cones made inter‐individual differences in the size of the canopy cone bank to narrow or even to reverse from 2004 to 2008. These results may help to understand the decrease in serotiny when pines grow and accumulate more cones and the large inter‐individual variability in the degree of serotiny observed in P. halepensis forests. In addition, the negative effects of drought episodes for the size of the canopy cone bank and the seeds contained can be an unexplored cause of post‐fire regeneration constraint.