Intestinal carriage of Staphylococcus aureus: How does its frequency compare with that of nasal carriage and what is its clinical impact?

The bacterial species Staphylococcus aureus, including its methicillin-resistant variant (MRSA), finds its primary ecological niche in the human nose, but is also able to colonize the intestines and the perineal region. Intestinal carriage has not been widely investigated despite its potential clinical impact. This review summarizes literature on the topic and sketches the current state of affairs from a microbiological and infectious diseases' perspective. Major findings are that the average reported detection rate of intestinal carriage in healthy individuals and patients is 20% for S. aureus and 9% for MRSA, which is approximately half of that for nasal carriage. Nasal carriage seems to predispose to intestinal carriage, but sole intestinal carriage occurs relatively frequently and is observed in 1 out of 3 intestinal carriers, which provides a rationale to include intestinal screening for surveillance or in outbreak settings. Colonization of the intestinal tract with S. aureus at a young age occurs at a high frequency and may affect the host's immune system. The frequency of intestinal carriage is generally underestimated and may significantly contribute to bacterial dissemination and subsequent risk of infections. Whether intestinal rather than nasal S. aureus carriage is a primary predictor for infections is still ill-defined

A Polymorphism in Gasdermin B (GSDMB) gene is associated with severe asthma exacerbations in childhood: A population-based birth cohort study.

Rationale. Markers on chromosome 17q12 have been associated withchildhood asthma in genome-wide association studies. Objective.We investigated the association of a single nucleotide polymorphism(SNP) in GSDMB (rs7216389) on 17q12 with asthma presence andseverity in a population-based birth cohort study. Methods. Childrenwere followed from birth to age 8 years. Data on parentally-reportedsymptoms were collected using an interviewer-administered questionnaire at age 1, 3, 5 and 8 years. Atopy was assessed by skin testing at age 3, 5 and 8 years. Information on asthma/wheeze hospital admissions and severe asthma exacerbations was collected from child’s primary care medical record. Data were analyzed as a recessive genetic model, with T-allele homozygotes as the risk group. Results. Compared to C allele carriers, T-allele homozygotes of rs7216389 were significantly more likely to: wheeze at age 3, 5 and 8 years; have persistent wheeze (OR 1.69, 95% CI 1.05-2.71, p=0.03); have frequent episodes of wheezing and be on asthma medication. In a multiple logistic regression model adjusted for gender, atopic sensitisation and maternal smoking, T allele homozygotes were significantly more likely to be hospitalized (aOR 2.20 [1.22-3.99], p=0.0009) with Cox regression hazard ratio for T-allele homozygotes of 1.94 [1.13-3.33], p=0.016. Results of Cox regression analysis investigating the eff ect of genotype on the age of first severe exacerbation of asthma indicated an overall hazard ratio of severe asthma exacerbation among T-allele homozygotes of 1.53 [1.04-2.27], p=0.03. Conclusions. Th is is the fi rst population-based birth cohort study to confirm that the risk of childhood wheeze and severe asthma/wheeze exacerbations is increased among rs7216389 TT homozygotes

Breastfeeding and the Development of Asthma and Atopy during Childhood: a Birth Cohort Study.

Objective. Within the context of a population based-birth cohort, we investigated the association between breastfeeding and development of asthma and atopy in childhood. Methods. Children (n=1072) were followed from birth and reviewed at age one, three, five and eight years. Based on the onset and resolution of symptoms, we assigned children into the wheeze phenotypes (never, transient, intermittent, lateonset and persistent). Atopy was determined by skin testing and specific IgE measurement. According to the duration of breastfeeding, participants were assigned as not breastfed, breastfed ≤ four months and breastfed > four months. Results. In a multinomial regression model adjusted for gender, we found that breastfeeding > four months was protective of transient early wheeze (aOR: 0.61, 95% CI 0.41-0.90, p=0.01), with no significant association between breastfeeding and other wheeze phenotypes. In a multivariate model, we found a significant protective effect of breastfeeding >four months on doctor-diagnosed asthma by age eight (aOR 0.59, 95% CI 0.39-0.88, p=0.01). However, we observed a strong trend which failed to reach statistical significance for breastfeeding >four months to increase the risk of atopy at age one year (aOR 2.41, 95% CI 0.94-6.14, p=0.07). There was no significant association between breastfeeding and atopy at any other time point. Conclusion. Breastfeeding may prevent viral-infection induced wheezing illnesses in early childhood (transient early wheezing)

Insoluble and soluble roasted walnut proteins retain antibody reactivity

Thermal processing techniques commonly used during food production have the potential to impact food allergens by inducing physical and/or chemical changes to the proteins. English walnuts (Juglans regia) are among the most commonly allergenic tree nuts, but little information is available regarding how walnut allergens respond to thermal processing. This study evaluated the effects of dry roasting (132 or 180°C for 5, 10, or 20min) on the solubility and immunoreactivity of walnut proteins. A dramatic decrease in walnut protein solubility was observed following dry roasting at 180°C for 20min. However, both the soluble and insoluble protein fractions from roasted walnuts maintained substantial amounts of IgG immunoreactivity (using anti-raw and anti-roasted walnut antisera), with similar patterns of reactivity observed for human IgE from walnut-allergic individuals. Thus, walnut proteins are relatively stable under certain thermal processing conditions, and IgE reactivity remains present even when insoluble aggregates are formed