Exposure to environmental chemical mixtures is associated with nasal colonization by Staphylococcus aureus: NHANES 2001-2004

Conceptualizing the Role of the Microbiome as a Mediator and Modifier in Environmental Health Studies: A Scoping Review of Studies of Triclosan and the Microbiome

PURPOSE OF REVIEW

Triclosan is an endocrine-disrupting antimicrobial additive that is suspected of contributing to antibiotic resistance and altering the microbiome. In this scoping review, we summarize what is known about the association between triclosan exposure and the microbiome using evidence from in vivo and epidemiologic studies.

RECENT FINDINGS

Our review includes 11 rodent studies, seven fish studies, and five human studies. Evidence from animal studies suggests that triclosan decreases the diversity of the microbiome, although only one epidemiologic study agreed. Most studies suggest that triclosan alters the microbial community beta diversity, but disagree on which taxa contributed to compositional differences. Taxa in the Bacteroidetes, Firmicutes, and Proteobacteria may be more influenced by triclosan than those in other phyla. Studies on triclosan and the microbiome were scarce and were inconclusive as to the effects of triclosan on the microbiome. Additional research is needed to clarify windows of heightened susceptibility of the microbiome to triclosan. We recommend guidelines for future microbiome research in environmental health to increase comparability across studies.

Update of the risk assessment of polybrominated diphenyl ethers (PBDEs) in food

The European Commission asked EFSA to update its 2011 risk assessment on polybrominated diphenyl ethers (PBDEs) in food, focusing on 10 congeners: BDE-28, -47, -49, -99, -100, -138, -153, -154, -183 and ‑209. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour and reproductive/developmental effects are the critical effects in rodent studies. For four congeners (BDE-47, -99, -153, -209) the Panel derived Reference Points, i.e. benchmark doses and corresponding lower 95% confidence limits (BMDLs), for endpoint-specific benchmark responses. Since repeated exposure to PBDEs results in accumulation of these chemicals in the body, the Panel estimated the body burden at the BMDL in rodents, and the chronic intake that would lead to the same body burden in humans. For the remaining six congeners no studies were available to identify Reference Points. The Panel concluded that there is scientific basis for inclusion of all 10 congeners in a common assessment group and performed a combined risk assessment. The Panel concluded that the combined margin of exposure (MOET) approach was the most appropriate risk metric and applied a tiered approach to the risk characterisation. Over 84,000 analytical results for the 10 congeners in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary Lower Bound exposure to PBDEs were meat and meat products and fish and seafood. Taking into account the uncertainties affecting the assessment, the Panel concluded that it is likely that current dietary exposure to PBDEs in the European population raises a health concern.

Cellular and physiological mechanisms of halogenated and organophosphorus flame retardant toxicity

Flame retardants (FRs) are chemical substances used to inhibit the spread of fire in numerous industrial applications, and their abundance in modern manufactured products in the indoor and outdoor environment leads to extensive direct and food chain exposure of humans. Although once considered relatively non-toxic, FRs are demonstrated by recent literature to have disruptive effects on many biological processes, including signaling pathways, genome stability, reproduction, and immune system function. This review provides a summary of research investigating the impact of major groups of FRs, including halogenated and organophosphorus FRs, on animals and humans in vitro and/or in vivo. We put in focus those studies that explained or referenced the modes of FR action at the level of cells, tissues and organs. Since FRs are highly hydrophobic chemicals, their biophysical and biochemical modes of action usually involve lipophilic interactions, e.g. with biological membranes or elements of signaling pathways. We present selected toxicological information about these molecular actions to show how they can lead to damaging membrane integrity, damaging DNA and compromising its repair, changing gene expression, and cell cycle as well as accelerating cell death. Moreover, we indicate how this translates to deleterious bioactivity of FRs at the physiological level, with disruption of hormonal action, dysregulation of metabolism, adverse effects on male and female reproduction as well as alteration of normal pattern of immunity. Concentrating on these subjects, we make clear both the advances in knowledge in recent years and the remaining gaps in our understanding, especially at the mechanistic level.

Differences between Staphylococcus aureus nasal carriage and IgE-sensitization to Staphylococcus aureus enterotoxin on risk factors and effects in adult population

Background

Staphylococcus aureus (SA) nasal carriage (SA carriage) and IgE-sensitization to SA enterotoxin (SE IgE-sensitization) are known to be associated with chronic airway disease.

Objective

This study aimed to evaluate the differences in risk factors, type 2 inflammation and respiratory symptoms between SA carriage and SE IgE-sensitization.

Methods

We conducted a cross-sectional study of a community-based adult population to evaluate the environmental exposure and health impact of the Pohang Industrial Complex, Korea. Participants were examined based on self-reported questionnaires, nasal swab, and blood sampling.

Results

There were 307 participants, and the overall prevalence of SA carriage and SE IgE-sensitization was 26.1% (80/307) and 25.7% (79/307), respectively. An urban environment was significantly correlated with SA carriage, whereas age and obesity were significantly correlated with SE IgE-sensitization. SA carriage was not associated with an increase in total IgE and blood eosinophil count, whereas SE IgE-sensitization was associated with an increased total IgE and blood eosinophil count. SA carriage was significantly correlated with cough persisting for more than three weeks (OR, 3.044; 95% CI, 1.137–8.153) and sputum (OR, 2.429; 95% CI, 1.008–5.854). SE IgE-sensitization was a significant correlation with only sputum (OR, 2.452; 95% CI, 1.066–5.640). SA carriage and SE IgE-sensitization showed a synergistic effect on the prevalence of cough and sputum.

Conclusion

SA carriage was associated with the urban environment, and SE IgE-sensitization was associated with the elderly and obesity. SA carriage and SE IgE-sensitization had different correlation with type 2 inflammation and airway symptoms.

Associations between exposure to polycyclic aromatic hydrocarbons and metabolic syndrome in U.S. adolescents: Cross-sectional results from the National Health and Nutrition Examination Survey (2003-2016) data

BACKGROUND

The metabolic syndrome is a constellation of risk factors, including abdominal obesity, hypertension, dyslipidemia, and hyperglycemia. Polycyclic aromatic hydrocarbons (PAHs) constitute a group of chemicals that are formed during the incomplete combustion of coal, oil and gas, garbage, and other organic substances. In the occupational exposure population, PAHs exposure increased the prevalence ratio of metabolic syndrome. However, the effect of PAHs on prevalence of metabolic syndrome in adolescents has not been reported. Because of the propensity for childhood metabolic risk to track into adulthood, there is a great need to identify risk factors for childhood metabolic syndrome.

METHOD

Using data from the 2003-2016 National Health and Nutrition Examination Survey. We defined metabolic syndrome using a modified version of the National Cholesterol Education Program Adult Treatment Panel Ⅲ definition for adolescents. Weighted logistic regression was used to calculate the odds ratio and 95 % confidence intervals for each biomarker. In addition, we applied the weighted quantile sum (WQS) regressions to adolescent metabolic syndrome to reveal the multiple exposure effects and relative weights of each PAH.

RESULTS

Among the 827 adolescents, 183 (22.13 %) had metabolic syndrome. The levels of 2-hydroxynaphthalene (2-NAP), 2-hydroxyphenanthrene (2-PHE), 2-hydroxyfluorene (2-FLU), 1-hydroxynaphthalene (1-NAP), 3-hydroxyfluorene (3-FLU) and 1-hydroxypyrene (1-PYR) were higher in the group of adolescents with metabolic syndrome. There were positive associations between higher concentrations of 2-NAP, 2-FLU and odds of metabolic syndrome after adjustment, which odds ratios (ORs) in the 3rd tertile were 2.22 (95%CI:1.45-3.44) and 2.09 (95%CI:1.36-3.10), respectively. In subgroups analysis, the ORs between the 3 tertile concentrations of 2-NAP, 2-PHE and high fasting blood glucose (FBG) were 2.20 (95%CI:1.37-3.57) and 1.99 (95%CI:1.16-3.48).

CONCLUSION

The present study suggested that PAHs may be associated with odds of metabolic syndrome as well as individual metabolic syndrome components among adolescents. A cohort study should be designed to clarify the cause and effect between PAHs and metabolic syndrome in future research.