Phthalate exposures are associated with Staphylococcus aureus nasal colonization in the U.S. population

Abstract

PDS 75: Microbiome, infections and respiratory effects, Johan Friso Foyer, Floor 1, August 27, 2019, 1:30 PM - 3:00 PM Background/Aim: There are emerging concerns that endocrine disrupting chemicals (EDCs) with immunomodulatory properties could attenuate immunity against infections and alter disease outcomes. A related concern is the potential for EDCs with antimicrobial properties to select for drug-resistant pathogens. Phthalates are EDCs with immunomodulatory and antimicrobial properties; however, the potential impacts of phthalate exposures on Staphylococcus aureus (SA) colonization have not been explored. Methods: We used publicly-available 2001-2004 data on 5303 participants (6-85 years) from the U.S. population-based National Health and Nutrition Examination Survey (NHANES). Exposures to 12 phthalate metabolites were quantified in urine samples and SA nasal colonization was detected using microbial culture. Measured Di(2-ethylhexyl) phthalate (DEHP) metabolites were summed by molecular weight. We used survey-weighted and covariate-adjusted logistic regression models to examine associations between SA colonization and phthalate exposures. Results: A total of 1637 (30%) participants had detectable SA nasal colonization. Increasing concentrations of the two high-molecular-weight phthalates—Mono-(3-carboxypropyl) phthalate (MCPP) and ∑DEHP—were associated with SA colonization; e.g. participants had 14% higher odds of SA nasal colonization with each log10 increase in MCPP [95% Confidence Interval (CI) 1.05, 1.23, p≤0.001]. Three of seven low-molecular-weight phthalates—Mono-benzyl (MBzP), Mono-isobutyl (MiBP) and Mono-cyclo-hexyl phthalate (MCHP)—were associated with SA colonization; e.g. participants had 17% higher odds of SA nasal colonization with each log10 increase in MBzP [95% CI: 1.05, 1.32, p≤0.008]. Conclusions: Phthalates, particularly high-molecular-weight phthalates that may be found in building materials, are associated with SA nasal colonization in the U.S. population. SA nasal colonization increases infection risk. Further, exposure to phthalates and SA nasal colonization are factors known to be associated with similar chronic disease outcomes, such as asthma and wheeze. Future studies are needed to identify if there is a casual relationship between phthalate exposure and SA nasal colonization and if such joint exposures impact disease outcomes.