TY - JOUR
T1 - Crawling-induced floor dust resuspension affects the microbiota of the infant breathing zone
AU - Hyytiäinen, Heidi K.
AU - Jayaprakash, Balamuralikrishna
AU - Kirjavainen, Pirkka V.
AU - Saari, Sampo E.
AU - Holopainen, Rauno
AU - Keskinen, Jorma
AU - Hämeri, Kaarle
AU - Hyvärinen, Anne
AU - Boor, Brandon E.
AU - Täubel, Martin
N1 - Funding Information:
We are thankful to the families who donated their carpets to this study and the Finnish Institute for Occupational Health for providing access to the experimental facilities and support during the experiments. The authors wish to thank the research analysts at THL's Living Environment and Health Unit, Katja Saarnio, Mervi Ojala, and Heli Martikainen, for their excellent laboratory assistance. Statistician Asko Veps?l?inen is acknowledged for the data management and statistical analyses and support. This work was financially supported by the Academy of Finland (PROBIOM, grant numbers 296814 and 296817) and Juho Vainion S??ti? (201710468). BB received financial support from the U.S. Environmental Protection Agency Science to Achieve Results (STAR) Fellowship (F13D10740). The funding organizations were not involved in the design of the study and the collection, analysis, and interpretation of data or in writing the manuscript.
Publisher Copyright:
© The Author(s). 2018.
Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 2018/2/2
Y1 - 2018/2/2
N2 - Background: Floor dust is commonly used for microbial determinations in epidemiological studies to estimate early-life indoor microbial exposures. Resuspension of floor dust and its impact on infant microbial exposure is, however, little explored. The aim of our study was to investigate how floor dust resuspension induced by an infant's crawling motion and an adult walking affects infant inhalation exposure to microbes. Results: We conducted controlled chamber experiments with a simplified mechanical crawling infant robot and an adult volunteer walking over carpeted flooring. We applied bacterial 16S rRNA gene sequencing and quantitative PCR to monitor the infant breathing zone microbial content and compared that to the adult breathing zone and the carpet dust as the source. During crawling, fungal and bacterial levels were, on average, 8-to 21-fold higher in the infant breathing zone compared to measurements from the adult breathing zone. During walking experiments, the increase in microbial levels in the infant breathing zone was far less pronounced. The correlation in rank orders of microbial levels in the carpet dust and the corresponding infant breathing zone sample varied between different microbial groups but was mostly moderate. The relative abundance of bacterial taxa was characteristically distinct in carpet dust and infant and adult breathing zones during the infant crawling experiments. Bacterial diversity in carpet dust and the infant breathing zone did not correlate significantly. Conclusions: The microbiota in the infant breathing zone differ in absolute quantitative and compositional terms from that of the adult breathing zone and of floor dust. Crawling induces resuspension of floor dust from carpeted flooring, creating a concentrated and localized cloud of microbial content around the infant. Thus, the microbial exposure of infants following dust resuspension is difficult to predict based on common house dust or bulk air measurements. Improved approaches for the assessment of infant microbial exposure, such as sampling at the infant breathing zone level, are needed.
AB - Background: Floor dust is commonly used for microbial determinations in epidemiological studies to estimate early-life indoor microbial exposures. Resuspension of floor dust and its impact on infant microbial exposure is, however, little explored. The aim of our study was to investigate how floor dust resuspension induced by an infant's crawling motion and an adult walking affects infant inhalation exposure to microbes. Results: We conducted controlled chamber experiments with a simplified mechanical crawling infant robot and an adult volunteer walking over carpeted flooring. We applied bacterial 16S rRNA gene sequencing and quantitative PCR to monitor the infant breathing zone microbial content and compared that to the adult breathing zone and the carpet dust as the source. During crawling, fungal and bacterial levels were, on average, 8-to 21-fold higher in the infant breathing zone compared to measurements from the adult breathing zone. During walking experiments, the increase in microbial levels in the infant breathing zone was far less pronounced. The correlation in rank orders of microbial levels in the carpet dust and the corresponding infant breathing zone sample varied between different microbial groups but was mostly moderate. The relative abundance of bacterial taxa was characteristically distinct in carpet dust and infant and adult breathing zones during the infant crawling experiments. Bacterial diversity in carpet dust and the infant breathing zone did not correlate significantly. Conclusions: The microbiota in the infant breathing zone differ in absolute quantitative and compositional terms from that of the adult breathing zone and of floor dust. Crawling induces resuspension of floor dust from carpeted flooring, creating a concentrated and localized cloud of microbial content around the infant. Thus, the microbial exposure of infants following dust resuspension is difficult to predict based on common house dust or bulk air measurements. Improved approaches for the assessment of infant microbial exposure, such as sampling at the infant breathing zone level, are needed.
KW - 16S rRNA gene sequencing
KW - Indoor microbial exposure
KW - Infant exposure
KW - Particle resuspension
KW - QPCR
KW - Floors and Floorcoverings
KW - Environmental Monitoring
KW - Bacteria/classification
KW - Air Microbiology
KW - Humans
KW - RNA, Ribosomal, 16S/genetics
KW - Infant
KW - DNA, Ribosomal/genetics
KW - Sequence Analysis, DNA/methods
KW - Air Pollution, Indoor/analysis
KW - Microbiota
KW - DNA, Fungal/genetics
KW - Fungi/classification
KW - Dust/analysis
KW - DNA, Bacterial/genetics
UR - http://www.scopus.com/inward/record.url?scp=85042866933&partnerID=8YFLogxK
U2 - 10.1186/s40168-018-0405-8
DO - 10.1186/s40168-018-0405-8
M3 - Article
C2 - 29394954
AN - SCOPUS:85042866933
SN - 2049-2618
VL - 6
JO - Microbiome
JF - Microbiome
IS - 1
M1 - 25
ER -