Dog introduction alters the home dust microbiota.
Sitarik A, Havstad S, Levin A, Lynch SV, Fujimura K, Ownby D, Johnson C, Wegienka G
Indoor Air. Feb 2018. doi: 10.1111/ina.12456
COMMENT: In many studies, living with dogs has been shown to decrease the subsequent risk of allergies and asthma; however, the mechanisms are not well understood. Recent and current investigations are examining the role of the gut microbiome in allergic disease development. The goal of this study was to investigate whether introducing a dog into the home changes the home's dust microbiota. Families without dogs or cats planning to adopt a dog and those who were not were recruited. Dust samples were collected from the homes at recruitment and 12 months later. Microbiota composition and taxa (V4 region of the 16S rRNA gene) were compared between homes that did and did not adopt a dog. A total of 91 dust samples from 54 families (27 each, dog and no dog; 17 dog and 20 no dog homes with paired samples) were analyzed.
A significant dog effect was seen across time, indicating that dog introduction may result in rapid establishment of rarer and phylogenetically related taxa. A significant dog-time interaction was seen in both weighted UniFrac (p<0.001) and Bray-Curtis (p=0.002) metrics, suggesting that while there may not initially be large relative abundance shifts following dog introduction, differences can be seen within a year.
In summary, this work demonstrates that dogs can rapidly alter the home dust microbiota, primarily by increasing the presence and relative abundance of specific bacteria and that this alteration is more easily seen after one year. This evidence, partnered with epidemiological studies relating early dog exposure to the diminished occurrence of allergic disorders, supports the Microbiota Hypothesis for impacting asthma and allergies.