title: Exposure to household furry pets influences the gut microbiota of infant at 3-4 months following various birth scenarios.
abstract: Early-life exposure to household pets has the capacity to reduce risk for overweight and allergic disease, especially following caesarean delivery. Since there is some evidence that pets also alter the gut microbial composition of infants, changes to the gut microbiome are putative pathways by which pet exposure can reduce these risks to health. To investigate the impact of pre- and postnatal pet exposure on infant gut microbiota following various birth scenarios, this study employed a large subsample of 746 infants from the Canadian Healthy Infant Longitudinal Development Study (CHILD) cohort, whose mothers were enrolled during pregnancy between 2009 and 2012. Participating mothers were asked to report on household pet ownership at recruitment during the second or third trimester and 3 months postpartum. Infant gut microbiota were profiled with 16S rRNA sequencing from faecal samples collected at the mean age of 3.3 months. Two categories of pet exposure (i) only during pregnancy and (ii) pre- and postnatally were compared to no pet exposure under different birth scenarios.
  
  
  
  Over half of studied infants were exposed to at least one furry pet in the prenatal and/or postnatal periods, of which 8% were exposed in pregnancy alone and 46.8% had exposure during both time periods. As a common effect in all birth scenarios, pre- and postnatal pet exposure enriched the abundance of Oscillospira and/or Ruminococcus (P < 0.05) with more than a twofold greater likelihood of high abundance. Among vaginally born infants with maternal intrapartum antibiotic prophylaxis exposure, Streptococcaceae were substantially and significantly reduced by pet exposure (P < 0.001, FDRp = 0.03), reflecting an 80% decreased likelihood of high abundance (OR 0.20, 95%CI, 0.06-0.70) for pet exposure during pregnancy alone and a 69% reduced likelihood (OR 0.31, 95%CI, 0.16-0.58) for exposure in the pre- and postnatal time periods. All of these associations were independent of maternal asthma/allergy status, siblingship, breastfeeding exclusivity and other home characteristics.
  
  
  
  The impact of pet ownership varies under different birth scenarios; however, in common, exposure to pets increased the abundance of two bacteria, Ruminococcus and Oscillospira, which have been negatively associated with childhood atopy and obesity.
authors.affiliation: Department of Pediatrics, University of Alberta, 3-527 Edmonton Clinic Health Academy, 11405-87th Avenue, Edmonton, AB, T6G IC9, Canada.
authors.forename: Hein M
authors.initials: HM
authors.lastname: Tun
authors.affiliation: Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada.
authors.forename: Theodore
authors.initials: T
authors.lastname: Konya
authors.affiliation: Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada.
authors.forename: Tim K
authors.initials: TK
authors.lastname: Takaro
authors.affiliation: Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Brook
authors.affiliation: Department of Obstetrics and Gynecology, University of Alberta, Edmonton, AB, Canada.
authors.forename: Radha
authors.initials: R
authors.lastname: Chari
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Field
authors.affiliation: Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON, Canada.
authors.forename: David S
authors.initials: DS
authors.lastname: Guttman
authors.affiliation: Department of Pediatrics and Child Health, Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: Allan B
authors.initials: AB
authors.lastname: Becker
authors.affiliation: Department of Pediatrics, University of Alberta, 3-527 Edmonton Clinic Health Academy, 11405-87th Avenue, Edmonton, AB, T6G IC9, Canada.
authors.forename: Piush J
authors.initials: PJ
authors.lastname: Mandhane
authors.affiliation: Department of Pediatrics, Child & Family Research Institute, BC Children's Hospital, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Stuart E
authors.initials: SE
authors.lastname: Turvey
authors.affiliation: Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
authors.forename: Padmaja
authors.initials: P
authors.lastname: Subbarao
authors.affiliation: Department of Medicine, McMaster University, Hamilton, ON, Canada.
authors.forename: Malcolm R
authors.initials: MR
authors.lastname: Sears
authors.affiliation: Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada.
authors.forename: James A
authors.initials: JA
authors.lastname: Scott
authors.affiliation: Department of Pediatrics, University of Alberta, 3-527 Edmonton Clinic Health Academy, 11405-87th Avenue, Edmonton, AB, T6G IC9, Canada. kozyrsky@ualberta.ca.
authors.forename: Anita L
authors.initials: AL
authors.lastname: Kozyrskyj
mesh_terms: D000818:Animals; D019072:Antibiotic Prophylaxis; D001249:Asthma / Q000517:prevention & control; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D001942:Breast Feeding; D002170:Canada; D002585:Cesarean Section; D015331:Cohort Studies; D005191:Family Characteristics; D005243:Feces / Q000382:microbiology; D005260:Female; D000069196:Gastrointestinal Microbiome; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D006967:Hypersensitivity / Q000517:prevention & control; D007223:Infant; D008297:Male; D018811:Maternal Exposure; D009765:Obesity / Q000209:etiology / Q000517:prevention & control; D057805:Pets / Q000382:microbiology*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S
chemical_list: D012336:RNA, Ribosomal, 16S
keywords: Birth; Infant gut microbiota; Pets; Postnatal; Prenatal