title: Microbiota of human breast tissue.
abstract: In recent years, a greater appreciation for the microbes inhabiting human body sites has emerged. In the female mammary gland, milk has been shown to contain bacterial species, ostensibly reaching the ducts from the skin. We decided to investigate whether there is a microbiome within the mammary tissue. Using 16S rRNA sequencing and culture, we analyzed breast tissue from 81 women with and without cancer in Canada and Ireland. A diverse population of bacteria was detected within tissue collected from sites all around the breast in women aged 18 to 90, not all of whom had a history of lactation. The principal phylum was Proteobacteria. The most abundant taxa in the Canadian samples were Bacillus (11.4%), Acinetobacter (10.0%), Enterobacteriaceae (8.3%), Pseudomonas (6.5%), Staphylococcus (6.5%), Propionibacterium (5.8%), Comamonadaceae (5.7%), Gammaproteobacteria (5.0%), and Prevotella (5.0%). In the Irish samples the most abundant taxa were Enterobacteriaceae (30.8%), Staphylococcus (12.7%), Listeria welshimeri (12.1%), Propionibacterium (10.1%), and Pseudomonas (5.3%). None of the subjects had signs or symptoms of infection, but the presence of viable bacteria was confirmed in some samples by culture. The extent to which these organisms play a role in health or disease remains to be determined.
authors.affiliation: Lawson Health Research Institute, London, Ontario, Canada.
authors.forename: Camilla
authors.initials: C
authors.lastname: Urbaniak
authors.forename: Joanne
authors.initials: J
authors.lastname: Cummins
authors.forename: Muriel
authors.initials: M
authors.lastname: Brackstone
authors.forename: Jean M
authors.initials: JM
authors.lastname: Macklaim
authors.forename: Gregory B
authors.initials: GB
authors.lastname: Gloor
authors.forename: Chwanrow K
authors.initials: CK
authors.lastname: Baban
authors.forename: Leslie
authors.initials: L
authors.lastname: Scott
authors.forename: Deidre M
authors.initials: DM
authors.lastname: O'Hanlon
authors.forename: Jeremy P
authors.initials: JP
authors.lastname: Burton
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Francis
authors.forename: Mark
authors.initials: M
authors.lastname: Tangney
authors.forename: Gregor
authors.initials: G
authors.lastname: Reid
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D044822:Biodiversity; D001940:Breast / Q000382:microbiology*; D002170:Canada; D005260:Female; D006801:Humans; D064307:Microbiota; D008875:Middle Aged; D055815:Young Adult