. Author manuscript; available in PMC: 2022 Aug 5.

Published in final edited form as: Nat Rev Microbiol. 2009 Nov 9;7(12):887–894. doi: 10.1038/nrmicro2245

Table 1 |.

Changes in human ecology that might affect microbiota composition

change	consequence
clean water	reduced faecal transmission
Increase in caesarean sections	reduced vaginal transmission
Increased use of pre-term antibiotics	reduced vaginal transmission
reduced breastfeeding	reduced cutaneous transmission and a changed immunological environment
smaller family size	reduced early life transmission
Widespread antibiotic use	selection for a changing composition
Increased bathing, showering and use of antibacterial soaps	selection for a changing composition
Increased use of mercury-amalgam dental fillings	selection for a changing composition