The natural history of bacterial colonization of the newborn in a maternity hospital (Part II).
The object of this study was to determine the sources from which the newborn infant derives his bacterial flora during the first 5 days after birth. Detailed bacteriological data was obtained from 193 mothers antenatally and during labour, and from their infants on the day of birth and on Day 5. Organisms were typed by appropriate methods and the 193 mother-baby pairs declared to be a 'match' or a 'non-match' according as to whether or not identical bacteria were isolated from both members of the pair. Weekly swabs from hands and noses of staff were taken throughout the 12 months of the study. Swabs were also taken from the environment and air samples from different areas in the hospital. In approximately one third of infants the colonizing bacteria are derived from their mothers, in over 70 per cent of instances from the mother's rectum. The mother's birth canal is not a common source of bacteria and there is no direct relationship with the noses or hands of staff. Artificial feeds are not a source of the colonizing bacteria. The overall distribution of the bacterial species in the infants differed from that found in the hospital environment but this does, none the less, constitute a reservoir of bacteria which is being continually replenished from human sources. Pathogens such as Staph, aureus and Strep. pyogenes are no longer commonly found in newborn infants in the modern maternity hospital, but the need for continual vigilance and an efficient bacteriological service in all maternity units has been in no way diminished.