Vertical transmission of enteric pathogens at birth.

To determine how frequently mothers infect their infants with enteric pathogens at birth, stools were collected from 75 Thai mothers immediately before delivery and from their infants 24-48 h later. Enteropathogenic Escherichia coli (EPEC) were isolated from 25 of the 75 mothers just prior to delivery (32%), enteroviruses from six (8%), enterotoxigenic E. coli from five (7%), and shigella, salmonella and Vibrio parahaemolyticus each from one (1%). EPEC serotype 0128:K67 was isolated from one mother and from her infant, neither of whom had diarrhoea. Cultures from the other 74 mother-infant pairs did not detect identical enteric pathogens. Eighteen infants, nine of whose mothers submitted stools prior to delivery, developed diarrhoea within 5 days of birth. Five infants were infected with ETEC (28%), three with EPEC serotype 020a020cK61 (17%), one with Campylobacter jejuni (6%), and one with rotavirus (6%). None of these enteropathogens was found in 66 infants without diarrhoea. ECHO viruses of two different serotypes were isolated from two of 18 newborns with diarrhoea and unidentified enteroviruses from three of 66 without diarrhoea. Mothers and nurses are frequently infected with enteric pathogens in Thailand, but transmission to newborns at birth appears to be uncommon.