Escherichia coli serotypes in the faeces of healthy adults over a period of several months.

The faeces of nine subjects eating mainly at home were collected at regular intervals over periods ranging from 2--5 months. Although a large number of serotypes of E. coli were isolated, the variety per subject was lower than is usually found. In most subjects only a limited number of serotypes persisted over most of the periods of study while many serotypes were only isolated on single occasions.

Colonization of caesarean section babies by Excherichia coli.

Eight babies all delivered by Caesarean section were observed for evidence of colonization by E. coli from birth until discharge from hospital 10 to 14 days later. Faecal specimens were cultured daily for E. coli as were swabs from the rectum, groin, umbilicus, head, hands und mouth. Different serotypes of E. coli were isolated from four babies on day 1, one baby on day 2, one baby on day 7 and two babies on day 9. Three babies excreted more than one serotype of E. coli. Serotypes of E. coli isolated from the faeces and rectum were usually isolated from the groin but less often from the umbilicus. Other sides were rarely colonized. In all instances except one the primary site of colonization appeared to be the gastrointestinal tract. Colonization by E. coli was influenced by antibiotic therapy and possibly by the method of feeding.

Escherichia coli isolated from babies delivered by caesarean section and their environment.

The sources from which eight Caesarean section babies acquired E. coli are described and the probable routes by which the organisms reached the babies are outlined. Suggestions are made concerning the control of the spread of E. coli in premature nurseries and during outbreaks of E. coli gastroenteritis.

Escherichia coli in a maternity ward.

The Escherichia coli isolated from faecal and nasal swabs from all babies present in a maternity ward were serotyped and their anbitiotic resistance patterns and fermentation characteristics with six carbohydrates were determined. These were compared with E. coli isolated from hands and clothing of attendants and samples of ward air. The results suggest that mothers may be the primary source of E. coli in the ward but the colonized babies themselves provide the main reservoir of nursery E. coli. As most of these serotypes of E. coli were found on the attendant's hands or clothing or in the air, it is difficult to assess transmission routes for E. coli, particularly as some strains appear to possess a greater inherent ability to colonize babies than others. By the use of markers other than O antigens it was possible to characterize strains to a far greater extent.

The acquisition of Escherichia coli by new-born babies.

In discussing the background of these studies the importance of faecal carriage of Gram negative organisms by hospital patients is stressed. In many instances it was shown that transmission is by an oral route. This discussion leads on to an assessment of the dose required for Escherichia coli to implant in the bowel. The difficulties of studying the spread of E. coli within a faecal specimen are discussed. A number of papers are quoted which show that E. coli are present in the vagina of women and that the acquisition of these E. coli by babies is related to the length of time that the birth takes, and that there is a relationship between the E. coli found in the faeces of the mothers, the mucus swallowed by the babies at birth and subsequently in the faeces of the babies. Most of the eralier studies quoted deal predominantly with enteropathogenic serotypes, but it was later shown that other serotypes can be similarly acquired by the babies. Although this appears to be the general method by which babies acquire their faecal E. coli, it is well established that they can also be obtained from the environment, hence ward outbreaks of infantile gastroenteritis. Studies on normally delivered babies show that generally two thirds obtain their faecal E. coli from their mothers while the rest appear to pick up environmental strains. Very detailed biochemical and serological studies need to be performed to assess this. Caesarian section babies are generally not likely to become colonized by their mothers' faecal E. coli and studies are described which show that the babies faeces or rectal swabs are usually the first areas colonized and that the E. coli are spread from there. Extensive environmental studies suggest that contaminated hands and uniforms of the nursing staff may be the main vector for transmitting E. coli. There is a wide variety of E. coli serotypes present in a maternity ward at any time and these are related to the presence of the babies excreting them. A variation in the ability of strains to spread was noted.