Colonization of the gastric contents in critically ill patients.

In a study of 28 ventilated patients in the ICU, cimetidine was ineffective in maintaining gastric pH above 4. Quantitative and qualitative bacteriological examination of daily gastric aspirates showed that when the pH was above 4, there was rapid colonization with high counts of organisms, predominantly coliforms. Progressive colonization by yeasts, independent of pH, was noted in nearly one-half of the patients. Gastric colonization has possible implications in terms of crossinfection of development of aspiration pneumonia. As these are seriously ill patients with compromised gastrointestinal (GI) barriers and decreased immunity, the large numbers of bacteria or their endotoxins may contribute to the high incidence of septicemia.

Studies on the enterotoxigenicity of environmental Escherichia coli, belonging to serotypes normally considered enterotoxigenic.

Fifteen strains of Escherichia coli which had been collected in previous studies from animals and meat were studied. They belonged to serotypes considered enterotoxigenic and were examined for the production of the heat-labile and heat-stable enterotoxins. Only one of these strains (O8.Hnt) isolated from a cowpat in Cheshire produced heat-labile enterotoxin. Another strain (O8.H9) isolated from a cowpat in another part of Cheshire gave results suggesting production of small amounts of the heat-stable enterotoxin. The ecological aspects of these results are discussed.

Microbial contamination of pharmaceutical products in the home.

One thousand, nine hundred and seventy-seven pharmaceutical products used in the home were examined for microbial contamination. Viable micro-organisms were recovered from 14.0% of samples. Medicines used in the home are apparently not exposed to the same opportunities for contamination as those used in hospital.

Antigenic degradation in Escherichia coli.

Strains of Escherichia coli isolated in a maternity unit were examined serologically. On primary isolation the strains were shown to be O-antigenically distinguishable, although having the same H antigen, biotype and antibiogram. Subsequent detailed serological studies revealed that the colonial variants derived from them showed similar antigenic diversity, irrespective of the original antigenic structure.

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.

Spread of Escherichia coli colonizing newborn babies and their mothers.

Most babies are colonized by the predominant strains of Escherichia coli present in their own mother's faecal flora. Those babies who did not acquire their maternal faecal flora acquired strains of E. coli belonging to a small number of the possible serotypes. Moreover, the same serotypes were found in several babies and other mothers, suggesting spread within the ward. These few strains included some of the O groups which had previously commonly been found as urinary pathogens. These strains may have increased potentialities for colonization of human bowel. Antigenic and biochemical variation was observed among the strains.

Further studies of Escherichia coli in babies after normal delivery.

Previous work showed that on the basis of O serotyping alone of Escherichia coli, the majority of babies acquired the same O serotype as was found in the stools of their respective mothers. Further characterization of the E. coli by H serotyping, determination of their antibiotic resistance and ability to ferment six carbohydrates showed that in the majority of cases the previous results were confirmed. In a minority of cases this further testing showed that the strains were not identical. In some instances a number of strains isolated from the same pair showed different combinations of the markers used.

The origin of O serotypes of Escherichia coli in babies after normal delivery.

A total of 2525 strains of Escherichia coli were isolated from the faeces of 33 mothers, the faeces of their babies and the mucus extracted from the babies' mouths after delivery. Of these strains 1832 could be O-serotyped with 150 O antisera. E. coli were isolated from 28 babies and the same serotypes as were found in their mothers were found in 22 of them. E. coli was isolated from only 14 of the mucus specimens but in 12 of these at least one of the serotypes present was subsequently found in the babies' stools.