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.

Contaminated medicaments in use in a hospital for diseases of the skin.

Topical medicaments used by patients with diseases of the skin were examined for microbial contamination. Ps. aeruginosa was isolated from stock pots of a diluted emulsifying ointment used as a soap substitute in the bath. Cross-contamination between patients and medicament was subsequently shown to have occurred.

Microbial contamination of topical medicaments used in the treatment and prevention of pressure sores.

Topical medicaments used in the treatment and prevention of pressure sores in patients in three hospitals were examined for Pseudomonas aeruginosa and Staphylococcus aureus contamination. Contamination rates were found to vary between hospitals and were affected by differences in the packaging of the product and in the method of application used by the nursing staff.

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.

The effect of travel on faecal Escherichia coli serotypes.

In a study on the serotypes of Escherichia coli which are present in the faeces of students travelling from many parts of the world to Dublin, a great variety of types was found. It was not possible to relate certain types to the various parts of the world where the students came from. There was no decrease in variety of serotypes after the students had been in Dublin for a few months and no distinctive 'Dublin' types were acquired. Serological variation of the E. coli was suggested as partially explaining some of the variety of the serotypes found. Although eight students developed diarrhoea without an aetiological agent being isolated after arrival in Dublin, no distinct pattern of E. coli could be related to this.

Changes in antibiotic sensitivity in strains of Staphylococcus aureus, 1952-78.

Two hundred strains of Staphylococcus aureus isolated from outpatients with infections of the skin and subcutaneous tissues were tested for sensitivity to penicillin, erythromycin, tetracycline, sodium fusidate, methicillin, clindamycin, chloramphenicol, and gentamicin. One hundred and sixty-three (81.5%) of the strains were resistant to penicillin and 16 (8%) resistant to tetracycline. Incidence of resistance to other antibiotics was low. No strain was resistant to chloramphenicol, gentamicin, or methicillin. When compared with results of earlier studies, there was an increase in the incidence of resistance to penicillin and tetracycline, but no appreciable increase in resistance to other antibiotics.

The effect of diet on intestinal Escherichia coli.

During an 8-week period all specimens of stool passed by six nurses were examined for the presence of Escherichia coli and all isolations of this organism were serotyped. During the middle 4 weeks of the period the nurses ate a sterile diet. A smaller number of serotypes was isolated during the period of sterile diet than during the period when normal food was eaten. This finding supports the view that normal food is a source of strains of E. coli present in the bowel. Some new serotypes of E. coli did appear during the period of sterile diet. The possible sources of these are discussed.

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.

Pseudomonas aeruginosa infections associated with use of contaminated medicaments.

Pseudomonas aeruginosa was recovered from three hospital-prepared medicaments being used on the wards. Sixty-six patients were studied to observe the effect of using these contaminated medicaments. Psaeruginosa was recovered from 29 patients; in five the strains recovered bore a close resemblance to strains previously isolated from the contaminated medicaments.

The distribution of serotypes of Escherichia coli in cow-pats and other animal material compared with serotypes of E. coli isolated from human sources.

The serotypes of 13,139 strains of Escherichia coli isolated from humans were compared with the serotypes of 1076 strains isolated from animals. 689 of these strains were isolated from fresh cow-pats on 22 sites in England and Wales. 708 different O/H combinations were found. Of these, 520 were found in human strains only, 130 from animal strains only and 58 O/H serotypes from humans and animals. Approximately half of the animal strains could not be typed with the full set of sera used.

Pseudomonas aeruginosa in hospital pharmacies.

The environments of hospital pharmacies and the preparations made in these pharmacies were examined for Pseudomonas aeruginosa. This organism was widely distributed in the pharmacies and was isolated from 9% of preparations. In 11 instances strains of Ps aeruginosa from the preparations bore a close resemblance to strains previously found in the pharmacy environments.

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.

Airborne infection in a fully air-conditioned hospital. IV. Airborne dispersal of Staphylococcus aureus and its nasal acquisition by patients.

Studies in a newly built hospital furnished with complete air conditioning where most of the patients are nursed in 6-bed rooms showed that the transfer of air from one patient room to another was very small, especially when there was substantial flow of air in a consistent direction between the patient rooms and the corridor, and that the direct transfer of airborne particles was even less. There was, however, no evidence of any reduction in the rates of nasal acquisition of Staphylococcus aureus compared with those to be found in naturally ventilated hospitals. The numbers of Staph. aureus found in the air of a given room that appeared to have originated from patient carriers in other rooms were many times greater than could be accounted for by direct airborne transfer. Although there was evidence that many carriers were not detected, detailed study showed that this excess transfer to the air of other rooms was genuine. It seems probable on the basis of investigations in this hospital and elsewhere that this excess transfer occurs indirectly, through dispersal from the clothing of the nursing and medical staff into the air of another room of strains with which their outer clothes have become contaminated while dealing with patients. Reduction in direct airborne transfer of micro-organisms from one room to another, whether by ventilation or other means, can only be of clinical advantage if transfer by other routes is, or can be made, less than that by the direct airborne route.

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.

Escherichia coli serotype distribution in man and animals.

The serotype distributions of Escherichia coli isolated from animal faeces, human faeces and from meat have been compared. There were marked differences in serotype distribution in strains from man and animals. The meat strains generally resembled animal strains. The results suggest either that animal strains of E. coli are not reaching the general human population outside hospital to any great extent, or, if they do so, are failing to implant in the bowel.

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 isolation of Escherichia coli from a poultry packing station and an abattoir.

The distribution and serotype of strains of Escherichia coli from a poultry packing station and an abattoir are described. The results indicated that animal faecal strains contaminated the environment and the animal carcasses.Using 150 O antisera, a high proportion of the E. coli strains were non-typable. This suggests that the serotype distribution of E. coli in animals is different from that in man.Strains with single antigenic differences were isolated, and the possibility of genetic transfer of these antigenic structures is suggested.