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Biomedical subjects

B Rowe

Publications and source records attributed to B Rowe.

At least 361 records · Page 20Linked to original sources

Escherichia coli in gastroenteritis of children in London and Jamaica.

The jejunal and stool flora of children with gastroenteritis in London and in Jamaica was examined. Although bacterial colonization of the small bowel was commonly detected, it was unusual to find the same serotype of E. coli in both jejunum and stool, and none of the jejunal strains of E. coli produced either heatlabile or heat-stable enterotoxin. Some strains of E. coli causing infant gastroenteritis are neither toxigenic nor invasive, and other mechanisms must be sought to account for their pathogenicity.

Acute Disease↗

The occurrence of plasmids carrying genes for both enterotoxin production and drug resistance in Escherichia coli of human origin.

Twenty-three of 89 enterotoxigenic strains of Escherichia coli were resistant to one or more antimicrobial agents. Eleven strains transferred resistance directly and five transferred resistance after mobilization. In three cases a resistant recipient was enterotoxigenic. One of these strains contained a conjugative plasmid carrying genes for both drug resistance and enterotoxin production. In the two other strains genes for drug resistance and enterotoxin production were carried on separate co-transferable plasmids.

Bacteriocin Plasmids↗

Transposition of ampicillin resistance to an enterotoxin plasmid in an Escherichia coli strain of human origin.

We examined a strain of Escherichia coli, serotype O159.H34, of human origin which produced heat-stable and heat-labile enterotoxins, was resistant to ampicillin, and produced colicin. By conjugation and transformation experiments plasmids coding for enterotoxin production (Ent), enterotoxin production and ampicillin resistance (Ap-Ent), ampicillin resistance (Ap), and colicin production were isolated. Both the Ent and Ap-Ent plasmids were autotransferring and belonged to the F-incompatibility complex. However, the Apr Ent+ transconjugants showed differences in their levels of resistance and in their abilities to propagate F-specific phages and to transfer resistance. The results suggested there was transposition from the small Ap plasmid to the Ent plasmid. The Ap-Ent plasmids were larger than the enterotoxin factor and when treated with restriction endonuclease BamHI showed an additional fragment not present in the enterotoxin plasmid. The insertion of ampicillin resistance probably occurred at different sites on the enterotoxin plasmid, resulting in the observed variation in phenotype.

Ampicillin↗

The role of Escherichia coli in gastroenteritis.

During the last 10 years there has been a major break-through in understanding the pathogenic mechanisms of E. coli as a cause of acute diarrhoea. The current situation is briefly tabulated in Table 3. In the near future the field of interest is likely to centre on the investigation of adhesive factors and certainly on the possibility of using preparations of adhesive factors as vaccines. The successful use of such vaccines may have enormous benefit as intervention measures to break the acute diarrhoea--malnutrition syndrome which is so damaging to the life of infants and young children in developing countries.

Acute Disease↗

A prospective study of enteropathogenic Escherichia coli in endemic diarrheal disease.

The rate of isolation of Escherichia coli belonging to the traditional serotypes enteropathogenic for infants was studied prospectively in two groups. Group 1 consisted of children with diarrhea and of controls without gastrointestinal disease who were matched for age and inpatient or outpatient status. Group 2 consisted of families entered in a prospective study of rotavirus infections. In group 1 enteropathogenic Escherichia coli were found in 13 (6%) of 220 children younger than 12 months of age and in nine (6%) of 143 children 12--35 months of age, all of whom had diarrhea. Enteropathogenic E. coli were found in only one of an equal number of matched controls (P = 0.002 and 0.004, respectively). In group 2 enteropathogenic E. coli were present in seven (18%) of 38 specimens obtained during diarrheal episodes, as compared with five (1%) of 492 specimens obtained when there was no diarrhea (P less than 0.001). The enteropathogenic E. coli isolated were not enterotoxigenic. The most common serogroup was O111, but many different O:H serotypes were detected. Thus, the association of enteropathogenic E. coli with endemic diarrhea was significant, even though no enteropathogenic mechanism was apparent.

Adolescent↗

Enterotoxigenicity of enteropathogenic serotypes of Escherichia coli isolated from infants with epidemic diarrhea.

Enteropathogenic serotypes of Escherichia coli which have been incriminated by epidemiological evidence as responsible for epidemics of acute diarrhea in infants are often found to be nontoxigenic when tested by conventional systems such as Y1-adrenal, Chinese hamster ovary, and suckling mouse assays. Twelve such strains, representing four different enteropathogenic serotypes, were examined for their capacity to elaborate toxic materials which alter water transport. Ultrafiltration fractions prepared to contain either a high-molecular-weight, heatlabile or a low-molecular-weight, heat-stable form of toxin from each strain were perfused through rat jejuna in graded concentrations ranging from 100 mug to 0.1 ng/ml. Ten of the twelve enteropathogenic strains produced one or both toxin forms that induced water secretion at concentrations of 1 to 10 ng/ml. Values in this range are considered indicative of clinically significant enterotoxigenicity in this assay system, and toxins from well-documented toxigenic strains examined in this study were active at these same concentrations. Similar preparations from ten control strains from healthy persons were either inactive or evoked water secretion only at concentrations of 10 to 100 mug/ml. These observations suggest that enteropathogenic serotypes of E. coli isolated from epidemics of infantile diarrhea produce diarrhea by elaborating potent heat-labile and heat-stable toxin forms which alter water transport but which are inactive in conventional assay systems. The manner in which these toxins differ either quantitatively or qualitatively from those which stimulate the conventional test systems is unknown.

Animals↗

Outbreak of infantile enteritis caused by enterotoxigenic Escherichia coli O6.H16.

Ten out of 18 babies at risk developed enteritis in an outbreak in a special-care baby unit. Salmonella, Shigella, and Escherichia coli belonging to the traditional infantile enteropathogenic serogroups were not found in faeces from the babies and the staff, and no virus particles were found by electron microscopy. Detailed serotyping of E. coli showed that five of the 10 babies with diarrhoea and one of the eight without diarrhoea were excreting E. coli O6.H16. All six isolates of this serotype produced both heat-labile and heat-stable enterotoxin. Enterotoxigenic strains of E. coli O6.H16 have caused outbreaks of enteritis in adults in the USA and Japan.

Disease Outbreaks↗