No abstract

The epidemiology of Clostridium difficile was studied prospectively in 451 newborn infants by daily screening of fecal samples. Colonization rates in three postnatal wards ranged from 2% to 52%. Many colonizations were sporadic, but on two wards there was evidence of clustering. On one of these occasions prospective environmental sampling yielded C. difficile organisms from a potential common source. Mothers were shown not to be the sources of their infants' organisms. Both toxin-producing and non-toxigenic strains were common; differentiation according to toxin type was epidemiologically useful. Cross contamination is the most likely explanation of the spread of C. difficile among hospitalized infants; the organism could spread among adults who are at risk of developing antibiotic-associated colitis in a similar manner.

SUMMARY The purpose of this study was to assess the carriage of Clostridium difficile by household pets to determine their potential as a reservoir of infection. The selective cycloserine-cefoxitin medium was used for C difficile isolation, and tissue culture used for detection of cytotoxin.Carriage of C difficile by household pets was found to be common (23%). The carriage tends to be transient and does not appear to be associated with gastrointestinal disease. Although carriage was higher in animals who had antecedent antibiotic treatment (31%) compared to those which had not (19%), the differences were not statistically significant. In most cases non-cytotoxigenic strains were isolated. Of the cytotoxigenic strains isolated at least one strain was pathogenic in a well documented animal model of human disease. Both cytotoxigenic and non-cytotoxigenic strains of C difficile could be isolated from the environment of the animals studied.

There has been an increasing body of evidence generated during the last few years which firmly implicates Clostridium difficile as the aetiological agent of both antibiotic and non-antibiotic associated pseudomembranous colitis (PMC).1-4 There is also recent evidence to implicate this microorganism in diarrhoea unrelated to PMC,4 and as a possible factor in some exacerbations of inflammatory bowel disease.5 6 As a result of these findings, an increasing number of laboratories are receiving requests to analyse stools for the presence of C difficile. These investigative procedures were greatly facilitated by the development of a sensitive selective agar incorporating cycloserine and cefoxitin as selective agents.7 8 The purpose of this study was to evaluate a simplified procedure for the isolation of C difficile from stools that was independent of a selective agar, and to further modify this procedure so that it was also independent of sophisticated anaerobic facilities.This study was divided into two parts. The first part was concerned with the evaluation of the use of alcohol to select for clostridial spores as a selective procedure (alcohol shock), compared to a selective antibiotic-containing medium, for the recovery of C difficile from faeces. The second part of the study evaluated a modification of this procedure that employed the minimum of anaerobe culture facilities (bench procedure).

Hypertension was produced in Sprague-Dawley rats by intramuscular injections of either corticosterone or ACTH. Lower increases in blood pressure to these challenges were observed in Sprague-Dawley rats pretreated with neomycin or vancomycin which alone had no effect on blood pressure or growth. The development of high blood pressure in spontaneously hypertensive rats of a stroke-prone substrain was also attenuated by oral administration of neomycin. These results suggest that experimental hypertension can be modulated by the administration of antibiotics.