Biomedical subjects
Publications and source records attributed to P Gianfrilli.
A cell-culture assay was used to detect toxins directly in stools from sporadic cases of infantile diarrhoea. Cytotoxins were revealed in 11 out of 58 samples from children with diarrhoea, nine of whom had no common enteric pathogens in their stools. A preliminary characterisation of the cytotoxins was obtained by neutralisation tests with clostridial antitoxins.
The in vitro activity of teicoplanin was compared with that of vancomycin against fecal isolates of Clostridium difficile. All strains were susceptible to both antibiotics, but teicoplanin was fourfold more active than vancomycin. Cholestyramine was found to bind teicoplanin almost completely, reducing its activity to nondetectable levels.
Direct gas-liquid chromatography of faecal specimens with isocaproic acid as a marker was used for the rapid diagnosis of Clostridium difficile associated diarrhoeal diseases. Ninety stools were examined and results were compared with conventional culture on selective medium and cytotoxin assay in tissue culture. Using a combined analysis of isocaproic acid and butyric acid peak heights we defined three categories: positive, negative, and indeterminate. When the indeterminate group was excluded, the positive and negative predictive values of gas-liquid chromatography analysis were 86.9% and 85% respectively compared with culture and 71.4% and 95% respectively compared with cytotoxin assay.
Between December 1982 and November 1983, stool specimens from 15 children with acute lymphoblastic leukemia, who were on maintenance cancer chemotherapy, were examined weekly for the presence of Clostridium difficile and its toxin. Four out of 15 patients were positive for C. difficile: three patients had stool specimens that did not contain toxin, but cultures yielded growth of toxigenic C. difficile on only one occasion. The fourth patient, who had a recent history of hospitalization, particularly aggressive cancer chemotherapy, neutropenia, and antibiotic therapy, excreted both C. difficile and its toxin for at least 1 month. All children were asymptomatic at the time of positive cultures. This preliminary study reveals a low rate of C. difficile colonization in leukemic children on maintenance cancer chemotherapy.
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30 strains of Cl. difficile isolated from faeces of patients with pseudomembranous colitis (PMC), antibiotic associated diarrhoea (AAC) and other intestinal disorders and from faeces of asymptomatic carriers were studied for production of toxins. Tissue culture assay was used for the detection of cytotoxin (toxin B) and ileal loop test for enterotoxin (toxin A). All Cl. difficile isolates from patients with PMC and AAC were found to produce cytotoxin, whereas enterotoxin was demonstrated only in approximately 70% of strains.
The "in vitro" susceptibility of 48 strains of "Clostridium difficile" to 12 antimicrobial agents was determined by agar dilution method. All isolates were susceptible to ampicillin, metronidazole, piperacillin, vancomycin and N-formimidoylthienamycin, resistant or intermediate to the new cephalosporins: cefoxitin, cefotaxime and moxalactam. For clindamycin, the MIC distribution appeared to be bimodal with 41.7% of the strains susceptible to 8 micrograms/ml and 58.3% resistant to 128 micrograms/ml; 90% of these strains were also resistant to erythromycin, tetracycline and chloramphenicol. The percentage of resistant strains in the isolates from patients with pseudomembranous colitis is significantly higher than in the isolates from patients with antibiotic-associated colitis.
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