SUMMARY In order to determine if gas-liquid chromatography (GLC) on concentrated stool extracts could be substituted to cell culture assay for cytotoxicity, we prospectively studied 154 diarrhoeal stools submitted for detection of Clostridium difficile toxin. Isocaproic-positive samples were cultured on egg yolk agar supplemented with cycloserine, cefoxitin and fructose for isolation of C difficile, and on egg yolk agar plus kanamycin for isolation of other clostridium species. Of the 154 samples, 129 were GLC-negative (height of the isocaproic peak less than 1-2 cm) and were toxin-negative. Twenty-five stools yielded isocaproic acid; C difficile isolated from 13 of them, six of which were also toxin-positive. Four other isocaproic-positive samples yielded C bifermentans and C sordellii; all were toxin-negative. These results indicate that a negative GLC is an excellent screening test for excluding C difficile infection; positive results must be checked by toxin testing and culture since they are not necessarily associated with the presence of C difficile or its toxin.

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We have studied 85 patients who received a renal transplant for CMV infection as well as for herpes simplex (HSV), herpes zoster (HZ), measles, mumps, rubella and hepatitis B. We found no evidence of primary or secondary infections for the non herpetic viruses except for hepatitis B infection that occurred in 17 per cent of the patients. CMV infection occurred in 87 per cent of the patients while antibody rises to HZ and HSV occurred in 30 and 13 per cent of the patients, respectively. The CMV infections occurred 2 to 4 months after the transplantation (mean time 11.1 weeks) and seemed to trigger the first episode of renal rejection that occurred earlier in the CMV infected group (mean time 12.1 weeks) than in the uninfected group (mean time 18.6 weeks). This difference in time is highly significant, p less than 0.001). However these CMV injections did not decrease the longterm survival of the grafted kidneys.

In vitro antibacterial activity of BL-S640 was compared to that of cephalothin and cephalexin against Gram-negative and Gram-positive bacteria isolated from clinical specimens. BL-S640 demonstrated the best activity on nearly all microbial species studied, except for Haemophilus influenzae and Diplococcus pneumoniae against which cephalothin was slightly more active.new broad-sepctrum semi-synthetic cephalosporin, which is water-soluble and well absorbed by man1) and animals after oral administration2).The present study reports the comparative minimal inhibitory concentrations (MIC) for BL-S640, cephalothin (considered as the leading cephalosporin) and cephalexin (considered as the most representative of the oral cephalosporins) against strains isolated in human pathology. Material and Methods Microbial strainsThe 99 bacteria studied were recently isolated from clinical specimens (urine, blood, pus, sputum, etc.) collected at the Hepital Universitaire Brugmann, Brussels. Included in the survey were 13 strains each of Salmonella, Proteus, Klebsiella, Escherichia coli, H. influenzae, 8 strains of Listeria monocytogenes, 13 strains of Streptococcus faecalis and 13 strains of D. pneumoniae.Antibiotic sensitivity testing MIC were determined by an agar dilution technique, on MUELLER-HINTON Agar BBL, to which were added, in the case of D. pneumoniae, Haemophilus and St. faecalis, 3 ug per ml of factor V (nicotinamide-adenine dinucleotide phosphate-BDH Chemicals Ltd.) and 2% defibrinated horse blood. Serial twofold dilutions of the antibiotics (BL-S640, powder for analysis, Bristol; cephalothin and cephalexin, Lilly) were prepared, starting from initial concentrations of 100 pg per ml. Overnight MUELLER-HINTON broth cultures were diluted to contain 10 5 organisms per ml for E. coli, Klebsiella, Listeria, Proteus and Salmonella. D. pneumoniae, Haemophilus and St. faecalis were grown in the same medium supplemented with 0.5% defibrinated horse blood in a 5 % CO2-enriched atomsphere, and diluted to contain 10 6 organisms per ml. These inocula were spotted with an automatic multipoint inoculator onto the surface of the agar plates'). D.pneumoniae and Haemophilus were incubated in a 5 % CO2 -enriched atmosphere.Results were read after overnight incubation at 37°C. The MIC was designated as the lowest antibiotic concentration yielding no colony at the site of inoculation.Disk diffusion tests were performed according to the method described by BAUER et al.4) using the same media as in the MIC determination, and disks containing 30 leg of cephalothin, cephalexin or BL-S640.Inhibition zones were measured with a caliper after overnight incubation at 37°C.

The antibacterial activity of thiamphenicol was compared to that of chloramphenicol against 313 strains of gram-negative bacilli isolated from various clinical specimens. These two antibiotics were equally active against the 106 isolates of Haemophilus (MIC = 0.1–1.56 μg/ml) and against 40 strains of Bacteroides fragilis (almost all strains being inhibited by 12.5 μg/ml of the two drugs). In contrast, when compared with chloramphenicol, 2–16 times as much of thiamphenicol was required to inhibit Enterobacteriaceae, making prediction of the susceptibility of these strains to thiamphenicol on the basis of chloramphenicol testing alone likely to be hazardous. Disc diffusion test using 30-μg discs and 12 mm as cut-off point was a reliable technique to determine susceptibility of bacteria either to chloramphenicol or thiamphenicol. When thiamphenicol discs of greater potency (50 μg) were employed, many strains exhibited wide zones of inhibition although most of them were resistant by the agar dilution method (MIC > 12.5 μg/mL). This practice is not advisable for testing organisms isolated outside of the urinary tract.