Selective and differential medium for isolation of Clostridium difficile

Application of a technique for serogrouping Clostridium difficile in an outbreak of antibiotic-associated diarrhoea

A severe outbreak of Clostridium difficile antibiotic-associated diarrhoea (AAD) in an orthopaedic surgical unit is reported. Thirty-seven cases and eight relapses were observed. The 45 related strains together with another 13 strains of C. difficile isolated during the same period in other wards of the same hospital were typed by detection of cytotoxin production, determination of sorbitol fermentation and serogrouping by agglutination with six rabbit antisera defining the serogroups A, B, C, D, F and G. All the strains from the outbreak belonged to serogroup C, were toxigenic and fermented sorbitol. In contrast, four different patterns were observed in seven isolates from cases of AAD in other wards. Finally, six strains isolated from four asymptomatic adults, one adult suffering from shigellosis and one child with salmonellosis demonstrated two patterns different from that of the epidemic isolates. The data strongly suggest nosocomial spread of this micro-organism.

Idiopathic chronic watery diarrhea from excluded rectosigmoid with goblet cell hyperplasia cured by restoration of large bowel continuity

A 73-year-old woman developed abnormal electrolyte and water loss from an excluded rectosigmoid segment after surgical treatment of a volvulus of the sigmoid colon. Rectal discharges lasted almost for a year, until it spontaneously resolved after restoration of large bowel continuity. Despite extensive investigation, including endoscopic, radiologic, microscopic, bacteriologic and parasitic examinations, no satisfactory explanation of the diarrhea could be found. The histologic pattern of the excluded segment showed a striking increase in mucosal thickness and in number and height of goblet cells. These abnormalities disappeared after closure of the colostomy. Electrolyte composition of the rectal fluid, which contained 134 mmol potassium and 22 mmol sodium per liter was remarkable and similar to that of normal stool water and anal discharges of patients with ulcerative proctitis.

Review of Clostridium difficile-associated diseases

Clostridium difficile has recently become recognized as an important nosocomial pathogen. This review summarizes what is known about the isolation of the organism, the spectrum of clinical disease, virulence factors, treatments, and methods of prevention. Risk factors for C. difficile disease are also discussed. The most important risk factor is the use of certain antibiotics (ampicillin, cephalosporins, and clindamycin). C. difficile is associated with 96% to 100% of cases of pseudomembraneous colitis, 60% to 75% of antibiotic-associated cases of colitis, and 11% to 33% of antibiotic-associated cases of diarrhea. Other risk factors include gastrointestinal manipulations, advanced age, female sex, inflammatory bowel disease, cancer chemotherapy, and renal disorders. Hospital outbreaks of C. difficile disease are examined. Data from nosocomial outbreaks support transmission of C. difficile by contaminated fomites and hand carriage by hospital personnel.

Antibacterial susceptibility of Clostridium sordellii strains

A total of 24 Clostridium sordellii strains was tested for susceptibility to 24 antibacterial agents. All strains exhibited a high degree of resistance to streptomycin, kanamycin, sulfamethoxazole, and trimethoprim.

Effect of clindamycin on the ability of a continuous culture of colonic bacteria to ferment carbohydrate

A continuous culture model of the proximal colon was used to study the effect of clindamycin on the ability of colonic bacteria to ferment carbohydrate. Six steady state anaerobic cultures of human faeces, in a medium simulating ileostomy effluent, were treated with 26 micrograms/ml clindamycin. They were paired with six untreated cultures, run under identical conditions. Clindamycin treatment eliminated the anaerobic bacteria, significantly decreased osmolality and the output of volatile fatty acids, particularly propionic acid and increased the residual carbohydrate concentration. Doubling the amount of carbohydrate in the medium increased osmolality and the production of volatile fatty acid, though the response of clindamycin treated cultures was less than that of untreated cultures. Attempts to introduce Clostridium difficile into three pairs of cultures were successful in only two cultures after administration with clindamycin and when a heavy inoculum (10(6)-10(9) organisms) had been used.

Selective medium for the isolation of Bacteroides gingivalis

Bacteroides gingivalis has been implicated in various forms of periodontal disease and may be responsible for other diseases in humans. The role of B. gingivalis in disease has been difficult to assess, because it is inhibited by most selective media commonly used by clinical laboratories to aid in isolating gram-negative, nonsporeforming anaerobes. We have developed a new medium, Bacteroides gingivalis agar, which contains bacitracin, colistin, and nalidixic acid as selective agents. This medium allowed B. gingivalis to be isolated from oral specimens with little difficulty and also allowed B. gingivalis to be isolated from phenotypically similar Bacteroides species, such as B. asaccharolyticus and B. endodontalis, with which it can easily be confused.

Clinical considerations in the diagnosis of antimicrobial agent-associated gastroenteritis

Most gastrointestinal infections secondary to the use of antimicrobial agents that have been documented are related to overgrowth of Clostridium difficile which produces a spectrum from severe pseudomembranous colitis to mild diarrhea or asymptomatic carriage. The most common inducers of pseudomembranous colitis or antimicrobial agent-associated diarrhea are ampicillin, clindamycin, and various cephalosporins, but almost all antimicrobials may cause this problem. Symptoms vary from watery to bloody diarrhea; the extent and severity of the diarrhea, fever, and abdominal cramps and the incidence of complications (such as toxic megacolon and perforation of the bowel) and of fatality are variable. Normal carriage of C. difficile in infants and asymptomatic carriage in adults who have received antimicrobial therapy make it impossible to rely on culture for diagnosis. The presence of cytotoxin or enterotoxin produced by C. difficile is much more reliable diagnostically, but there may be false-positives with this as well, particularly in infants. However, the combination of the appropriate clinical picture and background and presence of toxin usually permit accurate diagnosis. The definitive method of diagnosis, often not feasible to employ, is demonstration by colonoscopy or sigmoidoscopy of the pathognomonic yellow, elevated plaques on the colonic mucosa. Colonoscopy is preferred since the plaques may be restricted to the right colon, particularly in early cases. From the practical standpoint, the best diagnostic test is demonstration of C. difficile toxin.

Considerations in the laboratory diagnosis of antibiotic-associated gastroenteritis

Clostridium difficile has been shown to be the major cause of antibiotic-associated gastroenteritis in both humans and experimental animals. During the past few years an increasing number of laboratories have attempted to detect, isolate, and identify this organism and its toxin from clinical samples. Direct visualization of C. difficile in patient specimens using immunofluorescent microscopy has been proposed. The major disadvantage of this method was its lack of specificity due to crossreaction with other clostridial species. Attempts to absorb the antisera with crossreacting strains also failed. Laboratory diagnosis of C. difficile in clinical specimens has relied on either culture using one or more selective media or on the detection of specific cytotoxin in stool filtrates. Until recently the cytotoxicity assay was the only procedure available for the routine detection of cytotoxin and, as a result, has limited this test to laboratories with access to tissue culture facilities. As a result, there has been much interest in the development of immunochemical methods for the detection of C. difficile toxins. We originally reported on the detection of C. difficile toxin in stool filtrates using counterimmunoelectrophoresis. We examined 140 fecal specimens submitted for C. difficile toxin assay by counterimmunoelectrophoresis, using both unabsorbed and absorbed antitoxin, tissue culture, and bacterial culture. Using tissue culture assay as the reference method, the sensitivity of counterimmunoelectrophoresis and counterimmunoelectrophoresis-absorbed was 100% and the specificity 63.0% and 77.5%, respectively. Enzyme immunosorbent assays for the detection of toxin A from C. difficile have also been reported, however, at the present time they do not appear to be as sensitive as the cytotoxicity assay for toxin B (cytotoxin).(ABSTRACT TRUNCATED AT 250 WORDS)

Significance of Clostridium difficile and its cytotoxin in children

Stools of 147 children belonging to different age groups were examined for the presence of Clostridium difficile, its cytotoxin and other enteric pathogens. None of the 31 full-term neonates, 5 (16%) of the 32 premature neonates, 27 (46%) of the 59 infants and 1 (4%) of the 25 older children excreted C. difficile in their stools. Faecal cytotoxin was only detected in four infants (7%). There was no correlation with diarrhoea, previous antibiotic therapy, type of diet, or the concomitant presence of other intestinal pathogens. We conclude that colonisation of the intestine by C. difficile is probably acquired from environmental sources and that it cannot be regarded as a significant cause of diarrhoea in children.

Latex particle agglutination for detecting and identifying Clostridium difficile

A total of 329 selective enrichment broth cultures were tested for detection of Clostridium difficile by latex particle agglutination (LPA), gas-liquid chromatography, and bacterial culture. Of 53 broths positive by LPA, 36 were positive by gas-liquid chromatography, and 42 were positive by bacterial culture. The sensitivity and specificity of LPA relative to bacterial culture was 95.6% and 96.3%, respectively, while the sensitivity and specificity of gas-liquid chromatography relative to bacterial culture was 84.6% and 100%, respectively. The high predictive value of a negative test (99%) should make LPA on broth cultures a good screening test for detecting C difficile. Of several other Clostridium spp tested in pure culture, strains of C sordellii and C bifermentans also gave a positive result by LPA. These results, together with the low cost and simple facilities required, suggest that the LPA test will be a useful procedure for the presumptive identification of C difficile in selective enrichment broths and for the identification of pure cultures.

Variations in the anaerobic faecal flora of ten healthy human volunteers with special reference to the Bacteroides fragilis-group and Clostridium difficile

Ninety nine stool specimens of ten healthy human volunteers were collected over a one year period, and processed anaerobically. The individual variations in intestinal colonization with bacteria of the Bacteroides fragilis-group were detected, using the Bacteroides Bile Esculin medium and an identification scheme for bile-resistant Bacteroides species. Clostridium difficile agar supplemented with cycloserine/cefoxtin was used to detect the incidence of C. difficile in this group. The species of the B. fragilis-group most often detected were: B. vulgatus (in 31 samples from ten persons), B. uniformis (22/9), B. fragilis (19/7). C. difficile was never detected in this group. The mean total anaerobic cultural counts (log) of the ten volunteers varied between 9.94 and 10.91. This shows that interindividual variations in anaerobic cultural counts of about one log are common. In spite of these moderate interindividual variations, intraindividual variations in time of up to three log were detected. The mean Bacteroides cultural counts showed a variation between 8.83 and 10.24. The mean DMCCs of the ten volunteers were between 10.22 and 10.73. We conclude that at least a three to four log difference from the control samples will be required to establish a significant change in anaerobic cultural count due to antibiotic treatment.

Diagnosis of Clostridium difficile-associated intestinal disease

Toxigenic Clostridium difficile is the major cause of antimicrobial agent-associated pseudomembranous colitis and is the etiological agent of approximately 30% of cases of nonspecific colitis and diarrhea (without colitis) induced by antimicrobial agents. In addition, C. difficile has been implicated in certain intestinal diseases not related to prior antimicrobial administration. C. difficile has been reported to be one of the most common enteropathogens isolated from stool specimens submitted to hospital laboratories. Thus, diagnosis of C. difficile-associated intestinal disease should now be routinely performed in diagnostic clinical laboratories. The diagnosis of C. difficile-associated intestinal disease relies on the demonstration of either the organism or the toxin(s) in stool specimens or antibody response in serum to the toxin(s). Several selective medium are available for the recovery of C. difficile from stool specimens. The toxin(s) of C. difficile can be demonstrated using a variety of techniques, including biological assays as well as immunological assays. This article will review the techniques currently available to aid in the diagnosis of C. difficile-associated intestinal disease.

Effect of moxalactam on human fecal microflora

Five healthy male adults received 2 g of moxalactam every 12 h for 7 days. The alterations of fecal microflora were investigated before, during, and after treatment with moxalactam. On day 7 of treatment, the number of total bacteria was decreased in all subjects. There was marked suppression of the obligate anaerobic bacteria and enterobacteria to undetectable levels, but the counts of Streptococcus spp. and Lactobacillus spp. increased. On day 7, two subjects had Clostridium innocuum and Clostridium ramosum in their feces but not Clostridium difficile. On day 7 after treatment, the counts of Streptococcus spp., enterobacteria, Lactobacillus spp., and Clostridium spp. in all subjects were still not normal.

Clostridium difficile-associated diarrhea follows perioperative prophylaxis with cefoxitin

Clostridium difficile-associated diarrhea during prolonged therapy of obstetric and gynecologic infections is known to occur with use of all classes of antibiotics except vancomycin and the aminoglycosides. We present 11 cases of C. difficile-associated diarrhea which followed a short course of perioperative prophylaxis with cefoxitin during a 1-year period. Nine of the cases of C. difficile-associated diarrhea were among 162 women who received cefoxitin perioperative prophylaxis for cesarean section or hysterectomy, but none occurred in 85 women who received one of four other antibiotics for perioperative prophylaxis (p = 0.024, Fisher's exact test). The two other occurrences of C. difficile-associated diarrhea following perioperative prophylaxis with cefoxitin were in women who underwent exploratory laparotomy. We conclude that C. difficile-associated diarrhea is related to perioperative prophylaxis with cefoxitin.

The significance of quantitative results of C. difficile cultures and toxin assays in patients with diarrhea

The clinical courses of 114 patients with positive Clostridium difficile cultures or toxin assays performed between 1981 and 1984 were reviewed to determine the relationship between outcome of treatment and quantitative bacteriologic test results. C. difficile culture was positive in 60 of 91 patients while toxin assay was positive in 99 of 114. One third of the patients received supportive therapy only, and 30 percent of these failed to resolve their symptoms. Ninety-one percent of the patients treated with vancomycin resolved, although 11 percent of these suffered relapse. Patients with high toxin titers receiving supportive treatment alone showed a lower response rate than patients with lower toxin titers. This effect was not seen in patients treated with specific therapy nor with different culture quantities. C. difficile colitis has a range of clinical and microbiologic manifestations. Endoscopy is not always diagnostic, both culture and toxin assays are needed for diagnosis, and toxin titer may help in planning treatment. Patients with low toxin titers may be treated supportively, but high toxin titers are an indication for specific therapy. Quantitative culture results have little diagnostic or therapeutic value.

Antibiotic-associated colitis due to Clostridium difficile: double-blind comparison of vancomycin with bacitracin

A randomized double-blind study was carried out in patients with unresolving antibiotic-associated colitis due to Clostridium difficile, to compare the effect of bacitracin (80,000 U/day) with vancomycin (500 mg/day) on the resolution of symptoms, clearance of organism, and prevention of relapse. Forty-two patients with colitis, 9 of whom had a pseudomembrane, were randomized, 21 patients to each treatment group. The two groups were comparable in age, disease severity, and antibiotic exposure. For a 50% reduction in stool frequency the mean times (+/- SE) were 4.1 +/- 0.4 days for bacitracin and 4.2 +/- 0.4 days for vancomycin. Sixteen patients (76%) had symptom resolution after 7 days of treatment with bacitracin, compared with 18 patients (86%) given vancomycin. Patients who failed to respond were crossed over (blind) to the alternative antibiotic, but tended to be refractory to the alternative medication as well. Vancomycin-treated patients had negative toxin (83% vs. 53%, p = 0.04) and negative stool cultures (81% vs. 52%, p = 0.02) more frequently than did those patients given bacitracin. Similar numbers of patients in each group had symptomatic relapse during 1 mo of follow-up, but most of them relapsed yet again after blinded crossover therapy. Although bacitracin was significantly less effective than vancomycin in clearing C. difficile from the stools, both were of similar value in the control of symptoms in a group of patients with predominantly nonpseudomembranous colitis. In view of its low cost, bacitracin is a reasonable first-line alternative to vancomycin in the treatment of antibiotic-associated colitis.

Identification of Clostridium difficile using the API ZYM system

The use of the API ZYM system for the identification of Clostridium difficile was investigated. The enzyme profiles generated by this system readily distinguished strains of Clostridium difficile from other clostridia commonly isolated from faeces. Enzyme activity of Clostridium difficile was influenced by the composition of the culture medium but appeared to be independent of the age of the culture. Given careful standardisation of techniques the API ZYM system is a suitable alternative to conventional techniques for identification of Clostridium difficile.

Clostridium difficile colitis in leukemia patients

Leukemia patients with diarrhea or other abdominal symptoms have been investigated for the presence of Clostridium difficile and its cytotoxin in stools. Of the patients studied 19% had C. difficile, in most cases together with cytotoxin. All patients but one had received antibiotics, while one had been treated with cytotoxic agents only. Symptoms of colitis were most often abdominal pain and distension rather than diarrhea. Owing to the not infrequent fatal evolution, it is recommended that routine search for C. difficile in leukemia patients with abdominal symptoms be performed and appropriate therapy started immediately.

Evaluation of gas-liquid chromatography for the rapid diagnosis of Clostridium difficile associated disease

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.

The development of bacterial flora of premature neonates

The sequential acquisition of bacterial flora by premature neonates was studied during a 10 month period. Mean gestational age of the babies was 29.01 weeks and the mean birth weight was 1.728 kg. Escherichia coli and group B streptococci (GBS) colonized the umbilicus of 7 and 6 babies respectively, out of 23 studied, on the first day of life. E. coli and staphylococci were the predominant flora on the 6th day and they colonized 12 and 13 respectively. The oral flora was predominantly Gram-positive cocci, mainly Streptococcus salivarius which was isolated from 17 out of 22 babies on the 6th day, viridans streptococci were isolated from 14 babies, Staphylococcus albus from 16 babies and group D streptococci from 11 babies. Candida spp. also colonized the oral cavities of 17 out of 22 babies on the 6th day. At the end of the first week of life, the faecal flora was predominantly anaerobic represented by Bifidobacterium spp., Bacteroides spp. and Clostridium spp. The commonest facultative faecal flora were E. coli, which was isolated from all the babies, and Strept. faecalis isolated from 20 babies. Early gut colonization by GBS, Bacteroides spp. and Clostridium spp. was noticed in more babies delivered vaginally than by caesarean section where colonization by these bacteria was relatively delayed. The use of prophylactic penicillin plus gentamicin in the special neonatal unit probably prevented systemic spread of any of the potential opportunistic pathogens during the study.

Clostridium difficile isolation in leukemic children on maintenance cancer chemotherapy. A preliminary study

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.

Enzyme immunoassay for detection of Clostridium difficile toxins A and B in patients with antibiotic-associated diarrhoea and colitis

A sandwich enzyme immunoassay (ELISA) was developed to detect Clostridium difficile toxins A and B in stools from patients with antibiotic associated diarrhoea and colitis. Immune serum to crude Clostridium difficile toxin and non-immune serum were coated onto polystyrene microtiter plates to act as capture antibodies; toxins A and B in human stools were detected by antibodies from rabbits immunized with purified toxins A and B. The ELISA for toxin B showed cross-reactions with Clostridium bifermentans and Clostridium sordellii and lacked diagnostic sensitivity in clinical samples. The ELISA for toxin A showed no cross-reactions with other clostridiae investigated and was positive in 33% (62/189) of patients with antibiotic associated diarrhoea. This compared with 38% (71/189) positive in the tissue culture assay for Clostridium difficile cytotoxin. With a predictive value of 96% in clinical specimens, the ELISA for toxin A constitutes a sensitive and specific tool for diagnosis of Clostridium difficile associated diarrhoea and colitis.

Effect of adding sodium taurocholate to selective media on the recovery of Clostridium difficile from environmental surfaces

The recovery of Clostridium difficile on a medium containing cefoxitin, cycloserine, fructose, and egg yolk was compared with that on media containing one of three preparations of sodium taurocholate. In aerobic environments contaminated with C. difficile, media containing either crude taurocholate from Mann Research Laboratories, New York, N.Y., or pure taurocholate from Sigma Chemical Co., St. Louis, Mo., recovered organisms significantly more often than did cefoxitin-cycloserine-fructose-egg yolk agar.

Serogrouping of Clostridium difficile strains by slide agglutination

Six different agglutinating antisera were obtained by immunizing rabbits with Formol-treated strains of Clostridium difficile. After appropriate absorption, these antisera were used to define six serogroups designated by the letters A, B, C, D, F, and G. Altogether, 315 strains of C. difficile from various origins were tested for slide agglutination by these antisera; 312 (99%) of them were agglutinated by one of these antisera. A and C were the most common serogroups. An excellent correlation, ranging from 85 to 100%, was found between the serogroup and the toxigenicity of the strains. The correlation between serogroup and sorbitol fermentation was higher, ranging from 89 to 100%. The results of this typing were compared with the clinical origin of the strains. Only strains of serogroups A, C, and D were isolated in 153 cases of antibiotic-associated diarrhea. This series included strains from three outbreaks; all the strains in two of the outbreaks belonged to serogroup C, and in the third, all the strains belonged to serogroup A. Strains of serogroups B, F, and G were only found in the stools of asymptomatic neonates or young children. In the latter samples, strains of serogroups A and D were found in the same ratio as in adults with antibiotic-associated diarrhea, but strains of serogroup C were seldom isolated. In patients treated with antineoplastic drugs and suffering from diarrhea, the distribution of the strains was the same as in cases of antibiotic-associated diarrhea.

Etiology of acute infectious diarrhea in a highly industrialized area of Switzerland

During an 18-mo period between 1981 and 1982, a prospective study was conducted in 119 adult patients with acute diarrhea. A diarrhea-inducing microorganism or toxin could be identified in 38.7% of the patients. Salmonella sp and Campylobacter jejuni were the leading agents that caused diarrheal illness in 25% of the investigated population. Clostridium difficile was found in 6%, mainly after previous antibiotic therapy. Rotavirus was rarely isolated and enterotoxigenic Escherichia coli were not found. Clinical features in patients in whom an invasive agent was isolated did not differ from those in patients in whom no enteropathogens were found, although the occurrence of fecal leukocytes and positive hemoccult tests in the former group was significantly more frequent. More than 30% of the patients with negative stool cultures, however, showed fecal leukocytes and positive occult blood, which is suggestive of the existence of one or more invasive agent(s) so far unknown or not recognized.

Gas chromatographic identification of Clostridium difficile and detection of cytotoxin from a modified selective medium

A modification of an existing selective medium for Clostridium difficile is described. Inclusion in the medium of DL nor-leucine and p-hydroxyphenylacetic acid enables identification of C difficile to be made directly from primary isolation plates by gas chromatographic detection of caproic acid and p-cresol. Plugs of agar withdrawn from the selective medium also allow the detection of cytotoxin production in vitro.

Clinical and endoscopic findings in patients early in the course of clostridium difficile-associated pseudomembranous colitis

Endoscopic and clinical features are reported for 39 patients detected early in the course of pseudomembranous colitis. Disease was detected early by virtue of careful surveillance in patients in whom diarrhea developed. Early proctosigmoidoscopic findings in pseudomembranous colitis are illustrated. Clinical presentation includes development of fever, leukocytosis, abdominal pain, and even an ileus picture on radiography in addition to diarrhea.

Criteria for detection of Clostridium difficile toxin production by counterimmunoelectrophoresis

Counterimmunoelectrophoresis (CIE) was compared with a cytotoxicity assay and isolation of toxin-producing Clostridium difficile for the diagnosis of antibiotic-associated diarrhea. Standardized criteria for CIE positivity were established as two major precipitin lines with specific C. difficile antitoxin. Using these criteria on 425 fecal specimens, we determined the sensitivity of CIE (80%) to be comparable to that of the cytotoxicity assay (82%). Both methods were highly specific. With carefully controlled techniques, CIE can be used in routine diagnostic laboratories to screen for toxigenic C. difficile.

Clostridium difficile colitis

We reviewed all rectal biopsies performed on patients with proven C. difficile infection between 1977 and 1982 (36 patients). All patients were symptomatic and all had received antibiotic treatment recently, the commonest antibiotic treatment being ampicillin or amoxycillin. There was poor correlation between the histological appearances and the severity of symptoms. A range of histological appearances was observed: normal (8%), congestion and edema (8%), nonspecific colitis (3%), infective colitis (28%) and pseudomembranous colitis (53%) (PMC). Most cases of PMC showed 'early' features, involving predominantly the surface epithelium, where attenuation and inflammation, intraepithelial microabscesses, and small eruptive lesions were seen. Recognition of these features, in the context of an acute infective-type colitis, may lead to early diagnosis of C. difficile colitis.

Frequency-pulsed electron capture gas-liquid chromatographic analysis of metabolites produced by Clostridium difficile in broth enriched with amino acids

Clostridium difficile strain CDC A-567 was cultured in Trypticase (BBL Microbiology Systems)-yeast-salt broth supplemented with 0.2% L-leucine, L-norleucine, L-isoleucine, L-tyrosine, or L-tryptophan. Four extractions were done on the spent medium, three at pH 2 and one at pH 10, using CHCL3 or ether. Derivatizations were done with trichloroethanol, heptafluorobutyric anhydride, and heptafluorobutyric anhydride-ethanol. All samples were analyzed with frequency-pulsed electron capture gas-liquid chromatography. A dedicated computer was used to assist in data analysis. C. difficile produced both short-chain and aromatic acids in Trypticase-yeast-salt broth; hydroxy acids were also detected. p-Cresol, indoleacetic acid, 4-methylthio-2-hydroxybutyric acid, and some unidentified alcohols were observed. The basic chloroform extraction contained cadaverine and putrescine. Leucine, norleucine, and isoleucine influenced the production of C5 and C6 acids and alcohols. L-Tyrosine underwent successive degradation to produce p-cresol and aromatic acids as final products. Tryptophan increased the production of indoleacetic, indolepropionic, and indolebutyric acids. Isocaproic acid was produced in relatively high concentrations regardless of medium substitution. The consistent production of iC6 under various substrate conditions indicates that the production of this compound might be consistent enough in vitro to form the basis of a rapid test for detection of C. difficile in stool specimens by frequency-pulsed electron capture gas-liquid chromatography.

Studies of stools from pseudomembranous colitis, rotaviral, and other diarrheal syndromes by frequency-pulsed electron capture gas-liquid chromatography

Thirty-five patients with various diarrheal syndromes and 22 controls were studied. All stool samples were carefully cultured for Clostridium difficile, using selective isolation media. Cytotoxin assays with proper antitoxin neutralization were done in MRC-5 cells. The stool samples were extracted four times, three times at pH 2 and once at pH 10, using CHCl3 or ether. Derivatizations of extracts were done with trichloroethanol, heptafluorobutyric anhydride, and heptafluorobutyric anhydride-ethanol, and all derivatives were analyzed by frequency-pulsed electron capture gas-liquid chromatography (FPEC-GLC). A dedicated computer was used to assist in both qualitative and quantitative data analysis. Isocaproic acid (iC6) was always found in stool from which C. difficile was isolated and was absent in C. difficile-negative specimens. p-Cresol was found frequently in both persons with pseudomembranous colitis and controls. Tryptamine was found in stool containing C. bifermentans. The FPEC-GLC profiles of persons with acute diarrhea were very different from those of normal persons. Diarrhea associated with adenovirus and rotavirus, Klebsiella spp., and Escherichia spp. showed different FPEC-GLC patterns. Stools from well persons consistently contained full-scale peaks of pyruvic, acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids. In rotavirus stools isobutyric, isovaleric, and valeric acids were reduced in quantity from those found in control stools, whereas propionic and butyric acids were increased.

Clostridium difficile-associated diarrhoea

During the course of 1 year, Clostridium difficile was isolated from 145 (4 per cent) of 3591 faecal specimens submitted to a hospital routine bacteriology laboratory. These C. difficile positive specimens came from 95 patients or 10.99 per cent of 864 patients investigated for suspected gastroenteritis. In a control population of 318 persons C. difficile was isolated from only 10 of them or 3.1 per cent; this difference was statistically significant. We conclude that as this increase in the isolation of C. difficile from patients with diarrhoea is significant and is about as frequent as that of Campylobacter spp., faecal specimens submitted for routine bacteriology should also be cultured for C. difficile . As with diarrhoea caused by other enteric pathogens, most C. difficile -associated episodes of diarrhoea are mild and spontaneously reversible but approximately 20 per cent of patients have prolonged diarrhoea and may benefit from treatment.

Enterotoxigenic Clostridium perfringens: a possible cause of antibiotic-associated diarrhoea

Free Clostridium perfringens enterotoxin was detected in the stools of 11 patients with diarrhoea. All had high faecal counts of enterotoxigenic strains of C perfringens, mostly of serotypes not commonly associated with food poisoning. 10 of these 11 patients had severe or prolonged diarrhoea which had developed after antibiotic treatment. Enterotoxigenic C perfringens appears to be one of the causes of antibiotic-associated diarrhoea.

Detection of Clostridium difficile in faeces by direct gas liquid chromatography

Stool specimens examined for the presence of Clostridium difficile and its cytotoxin were screened by gas liquid chromatography for the presence of volatile fatty acids and p-cresol. Twenty seven of 110 (25%) stools yielded C difficile or cytotoxin; iso-valeric acid was detected in 63/110 (57%) and iso-caproic acid in 18/110 (16%) stools. Para-cresol was found in 24/71 (34%) stools examined. Iso-valeric acid was detected in 85% of stools positive for C difficile, whereas iso-caproic acid (41%) and p-cresol (52%) were found in much lower numbers of C difficile-positive stools. It is concluded that gas chromatographic detection of volatile fatty acids or p-cresol in faeces are not satisfactory screening tests for the presence of C difficile.

Relapsing Clostridium difficile enterocolitis cured by rectal infusion of normal faeces

Repeated recurrence of Clostridium difficile-associated enterocolitis is uncommon but troublesome for the afflicted patient. The patient described here received vancomycin treatment several times but always had a relapse of C. difficile enterocolitis 2-3 weeks after discontinuation of treatment. She did not form serum antibodies to C. difficile cytotoxin (toxin B). Rectal infusion of enemas prepared from fresh faeces resulted in final cure.

A screen for Clostridium difficile in the vagina: an out-patient study using and comparing selective media

Cycloserine-Cefoxitin-Fructose Agar (CCFA) gives good presumptive identification of Clostridium difficile after 1- or 2-day incubation whereas Reinforced Clostridial Medium (RCM)/p-cresol is not very selective for the organism from the vagina. The identification of 91.5% of the isolates from an initial screen subjected to biochemically based tests was achieved. Conventional screening of vaginal swabs failed to confirm any significant occurrence of Cl. difficile in the vagina of pregnant or non-pregnant women. The incorporation of an enrichment stage in the isolation procedure, however, did reveal a significant presence of the organism in the vagina of both pregnant and non-pregnant women.

Clostridium difficile in young children. Association with antibiotic usage

Clostridium difficile was isolated from the stools of 11/52 (21%) of children aged 0 to 2 years hospitalized with diarrhoea, and from 17/52 (33%) of a control group of hospitalized children with no diarrhoea; this difference was not significant. Direct demonstration of C. difficile toxin from the stools was positive in 1 case with diarrhoea and in 5 control cases. The children with positive stool culture for C. difficile had had significantly more treatments with antibiotics or chemotherapeutics than those with negative C. difficile culture (3.3 +/- 2.7 vs. 1.6 +/- 1.8, p less than 0.001), but there was no significant difference in the incidence of diarrhoea in the past. During a 4-6-month follow-up, C. difficile disappeared from the stools of 24 out of 28 initially culture-positive children; 3 of the 4 children with persistent C. difficile had received antibiotics during the follow-up period. We conclude that the presence of C. difficile is common in the stools of young children up to the age of 2 years, and that C. difficile is more frequently found in children who have received antimicrobial therapy. Most cases of C. difficile carriage state are symptomless at this age.

Pseudomembranous colitis with recurring diarrhoea and prolonged persistence of Clostridium difficile in a 10-year-old girl

A 10-year-old girl developed, after treatment with amyxocillin, a clinically and sigmoidoscopically apparent pseudomembranous colitis with positive Clostridium difficile stool culture. Treatment with vancomycin resulted in rapid clinical cure, but there was a relapse of diarrhoea and reappearance of C. difficile, with no pseudomembranous colitis, within one month. Clinical symptoms subsided spontaneously but C. difficile persisted for 2 more months in the stools. This case reflects three different aspects of C. difficile infection in one child: pseudomembranous colitis, ordinary diarrhoea, and symptomless carrier state.

Incidence and origin of Clostridium difficile in neonates

The stools of 65 of 92 (71%) infants in a special care nursery yielded Clostridium difficile on culture. Ninety percent of stools collected after 6 to 35 days in the unit were positive, and 36% of these also contained toxin. When tested in vitro, 94% of the isolates produced toxin. Of 110 swabs collected from the environment of the unit, 9% were positive for C. difficile, but the stools of 12 nurses working on the unit were negative. Thirty-five vaginal swabs collected from mothers just before delivery were negative for C. difficile on culture, but 16 of their infants had C. difficile in their stools. It was concluded that there is a high carriage rate in the stools of neonates of C. difficile acquired progressively during the course of their stay in the special care unit. Infection is mainly from environmental sources rather than maternal transmission.

Prospective randomised trial of metronidazole versus vancomycin for Clostridium-difficile-associated diarrhoea and colitis

101 patients with Clostridium-difficile-associated diarrhoea or colitis were prospectively randomised to 10-day oral courses of metronidazole, 250 mg four times a day, or vancomycin, 500 mg four times a day. 7 did not complete the protocol and were dropped from analysis. Pseudomembranous colitis (PMC) was diagnosed after endoscopy in 33 patients. Of the remaining patients without PMC, 38 had both C difficile culture and cytotoxin and 23 had only culture evidence of C difficile. 52 evaluable patients received vancomycin and 42 received metronidazole. There were two treatment failures with metronidazole and none with vancomycin (p = 0.20); and two relapses with metronidazole versus six with vancomycin (p = 0.17). Treatment in 1 patient in each group was discontinued because of drug intolerance. Response and relapse rates of the 33 patients with PMC were no different from those of the remaining patients. Pharmacy cost for the dosage used was $387.48 to $520.00 for vancomycin and $11.84 for metronidazole. Metronidazole and vancomycin have equivalent efficacy and relapse rates and are tolerated to a similar extent by patients with C-difficile-related diarrhoea and colitis, but metronidazole is considerably more economical.

[Clostridium difficile and antibiotic-associated colitis in risk patients: 2-month epidemiologic study in an intensive care unit]

A toxin produced by Clostridium difficile has been implicated in the pathogenesis of antibiotic-associated colitis. It is not known how often the microorganism is encountered in Germany particularly in high risk patients. Therefore, following a lethal case of colitis, stool samples of 90 patients and 30 staff members of an intensive care unit were screened routinely for C. difficile over 2 months. The organism was found in 6 of 41 patients treated with antibiotics (14.6%); four of them apparently acquired C. difficile while in hospital whereas in 2 a pre-existing carrier state could not be excluded. Colitis developed in 3 of the 6 patients as judged from endoscopy or a positive cytotoxin assay; in 2 patients (not subjected to endoscopy) colitis was suspected on clinical grounds, and 1 patient became an asymptomatic carrier. C. difficile was not found in 49 patients without antibiotic medication, in the health personal and in 12 patients of a general ward. Patients harbouring C. difficile were clustered in certain bed sites of the unit. Environmental studies recovered the microorganism from bed pan washing machines of bedridden and from toilets of ambulant patients but not from other sites like the hands of the personal. These results suggest that chronic carriers of C. difficile, as far as they are identified by current bacteriological methods, are rare in Germany (not more than 2 out of 132 persons investigated, i.e. 1.5%). The frequent finding of C. difficile in patients treated in certain bed sites supports the view that the infection may be acquired from exogenous sources. Antibiotic-associated colitis should be considered more often when intensive care patients are treated with antibiotics.

Use of gas-liquid chromatography as a screening test for toxigenic Clostridium difficile in diarrhoeal stools

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.