Incidence and origin of Clostridium difficile in neonates

Clostridium difficile infection: monoclonal or polyclonal genesis?

Clostridium difficile is considered to be a leading cause of hospital-acquired diarrhea. C. difficile (CDI) infection shows a high rate of recurrence. There would have to be a predominantly monoclonal mechanism of CDI within individual patients in order for molecular epidemiologic tools such as polymerase chain reaction (PCR) ribotyping to be useful in outbreak investigation or differentiation between infection relapse versus re-infection. It was the aim of our study to determine whether CDI is of monoclonal or of polyclonal genesis. Between December 2009 and June 2010, 11 patients with nosocomial CDI were chosen arbitrarily. Five individual colonies of C. difficile were picked from each of the primary culture plates. Of 55 isolates gained, 47 were available for PCR ribotyping (eight isolates failed attempts to re-culture). Among these 47 isolates, eight different PCR ribotypes were identified. Only one of the 11 patients had a stool sample that yielded more than one ribotype (PCR ribotypes 438 and 232); this 67-year-old female cancer patient was already suffering from recurring diarrhea prior to the fatal episode of colitis which was subsequently investigated. We conclude that polyclonal infections may occasionally occur in patients with CDI. Our findings of predominantly monoclonal origin of CDI within patients suggest that molecular epidemiologic investigations can be used reliably for outbreak investigations or discrimination between relapse and re-infection.

Epidemiology and risk factors for Clostridium difficile infection in children

BACKGROUND

Pediatric Clostridium difficile infection (CDI)-related hospitalizations are increasing. We sought to describe the epidemiology of pediatric CDI at a quaternary care hospital.

METHODS

Nested case-control study within a cohort of children <18 years tested for C. difficile between January and August 2008. The study included patients who were ≥ 1 year with a positive test and diarrhea; those without diarrhea (ie, presumed colonization) were excluded. Two unmatched controls per case were randomly selected from patients ≥ 1 year with a negative test. Potential predictors of CDI included age, gender, comorbidities, prior hospitalization, receipt of C. difficile-active antibiotics in the prior 24 hours, and recent (≤ 4 weeks) exposure to antibiotics or acid-blocking medications. Multivariate logistic regression models were created to identify independent predictors of CDI.

RESULTS

Of 1891 tests performed, 263 (14%) were positive in 181 children. Ninety-five patients ≥ 1 year with CDI were compared with 238 controls. In multivariate analyses, predictors of CDI included solid organ transplant (odds ratio [OR], 8.09; 95% confidence interval [CI], 2.10-31.12), lack of prior hospitalization (OR, 8.43; 95% CI, 4.39-16.20), presence of gastrostomy or jejunostomy (G or J) tube (OR, 3.32; 95% CI 1.71-6.42), and receipt of fluoroquinolones (OR, 17.04; 95% CI, 5.86-49.54) or nonquinolone antibiotics (OR, 2.23; 95% CI, 1.18-4.20) in the past 4 weeks. Receipt of C. difficile-active antibiotics within 24 hours before testing was associated with a lower odds of CDI (OR, 0.22; 95% CI, 0.09-0.58).

CONCLUSIONS

Recent antibiotic exposure and certain comorbid conditions (solid organ transplant, presence of a gastrostomy or jejunostomy tube) were associated with CDI. Diagnostic testing has less utility in patients being treated with C. difficile-active antibiotics.

Clostridium difficile in children: colonisation and disease

Clostridium difficile is the commonest cause of hospital acquired diarrhoea in adults and is associated with significant mortality and morbidity. The clinical significance of C. difficile in children, however, is less certain. In this article we discuss colonisation and infection and describe C. difficile in childhood in terms of risk factors, epidemiology and management.

Clostridium difficile infection in hospitalized children in the United States

OBJECTIVES

To evaluate the trend in Clostridium difficile infection (CDI) among hospitalized children in the United States and to evaluate the severity of and risk factors associated with these cases of CDI.

DESIGN

A retrospective cohort study using the triennial Healthcare Cost and Utilization Project Kids' Inpatient Database for the years 1997, 2000, 2003, and 2006.

SETTING

Hospitalized children in the United States.

PARTICIPANTS

A nationally weighted number of patients (10 474 454) discharged from the hospital, 21 274 of whom had CDI.

MAIN EXPOSURE

Discharge diagnosis of CDI.

MAIN OUTCOME MEASURES

Trend in cases of CDI; effect and severity were measured by length of hospital stay, hospitalization charges, colectomy rate, and death rate.

RESULTS

There was an increasing trend in cases of CDI, from 3565 cases in 1997 to 7779 cases in 2006 (P < .001). Patients with CDI had an increased risk of death (adjusted odds ratio [OR], 1.20; 95% confidence interval [95% CI], 1.01-1.43), colectomy (adjusted OR, 1.36; 95% CI, 1.04-1.79), a longer length of hospital stay (adjusted OR, 4.34; 95% CI, 3.97-4.83), and higher hospitalization charges (adjusted OR, 2.12; 95% CI, 1.98-2.26). There was no trend in death, colectomy, length of hospital stay, or hospitalization charges during the 4 time periods (ie, 1997, 2000, 2003, and 2006). The risk of comorbid diagnoses associated with CDI included inflammatory bowel disease, with an OR of 11.42 (95% CI, 10.16-12.83), and other comorbid diagnoses associated with immunosuppression or antibiotic administration.

CONCLUSIONS

There is an increasing trend in CDI among hospitalized children, and this disease is having a significant effect on these children. In contrast to adults, there is no increasing trend in the severity of CDI in children. Children with medical conditions (including inflammatory bowel disease and immunosuppression) or conditions requiring antibiotic administration are at high risk of CDI.

Preventing Clostridium difficile infections: an executive summary of the Association for Professionals in Infection Control and Epidemiology's elimination guide

This article is an executive summary of the Association for Professionals in Infection Control and Epidemiology's Clostridium difficile infection elimination guide. Infection preventionists are encouraged to obtain the original, full-length elimination guide for more thorough coverage of C difficile infection prevention.

The enterotoxicity of Clostridium difficile toxins

The major virulence factors of Clostridium difficile infection (CDI) are two large exotoxins A (TcdA) and B (TcdB). However, our understanding of the specific roles of these toxins in CDI is still evolving. It is now accepted that both toxins are enterotoxic and proinflammatory in the human intestine. Both purified TcdA and TcdB are capable of inducing the pathophysiology of CDI, although most studies have focused on TcdA. C. difficile toxins exert a wide array of biological activities by acting directly on intestinal epithelial cells. Alternatively, the toxins may target immune cells and neurons once the intestinal epithelial barrier is disrupted. The toxins may also act indirectly by stimulating cells to produce chemokines, proinflammatory cytokines, neuropeptides and other neuroimmune signals. This review considers the mechanisms of TcdA- and TcdB-induced enterotoxicity, and recent developments in this field.

Asymptomatic colonization by Clostridium difficile in infants: implications for disease in later life

Approximately 60% to 70% of healthy newborns and infants are colonized by the enteric pathogen Clostridium difficile. For reasons that remain obscure, these colonized infants show no ill effects from the potent exotoxins released by this anaerobe, in contrast to older children and adults who are susceptible to severe diarrhea and colitis. The organism is acquired in infancy, as in adults, from environmental contamination in the nursery or home environment. Between 12 and 24 months C difficile is evicted as a commensal, presumably by the gradual development of the adult colonic microflora. The carrier state is well tolerated by infants, and the immunoglobulin G antitoxin response that develops during the carrier state appears to provide durable protection against subsequent C difficile disease.

Clostridium difficile PCR ribotype 078 toxinotype V found in diarrhoeal pigs identical to isolates from affected humans

In diseased piglets from two Dutch pig-breeding farms with neonatal diarrhoea for more than a year, culture and PCR analyses identified the involved microorganism as Clostridium difficile PCR ribotype 078 harbouring toxin A (tcdA) and B (tcdB), and binary toxin genes. Isolated strains showed a 39 bp deletion in the tcdC gene and they were ermB gene-negative. A number of 11 porcine and 21 human isolated C. difficile PCR ribotype 078 toxinotype V strains were found genetically related by multiple-locus variable-number tandem-repeat analysis (MLVA). Moreover, a clonal complex was identified, containing both porcine and human isolates. The porcine isolates showed an antimicrobial susceptibility profile overlapping that of isolates from Dutch human patients. On the basis of these pheno- and genotypical analyses results, it was concluded that the strains from affected piglets were indistinguishable from increasingly encountered C. difficile PCR ribotype 078 strains of human C. difficile infections in the Dutch population and that a common origin of animal and humans strains should be considered.

Changing epidemiology of Clostridium difficile-associated disease in children

OBJECTIVE

To determine temporal trends in the incidence rate for Clostridium difficile-associated disease (CDAD) in a pediatric patient population.

METHODS

We performed an observational, retrospective cohort study that included children who visited or were admitted to Children's National Medical Center during the period from July 2001 through June 2006. The CDAD incidence rates were determined and examined for changes over time using the Poisson regression method.

RESULTS

A total of 513 patients whose stool specimens tested positive for C. difficile toxin were identified. Of these patients, 61% were children aged 2 years or older. The proportion of patients with CDAD in this age group has steadily increased from 46% in 2001 to 64% in 2006. Largely as a result of an increasing number of cases of community-associated CDAD, the incidence of CDAD increased significantly in the outpatient setting, particularly in the emergency department (1.18 cases per 1,000 visits in 2001 vs 2.47 cases per 1,000 visits in 2006; P=.02). The incidence among inpatients decreased during the study period (1.024 cases per 1,000 patient-days in 2001 vs 0.680 cases per 1,000 patient-days in 2006; P=.004). In the neonatal intensive care unit, C. difficile toxin was detected in stool specimens collected from 22 patients aged from 15 days to 6 months.

CONCLUSION

This study revealed a steady increase in the number of patients seen in the emergency department with community-acquired CDAD. Findings from this study suggest that the characteristics of CDAD in children--a population that has not been considered to be at high risk for this disease in the past--are changing. Further investigations are warranted to explore deviations from the established burdens of the disease and patient risk factors.

Factors influencing the composition of the intestinal microbiota in early infancy

OBJECTIVE

The aim of this study was to examine the contribution of a broad range of external influences to the gut microbiotic composition in early infancy.

METHODS

Fecal samples from 1032 infants at 1 month of age, who were recruited from the KOALA Birth Cohort Study in the Netherlands, were subjected to quantitative real-time polymerase chain reaction assays for the enumeration of bifidobacteria, Escherichia coli, Clostridium difficile, Bacteroides fragilis group, lactobacilli, and total bacterial counts. Information on potential determinants of the gut microbiotic composition was collected with repeated questionnaires. The associations between these factors and the selected gut bacteria were analyzed with univariate and multivariate analyses.

RESULTS

Infants born through cesarean section had lower numbers of bifidobacteria and Bacteroides, whereas they were more often colonized with C difficile, compared with vaginally born infants. Exclusively formula-fed infants were more often colonized with E coli, C difficile, Bacteroides, and lactobacilli, compared with breastfed infants. Hospitalization and prematurity were associated with higher prevalence and counts of C difficile. Antibiotic use by the infant was associated with decreased numbers of bifidobacteria and Bacteroides. Infants with older siblings had slightly higher numbers of bifidobacteria, compared with infants without siblings.

CONCLUSIONS

The most important determinants of the gut microbiotic composition in infants were the mode of delivery, type of infant feeding, gestational age, infant hospitalization, and antibiotic use by the infant. Term infants who were born vaginally at home and were breastfed exclusively seemed to have the most "beneficial" gut microbiota (highest numbers of bifidobacteria and lowest numbers of C difficile and E coli).

Pitfalls in the diagnosis of enteroviral infection in young children

BACKGROUND

Three infants with enteroviral infections were admitted to a neonatal intensive care unit (NICU). Investigation into the possible nosocomial spread of enterovirus identified 31 other infected infants. Only 1 of the 31 was truly positive; 30 were false-positive results.

METHODS

This was a retrospective observational study. Investigational laboratory studies were conducted to identify problems in diagnostic procedures.

RESULTS

Stool cultures were used to identify asymptomatic infections. Investigation identified several problems in the procedures in identification of enterovirus: (1) stool specimens were not properly filtered, (2) insufficient number of tissue culture cell types were used, (3) nonspecific toxicity due to stool and the presence of Clostridia difficile toxin was responsible for cytopathic effects in tissue culture, (4) the failure to block nonspecific fluorescent staining led to misidentification of enteroviruses.

CONCLUSIONS

The use of stool cultures to identify asymptomatic enteroviral infections in infants in an NICU can be fraught with problems because of high frequency of C. difficile toxin and the nonspecific toxic effects of stool on tissue culture cells. These problems can be rectified when proper procedures are followed.

Colitis due to Clostridium difficile toxins: underdiagnosed, highly virulent, and nosocomial

Clostridium difficile colitis is a major complication of antibiotic therapy. Antibiotics cause a reduction in bacteria that normally reside in the colon. If an antibiotic-treated patient ingests C. difficile bacteria, this organism may proliferate in the colon because it is resistant to most antibiotics and because it does not have to compete with the normal bacteria for nutrients. If the C. difficile organism has the gene for toxin production, the toxin can produce a colitis. In addition to antibiotics, other proposed risk factors for development of C. difficile colitis include advanced age, contact with infected patients and with their health care providers, impaired immune function, suppression of gastric acid secretion by a proton pump inhibitor, and postpyloric tube feeding. Many of the risk factors become simultaneously focused on patients admitted to the hospital. The incidence of C. difficile disease has been rising, and strains have become more virulent. In some forms of the disease, the patient doesn't have diarrhea, and in such patients C. difficile can be deadly but difficult to diagnose. The standard treatment, with metronidazole or vancomycin, fails to work in up to 25% of patients with the fulminant form of colitis. Since C. difficile causes only 20% of cases of antibiotic-associated diarrhea, a specific test is needed to diagnose this organism. Toxigenic cultureis highly specific but not available at most institutions. The tests that are available--enzyme-linked immunosorbent assay and fecal cytotoxicity assay--have high false-negative rates, even in patients with severe clinical disease, creating a diagnostic dilemma. The only proven way to reduce the risk of C. difficile disease is implementation of an antibiotic management program in conjunction with enhanced infection control procedures.

Clostridium difficile-associated diarrhea in a pediatric hospital

This retrospective cohort analysis examined the risk factors, symptoms, and severity of disease associated with C. difficile in pediatric inpatients. Risk factors for a C. difficile-positive test were an oncologic diagnosis, diarrhea of more than 2 days' duration, and gastrointestinal symptoms, especially abdominal pain. Over a 3.5-year period, there was a total of 22 C. difficile-positive patients, and most had mild, self-limiting diarrheal illness. No cases of C. difficile diarrhea were identified. Seventy-eight percent of the C. difficile-positive patients were found to have alternate risk factors for diarrhea. Our data indicate that C. difficile rarely causes severe diarrhea in pediatric inpatients and that C. difficile testing should be limited to patients with severe prolonged diarrhea and abdominal pain.

Clostridium difficile-associated diarrhea and colitis

OBJECTIVES

To review and summarize the status of diagnosis, epidemiology, infection control, and treatment of Clostridium difficile-associated disease (CDAD).

DIAGNOSIS

A case definition of CDAD should include the presence of symptoms (usually diarrhea) and at least one of the following positive tests: endoscopy revealing pseudomembranes, stool cytotoxicity test for toxin B, stool enzyme immunoassay for toxin A or B, or stool culture for C difficile (preferably with confirmation of organism toxicity if a direct stool toxin test is negative or not done). Testing of asymptomatic patients, including those who are asymptomatic after treatment, is not recommended other than for epidemiologic purposes. Lower gastrointestinal endoscopy is the only diagnostic test for pseudomembranous colitis, but it is expensive, invasive, and insensitive (51% to 55%) for the diagnosis of CDAD. Stool culture is the most sensitive laboratory test currently in clinical use, but it is not as specific as the cell cytotoxicity assay.

EPIDEMIOLOGY

C difficile is the most frequently identified cause of nosocomial diarrhea. The majority of C difficile infections are acquired nosocomially, and most patients remain asymptomatic following acquisition. Antimicrobial exposure is the greatest risk factor for patients, especially clindamycin, cephalosporins, and penicillins, although virtually every antimicrobial has been implicated. Cases of CDAD unassociated with prior antimicrobial or antineoplastic use are very rare. Hands of personnel, as well as a variety of environmental sites within institutions, have been found to be contaminated with C difficile, which can persist as spores for many months. Contaminated commodes, bathing tubs, and electronic thermometers have been implicated as sources of C difficile. Symptomatic and asymptomatic infected patients are the major reservoirs and sources for environmental contamination. Both genotypic and phenotypic typing systems for C difficile are available and have enhanced epidemiologic investigation greatly.

INFECTION CONTROL

Successful infection control measures designed to prevent horizontal transmission include the use of gloves in handling body substances and replacement of electronic thermometers with disposable devices. Isolation, cohorting, handwashing, environmental disinfection, and treatment of asymptomatic carriers are recommended practices for which convincing data of efficacy are not available. The most successful control measure directed at reduction in symptomatic disease has been antimicrobial restriction.

TREATMENT

Treatment of symptomatic (but not asymptomatic) patients with metronidazole or vancomycin for 10 days is effective; metronidazole may be preferred to reduce risk of vancomycin resistance among other organisms in hospitals. Recurrence of symptoms occurs in 7% to 20% of patients and is due to both relapse and reinfection. Over 90% of first recurrences can be treated successfully in the same manner as initial cases. Combination treatment with vancomycin plus rifampin or the addition orally of the yeast Saccharomyces boulardii to vancomycin or metronidazole treatment has been shown to prevent subsequent diarrhea in patients with recurrent disease.

Application of typing by pulsed-field gel electrophoresis to the study of Clostridium difficile in a neonatal intensive care unit

Pulsed-field gel electrophoresis (PFGE) analysis of restriction pattern polymorphism was applied to type Clostridium difficile isolated from neonates hospitalized in a neonatal intensive care unit, and the results were compared with those of immunoblot analysis. C. difficile was isolated from fecal specimens of 41 (61%) of 67 neonates during a 5-month investigation. All of these neonates were asymptomatic. Fifty-five C. difficile isolates from 32 patients were analyzed by PFGE after digestion with SmaI and SacII endonucleases and by immunoblotting with 10 different antisera. Fifty-three of 55 isolates from 30 patients were identical by PFGE analysis after SmaI and SacII digestion and immunoblot analysis. Two isolates were different from each other and from the epidemic group by both PFGE and immunoblot analysis. All 53 epidemic isolates were nontoxigenic, while the two remaining isolates were toxigenic. These results suggest that nosocomial spread of nontoxigenic C. difficile infection in the neonatal intensive care unit and suggest that both PFGE and immunoblot are powerful typing tools for the epidemiological study of C. difficile.

Diminished Clostridium difficile toxin A sensitivity in newborn rabbit ileum is associated with decreased toxin A receptor

Human infants are relatively resistant to Clostridium difficile-associated diarrhea and colitis compared to adults. In that toxin A is the major cause of intestinal damage with this organism, we compared toxin A receptor binding and biological effects in newborn vs adult rabbit ileum. Purified toxin A (M(r) 308 kD) was labeled with tritium or biotin with full retention of biologic activity. Appearance of specific toxin A brush border (BB) binding was strongly age dependent with minimal [3H]toxin A specific binding at 2 and 5 d of life, followed by gradual increase in binding to reach adult levels at 90 d. Absence of toxin A binding sites in newborn and presence in adult rabbits was confirmed by immunohistochemical studies using biotinylated toxin A. Toxin A (50 ng to 20 micrograms/ml) inhibited protein synthesis in 90-d-old rabbit ileal loops in a dose-dependent fashion. In contrast, inhibition of protein synthesis in 5-d-old rabbit ileum occurred only at the highest toxin A doses (5 and 20 micrograms/ml) and at all doses tested was significantly less than the adult rabbit ileum. In addition, toxin A (5 micrograms/ml) caused severe mucosal damage in adult rabbit ileal explants but had no discernable morphologic effect on 5-d-old rabbit intestine. Our data indicate that newborn rabbit intestine lacks BB receptors for toxin A. The absence of the high-affinity BB receptor for toxin A in the newborn period may explain lack of biologic responsiveness to purified toxin, and the absence of disease in human infants infected with this pathogen.

Laboratory diagnosis of Clostridium difficile-associated gastrointestinal disease: comparison of a monoclonal antibody enzyme immunoassay for toxins A and B with a monoclonal antibody enzyme immunoassay for toxin A only and two cytotoxicity assays

A total of 320 stool specimens obtained from 262 patients suspected of having Clostridium difficile-associated gastrointestinal disease were examined with two cytotoxicity assays (CTAs) and two commercially available enzyme immunoassays (EIAs). The CTAs were an in-house-developed procedure (University of Massachusetts Medical Center [UMMC], Worcester, Mass.) and a commercial test (Bartels CTA; Baxter Healthcare Corp., West Sacramento, Calif.). One EIA was a monoclonal antibody-based assay for C. difficile toxins A and B (Cambridge Biotech Corp. [CBC], Worcester, Mass.). The other EIA employed monoclonal antibodies directed against only toxin A (Meridian Diagnostics, Cincinnati, Ohio). True-positive and true-negative results were defined on the basis of the results of the four assays, clinical assessments of patients, and the results of other laboratory tests. The sensitivities of the four assays were as follows: Bartels CTA, 100%; UMMC CTA, 97.2%; CBC EIA, 84.5%; and Meridian EIA, 69.0%. The Bartels CTA demonstrated a specificity of 99.2%. The other three assays had a specificity of 100%.

New Clostridium difficile serotypes in Poland

Polish isolates of Clostridium difficile strains of different origin were studied. All strains were serotyped according to the Delmee scheme. Twenty-one strains remained untypeable. By typing them with antisera against 5 Polish strains we observed 5 new serotypes.

Incidence of Clostridium difficile in hospitalized children. A prospective study

A total of 394 children, aged 0-14 years, referred to a paediatric department were investigated for the occurrence of Clostridium difficile, its cytotoxin in faeces, and its clinical significance in a prospective study over one year. Of the children in the investigation, 337 suffered from gastrointestinal diseases or had been treated with antibiotics prior to the investigation. Twenty-four percent of these children had Cl. difficile in one or more faecal samples and toxin was demonstrated in half of these patients. In 18/148 (12%) of the patients with acute gastroenteritis Cl. difficile was isolated as the only pathogen. In contrast, among 57 control children with no gastrointestinal symptoms and no prior antibiotic treatment significantly fewer harboured Cl. difficile (p less than 0.01). Cl. difficile was isolated with similar frequency in children with or without prior antibiotic treatment. Isolation of Cl. difficile was significantly higher in patients under one year of age (p less than 0.001). In 78% of the patients with Cl. difficile the bacteria were found in faeces during the initial two days of hospitalization indicating that most of the cases were community acquired. The occurrence of Cl. difficile was not influenced by seasonal variation and the distribution between sexes was equal.

Nosocomial acquisition of Clostridium difficile infection

We studied the acquisition and transmission of Clostridium difficile infection prospectively on a general medical ward by serially culturing rectal-swab specimens from 428 patients admitted over an 11-month period. Immunoblot typing was used to differentiate individual strains of C. difficile. Seven percent of the patients (29) had positive cultures at admission. Eighty-three (21 percent) of the 399 patients with negative cultures acquired C. difficile during their hospitalizations. Of these patients, 52 (63 percent) remained asymptomatic and 31 (37 percent) had diarrhea; none had colitis. Patient-to-patient transmission of C. difficile was evidenced by time-space clustering of incident cases with identical immunoblot types and by significantly more frequent and earlier acquisition of C. difficile among patients exposed to roommates with positive cultures. Of the hospital personnel caring for patients with positive cultures, 59 percent (20) had positive cultures for C. difficile from their hands. The hospital rooms occupied by symptomatic patients (49 percent) as well as those occupied by asymptomatic patients (29 percent) were frequently contaminated. Eighty-two percent of the infected cohort still had positive cultures at hospital discharge, and such patients were significantly more likely to be discharged to a long-term care facility. We conclude that nosocomial C. difficile infection, which was associated with diarrhea in about one third of cases, is frequently transmitted among hospitalized patients and that the organism is often present on the hands of hospital personnel caring for such patients. Effective preventive measures are needed to reduce nosocomial acquisition of C. difficile.

[Occurrence of Clostridium difficile in the feces of children of Rio de Janeiro, RJ, Brazil]

A ocorrência de Clostridium difficile foi analisada em amostras de fezes de 175 crianças com idade variando de 1 a 35 meses. Para o isolamento primário do microrganismo foi empregado o meio de cultura seletivo diferencial "CCFA" (cicloserina-cefoxitina-frutose-agar). Num grupo de 67 crianças sem distúrbios gastrintestinais e que não estavam sob uso de agentes antimicrobianos a ocorrência do C. difficile foi de 22,4%, enquanto que num outro grupo de 28 crianças nas mesmas condições, porém, sob tratamento com antimicrobianos a ocorrência do microrganismo foi de 50%. Num terceiro grupo de 58 crianças com diarréia e sob antibiótico-terapia a ocorrência de C. difficile atingiu 13,8%. Este mesmo percentual foi encontrado num quarto grupo de 22 crianças com diarréia, porém, sem tratamento com agentes antimicrobianos. De um modo geral, os maiores índices de ocorrência de C. difficile foram encontrados em crianças com idade variando entre 1 a 12 meses (28,1%). Índices inferiores foram verificados entre crianças com idade superior a 1 ano. Outrossim, os resultados evidenciam que crianças com distúrbios gastrintestinais apresentam menor incidência deste microrganismo nas fezes. Por outro lado. não houve diferença estatísticamente significativa entre os grupos de crianças com e sem terapia antimicrobiana.

Clostridium difficile: its disease and toxins

Clostridium difficile is the etiologic agent of pseudomembranous colitis, a severe, sometimes fatal disease that occurs in adults undergoing antimicrobial therapy. The disease, ironically, has been most effectively treated with antibiotics, although some of the newer methods of treatment such as the replacement of the bowel flora may prove more beneficial for patients who continue to relapse with pseudomembranous colitis. The organism produces two potent exotoxins designated toxin A and toxin B. Toxin A is an enterotoxin believed to be responsible for the diarrhea and mucosal tissue damage which occur during the disease. Toxin B is an extremely potent cytotoxin, but its role in the disease has not been as well studied. There appears to be a cascade of events which result in the expression of the activity of these toxins, and these events, ranging from the recognition of a trisaccharide receptor by toxin A to the synergistic action of the toxins and their possible dissemination in the body, are discussed in this review. The advantages and disadvantages of the various assays, including tissue culture assay, enzyme immunoassay, and latex agglutination, currently used in the clinical diagnosis of the disease also are discussed.

Rectal swab cultures for Clostridium difficile surveillance studies

We compared the recovery of Clostridium difficile from hospitalized patients by two collection methods: rectal swabs and stool cultures. Rectal swab cultures were as sensitive as stool cultures and were more easily obtained. Transport of swabs in an anaerobic VACUTAINER system resulted in longer survival times compared with transport in Amies medium.

Isolation of Clostridium difficile and detection of cytotoxin in the feces of diarrheic foals in the absence of antimicrobial treatment

Clostridium difficile was isolated from the feces of 27 of 43 diarrheic foals (63%), and cytotoxin was detected in feces from 28 diarrheic foals (65%). The foals had not received any antimicrobial treatment before the onset of diarrhea. C. difficile was not isolated from feces of 18 normal foals without diarrhea and 62 adult horses (P less than 0.005). This finding of C. difficile and its toxins in association with diarrhea in foals adds another possible cause to the list of infectious agents which may cause diarrhea in foals.

Comparison of serogrouping and polyacrylamide gel electrophoresis for typing Clostridium difficile

A typing scheme for Clostridium difficile based on slide agglutination with rabbit antisera was previously described. It allows the differentiation of 10 serogroups designated A, B, C, D, F, G, H, I, K, and X. We studied the correlation between serogrouping and polyacrylamide gel electrophoresis (PAGE) of whole-cell proteins. A total of 202 isolates from different sources were analyzed by PAGE after ultrasonic disintegration of cells from an 18-h liquid culture and treatment with sodium dodecyl sulfate and 2-mercaptoethanol. A total of 21 different patterns were observed. The reference strains from the 10 serogroups showed different profiles. For each serogroup except A, the patterns obtained with the clinical isolates were identical to the patterns obtained with the reference strains. For the 48 strains belonging to serogroup A, 12 different profiles were observed. Five of these involved strains isolated from patients with antibiotic-associated diarrhea. Typing by sodium dodecyl sulfate-PAGE thus correlates with serogrouping. In addition, it allows discrimination within the heterogeneous serogroup A.

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.

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.

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.

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.