Clostridium difficile-associated diarrhea and colitis

Preliminary assessment of an automated surveillance system for infection control

BACKGROUND AND OBJECTIVE

Rapid identification and investigation of potential outbreaks is key to limiting transmission in the healthcare setting. Manual review of laboratory results remains a cumbersome, time-consuming task for infection control practitioners (ICPs). Computer-automated techniques have shown promise for improving the efficiency and accuracy of surveillance. We examined the use of automated control charts, provided by an automated surveillance system, for detection of potential outbreaks.

SETTING

A 656-bed academic medical center.

METHODS

We retrospectively reviewed 13 months (November 2001 through November 2002) of laboratory-patient data, comparing an automated surveillance application with standard infection control practices. We evaluated positive predictive value, sensitivity, and time required to investigate the alerts. An ICP created 75 control charts. A standardized case investigation form was developed to evaluate each alert for the likelihood of nosocomial transmission based on temporal and spatial overlap and culture results.

RESULTS

The 75 control charts were created in 75 minutes and 18 alerts fired above the 3-sigma level. These were independently reviewed by an ICP and associate hospital epidemiologist. The review process required an average of 20 minutes per alert and the kappa score between the reviewers was 0.82. Eleven of the 18 alerts were determined to be potential outbreaks, yielding a positive predictive value of 0.61. Routine surveillance identified 5 of these 11 alerts during this time period.

CONCLUSION

Automated surveillance with user-definable control charts for cluster identification was more sensitive than routine methods and is capable of operating with high specificity and positive predictive value in a time-efficient manner.

Outbreak of Clostridium difficile infection in a long-term care facility: association with gatifloxacin use

To determine the cause of an increase in the rate of Clostridium difficile-associated diarrhea (CDAD) in a long-term care facility (LTCF), we analyzed CDAD cases among LTCF patients from October 2001 through June 2002. CDAD cases were identified from review of all enzyme immunoassays positive for C. difficile toxin A. The increase coincided with a formulary change from levofloxacin to gatifloxacin. We performed a case-control study in which we randomly selected control subjects from 612 LTCF admissions during this period. Although we examined a variety of risk factors, logistic regression analysis only demonstrated associations between CDAD and use of clindamycin (P=.005) and gatifloxacin, the latter being associated with an increasing risk of CDAD with increasing duration of gatifloxacin therapy (P<.0001). We concluded that an outbreak of CDAD in an LTCF was associated with a formulary change from levofloxacin to gatifloxacin. The rate of CDAD in the LTCF decreased after a change back to levofloxacin.

Clostridium difficile colitis after forced anal-receptive intercourse

Colitis caused by Clostridium difficile toxin has been reported in homosexual men. We report a case of C. difficile colitis that occurred in an immunocompetent heterosexual man after forced anal-receptive intercourse.

Effectiveness and appropriateness of empiric metronidazole for Clostridium difficile-associated diarrhea

OBJECTIVE

Although Clostridium difficile is the most common infectious etiology of nosocomial diarrhea, noninfectious causes are far more common. Empiric initiation of therapy for all patients is of unknown value. The aim of this study was to determine benefits of empiric metronidazole for Clostridium difficile-associated diarrhea (CDAD).

METHODS

We conducted a 4-month prospective surveillance of all patients in two community teaching hospitals receiving metronidazole for empiric treatment of presumptive CDAD. A database including antibiotic usage, fever, white blood cell count, feeding formula usage, comorbidity, and response to therapy was maintained.

RESULTS

Seventy-one patients on the medical (50), surgical (18), obstetric (two), and trauma (one) service were identified. Sixty-two had nosocomial diarrhea; nine had diarrhea on admission. Seventy (97%) received antibiotics; one (3%) was on nelfinavir only. Eighteen (25%) were subsequently proven to have CDAD; two (3%) had laxative-induced diarrhea; two (3%) had diarrhea secondary to a medication (colchicine [one] and nelfinavir [one]); one (1%) had diarrhea caused by bowel preparation for colonoscopy. The remaining 49 (68%) did not have a clearly established diarrhea etiology. (Four did not undergo stool examination.) Statistical analysis (chi(2) test) demonstrated a significant decrease in symptoms for metronidazole-treated patients with CDAD versus those with a different diagnosis (p = 0.05). Not surprisingly, multivariate regression analysis identified a strong correlation of diagnosing CDAD with age >60 yr, antibiotics exposure, fever, elevated white blood cell count, and resolution of symptoms with specific metronidazole treatment. CDAD was definitively diagnosed in 25% of our hospitalized patients with diarrhea, consistent with published data. Although some cases might have been missed, most patients did not have CDAD and received no benefit (and were potentially harmed) by empiric metronidazole. There was no way a priori to distinguish CDAD from non-CDAD.

CONCLUSIONS

In the absence of clear guidelines, empiric metronidazole should be reserved for strongly presumptive CDAD patients (older patients with comorbid conditions receiving broad-spectrum antibiotics associated with CDAD) who cannot hemodynamically or otherwise tolerate diarrhea. Used judiciously, empiric therapy may more rapidly resolve symptoms, and could conceivably prevent/abate severe complications and nosocomial spread.

Six rapid tests for direct detection of Clostridium difficile and its toxins in fecal samples compared with the fibroblast cytotoxicity assay

Clostridium difficile is one of the most frequent causes of nosocomial gastrointestinal disease. Risk factors include prior antibiotic therapy, bowel surgery, and the immunocompromised state. Direct fecal analysis for C. difficile toxin B by tissue culture cytotoxin B assay (CBA), while only 60 to 85% sensitive overall, is a common laboratory method. We have used 1,003 consecutive, nonduplicate fecal samples to compare six commercially available immunoassays (IA) for C. difficile detection with CBA: Prima System Clostridium difficile Tox A and VIDAS Clostridium difficile Tox A II, which detect C. difficile toxin A; Premier Cytoclone A/B and Techlab Clostridium difficile Tox A/B, which detect toxins A and B; and ImmunoCard Clostridium difficile and Triage Micro C. difficile panels, which detect toxin A and a species-specific antigen. For all tests, Triage antigen was most sensitive (89.1%; negative predictive value [NPV] = 98.7%) while ImmunoCard was most specific (99.7%; positive predictive value [PPV] = 95.0%). For toxin tests only, Prima System had the highest sensitivity (82.2%; NPV = 98.0%) while ImmunoCard had the highest specificity (99.7%; PPV = 95.0%). Hematopoietic stem cell transplant (HSCT) patients contributed 44.7% of all samples tested, and no significant differences in sensitivity or specificity were noted between HSCT and non-HSCT patients. IAs, while not as sensitive as direct fecal CBA, produce reasonable predictive values, especially when both antigen and toxin are detected. They also offer significant advantages over CBA in terms of turnaround time and ease of use.

[Antibiotic induced diarrhea and pseudomembranous colitis]

The spore-forming anaerobic bacterium Clostridium difficile has become a serious enteropathogen. Oral and parenteral administration of antibiotics can cause ecological disturbances in the normal intestinal microflora. Suppression of the normal microflora may lead to reduced colonization resistance with subsequent overgrowth by pre-existing, naturally resistant microorganisms, such as C. difficile. C. difficile infection shows a range of clinical presentations between an asymptomatic carrier state, light diarrhea without inflammatory changes, and pseudomembranous colitis. C. difficile infection is acquired by the fecal-oral or environmental-oral routes. From March 2000 through March 2001 we assessed 48 cases of nosocomial antibiotic-associated diarrhea (AAD). Of these, 21 were due to C. difficile (CDAD). Cephalosporin was the agent most commonly associated with CDAD. Avoidance of cephalosporins, strict use of "single shot" prophylaxis, isolation of infected, symptomatic patients in single-bed rooms, improved hygiene and complete room disinfection lead to a rapid decrease of CDAD. The etiology, prognosis and prophylaxis are discussed in this paper.

Clostridium difficile-associated Enteric Disease

Clostridium difficile was identified as the putative agent of antibiotic-associated pseudomembranous colitis in 1978 and is now recognized as the major identifiable cause of antibiotic-associated diarrhea. This microbe causes a spectrum of enteric disease ranging from nuisance diarrhea to life-threatening colitis. Risk factors include increasing age, exposure to antibiotics, colonization or acquisition of toxin-producing strains of C. difficile, and lack of circulating antibody to C. difficile toxin A. Detection is relatively simple by stool assay for C. difficile toxin--usually an enzyme immunoassay that will detect toxin A and B. Most nonsevere cases will respond with discontinuation of the implicated antibiotic. More severe cases require metronidazole and supportive care. The major complications include ileus, toxic megacolon, relapsing disease after antibiotic treatment, and nosocomial epidemics.

Treatment of Clostridium difficile-associated diarrhea

OBJECTIVE

To review the literature related to the treatment and infection control of Clostridium difficile-associated diarrhea (CDAD).

DATA SOURCES

A MEDLINE search (1966-August 2001) of the English literature was conducted.

DATA SYNTHESIS

C. difficile is a leading cause of antibiotic-related diarrhea. The clinical spectrum extends from simple diarrhea to fulminant colitis. Cessation of antibiotic therapy alone is sufficient for mild cases; however, the majority of cases require oral metronidazole as the drug of choice. Vancomycin orally is reserved for patients who have failed to respond to metronidazole, are pregnant, or are severely ill. There is an important role for infection control interventions.

CONCLUSIONS

CDAD is a common infection. Appropriate antibiotic treatment and infection control policies can prevent the spread and reduce the morbidity associated with this disease.

Difference in the incidence of Clostridium difficile among patients infected with human immunodeficiency virus admitted to a public hospital and a private hospital

OBJECTIVE

To compare the occurrence of Clostridium difficile among inpatients infected with human immunodeficiency virus (HIV) in two different hospitals.

DESIGN

Prospective, observational study.

SETTING

Specialized HIV inpatient units.

PATIENTS

HIV-infected inpatients at Cook County Hospital (CCH) and Rush Presbyterian St. Luke's Medical Center (RPSLMC).

INTERVENTIONS

A clinical and epidemiologic assessment of patient risk factors for C. difficile was performed. C. difficile isolates found on stool, rectal, and environmental cultures were typed by pulsed-field gel electrophoresis.

RESULTS

Twenty-seven percent of patients admitted to CCH versus 4% of patients admitted to RPSLMC had positive cultures for C. difficile (P = .001). At CCH, 14.7% of environmental cultures were positive versus 2.9% at RPSLMC (P = .002). Risk factors for C. difficile acquisition included hospitalization at CCH, more severe HIV, use of acyclovir and H2-blockers, and longer hospital stay. Patients admitted to CCH were taking more antibiotics, had longer hospital stays, and more frequently had a history of C. difficile infection. During the study, two strains (CD1A and CD4) extensively contaminated the CCH environment. However, only CD1A caused an outbreak.

CONCLUSIONS

The C. difficile acquisition rate at CCH was sevenfold higher than that at RPSLMC, and CCH had a more contaminated environment. Differences in patient acquisition rates likely reflect a greater prevalence of traditional C. difficile risk factors and a concurrent outbreak at CCH. Although two strains heavily contaminated the environment at CCH, only one caused an outbreak, suggesting that factors other than the environment are important in initiating C. difficile outbreaks.

Clostridium difficile in long-term-care facilities for the elderly

Antimicrobial agents are among the most frequently prescribed medications in long-term-care facilities (LTCFs). Therefore, it is not surprising that Clostridium difficile colonization and C. difficile-associated diarrhea (CDAD) occur commonly in elderly LTCF residents. C. difficile has been identified as the most common cause of non-epidemic acute diarrheal illness in nursing homes, and outbreaks of CDAD in LTCFs have also been recognized. This position paper reviews the epidemiology and clinical features of CDAD in elderly residents of LTCFs and, using available evidence, provides recommendations for the management of C. difficile in this setting.

Predominance of a single restriction endonuclease analysis group with intrahospital subgroup diversity among Clostridium difficile isolates at two Chicago hospitals

OBJECTIVE

To determine the epidemiology and relatedness of Clostridium difficile isolates in two geographically separated hospitals in a large metropolitan area, each with unique patients and personneL DESIGN: Observational descriptive molecular epidemiology of clinical C. difficile isolates.

SETTING

Two tertiary-care hospitals in Chicago.

METHODS

Consecutive C. difficile isolates from the clinical laboratory of a Veterans Affairs hospital during a 13-month period were typed by restriction endonuclease analysis (REA). During an overlapping 3-month period, stool specimens that tested positive for C. difficile toxin from patients at a nearby county hospital were cultured and the recovered isolates typed by the same method.

RESULTS

Nineteen (68%) of 28 nosocomial isolates at the smaller, Veterans Affairs hospital belonged to REA group K. Within this group of closely related strains, 9 distinct REA types were recognized. Twenty-one (72%) of 29 nosocomial isolates at the larger, county hospital also belonged to group K. However, the predominant REA types within group K differed markedly at each institution.

CONCLUSIONS

These findings demonstrate a high degree of similarity among nosocomial C. difficile strains from different hospitals in the same city and suggest the possibility of an extended outbreak of a prototype group K strain with subsequent genetic drift at the two different institutions.

The role of Clostridium difficile and viruses as causes of nosocomial diarrhea in children

OBJECTIVE

We report surveillance of nosocomial diarrhea in children at our institution during the past decade and note different epidemiology of diarrhea due to viruses and Clostridium difficile.

DESIGN

A prospective cohort study.

SETTING

A university-affiliated pediatric hospital with 180 beds serving an urban area and providing referral care for the Maritime Provinces of Canada.

PARTICIPANTS

Children younger than 18 years.

METHODS

Surveillance was conducted from 1991 to 1999 using personal contact with personnel and review of microbiology and medical records. Nosocomial diarrhea was defined as loose stools occurring more than 48 hours after admission, with at least two loose stools in 12 hours and no likely non-infectious cause.

RESULTS

Nosocomial diarrhea was the third most common nosocomial infection (217 of 1,466; 15%), after bloodstream and respiratory infections, with from 0.5 to 1 episode per 1,000 patient-days. Of 217 nosocomial diarrhea episodes, 122 (56%) had identified pathogens: C. difficile (39 of 122; 32%), rotavirus (38 of 122; 31%), adenovirus (36 of 122; 30%), and other viral (9 of 122; 7%). The median age was 1.3 years (range, 11 days to 17.9 years), 0.80 year for children with viral diarrhea, 3.9 years for children with C. difficile, and 1.5 years for children with diarrhea without a causative organism identified (P< .0001). Most children with nosocomial diarrhea were incontinent (diapered) at the time of their first episode (138 of 185; 75%), but preexisting incontinence was more common in those with viral diarrhea (93%) compared with those with no organism identified (71%) or those with C. difficile-associated diarrhea (CDAD) (49%) (P <.0001).

CONCLUSIONS

C. difficile is the single most common cause of nosocomial diarrhea in our tertiary-care center, although all viral pathogens account for 69% of cases. Diapered status appears to be a risk factor for CDAD in children, and CDAD occurs more often in older children than viral nosocomial diarrhea. Further characterization of risk factors for, and morbidity associated with, nosocomial CDAD in children is warranted.

Adjunctive intracolonic vancomycin for severe Clostridium difficile colitis: case series and review of the literature

Successful treatment of severe Clostridium difficile colitis has been reported with the use of adjunctive intracolonic vancomycin (ICV) therapy. We report a descriptive case series and review the literature on patients with C. difficile colitis who received adjunctive ICV therapy. Nine patients received antibiotics within 6 weeks prior to presentation. Complete resolution of the clinical presentation occurred in 8 patients (88.9%), and eradication of C. difficile cytotoxin production was documented in 3 (75%) of 4 patients who were tested after the completion of adjunctive ICV therapy. One patient (11.1%) died as a result of progressive multisystem organ failure. In the 6 weeks after the completion of treatment for C. difficile colitis, no patient had recurrent disease, required surgical intervention, or experienced complications from adjunctive ICV therapy. In this case series, administration of adjunctive ICV therapy appeared to be a safe, practical, and effective adjunctive therapy for severe C. difficile colitis.

Clostridium difficile-associated diarrhea: current strategies for diagnosis and therapy

Clostridium difficile, a spore-forming toxigenic bacterium, is one of the most common causes of infectious diarrhea and colitis in the United States. Most patients with C. difficile infection have recently received antimicrobial therapy--usually clindamycin, cephalosporins, or the extended-spectrum penicillins. Clinical presentation varies from asymptomatic colonization to mild diarrhea to severe colitis. The mainstay of diagnosis is detection of C. difficile toxin A, toxin B, or both with a cytotoxin test or enzyme immunoassay of the stool of patients who have received antibiotic therapy and have features of C. difficile-associated diarrhea. Enzyme immunoassays that detect both toxins are preferred because of their higher diagnostic accuracy. If the first assay is negative and C. difficile-associated diarrhea is strongly suspected, a second assay may be performed. Ten days of oral metronidazole is the preferred therapy for most initial infections. Vancomycin is considered second-line therapy because of its cost and potential to select for vancomycin resistance. About 20% to 25% of patients experience reinfection or relapse after initial therapy and require retreatment. The disease can best be prevented by limiting the use of broad-spectrum antibiotics and adhering to control techniques.

In vitro activity of linezolid against Clostridium difficile

We examined the in vitro activity of linezolid against Clostridium difficile, including isolates with reduced susceptibility to metronidazole or vancomycin. The MIC at which 50% of the isolates were inhibited (MIC50) and MIC90 were 0.5 and 2 microg/ml, respectively (range, 0.03 to 4 microg/ml). MICs were always <or= 4 microg/ml, and thus, all isolates were considered susceptible.

Morbidity, mortality, and healthcare burden of nosocomial Clostridium difficile-associated diarrhea in Canadian hospitals

OBJECTIVE

To assess the healthcare burden, morbidity, and mortality of nosocomial Clostridium difficile-associated diarrhea (N-CDAD) in Canadian hospitals.

DESIGN

Laboratory-based prevalence study.

SETTING

Nineteen acute-care Canadian hospitals belonging to the Canadian Hospital Epidemiology Committee surveillance program.

PATIENTS

Hospitalized patients in the participating centers.

METHODS

Laboratory-based surveillance was conducted for C. difficile toxin in stool among 19 Canadian hospitals from January to April 1997, for 6 continuous weeks or until 200 consecutive diarrhea stool samples had been tested at each site. Patients with N-CDAD had to fulfill the case definition. Data collected for each case included patient demographics, length of stay, extent of diarrhea, complications of CDAD, CDAD-related medical interventions, patient outcome, and details of death.

RESULTS

We found that 371 (18%) of 2,062 tested patients had stools with positive results for C difficile toxin, of whom 269 (13%) met the case definition for nosocomial CDAD. Of these, 250 patients (93%) had CDAD during their hospitalization, and 19 (7%) were readmitted because of CDAD (average readmission stay, 13.6 days). Forty-one patients (15.2%) died, of whom 4 (1.5% of the total) were considered to have died directly or indirectly of N-CDAD. The following N-CDAD-related morbidity was noted: dehydration, 3%; hypokalemia, 2%; gastrointestinal hemorrhage requiring transfusion, 1%; bowel perforation, 0.4%; and secondary sepsis, 0.4%. The cost of N-CDAD readmissions alone was estimated to be a minimum of $128,200 (Canadian dollars) per year per facility.

CONCLUSION

N-CDAD is a common and serious nosocomial infectious complication in Canada, is associated with substantial morbidity and mortality, and imposes an important financial burden on healthcare institutions.

Clostridium difficile infection in patients with neutropenia

Clostridium difficile is the most important cause of nosocomial infectious diarrhea. The importance of C. difficile-associated diarrhea (CDAD) has been poorly investigated in patients with neutropenia who have hematologic malignancies. A retrospective chart review of all patients treated in the leukemia ward of a university medical center during 1991-2000 determined that 875 courses of myelosuppressive chemotherapy were administered. CDAD occurred in 7.0% of all cycles. In 8.2% of the patients, severe enterocolitis developed. Two patients died while they had diarrhea. However, in no patient was C. difficile infection clinically considered to be the primary cause of death. The response rate to oral metronidazole was 90.9%. These data indicate that C. difficile infection is not rare and should be suspected whenever a hospitalized patient with neutropenia develops diarrhea. Oral metronidazole can be recommended as initial drug of choice for treatment of patients with neutropenia who have hematologic malignancies and CDAD.

Evaluation of methods for detection of toxins in specimens of feces submitted for diagnosis of Clostridium difficile-associated diarrhea

Clostridium difficile is the principal pathogen associated with hospital-acquired acute diarrheal disease. We have evaluated the performances of six approaches for diagnosis of C. difficile-associated diarrhea (CDAD). Consecutive stool specimens (n = 200) from 133 patients were examined by cytotoxin assay, by culture of C. difficile on cycloserine-cefoxitin-fructose agar, and by toxin detection using four rapid immunoassay systems (Oxoid Toxin A test, ImmunoCard Toxin A test, TechLab Tox A/B II test, and Premier Toxins A&B test). A diagnosis of CDAD was established for 35 (27%) patients (representing 29% of specimens). The adjusted sensitivity and specificity of the methods were, respectively, 98 and 99% for the cytotoxin assay, 54 and 99% for ImmunoCard, 50 and 98% for Oxoid, 79 and 98% for TechLab, 80 and 98% for Premier, and 57 and 100% for culture. The TechLab and Premier assays are acceptable tests for diagnosis of CDAD but are not equivalent to the cytotoxin assay.

Laboratory diagnosis of Clostridium difficile disease

The laboratory diagnosis of Clostridium difficile-associated disease (CDAD) is based on culture and toxin detection in fecal specimens. Culture is performed on a commercially available selective media. C. difficile colony morphology is typical when viewed under a dissecting microscope. Definitive identification is best obtained by gas liquid chromatography. Culture is very sensitive but, when used alone without toxin testing, it leads to low specificity and misdiagnosis of CDAD when high rates of asymptomatic carriage exist. Toxin detection by a tissue culture cytotoxin assay followed by neutralisation with specific antiserum is often considered the standard. However, this approach lacks sensitivity and has not detected up to 30% of patients with confirmed CDAD. Multiple enzyme immunoassays (EIAs) have been introduced by various manufacturers for the detection of toxin A alone or for both toxins A and B. Some of these are designed to give results in less than 1 h. Comparative studies of EIA kits reported that the sensitivity and specificity are slightly lower than cytotoxin assays. Toxigenic culture tests C. difficile isolates for toxin production: colonies isolated on selective media are tested for in-vitro toxin production either by a cytotoxicity assay or by direct EIA. It has higher sensitivity than the cytotoxicity assay and equivalent specificity. In the routine laboratory, culture and toxin detection should be performed on every specimen and, in culture-positive and fecal toxin-negative cases, toxigenic cultures should be performed on isolated colonies.

"Second-look" cytotoxicity: an evaluation of culture plus cytotoxin assay of Clostridium difficile isolates in the laboratory diagnosis of CDAD

Clostridium difficile is one of the most frequent causes of hospital-acquired diarrhoea. Our objective was to prove that some stool samples with a direct negative cytotoxicity assay may indeed harbour toxigenic C. difficile and that this can be demonstrated by performing a "second-look" cytotoxicity assay using the isolated C. difficile strains. Over an eight-year period (1992-1999), the 8241 stool samples submitted for direct cell culture from patients with suspected C. difficile-associated diarrhoea (CDAD) were simultaneously plated on cycloserine cefoxitin fructose agar. C. difficile strains isolated from samples with a negative direct cell culture assay were re-tested for toxin production "second-look" cell culture assay). Using both methods 6423 samples (78%) were negative. Of the remaining 1818 samples, 127 (7%) yielded C. difficile isolates which were confirmed as non-producers of toxin by both methods, 1437 (85%) were positive in direct cell culture assay, and 254 were positive only after the "second-look" cell culture assay. Thus, our approach allowed us to detect an extra 15% of toxin-producing strains that could have gone undetected otherwise.The combination of direct-cell culture assay, culture for toxigenic C. difficile and "second-look" cell culture assay enhances the potential for diagnosis of CDAD and enables us to be more efficient with our patient care resources.

Molecular analysis of relapse vs re-infection in HIV-positive patients suffering from recurrent Clostridium difficile associated diarrhoea

Recurrence is a major complication of Clostridium difficile associated diarrhoea, especially in human immunodeficiency virus (HIV) positive patients, and it is important to distinguish between relapse and re-infection in recurrent episodes. The aim of our study was to analyse C. difficile isolates obtained from HIV-positive patients with recurrent diarrhoea in order to distinguish between relapse and re-infection. This analysis was based on the study of DNA similarities among isolates obtained from different episodes within each patient. Relapses occurred in 64% of patients, 32% suffered re-infections and a combination of relapse plus re-infection was seen in 4%. DNA typing methods can be useful tools to characterize recurrent episodes of C. difficile associated disease.

Laboratory diagnosis of Clostridium difficile-associated diarrhea and colitis: usefulness of Premier Cytoclone A+B enzyme immunoassay for combined detection of stool toxins and toxigenic C. difficile strains

Detection of Clostridium difficile toxins A and B in stools by Premier Cytoclone A+B enzyme immunoassay (EIA) was compared with detection by stool culture for C. difficile followed by detection of toxigenic isolates using the same EIA. Chart reviews were performed to evaluate the likelihood of C. difficile-associated diarrhea and colitis (CADC) for all patients with at least one positive toxin assay. While the toxins were detected in 58 of 85 consecutive CADC patients by both assays, CADC in 5 patients was detected only by stool toxin assay, and in 22 patients CADC was detected only by toxigenic culture. Our results suggest that for laboratories using a rapid toxin A+B EIA, direct toxin detection in stools should be combined with toxigenic culture in cases in which there is a negative stool toxin assay.

Medical diagnoses and procedures associated with clostridium difficile colitis

OBJECTIVES

The aim of this study was to examine the associations of Clostridium difficile colitis with other comorbid conditions and procedural interventions among hospitalized patients.

METHODS

The Patient Treatment File of the Department of Veterans Affairs contains the computerized records of all inpatients treated in 172 Veterans Affairs hospitals distributed throughout the United States. The computerized medical records of 15,091 cases with C. difficile colitis and 61,931 controls without the diagnosis were extracted from the annual files between 1993 and 1998. In a multivariable logistic regression, the occurrence of C. difficile colitis served as outcome variable, whereas the occurrences of other diagnoses or procedures served as predictor variables.

RESULTS

The total numbers of diagnoses in the case and control group were 136,840 and 465,972, respectively. The numbers of procedures were 75,479 and 129,612, respectively. C. difficile colitis was significantly associated with HIV infection, candidiasis, malignant neoplasm and chemotherapy, malnutrition, pneumonia, aspiration pneumonitis, intestinal obstruction, diverticulitis, renal failure, urinary tract infection, decubitus, and osteomyelitis. Interventional procedures involving the respiratory tract, bone marrow biopsy, arterial and venous catheterization, urinary catheterization, dialysis, gastrostomy tube, and physical therapy were also frequently associated with the development of C. difficile colitis.

CONCLUSIONS

These associations reflect the influence of causal relationships (such as the use of antibiotics and chemotherapy), an increased risk of exposure to C. difficile among immobilized bedridden patients with chronic disease states, or a general system failure in patients with end-stage disease. Knowledge of such associations could help to alert physicians to an increased risk of C. difficile colitis among particular groups of susceptible patients.

Treatment of Clostridium difficile-associated diarrhea and colitis

Treatment of C. difficile diarrhea with metronidazole or vancomycin is highly effective at relieving symptoms. The high rate of diarrhea recurrence is concerning, but fortunately most patients respond to a second course of treatment. The problem of vancomycin resistance in hospital organisms has markedly reduced usage of this agent as a first-line treatment for C. difficile diarrhea, leaving metronidazole as the mainstay of treatment in the United States where teicoplanin and fusidic acid are not marketed. It is likely that any new antimicrobial agent used to treat C. difficile will be similarly plagued by a high rate of recurrence, presumably incurred as a result of disruption of normal bowel flora. There is a need for improved treatment and prevention of this increasingly frequent and debilitating nosocomial infection. Treatments that utilize passive antibodies, immunization, nontoxigenic C. difficile, or other forms of biotherapy may hold the key to improved treatment and prevention of C. difficile disease in the future. In the meantime, it behooves all practitioners to use antimicrobials judiciously in order to prevent as many cases of C. difficile diarrhea as possible.

Impact of nosocomial infection on length of stay and functional improvement among patients admitted to an acute rehabilitation unit

OBJECTIVE

To identify factors predictive of length of stay (LOS) and the level of functional improvement achieved among patients admitted to an acute rehabilitation unit for the first time, with special reference to the role of nosocomial infection.

SETTING

A 40-bed acute rehabilitation unit within a 300-bed, tertiary-care, public, university-affiliated hospital.

STUDY POPULATION

All patients admitted to the unit between January 1997 and July 1998.

DESIGN

Prospective cohort study in which demographic and clinical data, including occurrence of nosocomial infection, were collected during the entire unit admission of each patient. Multivariate linear regression analysis was used to identify factors predictive of unit LOS or improvement in functional status as measured by the change in the Functional Independence Measure (FIM) score between admission and discharge (deltaFIM).

RESULTS

There were 423 admissions to the rehabilitation unit during the study period, of which 91 (21.5%) had spinal cord injury (SCI) as a principal diagnosis. One hundred seven nosocomial infections occurred during 84 (19.9%) of the 423 admissions. The most common infections were urinary tract (31.8% of all infections), surgical-site (18.5%), and Clostridium difficile diarrhea (15%). Only one patient died of infection. After controlling for severity of illness on admission, functional status on admission, age, and other clinical factors, the significant positive predictors of unit LOS were as follows: SCI (P<.001), pressure ulcer (.002), and nosocomial infection (<.001). Significant negative predictors of deltaFIM were age (P<.001), FIM score on admission (<.001), prior hospital LOS (.002), and nosocomial infection (.007).

CONCLUSIONS

Several variables were identified as contributing to a longer LOS or to a smaller improvement in functional status among patients admitted for the first time to an acute rehabilitation unit. Of these variables, only nosocomial infection has the potential for modification. Studies of new approaches to prevent infections among patients undergoing acute rehabilitation should be pursued.

Leukocytosis as a harbinger and surrogate marker of Clostridium difficile infection in hospitalized patients with diarrhea

OBJECTIVES

Clostridium difficile is the etiological agent of antibiotic-associated diarrhea and pseudomembranous colitis and is a leading cause of nosocomial diarrhea. The objective of the study was to examine if leukocytosis could be a harbinger and surrogate marker of C. difficile infection in hospitalized patients.

METHODS

We retrospectively examined the medical records of 70 hospitalized patients who presented with diarrhea of variable severity and who underwent stool examination for enteric pathogens, including C. difficile. We specifically recorded the white blood cell count and the pattern and severity of leukocytosis in two groups of patients--those who were C. difficile-positive and those who were negative.

RESULTS

Leukocytosis was common in C. difficile-positive patients, compared to in C. difficile-negative patients (mean 15,800/mm3 vs 7700/mm3, p < 0.01). Review of the 35 C. difficile-positive patients revealed three patterns: Pattern A) sudden WBC increase coinciding with the onset of symptoms suggestive of C. difficile; Pattern B) unexplained leukocytosis preceding the appearance of C. difficile-related diarrhea and serving as a harbinger of the infection; and Pattern C) worsening of pre-existing leukocytosis as a surrogate marker of C. difficile infection. Treatment with metronidazole led to amelioration of symptoms and normalization of the leukocyte count in all cases.

CONCLUSIONS

Infection with C. difficile should be considered in the differential diagnosis of sudden onset of leukocytosis in hospitalized patients previously or concurrently treated with antibiotics. Doing so may obviate the need for expensive and time-consuming tests for other etiologies.

The search for a better treatment for recurrent Clostridium difficile disease: use of high-dose vancomycin combined with Saccharomyces boulardii

Recurrent Clostridium difficile disease (CDD) is a difficult clinical problem because antibiotic therapy often does not prevent further recurrences. In a previous study, the biotherapeutic agent Saccharomyces boulardii was used in combination with standard antibiotics and was found to be effective in reducing subsequent recurrences of CDD. In an effort to further refine a standard regimen, we tested patients receiving a regimen of a standard antibiotic for 10 days and then added either S. boulardii (1 g/day for 28 days) or placebo. A significant decrease in recurrences was observed only in patients treated with high-dose vancomycin (2 g/day) and S. boulardii (16.7%), compared with those who received high-dose vancomycin and placebo (50%; P=.05). No serious adverse reactions were observed in these patients. Comparison of data from this trial with data from previous studies indicates that recurrent CDD may respond to a short course of high-dose vancomycin or to longer courses of low-dose vancomycin when either is combined with S. boulardii.

Surveillance for nosocomial and central line-related infections among pediatric hematology-oncology patients

OBJECTIVE

To determine the incidence of all nosocomial infections (NIs) in pediatric hematology-oncology patients, as well as central venous access device (CVAD)-associated infections acquired during home care.

DESIGN

Prospective surveillance study.

SETTING

The Pediatric Hematology and Oncology Department at the University Hospital Bonn.

PATIENTS

All patients admitted from January through October 1998 (surveillance period).

METHODS

Standardized surveillance system based on the Centers for Disease Control and Prevention's National Nosocomial Infections Surveillance System.

RESULTS

A total of 143 patients were hospitalized for 3,701 days (776 admissions) during the surveillance period. Of the 40 NIs detected, 26 were CVAD-related, with 21 bloodstream infections (BSIs) and 5 local infections. Four were Clostridium difficile-associated diarrheal illnesses, 3 were pneumonias, and 7 were other infections. The incidence of NIs was 10.8 per 1,000 patient-days (5.2 NIs/100 admissions). The overall CVAD-related BSI rate was 7.4 per 1,000 utilization days, without a significant difference between implanted infusion ports and tunneled catheters. In addition, 7 CVAD-related infections occurred during home care. All 8 BSIs associated with tunneled catheters and 13 (76%) of the 17 BSIs associated with ports were acquired nosocomially. For inpatients and outpatients combined, the exit sites of tunneled catheters were more likely to become locally infected than were the needle entry sites of ports (relative risk, 8.0; P=.007). In 30 (75%) of the 40 NIs, the affected patients had severe neutropenia (<500/mm3) at the time of infection.

CONCLUSIONS

Most NIs in the pediatric hematology-oncology patients were associated with CVAD devices. Although many infections in this high-risk population may not be preventable through infection control measures, the careful evaluation of specific infection rates permits the identification of risk factors that may be targeted by infection control programs. Prospective surveillance for NIs on pediatric oncology units is an indispensable tool for this internal quality control.

Update on Clostridium difficile infection

Clostridium difficile is a major cause of antibiotic-associated diarrhea in hospital and community settings, spreading endemic and epidemic disease in developed and developing areas throughout the world. Its toxins A and B cause epithelial disruption, inflammation, and secretion. Diagnosis of infection with C. difficile is based on appropriate clinical presentation and demonstration of the presence of either toxin A or B, or both. Established treatment is still predominantly metronidazole and vancomycin. The association of antibiotic therapy with recurrent disease and antimicrobial resistance, especially vancomycin-resistant enterococci, highlights the need for new approaches to managing C. difficile infection.

Characterization of a toxin A-negative, toxin B-positive strain of Clostridium difficile responsible for a nosocomial outbreak of Clostridium difficile-associated diarrhea

Clostridium difficile-associated diarrhea (CAD) is a very common nosocomial infection that contributes significantly to patient morbidity and mortality as well as to the cost of hospitalization. Previously, strains of toxin A-negative, toxin B-positive C. difficile were not thought to be associated with clinically significant disease. This study reports the characterization of a toxin A-negative, toxin B-positive strain of C. difficile that was responsible for a recently described nosocomial outbreak of CAD. Analysis of the seven patient isolates from the outbreak by pulsed-field gel electrophoresis indicated that this outbreak was due to transmission of a single strain of C. difficile. Our characterization of this strain (HSC98) has demonstrated that the toxin A gene lacks 1.8 kb from the carboxy repetitive oligopeptide (CROP) region but apparently has no other major deletions from other regions of the toxin A or toxin B gene. The remaining 1.3-kb fragment of the toxin A CROP region from strain HSC98 showed 98% sequence homology with strain 1470, previously reported by M. Weidmann in 1997 (GenBank accession number Y12616), suggesting that HSC98 is toxinotype VIII. The HSC98 strain infecting patients involved in this outbreak produced the full spectrum of clinical illness usually associated with C. difficile-associated disease. This pathogenic spectrum was manifest despite the inability of this strain to alter tight junctions as determined by using in vitro tissue culture testing, which suggested that no functional toxin A was produced by this strain.

[Effects of restrictions on use of vancomycin in a German university hospital]

BACKGROUND

Recently, increasing antibiotic resistance has been observed among gram-positive bacteria. However, only few isolates were found to be resistant against glycopeptides. Therefore, internationally accepted guidelines recommend a restricted use of vancomycin and other glycopeptide antibiotics in order to prevent the development of resistance against these clinically important antibiotics. In many countries, the hospital pharmacies play a key role in control and reinforcement of antibiotic formulary restrictions. In Germany, however, the hospital pharmacies usually do not take over such control functions, and most wards keep a stock of regularly used drugs including antibiotics, which makes reinforcement of restrictions difficult.

METHODS

In an attempt to achieve a restriction of vancomycin use, the pharmacy of our university hospital was advised to deliver vancomycin to the wards only on request with a special order form signed by an attending, individually for every patient who should receive vancomycin. The efficacy of this restriction measure was evaluated in 3-month periods before and after the restriction became effective.

RESULTS

Hospitalwide, this led to a 20.1% reduction of i.v. vancomycin and an 85.7% reduction of oral vancomycin use per 1000 patient days. If the hematology/oncology units were not considered, the reduction of i.v. vancomycin use was 41.8%, and the total use after the restriction 24.2 g per 1000 patient days. Microbiology results which justified the use of vancomycin decreased by 8.3% (10.9% hematology/oncology units not considered) between the 2 observation periods. Assuming a 7-day mean course of i.v. vancomycin therapy, the empirical use of i.v. vancomycin decreased from 39.9% to 8% after the restriction had been instituted.

CONCLUSION

Allowing only experienced physicians (attendings) to decide on the use of vancomycin therapy, proved in our experience to be an effective measure to reduce unnecessary vancomycin use.

Enteric carriage of vancomycin-resistant Enterococcus faecium in patients tested for Clostridium difficile

OBJECTIVE

To identify independent risk factors for enteric carriage of vancomycin-resistant Enterococcus faecium (VREF) in hospitalized patients tested for Clostridium difficile toxin.

DESIGN

Retrospective case-cohort study.

SETTING

Tertiary-care teaching hospital.

PATIENTS

Convenience sample of 215 adult inpatients who had stool tested for C difficile between January 29 and February 25, 1996.

RESULTS

41 (19%) of 215 patients had enteric carriage of VREE Five independent risk factors for enteric VREF were identified: history of prior C difficile (odds ratio [OR], 15.21; 95% confidence interval [CI95], 3.30-70.10; P < .001), parenteral treatment with vancomycin for > or = 5 days (OR, 4.06; CI95, 1.54-10.73; P = .005), treatment with antimicrobials effective against gram-negative organisms (OR, 3.44; CI95, 1.20-9.87; P = .021), admission from another institution (OR, 2.95; CI95, 1.21-7.18; P =.017), and age > 60 years (OR 2.57; CI95, 1.13-5.82; P = .024). These risk factors for enteric VREF were independent of the patient's current C difficile status.

CONCLUSIONS

Antimicrobial exposures are the most important modifiable independent risk factors for enteric carriage of VREF in hospitalized patients tested for C difficile.

Clostridium difficile-associated diarrhea after short term vaginal administration of clindamycin

A 32-yr-old woman developed frequent watery diarrhea with occult blood after 3 days treatment with clindamycin vaginal cream. Clostridium difficile toxin was demonstrated in stool samples and was considered the cause of an antibiotic-associated diarrhea. No other antibiotic was used at least 3 months before the start of diarrhea. To our knowledge, antibiotic-associated diarrhea after vaginal application has previously been reported only once.

Pseudomembranous colitis after itraconazole therapy

A 53-yr-old man was admitted with new onset of abdominal pain and nonbloody diarrhea 1 month after exposure to the antifungal agent itraconazole. Flexible sigmoidoscopy demonstrated the presence of pseudomembranes, and subsequent evaluation excluded other causes of diarrhea. Disruption of the resident fungal flora of the colon by itraconazole is proposed as the mechanism by which this patient developed pseudomembranous colitis. This association has not previously been reported.

Winner of the Best Paper Award from the Gold Medal Forum: Clinical Characteristics and Antibiotic Utilization in Surgical Patients with Clostridium difficile-Associated Diarrhea

Clostridium difficile-associated diarrhea (CDAD) remains a significant problem in surgical patients. To address this, we prospectively studied all episodes of treated CDAD in surgical inpatients at the University of Virginia hospital from December 1996 through March 1998. CDAD accounted for 3.2 per cent (32) of 1000 total infections. Compared with a randomly selected control group with other nosocomial infections, patients with CDAD had a longer period from the time of admission to diagnosis of infection (19 ± 4 versus 9 ± 1; P = 0.01), were more likely to be female (66% versus 37%; P = 0.009), and had a higher overall crude mortality (31% versus 11%; P = 0.01), although there were no deaths directly attributable to CDAD. Ciprofloxacin (19%) and cefoxitin (16%) were the most common individual antibiotics prescribed before the diagnosis of CDAD. The average time from completion of antibiotic therapy to diagnosis of CDAD was 7 ± 2 days (range, 0-58). Sixteen per cent (5 of 32) developed CDAD after administration of prophylactic perioperative antibiotics only. The high crude mortality rate associated with CDAD suggests that this may be a significant predictor of poor outcome among infected surgical patients. Antibiotics used commonly but not classically associated with CDAD frequently precipitate this infection. Finally, the use of prophylactic antibiotics is not without risk, as demonstrated by the significant percentage of CDAD occurring after routine administration of these agents.

Recurrent Clostridium difficile disease: epidemiology and clinical characteristics

OBJECTIVE

To describe the epidemiology, diagnosis, risk factors, patient impact, and treatment strategies for recurrent Clostridium difficile-associated disease (CDAD).

DESIGN

Data were collected as part of a blinded, placebo-controlled clinical trial testing a new combination treatment for recurrent CDAD. Retrospective data regarding prior CDAD episodes were collected from interviews and medical-chart review. Prospective data on the current CDAD episode, risk factors, and recurrence rates were collected during a 2-month follow-up.

SETTINGS

National referral study.

PARTICIPANTS

Patients with recurrent CDAD.

INTERVENTIONS

Treatment with a 10-day course of low-dose (500 mg/d) or high-dose (2 g/d) vancomycin or metronidazole (1 g/d).

RESULTS

Recurrent CDAD was found to have a lengthy course involving multiple episodes of diarrhea, abdominal cramping, nausea, and fever. CDAD may recur over several years despite frequent treatment with antibiotics. Recurrence rates were similar regardless of the choice or dose of antibiotic. Recurrent CDAD is not a trivial disease: patients may have multiple episodes (as many as 14), may require hospitalization, and the mean lifetime cost of direct medical care was $10,970 per patient. Fortunately, the disease does not become progressively more severe as the number of episodes increase. Two risk factors predictive for recurrent CDAD were found: increasing age and a decreased quality-of-life score at enrollment.

CONCLUSIONS

Recurrent CDAD is a persistent disease that may result in prolonged hospital stays, additional medical costs, and rare serious complications.

Recent trends in diagnosis and treatment of Clostridium difficile in a tertiary care facility

BACKGROUND

With the prevalence of antibiotic use, the diagnosis and management of Clostridium difficile disease requires assessment.

METHODS

In a retrospective review, patients with a positive culture, toxin, or both during 1 year were identified. Recent literature was reviewed. Results of culture and toxin, prior antibiotic use, antibiotic treatment history and cost were analyzed.

RESULTS

Of 592 patients tested, 101 were positive; 96 of 101 were available for review. Of those positive tested for both, 45% were positive for toxin and culture. Sixty-two of 96 were treated with antibiotics; metronidazole was used in 90%. Ten of 62 antibiotic treatments were changed (mean 3 days). Ten days of metronidazole is 1/200th the cost of vancomycin.

CONCLUSIONS

In 55% of the positive cases in which culture and toxin were obtained, one test was negative. As metronidazole's efficacy and cost compares favorably with vancomycin, metronidazole is the drug of choice. Any changes made to antibiotic regimens occurred prior to the 6 days recommended in the literature.

Clostridium difficile toxin-induced colitis after use of clindamycin phosphate vaginal cream

OBJECTIVE

To report a case of toxin-positive Clostridium difficile-induced colitis (CDIC) after use of clindamycin phosphate vaginal cream.

CASE SUMMARY

A 25-year-old postpartum white woman developed multiple watery stools and abdominal cramping on day 6 of therapy with clindamycin vaginal cream for bacterial vaginosis. She received no other concomitant medications. The patient's stool sample was found to be positive for the C. difficile toxin. Due to the costs and risks of standard therapy, we decided to manage the patient supportively. Complete resolution of the diarrhea occurred shortly thereafter.

DISCUSSION

No published clinical studies in patients receiving clindamycin vaginal cream for bacterial vaginosis have documented C. difficile toxin in stool samples of patients with diarrhea. Approximately 5-6% of intravaginal clindamycin is absorbed in the bloodstream, making systemic effects possible.

CONCLUSIONS

This report indicates clindamycin phosphate vaginal cream as the most probable cause of CDIC due to the temporal relationship between the occurrence of diarrhea and clindamycin administration, lack of concomitant medications, and documentation of C. difficile toxin.

Comparison of four laboratory tests for diagnosis of Clostridium difficile-associated diarrhea

Four different laboratory tests for diagnosis of Clostridium difficile-associated diarrhea were compared to determine the optimal one for management of patients with hospital-acquired diarrhea. Stool samples from 231 patients with diarrhea were tested by the following methods: culture for Clostridium difficile with subsequent determination of exotoxin production, with a toxigenic Clostridium difficile positive (TCP) result considered truly positive; enzyme immunoassay (EIA); latex agglutination test; and an immunobinding blot assay. The rates of positive results were as follows: EIA 5.5%, TCP 7.3%, latex agglutination 16.7%, and immunobinding blot assay 26.1%. Compared to the TCP results, the sensitivity and specificity were, respectively, 61 and 98% for EIA, 47 and 85% for latex agglutination, and 60 and 76% for the immunobinding blot assay. Samples from patients with > or = 6 stools/day were TCP and EIA positive in 27 and 17% of cases, respectively, whereas in patients with < 6 stools/day, these percentages decreased to 2 and 3%, respectively (p < 0.001). In hospitalized patients with > or = 6 stools/day, EIA appears to be the optimal test for diagnosis of Clostridium difficile-associated diarrhea, with a 73% positive predictive value and a 97% negative predictive value. However, in patients with < 6 stools/day, the prevalence of Clostridium difficile is low, and laboratory detection of this organism remains problematic.