An epidemic of pseudomembranous colitis: importance of person to person spread

Defining the black box: a narrative review of factors associated with adverse outcomes from severe Clostridioides difficile infection

In the United States, Clostridioides difficile infection (CDI) is the leading cause of healthcare-associated infection, affecting nearly half a million people and resulting in more than 20,000 in-hospital deaths every year. It is therefore imperative to better characterize the intricate interplay between C. difficile microbial factors, host immunologic signatures, and clinical features that are associated with adverse outcomes of severe CDI. In this narrative review, we discuss the implications of C. difficile genetics and virulence factors in the molecular epidemiology of CDI, and the utility of early biomarkers in predicting the clinical trajectory of patients at risk of developing severe CDI. Furthermore, we identify associations between host immune factors and CDI outcomes in both animal models and human studies. Next, we highlight clinical factors including renal dysfunction, aging, blood biomarkers, level of care, and chronic illnesses that can affect severe CDI diagnosis and outcome. Finally, we present our perspectives on two specific treatments pertinent to patient outcomes: metronidazole administration and surgery. Together, this review explores the various venues of CDI research and highlights the importance of integrating microbial, host, and clinical data to help clinicians make optimal treatment decisions based on accurate prediction of disease progression.

Clostridium difficile -Associated Disease in Long-Term Care Facilities

Clostridium difficile is a major cause of gastrointestinal infections. In 1978, Bartlett and colleagues identified C difficile and its toxin as the cause of the antibiotic-associated pseudomembranous colitis (PMC). Within a few years, there was the development of a diagnostic assay, a description of a clinical and pathological spectrum of the disease, a definition of risk factors and characterization of the two toxins that account for the pathological event. Additional information regarding the microbiology, pathogenesis, clinical manifestations, diagnosis and treatment has rapidly developed. These features are beyond the scope of this report, and the reader is referred to several recent reviews.

Risk Factors for Clostridium difficile Toxin-Associated Diarrhea

The hospital-wide attack rate for Clostridium difficile-associated diarrhea at our tertiary-care university hospital was 0.02 per 100 patient discharges (0.02%) in 1982, but 0.41% and 1.47% in 1986 and 1987, respectively, with a peak incidence of 2.25% in the fourth quarter of 1987. Hospital antibiotic usage patterns showed concurrent increased use of third-generation cephalosporins, and intravenous vancomycin and metronidazole. Thirty-seven cases selected for study were older than 37 control patients, more likely to have an underlying malignancy and less likely hospitalized on the obstetrics/gynecology service. Their mean duration of hospitalization prior to diagnosis was 21 days, versus a mean total length of stay of eight days for controls. All cases received antibiotics, compared to 24 of the controls. Cases were given more antibiotics for longer periods, and more often received clindamycin, third-generation cephalosporins, aminoglycosides and vancomycin. Gender, race, duration of hospitalization, prior surgery and antiulcer therapy were not significant by logistic regression analysis. Epidemiologic variables with significantly different adjusted odds ratios (95% confidence intervals) were age greater than 65 years (14.1, 1.4-141), intensive care unit residence (39.2, 2.2-713), gastrointestinal procedure (23.2, 2.1-255) and more than ten antibiotic days (summation of days of each antibiotic administered) (16.1, 2.2-117). Control measures included encouraging earlier isolation and treatment of suspected cases and formulary restriction of clindamycin, with use of metronidazole for therapy of anaerobic infections. By the second half of 1988, the attack rate had dropped progressively to 0.74%.

Drug risk factors associated with a sustained outbreak of Clostridium difficile diarrhea in a teaching hospital

A case-control study was undertaken to identify and quantify antimicrobial and nonantimicrobial drug risk factors associated with a sustained outbreak of Clostridium difficile diarrhea on two medical (teaching and nonteaching) units and an oncology unit. In total, 80 cases associated with an endemic clone of toxigenic C difficile were compared with controls. Eighty controls were selected from a group of 290 controls randomly chosen from the outbreak period. The controls were matched to cases according to age, admitting diagnosis and unit of admission. Seventy (88%) patients in the case group received at least one antibiotic before diarrhea, compared with 37 (46%) patients in the control group. Major risk factors implicated in the development of C difficile diarrhea in hospitalized patients were the following antimicrobial agents: ceftazidime (adjusted odds ratio [aor]=26.01, 95% ci 5.67 to 119.19, P=0.0001); cefuroxime (aor=5.17, ci 1.86 to 14.36, P=0.005); ciprofloxacin (aor=3.81, ci 1.05 to 13.79, P=0.04); and clindamycin (aor=15.16, ci 2.93 to 78.44, P=0.004). This is the first time that the use of ciprofloxacin has been linked to the development of C difficile diarrhea. Use of gastrointestinal drugs (ranitidine, famotidine, cimetidine, omeprazole and sucralfate) was also an added risk (aor=3.20, ci 1.39 to 7.34, P=0.01); however, antineoplastic therapy was not significant (P<0.53). Recognition of the specific high risk drugs may spur more restricted use of these agents, which may help in controlling C difficile diarrhea in hospitalized patients.

Case-control analysis of clostridium difficile-associated diarrhea on a gynecologic oncology service

Objective: The incidence, morbidity, and risk factors associated with Clostridium difficile-associated diarrhea (CDAD) were studied in a group of gynecologic oncology patients.

Methods: A case-control analysis of gynecologic oncology patients with CDAD was carried out from August 1986 through January 1989 in a university medical center.

Results: One hundred twenty-three stool samples were tested for C. difficile using the CDT latex agglutination test (Marion Diagnostics, Kansas City, MO). Thirty episodes of CDAD developed in 23 patients. From August 1986 through July 1988, the incidence was stable at 1.5 episodes/100 admissions. From August 1988 through January 1989, the incidence increased to 9.9 episodes/100 admissions (P = 0.005). Compared with patients with nonspecific antibiotic-associated diarrhea, the study patients were hospitalized longer prior to the development of symptoms (mean 15.2 vs. 9.2 days, P = 0.006) and were admitted more frequently with diarrhea (37% vs. 11%, P = 0.015). The rates of surgery, chemotherapy, and radiation therapy were similar. Fever (57% vs. 14%, P < 0.001), abdominal pain (40% vs. 6%, P < 0.001), bloody stools (27% vs. 3%, P = 0.006), and leukocytosis (64% vs. 26%, P = 0.011) were more common among the study cases. The duration, indication, and number of antibiotics administered were similar, though once started, the mean time to symptoms was longer in the study cases (13.7 vs. 6.1 days, P = 0.004). Seven relapses, 1 death, and 1 unplanned colostomy occurred among women with CDAD.

Conclusions: C. difficile is a serious cause of nosocomial morbidity in gynecologic oncology patients. Diarrhea developing after antibiotic exposure is more likely to be associated with C. difficile in patients whose symptoms develop several days after completing antibiotics and in patients with a history of CDAD.

Infection control measures to limit the spread of Clostridium difficile

Clostridium difficile-associated diarrhoea (CDAD) presents mainly as a nosocomial infection, usually after antimicrobial therapy. Many outbreaks have been attributed to C. difficile, some due to a new hyper-virulent strain that may cause more severe disease and a worse patient outcome. As a result of CDAD, large numbers of C. difficile spores may be excreted by affected patients. Spores then survive for months in the environment; they cannot be destroyed by standard alcohol-based hand disinfection, and persist despite usual environmental cleaning agents. All these factors increase the risk of C. difficile transmission. Once CDAD is diagnosed in a patient, immediate implementation of appropriate infection control measures is mandatory in order to prevent further spread within the hospital. The quality and quantity of antibiotic prescribing should be reviewed to minimise the selective pressure for CDAD. This article provides a review of the literature that can be used for evidence-based guidelines to limit the spread of C. difficile. These include early diagnosis of CDAD, surveillance of CDAD cases, education of staff, appropriate use of isolation precautions, hand hygiene, protective clothing, environmental cleaning and cleaning of medical equipment, good antibiotic stewardship, and specific measures during outbreaks. Existing local protocols and practices for the control of C. difficile should be carefully reviewed and modified if necessary.

Clostridium difficile toxoid vaccine in recurrent C. difficile-associated diarrhea

BACKGROUND & AIMS

Recurrent C difficile -associated diarrhea (CDAD) is associated with a lack of protective immunity to C difficile toxins. A parenteral C difficile vaccine containing toxoid A and toxoid B was reported previously to be safe and immunogenic in healthy volunteers. Our aim was to examine whether the vaccine is also well tolerated and immunogenic in patients with recurrent CDAD.

METHODS

Subjects received 4, 50-microg intramuscular inoculations of the C difficile vaccine over an 8-week period. Serum antitoxin antibodies were measured by ELISA, and toxin neutralizing activity was evaluated using the tissue culture cytotoxin assay.

RESULTS

Three patients with multiple episodes of recurrent CDAD were vaccinated. Two of the 3 showed an increase in serum IgG antitoxin A antibodies (3-fold and 4-fold increases, respectively) and in serum IgG antitoxin B antibodies (52-fold and 20-fold, respectively). Both also developed cytotoxin neutralizing activity against toxin A and toxin B. Prior to vaccination, the subjects had required nearly continuous treatment with oral vancomycin for 7, 9, and 22 months, respectively, to treat recurrent episodes of CDAD. After vaccination, all 3 subjects discontinued treatment with oral vancomycin without any further recurrence.

CONCLUSIONS

A C difficile toxoid vaccine induced immune responses to toxins A and B in patients with CDAD and was associated with resolution of recurrent diarrhea. The results of this study support the feasibility of active vaccination against C difficile and its toxins in high-risk individuals but must be validated in larger, randomized, controlled trials.

Clostridium difficile infections related to antibiotic use and infection control facilities in two university hospitals

We investigated whether a reduction in antibiotic use at the Aker University Hospital (Aker) led to a reduction in Clostridium difficile-associated diarrhoea (CDAD). We compared the incidence of CDAD in Aker and Tromsoe University Hospitals (Tromsoe) and related it to antibiotic use and facilities for infection control between 1993-2001. For this purpose we also performed point prevalence studies. Total antibiotic use was the same in the two hospitals. In spite of a reduction in the use of broad-spectrum antibiotics in Aker the incidence of CDAD increased during 1993-1999. In Tromsoe the use of broad-spectrum antibiotics and clindamycin was two to three times higher than in Aker, but until 1999 the incidence of CDAD remained constant and only half that of Aker. After 1999 the incidence of CDAD was halved in Aker, and increased three-fold in Tromsoe. Point prevalence studies in 2001 revealed an equal prevalence of antibiotic-associated diarrhoea. The facilities for infection control were better in Tromsoe. The percentage of single rooms were 8% in Aker and 14% in Tromsoe, and the percentage of single rooms with a WC was 6% in Aker and 12% in Tromsoe. The bed occupancy was much higher in Aker than in Tromsoe. Lack of facilities for infection control and higher bed occupancy could have contributed to the higher incidence of CDAD in Aker in spite of decreased use of broad-spectrum antibiotics and clindamycin. To limit CDAD in hospitals the focus must be on both rational antibiotic use and infection control.

Co-morbidity, not age predicts adverse outcome in Clostridium difficile colitis

AIM: To examine whether age alone or co-morbidity is a risk factor for death in older adults who developed Clostridium difficile (Cd) colitis during hospitalization.

METHODS: A retrospective, observational study design was performed in our Lady of Mercy Medical Center, a 650-bed, urban, community-based, university-affiliated teaching hospital. 121 patients with a positive diagnosis of Cd colitis (aged 23-97 years) were studied, and data pertinent to demographic variables, medical history, co-morbidity, physical examination, and laboratory results were collected. Age was examined as a continuous variable and stratified into Age1 (＜ 80 vs 80+); Age2 (＜ 60, 60-69, 70-79 and 80+); or Age3 (＜ 60, 60-69, 70-79, 80-89, 90+).

RESULTS: Cd colitis occurs more frequently with advancing age (55% of cases ＞ 80 years). However, age, per se, had no effect on mortality. A history of cardiac disease (P = 0.036), recurrent or refractory infection ＞ 4 wk (P = 0.007), low serum total protein (P = 0.034), low serum albumin (P = 0.001), antibiotic use ＞ 4 wk (P ＜ 0.01 0), use of over 4 antibiotics (P = 0.026), and use of certain classes of antibiotics (P = 0.035-0.004) were predictive of death. Death was strongly predicted by the use of penicillin-like antibiotics plus clindamycin, in the presence of hypoalbuminemia, refractory sepsis, and cardiac disease (P = 0.00005).

CONCLUSION: Cd colitis is common in the very old. However, unlike co-morbidity, age alone does not affect the clinical outcome (survival vs death).

Control of nosocomial Clostridium difficile transmission in bone marrow transplant patients

This is a report of six cases of Clostridium difficile-associated diarrhea (CDAD) that occurred among cancer patients undergoing bone marrow transplantation in a tertiary-care cancer hospital. Specific infection control measures that were taken to minimize the nosocomial spread of CDAD also are discussed.

Pseudomembranous colitis: report of a severe case with unusual clinical signs in a young nurse

We describe the case of a young and otherwise healthy nurse who developed pseudomembranous colitis ten days after receiving oral clindamycin for dental infection. Her clinical course was particularly stormy and was characterized by severe diarrhea and vomiting, profuse ascites, pleural effusion, abdominal tenderness, peritoneal irritation, and systemic toxicity. The Clostridium difficile assay was negative on two occasions. Features compatible with pseudomembranous colitis were seen at sigmoidoscopy, and the diagnosis was confirmed by biopsies.

Low prevalence of nosocomial Clostridium difficile transmission, as determined by comparison of arbitrarily primed PCR and epidemiological data

An increased prevalence of patients with C. difficile-associated diarrhoea in a hospital setting suggested the possible existence of an endemic occurrence. A study was therefore designed to determine clonal relatedness among 173 isolates of C. difficile, collected consecutively during 1995 from 147 patients (89 inpatients and 58 outpatients) and to estimate the probability of nosocomial transmission. Arbitrarily primed PCR (AP-PCR) with three different primers, AP1, AP2 and CLD1, was used for fingerprinting and identified 21, 92 and 70 types, respectively. Overall DNA analysis of the combined AP-PCR data yielded 140 types, of which 130 were unique, whereas 10 types occurred repeatedly in 36 isolates from 33 patients; seven isolates were non-typeable by one of the primers. Epidemiological data confirmed that in eight of the 33 patients there was a high probability of nosocomial transmission. Despite a high prevalence of C. difficile among hospitalized patients, a low frequency of nosocomial transmission was suggested by high resolution molecular typing of bacterial isolates in conjunction with traditional epidemiological methods.

Effectiveness of infection control program in controlling nosocomial Clostridium difficile

OBJECTIVE

To report the effectiveness of use of comprehensive infection control measures to reduce the incidence of Clostridium difficile (CD) in an acute-care teaching hospital.

METHODS

All CD infections were reviewed by the infection control coordinator from 1987 to 1996. The Centers for Disease Control and Prevention's nosocomial infection definition was used. CD-inclusion criteria remained unchanged during the study period. Interventions were started in 1990.

INTERVENTIONS

The interventions used were: (1) Isolation policy-revision and enforcement, which included universal precautions policy, (2) educational program-monthly to all health care workers, (3) phenolic disinfectant for environmental cleaning, (4) triclosan (0.03%) soap for handwashing, (5) centralization of sterilization department, (6) cart-washer installation, and (7) aggressive surveillance activity.

RESULTS

From 1987 to 1989, before the interventions, a total of 466 CD infections (mean 155 per year) occurred. From 1990 to 1996, after the interventions, 475 infections (mean 67 per year) occurred. Incidence of CD decreased by 60% from 1990 to 1996.

CONCLUSION

The sustained decrease of nosocomial CD during the 7-year period demonstrated the effectiveness of aggressive infection control measures that involve multiple disciplines.

Extraintestinal Clostridium difficile: 10 years' experience at a tertiary-care hospital

OBJECTIVE

To determine the clinical characteristics of patients with extraintestinal Clostridium difficile (ECD).

MATERIAL AND METHODS

All cultures obtained during a 10.5-year period (from Jan. 1, 1985, to Jun. 30, 1995) at a tertiary-care hospital were retrospectively examined. The medical records of patients from whom ECD was isolated were then reviewed.

RESULTS

Fourteen patients from whom ECD was cultured were identified. Thirteen of these patients (93%) had underlying systemic disease. All but one patient had recent exposure to antibiotics, and all had major bowel pathologic conditions. Nine patients had colon perforation. Of the eight patients in whom the colonic mucosa was directly inspected at operation or endoscopy, only two had evidence of pseudomembranous colitis. Five patients (36%) had documentation of recent diarrhea. ECD was isolated from intraperitoneal sites (in nine patients), blood cultures (in three), a perianal abscess, and a prosthetic hip joint. In 13 patients (93%), the infection was polymicrobial. Seven of the 13 inpatients (54%) survived to dismissal.

CONCLUSION

C. difficile is a rare isolate outside of the gastrointestinal tract. ECD is found in patients with systemic illness who have been hospitalized (usually for an extended period), have intestinal pathologic conditions, and have received antibiotics. The isolation of ECD portends a poor prognosis.

Clostridium difficile infection

Clostridium difficile infection is associated with broad-spectrum antibiotic therapy and is the most common cause of infectious diarrhea in hospital patients. Pathogenic strains of C. difficile produce two protein exotoxins, toxin A and toxin B, which cause colonic mucosal injury and inflammation. Infection may be asymptomatic, cause mild diarrhea, or result in severe pseudomembranous colitis. Diagnosis depends on the demonstration of C. difficile toxins in the stool. The first step in management is to discontinue the antibiotic that caused diarrhea. If diarrhea and colitis are severe or persistent, oral metronidazole is the treatment of choice. Oral vancomycin is also effective, but it is more expensive than metronidazole and its widespread use may encourage the proliferation of vancomycin-resistant nosocomial bacteria. Diarrhea and colitis usually improve within three days after a patient starts taking metronidazole or vancomycin, but 20% suffer a relapse of diarrhea when these agents are discontinued.

Simultaneous outbreaks of two strains of toxigenic Clostridium difficile in a general hospital

We report an outbreak of Clostridium difficile-associated disease (CDAD) in a large Dublin hospital. From January to June 1995, inclusive, 139 patients were affected; the mean age of cases was 68.8 +/- 19 years. Clinical information is available for 73 cases identified during the first four months of the outbreak. The majority of patients presented with abrupt onset of watery diarrhoea; however, 19.2% presented with an unexplained pyrexia following a course of antimicrobial therapy and 5.5% presented with a surgical acute abdomen. Twenty patients (27.4%) experienced relapsing disease and seven (9.6%) patients died. Seventy-six percent of cases received a cephalosporin prior to the onset of disease, the highest relative risks occurring with third-generation agents; however, 9.6% of patients affected had not been exposed to antimicrobial therapy in the preceding eight weeks. Pyrolysis mass spectrometry identified two clusters of isolates, representing two strains of C. difficile. There was marked spatial clustering of these strains, with each confined to a separate area of the hospital. Infection control measures and an antibiotic policy were introduced. Throughout the outbreak period the use of the most frequently used cephalosporin in the hospital increased; this was accompanied paradoxically by a reduction in the number of new cases of CDAD.

The impact of Clostridium difficile on a surgical service: a prospective study of 374 patients

OBJECTIVE

To evaluate the epidemiology of Clostridium difficile colitis (CDC) in a subset of patients admitted specifically to a surgical service.

SUMMARY BACKGROUND DATA

CDC is an increasingly prevalent nosocomial infection that can prolong hospitalization and adversely affect patient outcome. Although this disease has been investigated extensively in patients admitted to medical services, the incidence and risk factors for the development of this disease in patients admitted to a surgical service have not been studied.

METHODS

Over a 5-month period, 374 patients admitted to the general, vascular, thoracic, and urologic surgery services were monitored for the development of symptomatic CDC (defined as >3 bowel movements per 24 hours and a positive cytotoxin assay or culture).

RESULTS

Twenty-one patients developed CDC (incidence, 5.6%). Factors that independently predisposed to infection included admission from a skilled care facility, use of the antibiotic cefoxitin, and an operative procedure for bowel obstruction. Other factors associated with CDC included colectomy, treatment with any antibiotic, nasogastric tube suction, advanced age, and prior antibiotic treatment. Abdominal pain and fever were also more common in patients with CDC. Morbidity included prolonged hospitalization in all patients and urgent colectomy in one.

CONCLUSIONS

CDC frequently affects surgical patients, producing morbidity ranging from mild diarrhea to life-threatening illness. A variety of factors, many of which are associated with intestinal stasis, predispose to the development of CDC.

Clostridium difficile-associated diarrhea: epidemiology, risk factors, and infection control

OBJECTIVES

To evaluate the effectiveness of specific infection control measures on the incidence of Clostridium difficile-associated diarrhea (CDAD) and to identify risk factors for its development.

SETTING

370-bed, tertiary-care teaching hospital with approximately 12,000 to 15,000 admissions per year.

METHODS

Several infection control measures were implemented in 1991 and 1992, and the attack rates of CDAD were calculated quarterly. Antibiotic use for 1988 through 1993 was analyzed. A case-control study was conducted from January 1992 to December 1992 to identify risk factors for acquisition of CDAD.

RESULTS

From 1989 to 1992, the attack rate of CDAD increased from 0.49% to 2.25%. An increase in antibiotic use preceded the rise in the incidence of CDAD in 1991. Despite implementation of various infection control measures, the attack rate decreased to 1.32% in 1993, but did not return to baseline. Ninety-two cases and 78 controls (patients with diarrhea but with negative toxin assay) were studied. By univariate analysis, history of prior respiratory tract infections (odds ratio [OR], 3.6; 95% confidence interval [CI95], 1.2-10.4), the number of antibiotics, and the duration of exposure to second-generation cephalosporins (OR, 3.55; CI95, 1.47-9.41) and to ciprofloxacin (OR, 7.27; CI95, 1.13-166.0) were related significantly to the development of CDAD. By stepwise logistic regression analysis, only exposure to antibiotics and prior respiratory tract infections (P = .0001 and .0203, respectively) were found to be significant.

CONCLUSION

Antibiotic pressure might have contributed to failure of infection control measures to reduce the incidence of CDAD to baseline.

Clostridium difficile infection as a cause of severe sepsis

Although colitis is often seen in critically all patients who have received multiple broad-spectrum antibiotics, there are no reports describing severe sepsis as a result of Clostridium difficile infection. We describe three cases of severe sepsis with local intestinal Clostridium difficile infection as the only identifiable etiology. The mechanism of severe sepsis may be a derangement of the gastrointestinal barrier function. This could result in absorption of microbes or endotoxin or activation of inflammatory cascades in the submucosa of the intestine or liver.

Clostridium difficile colitis in the critically ill

Morbidity and treatment of Clostridium difficile colitis (CDC) continue to be controversial. Some claim minimum morbidity, which may be a function of differences in patient population and/or bacterial virulence.

METHODS

To evaluate the effect of CDC in the critically ill, we retrospectively reviewed the records of 59 intensive care unit patients with CDC who were diagnosed by fecal toxin assays or clinical evidence of pseudomembranous colitis from January 1991 to October 1994. Symptoms, signs, antibiotic regimens, diagnostic tests, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, morbidity, and mortality were analyzed, and results of surgical treatment were compared with the literature.

RESULTS

Mean age was 66.4 (17-95) years, with a male to female ratio of 1.8:1. First treatment was metronidazole by mouth in 15 patients (25.4 percent), vancomycin by mouth in 30 patients (50.8 percent), sequential by mouth vancomycin/metronidazole in 3 patients (5.1 percent), and intravenous metronidazole in 5 patients (8.5 percent). Six patients had no medical therapy before surgery or discharge. Ten patients (17 percent) had recurrence and 12 (20.3 percent) required surgery for progressive toxicity or peritonitis. Of three patients who were initially treated by diverting stomas, one died and two required total colectomy (TAC). Two underwent partial resection (1 that was nearly a total colectomy), and seven others had a TAC. Surgical patients had worse mean APACHE II scores at diagnosis (24.4 vs. 19.9; P < 0.001). Thirty-day mortality in surgical patients was 41.7 vs. 14.7 percent in medical patients (P < 0.5).

CONCLUSION

Twenty percent of critically ill patients with CDC required operation. TAC and diversion appeared to be more effective surgical treatments than diversion alone.

Community-acquired toxigenic Clostridium difficile diarrhoea in the normoxaemic elderly who have received no antimicrobials: soft evidence for ischaemic colitis?

We report three examples of community-acquired toxigenic Clostridium difficile diarrhoea in elderly patients who had neither received antimicrobial therapy nor been institutionalised. These cases stimulated interest in the non-antimicrobial changes which might predispose the host to C. difficile-related disease and raised the spectre of bowel ischaemia as a possible aetiological factor.

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.

Lack of care giver hand contamination with endemic bacterial pathogens in a nursing home

Prevalences of Clostridium difficile and multiply resistant Staphylococcus aureus (MRSA) were determined in nursing staff and residents of a 233-bed long-term care facility. Twenty of 38 (52.6%) patients in the long-term care ward and three of 69 (4.3%) in the skilled-nursing ward were colonized with MRSA; 16 of 48 (33%) patients in the long-term care ward and seven of 52 (13%) in the nursing home ward were colonized with C. difficile. None of the 79 staff members whose hands were cultured had chronic C. difficile hand carriage and MRSA was present on only three of 79 (3.9%). Over a 6-month period, 128,000 pairs of gloves were worn. Since C. difficile and MRSA are rarely present on washed hands of care providers, appropriate handwashing and gloving should make a significant contribution to reducing the spread of these agents in long-term care facilities.

Oral rehydration therapy: a Third World solution applied to intensive care

Oral rehydration therapy (ORT)--World Health Organisation formula--has reduced the mortality of severe diarrhoea tenfold but its use in Intensive Care has not been reported. ORT was administered via a nasogastric tube to 3 adult intensive care patients who developed severe diarrhoea and post-operative acute renal impairment. The median intake of ORT was 2.21/day (range 1.5-3.0) and the mean duration of therapy was 7 days (range 6-10). Renal function improved (creatinine fell from 389 to 165 mmol/l) and both haemodynamic and metabolic stability (Na, K, Mg, PO4 and urea) were maintained. While it may not reduce the volume of diarrhoea, ORT provides a cheap, effective and physiological solution to severe gastrointestinal losses in intensive care and may have wider application in both adult and paediatric practice.

Human colonic aspirates containing immunoglobulin A antibody to Clostridium difficile toxin A inhibit toxin A-receptor binding

Clostridium difficile toxin A, a 308-kilodalton protein exotoxin, is the principal causative agent of antibiotic-associated, C. difficile-induced colitis. In the current study, the prevalence of specific human serum and secretory antibody to toxin A and the possible protective effect of secretory, intestinal anti-toxin A antibody are examined. Serum (n = 35), colonic aspirates (n = 35), and duodenal aspirates (n = 20) were collected from adults at diagnostic endoscopy. Patients with evidence of colitis or a history of recent antibiotic use were excluded from the study. Specific serum immunoglobulin (Ig) A and IgG antitoxin A antibodies were detected in 60% and 57% of subjects, respectively, by enzyme-linked immunosorbent assay. Fifty-seven percent of colonic aspirates contained IgA antitoxin, whereas only 10% of duodenal aspirates were positive (P = 0.002). Binding of toxin A to its intestinal receptor was studied using [3H]toxin A and purified rabbit ileal brush border membranes. Toxin A binding was significantly inhibited by colonic aspirates with high IgA anti-toxin A antibody levels (0.503 +/- 0.055 pmol toxin A bound per milligram of brush border membrane protein, mean +/- SE) in comparison with antitoxin A-negative aspirates (0.778 +/- 0.089 pmol; P = 0.02) and control (0.766 +/- 0.004 pmol; P = 0.03). In the current study, a specific intestinal secretory IgA antibody response to C. difficile toxin A in humans is reported. This antibody response is more evident in the colon, the site of C. difficile infection, than in the upper intestinal tract. Our data suggest that human colonic IgA antitoxin may protect against C. difficile colitis by inhibiting the binding of toxin A to its intestinal epithelial cell receptor.

Control of nosocomial transmission of Clostridium difficile based on sporadic case surveillance

The recognition of a cluster of antibiotic-associated nosocomial Clostridium difficile disease (NCDD) caused by serotype C in a surgical ward led to a hospital-wide NCDD surveillance and control program. The initial step included: (a) gas-liquid chromatography screening of inpatients' diarrheal stools; (b) enteric isolation precautions, cohorting and terminal room disinfection in wards with a cluster of two or more NCDD cases per month. During a 12-month period, the quarterly incidence of NCDD remained unchanged and six new clusters of serotype C, K, and H infections occurred, giving a global incidence of 1.5/1,000 admissions. C. difficile spores were recovered from 36.7% surfaces of case patient rooms versus 6.7% in control rooms. More intensive control measures were evaluated: (a) culture screening of inpatients' diarrheal stools; (b) early therapy, enteric isolation precautions, and daily meticulous room disinfection for each sporadic NCDD case. Surface disinfection reduced the contamination level four-fold (p = 0.04). In the following 12 months, no cluster occurred and the incidence of NCDD fell to 0.3/1,000 admission (protective efficacy 73%, 95% confidence interval: 46-87%). These observations suggest that early therapy, isolation precautions, and surface disinfection, focused on patients with sporadic NCDD detected by active surveillance, can prevent nosocomial transmission of C. difficile.

Acute abdomen as the first presentation of pseudomembranous colitis

Acute abdomen was the presenting manifestation of pseudomembranous colitis in six men who had previously been treated with antibiotics and presented with abdominal distention, pain, fever, and leukocytosis with absent or mild diarrhea. Plain abdominal radiographs revealed megacolon in two, combined small and large bowel dilation in three, with one of them showing volvuluslike pattern, and isolated small bowel ileus in one. Emergency colonoscopy was performed successfully in all patients and revealed pseudomembranes in five and nonspecific colitis in one. All patients had positive latex test results for Clostridium difficile, and two tested positive for cytotoxicity. All patients were treated with IV metronidazole, resulting in resolution of symptoms and abdominal findings. In addition, two patients underwent colonoscopic decompression with improvement. Endoscopically, complete resolution of the pseudomembranes occurred at 4 weeks in all cases. No patient had a recurrence. It is concluded that (a) pseudomembranous colitis may present as abdominal distention mimicking small bowel ileus. Ogilvie's syndrome, volvulus, or ischemia; (b) in such cases, emergency colonoscopy is safe and useful for diagnosis and therapeutic decompression and may obviate the need for surgery; and (c) treatment with IV metronidazole is effective. Colitis due to C. difficile should be considered in the differential diagnosis of acute abdomen in patients previously treated with antibiotics.

Clostridium difficile-associated disease in long-term care facilities

Clostridium difficile is a major cause of gastrointestinal infections. In 1978, Bartlett and colleagues identified C difficile and its toxin as the cause of the antibiotic-associated pseudomembranous colitis (PMC). Within a few years, there was the development of a diagnostic assay, a description of a clinical and pathological spectrum of the disease, a definition of risk factors and characterization of the two toxins that account for the pathological event. Additional information regarding the microbiology, pathogenesis, clinical manifestations, diagnosis and treatment has rapidly developed. These features are beyond the scope of this report, and the reader is referred to several recent reviews.

Risk factors for Clostridium difficile toxin-associated diarrhea

The hospital-wide attack rate for Clostridium difficile-associated diarrhea at our tertiary-care university hospital was 0.02 per 100 patient discharges (0.02%) in 1982, but 0.41% and 1.47% in 1986 and 1987, respectively, with a peak incidence of 2.25% in the fourth quarter of 1987. Hospital antibiotic usage patterns showed concurrent increased use of third-generation cephalosporins, and intravenous vancomycin and metronidazole. Thirty-seven cases selected for study were older than 37 control patients, more likely to have an underlying malignancy and less likely hospitalized on the obstetrics/gynecology service. Their mean duration of hospitalization prior to diagnosis was 21 days, versus a mean total length of stay of eight days for controls. All cases received antibiotics, compared to 24 of the controls. Cases were given more antibiotics for longer periods, and more often received clindamycin, third-generation cephalosporins, aminoglycosides and vancomycin. Gender, race, duration of hospitalization, prior surgery and antiulcer therapy were not significant by logistic regression analysis. Epidemiologic variables with significantly different adjusted odds ratios (95% confidence intervals) were age greater than 65 years (14.1, 1.4-141), intensive care unit residence (39.2, 2.2-713), gastrointestinal procedure (23.2, 2.1-255) and more than ten antibiotic days (summation of days of each antibiotic administered) (16.1, 2.2-117). Control measures included encouraging earlier isolation and treatment of suspected cases and formulary restriction of clindamycin, with use of metronidazole for therapy of anaerobic infections. By the second half of 1988, the attack rate had dropped progressively to 0.74%.

Infectious enteritis. A collective review

Enteric infections are a major cause of diarrhea in the United States. Pathogens can cause diarrhea by elaboration of toxins that affect the intestinal mucosa or by direct invasion of the intestinal wall. Clinical evaluation can provide important clues to aid in establishing a correct diagnosis in most patients with infectious enteritis. Appropriate cultures are necessary to confirm the diagnosis in most cases. Most types of infectious enteritis are self-limiting, but some pathogens can cause serious disease, requiring accurate diagnosis and suitable antibiotic therapy. Appropriate precautions are mandatory to prevent the spread of infectious diarrhea from occurring in the hospital environment. Dietary restrictions and appropriate hygiene should be observed during travel to foreign countries to reduce the chance of acquiring infectious enteritis.

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.