Epidemiology of antibiotic-associated colitis; isolation of Clostridium difficile from the hospital environment

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.

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.

Clostridium difficile

Clostridium difficile is a major cause of antibiotic-associated diarrhea and colitis. The incidence of infection with this organism is increasing in hospitals worldwide, consequent to the widespread use of broad-spectrum antibiotics. Pathogenic strains of C. difficile produce two protein exotoxins, toxin A and toxin B, that cause colonic mucosal injury and inflammation. Many patients who are colonized are asymptomatic, and recent evidence indicates that diarrhea and colitis occur in those individuals who lack a protective antitoxin immune response. In patients who do develop symptoms, the spectrum of C. difficile disease ranges from mild diarrhea to fulminant pseudomembranous colitis. Prevention of nosocomial C. difficile infection involves judicious use of antibiotics and multidisciplinary infection control measures to reduce environmental contamination and patient cross-infection. Ultimately, active or passive immunization against C. difficile may be an effective means of controlling the growing problem of nosocomial C. difficile diarrhea and colitis.

Clostridium difficile-associated diarrhea and colitis

Clostridium difficile is a spore-forming toxigenic bacterium that causes diarrhea and colitis, typically after the use of broad-spectrum antibiotics. The clinical presentation ranges from self-limited diarrhea to fulminant colitis and toxic megacolon. The incidence of this disease is increasing, resulting in major medical and economic consequences. Although most cases respond quickly to medical treatment, C difficile colitis may be serious, especially if diagnosis and treatment are delayed. Recurrent disease represents a particularly challenging problem. Prevention is best accomplished by limiting the use of broad-spectrum antibiotics and following good hygienic techniques and universal precautions to limit the transmission of bacteria. A high index of suspicion results in early diagnosis and treatment and potentially reduces the incidence of complications.

"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.

Gastrointestinal infections in the immunocompromised host

Gastrointestinal disease is a significant cause of morbidity and mortality in the immunocompromised patient. This article focuses on the infectious gastrointestinal complications associated with the treatment of malignant disease and with solid organ transplantation but not HIV. Gastrointestinal defenses and the various mechanisms by which they are impaired are reviewed. The major pathogens and malignancies of this patient population and an approach to their diagnosis, treatment, and prevention are discussed.

Epidemiology of recurrences or reinfections of Clostridium difficile-associated diarrhea

Approximately 15 to 35% of patients with a first episode of Clostridium difficile-associated diarrhea relapse within 2 months. Between 1994 and 1997, strains from 93 hospitalized patients with C. difficile recurrences were fingerprinted by using both serotyping and PCR-ribotyping. The results showed that 48.4% of clinical recurrences were, in fact, reinfections with a different strain of C. difficile. Rates of clinical recurrences could therefore be reduced by implementing strict isolation precautions.

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.

Value of lysozyme agar incorporation and alkaline thioglycollate exposure for the environmental recovery of Clostridium difficile

Clostridium difficile is an increasingly prevalent nosocomial pathogen. Environmental contamination by spores is believed to be a major factor propagating the spread of C. difficile. Various approaches including the use of bile salts have been described to enhance the recovery of C. difficile from clinical and environmental specimens. We found that lysozyme (5 mg/L) incorporated into a selective medium containing bile salts significantly increased the recovery of C. difficile from swabs of 197 environmental sites (11% versus 24% samples positive, P< 0.01). Furthermore, in a separate series of experiments additional use of cooked meat broth enrichment significantly enhanced the recovery of C. difficile (35% versus 45%, P = 0.009). Conversely, we found that pre-exposure to alkaline thioglycollate did not improve the yield of C. difficile. Lysozyme incorporation markedly increases the recovery of C. difficile from environmental samples probably by stimulation of spore germination. Our findings suggest that previous attempts to determine the level of environmental C. difficile contamination have markedly underestimated the true prevalence of this pathogen.

Epidemiology of nosocomial clostridium difficile diarrhoea

Clostridium difficile is a frequent and clinically important cause of diarrhoea that has been strongly but not exclusively associated with the hospital setting. The vast majority of cases of C. difficile diarrhoea are associated with antecedent treatment with antibiotics, of which cephalosporins and clindamycin appear to pose the highest risk. Within hospitals and chronic-care facilities, cross-infection of C. difficile has been related to transient carriage on hands of healthcare workers and contamination of diverse environmental surfaces, including electronic rectal thermometers. Prospective epidemiologic studies have demonstrated that acquisition of C. difficile is common in hospitalized patients. Although colonized patients contribute to nosocomial transmission of C. difficile, symptom-free carriage of C. difficile appears to reduce risk of subsequent development of C. difficile diarrhoea. Antimicrobial treatment with oral metronidazole or vancomycin to attempt to eradicate symptomless carriage is not recommended. Measures to control nosocomial C. difficile diarrhoea have focused on improved handwashing, use of barrier precautions with single rooms for symptomatic patients, reduction of environmental contamination, and antibiotic restriction. Restricting clindamycin has been particularly successful in terminating outbreaks of C. difficile diarrhoea associated with its use. The epidemiologic features of C. difficile and strategies for control are similar to those for micro-organisms that have acquired antimicrobial resistance. C. difficile may be indirectly or directly contributing to spread of resistant organisms, for instance, by causing diarrhoea and thereby enhancing environmental contamination with other gastrointestinal flora such as vancomycin-resistant enterococci. Thus, a consideration of C. difficile in the larger context of the world-wide spread of antibiotic resistance offers useful insights that may help form the basis for the development of more effective control measures.

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.

Clostridium difficile-associated diarrhea in the elderly

OBJECTIVE

It is widely believed that Clostridium difficile (C. difficile)-associated diarrhea is a more severe disease in the elderly than in the young, associated with increased morbidity and mortality. These beliefs are largely anecdotal, and there are few data supporting them.

METHODS

We conducted an evaluation in an urban, tertiary care hospital of 89 inpatients in whom C. difficile-associated diarrhea was identified. These patients were evaluated prospectively, and the group was divided by age into those < 60 yr of age (younger) and those > or = 60 yr (elderly).

RESULTS

There was no difference in mortality or morbidity in elderly individuals with C. difficile-associated diarrhea when compared with younger persons similarly infected. The response to standard treatment was similar in both groups. Older patients were more likely to have an elevated white blood cell count in association with C. difficile-associated diarrhea (60% vs 26%, p < 0.05), and were more likely to have acquired their infection in the hospital (89% vs 50%, p < 0.0001).

CONCLUSIONS

In the elderly, C. difficile-associated diarrhea is almost always acquired in institutions, and may not be obvious among patients' other problems. The elderly do not seem to have an increase in C. difficile diarrhea-associated morbidity or mortality. There is no evidence that C. difficile-associated diarrhea is more severe in the elderly than it is in the young.

Mopping up hospital infection

Hospital cleaning is a neglected component of infection control. In the UK, financial constraints have forced managers to re-evaluate domestic services and general cleaning has been reduced to the bare minimum. Services have been contracted out in some hospitals, which has further lowered standards of hygiene. Control of infection personnel believe that cleaning is important in preventing hospital-acquired infections but they do not manage domestic budgets and have failed to stop their erosion. It is difficult to defend high levels of hygiene when there is little scientific evidence to support cleaning practices. This review examines the common micro-organisms associated with hospital-acquired infection and their ability to survive in the hospital environment. It also describes studies which suggest that comprehensive cleaning disrupts the chain of infection between these organisms and patients. It is likely that restoring hygienic standards in hospitals would be a cost-effective method of controlling hospital-acquired infection. Furthermore, good cleaning is achievable whereas the enforcement of hand washing and good antibiotic prescribing are not.

The role of the hospital environment in the epidemiology of multi-resistant bacteria

The aim of this study was to use published data to assess the importance of the hospital environment as a possible secondary reservoir of multi-resistant bacteria capable of colonizing or infecting patients. This should make it possible to develop appropriate measures for preventing cross contamination in medical environments. Multi-resistant bacteria often contaminate the environment of the colonized or infected patients, and survive for long periods. However, measures proposed to reduce contamination and reduce the potential for cross infection such as disinfection when the patient is discharged, the use of materials with intrinsic antibacterial activity and the wearing of gloves by everyone entering the room whether or not they intend to actually touch the patient, have yet to be evaluated as part of an overall strategy to prevent infection with multi-resistant bacteria.

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.

Comparison of restriction enzyme analysis, arbitrarily primed PCR, and protein profile analysis typing for epidemiologic investigation of an ongoing Clostridium difficile outbreak

During an outbreak of diarrhea in a general hospital in 1992, 166 Clostridium difficile isolates from 102 patients were typed by restriction enzyme analysis (REA), arbitrarily primed PCR (AP-PCR), and protein profile analysis (PP) techniques. A total of 18 types and 5 subtypes were identified by REA, 32 types were identified by AP-PCR, and 9 types were identified by PP. Analysis of the data indicated the presence of a predominant strain among 76, 75, and 84% of the isolates by REA, AP-PCR, and PP, respectively. Subsequently, 45 C. difficile isolates which had been collected in 1990 from 33 patients in the same hospital following a significant increase in the number of cases of diarrhea caused by C. difficile were studied by REA, AP-PCR, and PP typing techniques. Thirteen types and one subtype were identified by REA, 12 types were identified by AP-PCR, and 5 types were identified by PP. As with the isolates from 1992, a dominant strain was identified. This strain was represented by 53, 64, and 70% of the total number of isolates when the strains were typed by REA, AP-PCR, and PP, respectively. Every isolate (210 of 211) from both 1990 and 1992 that was available for typing was typeable by all three methods. Furthermore, the same dominant strain was identified in both 1990 and 1992 by each method. This study demonstrates that each of the three typing methods can be useful in epidemiologic investigations of C. difficile outbreaks and that one strain can be dominant in an institution over a number of years.

Survey of incidence of Clostridium difficile infection in Canadian hospitals and diagnostic approaches

A questionnaire relating to Clostridium difficile disease incidence and diagnostic practices was sent to 380 Canadian hospitals (all with > 50 beds). The national questionnaire response rate was 63%. In-house testing was performed in 17.6, 61.5, and 74.2% of the hospitals with < 300, 300 to 500, and > 500 beds, respectively. The average test positivity rates were 17.2, 15.3, and 13.2% for hospitals with < 300, 300 to 500, and > 500 beds, respectively. The average disease incidences were 23.5, 30.8, and 40.3 cases per 100,000 patient days in the hospitals with < 300, 300 to 500, and > 500 beds, respectively. In the 81 hospitals where in-house testing was performed, cytotoxin testing utilizing tissue culture was most common (44.4%), followed by enzyme-linked immunosorbent assay (38.3%), culture for toxigenic C. difficile (32.1%), and latex agglutination (13.6%). The clinical criteria for C. difficile testing were variable, with 85% of hospitals indicating that a test was done automatically if ordered by a doctor. Our results show that C. difficile-associated diarrhea is a major problem in hospitals with > or = 200 beds. Despite a lower disease incidence in smaller hospitals, there was a higher diagnostic test positivity rate. This may reflect the preference of smaller hospitals for culture and latex agglutination tests.

Nosocomial diarrhea

Nosocomial diarrheas are an important problem in hospitals, and in critical care units in particular. Hospital-acquired diarrhea may be on an infectious or noninfectious basis. Common noninfectious causes of nosocomial diarrhea include medication-induced changes in the fecal flora or changes secondary to enteral hyperalimenation. Infectious causes of nosocomial diarrhea are due to enteric pathogens in outbreak situations and virtually all of the causes are due to Clostridium difficile. C. difficile is a resident of the human colon and does not cause disease if its toxins are not elaborated. Chemotherapeutic agents, and more commonly, antibiotics, induce the elaboration of toxin A and B from C. difficile in the distal gastrointestinal tract. The spectrum of disease of C. difficile in hospitalized patients includes asymptomatic carriage to mild watery diarrhea, fulminant and severe diarrhea, and pseudomembranous enterocolitis. The treatment of C. difficile diarrhea is usually with oral metronidazole or vancomycin, and C. difficile colitis is treated with intravenous metronidazole. Infection control measures are necessary to prevent the spread of this sporforming organism within the institution since it is capable of surviving in the hospital environment for prolonged periods.

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.

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.

Uses of inorganic hypochlorite (bleach) in health-care facilities

Hypochlorite has been used as a disinfectant for more than 100 years. It has many of the properties of an ideal disinfectant, including a broad antimicrobial activity, rapid bactericidal action, reasonable persistence in treated potable water, ease of use, solubility in water, relative stability, relative nontoxicity at use concentrations, no poisonous residuals, no color, no staining, and low cost. The active species is undissociated hypochlorous acid (HOCl). Hypochlorites are lethal to most microbes, although viruses and vegetative bacteria are more susceptible than endospore-forming bacteria, fungi, and protozoa. Activity is reduced by the presence of heavy metal ions, a biofilm, organic material, low temperature, low pH, or UV radiation. Clinical uses in health-care facilities include hyperchlorination of potable water to prevent Legionella colonization, chlorination of water distribution systems used in hemodialysis centers, cleaning of environmental surfaces, disinfection of laundry, local use to decontaminate blood spills, disinfection of equipment, decontamination of medical waste prior to disposal, and dental therapy. Despite the increasing availability of other disinfectants, hypochlorites continue to find wide use in hospitals.

Protective immunity against Clostridium difficile toxin A induced by oral immunization with a live, attenuated Vibrio cholerae vector strain

Clostridium difficile causes pseudomembranous colitis through the action of Rho-modifying proteins, toxins A and B. Antibodies directed against C. difficile toxin A prevent or limit C. difficile-induced colitis. We engineered plasmid pETR14, containing the hlyB and hlyD genes of the Escherichia coli hemolysin operon, to express a fusion protein containing 720 amino acid residues from the nontoxic, receptor-binding, carboxy terminus of C. difficile toxin A and the secretion signal of E. coli hemolysin A. We introduced pETR14 into Vibrio cholerae and found that the toxin A-HlyA fusion protein was secreted by a number of V. cholerae strains and recognized by both monoclonal and polyclonal anti-C. difficile toxin A antibodies. We introduced pETR14 into an attenuated V. cholerae strain, O395-NT, and inoculated rabbits orally with this construct. Colonization studies disclosed that the V. cholerae vector containing pETR14 was recoverable from rabbit ilea up to 5 days after oral inoculation. Vaccination produced significant systemic anti-C. difficile toxin A immunoglobulin G and anti-V. cholerae vibriocidal antibody responses. Vaccination also produced significant protection against toxin A in an ileal loop challenge assay, as assessed by determination of both fluid secretion and histological changes. These results suggest that the hemolysin system of E. coli can be used successfully in V. cholerae vector strains to effect secretion of large heterologous antigens and that a V. cholerae vector strain secreting a nontoxic, immunogenic portion of C. difficile toxin A fused to the secretion signal of E. coli HlyA induces protective systemic and mucosal immunity against this toxin.

Clinical and molecular epidemiology of sporadic and clustered cases of nosocomial Clostridium difficile diarrhea

PURPOSE

A prospective clinical and molecular epidemiologic study was conducted to define the frequency of nosocomial Clostridium difficile patient-to-patient transmission in an urban tertiary referral hospital.

PATIENTS AND METHODS

Over a 6-month period, environmental cultures for C difficile were obtained from patients with new positive stool cytotoxin assay (index cases); stool samples were obtained from selected patient contacts (the roommate, occupants of adjacent rooms, and the patient occupying the index room after discharge of the index case); and hand cultures were obtained from personnel contacts. C difficile isolates were analyzed by pulse-field gel electrophoresis (PFGE) or, for isolates that were nontypeable by PFGE, by restriction enzyme analysis.

RESULTS

During the study period, we identified 98 index cases of C difficile toxin-associated diarrhea, including focal outbreaks on two wards totaling 26 cases within a 2-month interval. Environmental contamination was detected at > or = 1 sites in 58% of rooms and often involved wide dispersed areas. Among 99 prospectively identified patient contacts, C difficile was cultured from the stool of 31 (31%), including 12 with diarrhea and 19 who were asymptomatic. C difficile was cultured from the hands of 10 (14%) of 73 personnel. Molecular analysis resolved 31 typing profiles among the index isolates; the most common profile (designated strain D1) was represented by 30 isolates. Among the isolates from patient contacts, 5 of 12 from symptomatic contacts matched the corresponding index isolate, and only 1 of 19 from asymptomatically colonized contacts matched. Transmission to personnel or patient contacts of the strain cultured from the corresponding index case was correlated strongly with the intensity of environmental contamination. Strain D1 was frequently represented among isolates associated with heavy environmental contamination, with personnel carriage, and with development of symptomatic illness among prospectively identified contacts.

CONCLUSIONS

Intense environmental contamination and transmission to close personnel and patient contacts represented coordinated properties of an individual epidemic strain. For most epidemiologically linked contacts, positive cultures for C difficile did not result from transmission from the presumed index case.

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.

Diagnosis and management of Clostridium difficile infection

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Clostridium difficile colitis: an increasing hospital-acquired illness

BACKGROUND

Colitis caused by Clostridium difficile is receiving increased attention as a nosocomial hospital-acquired infection.

METHODS

To determine the incidence of C difficile colitis in our facility and the relative proportion of patients dying from the colitis or requiring colectomy for it, we retrospectively reviewed 201 cases of colitis caused by C difficile from 1984 to 1994.

RESULTS

The incidence of C difficile colitis appears to be sharply increasing and is associated with the use of cephalosporins. Among patients who subsequently developed C difficile colitis, the most frequent indication for antibiotic use was perioperative prophylaxis; surgical patients comprised 55% of the total cases. Surgical intervention was required for 5% of patients with C difficile colitis, with an operative mortality of 30%. The overall mortality was 3.5% and was associated with a delay in diagnosis. The only discriminative factor between patients who died and those who survived was length of time from symptoms to treatment--5.43 days for survivors versus 10.7 days for those who died (P < 0.05).

CONCLUSIONS

Most cases of C difficile colitis seen by surgeons have followed the use of perioperative prophylactic antibiotics. Strict guidelines for using perioperative antibiotics should be observed. Prompt recognition of C difficile colitis and aggressive therapy for it are essential for a favorable outcome.

Identification of outbreak-associated and other strains of Clostridium difficile by numerical analysis of SDS-PAGE protein patterns

Seventy-three cultures of Clostridium difficile isolated both during, and in the period immediately following, an outbreak of infection in a group of three hospitals, were characterized by one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of whole-cell proteins. Each protein pattern was characterized by the presence of one or two dense bands which were highly reproducible. The protein patterns were used as the basis for a numerical analysis which divided the strains into five phenons (electrophoretic or EP types). The majority, 60 of the 73 cultures, belonged to a single phenon which included strains from both patients and the environment. We conclude that high-resolution SDS-PAGE of proteins provides an effective method for typing C. difficile and therefore for tracing the possible spread of epidemic strains in hospitals and other institutions, thereby allowing a better understanding of the epidemiology of the organism.

Pseudomembranous colitis: diagnostic sensitivity of the abdominal plain radiograph

We performed a retrospective study to determine the incidence of plain radiographic abnormalities in patients with pseudomembranous colitis (PMC). One hundred and fifty-two plain radiographs of the abdomen (taken within 3 days of pseudomembranous colitis diagnosis) from 152 patients with pseudomembranous colitis were reviewed. Forty-eight of 152 (32%) plain radiographs were abnormal, demonstrating: colonic ileus in 48/152 (32%), small bowel ileus in 31/152 (20%), ascites in 10/152 (7%), and nodular haustral thickening in 28/152 (18%). The distribution in 48 patients with colonic ileus included: right colon, 41/48 (86%), transverse colon, 35/48 (72%), and left colon, 26/48 (55%). Distribution in 28 patients with nodular haustral thickening included: right colon, 5/28 (18%), transverse colon, 15/28 (54%), and left colon, 14/28 (50%). Radiographic changes were non-specific in 32% of patients with changes more specific to PMC in only 18%.

Prospective study of oral teicoplanin versus oral vancomycin for therapy of pseudomembranous colitis and Clostridium difficile-associated diarrhea

A prospective, randomized study comparing oral teicoplanin with oral vancomycin in the treatment of pseudomembranous colitis (PMC) and Clostridium difficile-associated diarrhea (CDAD) was performed. Teicoplanin was administered at a dosage of 100 mg twice a day for 10 days, and vancomycin was administered at a dosage of 500 mg four times a day for 10 days. CDAD was diagnosed by demonstrating both C. difficile and cytotoxin in the feces of symptomatic patients (more than three loose stools per day). The diagnosis of PMC was also based on colonoscopy. Cytotoxin assay and cultures were checked in all patients 7 to 10 days after discontinuation of therapy and 25 to 30 days thereafter. Of the 51 patients enrolled, 46 were judged to be assessable. Among these, 26 received teicoplanin and 20 received vancomycin. At enrollment, both groups were comparable in terms of age, sex, occurrence of PMC or CDAD, and previous antibiotic treatment. Eighteen of the 20 patients in the vancomycin group and 10 of the 26 patients in the teicoplanin group had previously undergone surgery (P = 0.0004). Treatment resulted in the clinical cure of 20 (100%) vancomycin and 25 (96.2%) teicoplanin patients (P = 0.56). After discontinuation of therapy, clinical symptoms recurred in four (20%) vancomycin patients and two (7.7%) teicoplanin patients (P = 0.21). Posttherapy asymptomatic C. difficile carriage (positive follow-up cultures without any clinical symptoms) occurred in five (25%) vancomycin patients and two (7.7%) teicoplanin patients (P = 0.11).Overall, 9 of 20 (45%) vancomycin patients and 5 of 26 (19.2%) teicoplanin patients (P=0.059) appeared not to be cleared of C. difficile after treatment. No adverse effects related to vancomycin or teicoplanin therapy were observed.

Clostridium difficile infection: responses, relapses and re-infections

Clostridium difficile infection is a common and potentially lethal complication of antibiotic usage. Since the aetiology of antibiotic-associated colitis was discovered 14 years ago, two antibiotics in particular, metronidazole and vancomycin, have been used to treat C. difficile infection. Studies comparing the efficacy of these antibiotics are reviewed. It is now apparent that many of the so-called 'relapses' of C. difficile infection following antibiotic treatment are, in fact, re-infections. Such findings have major infection control implications.

Relapse versus reinfection with Clostridium difficile

Relapse of Clostridium difficile-associated diarrhoea occurs in 15-20% of patients; however, whether relapse is due to an endogenous source of the organism or reinfection from the environment remains unclear. Restriction enzyme analysis (REA) of chromosomal DNA was used to type multiple isolates from ten patients who had experienced apparent relapses. More than half the relapses were due to infection with a new strain of C. difficile. The remaining patients were infected with the same strain, but whether this strain was acquired from the environment or from endogenous sources could not be determined. Relapses with a different strain of C. difficile could occur if an individual harboured more than one strain in their gastrointestinal tract. To investigate this possibility ten other patients were assessed for carriage of multiple strains. Ten colonies from a primary culture plate from each patient were typed by REA and tested for their ability to produce cytotoxin. All isolates from the same patient were identical by both methods, indicating that multiple carriage of strains may be a rare event.

Clostridium difficile infection in a geriatric ward

In a prospective, longitudinal study we searched for the presence of Clostridium difficile in the stools of 100 consecutively hospitalized elderly patients (mean age: 82; SD: 9.5 years). C. difficile was found on admission in 6 patients, 3 of whom were asymptomatic carriers. Ten patients acquired C. difficile during hospitalization. Four different types of C. difficile were isolated. The various types were clustered in time, indicating that the infection was acquired from the environment.

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.