Epidemiology of nosocomial clostridium difficile diarrhoea

The identification and epidemiology of meticillin-resistant Staphylococcus aureus and Clostridium difficile in patient rooms and the ward environment

BACKGROUND

Research has indicated that the environment may play an important role in the transmission of meticillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile in healthcare facilities. Despite the significance of this finding, few data exist from longitudinal studies investigating MRSA and C. difficile contamination, concurrently, in both patient rooms and the general ward environment. The objectives of this study were to determine the prevalence of MRSA and C. difficile contamination in patient rooms and the ward environment and identify risk factors associated with a surface being contaminated with these pathogens.

METHODS

Environmental surfaces in patient rooms and the general environment in the medical and surgical wards of a community hospital were sampled six times over a 15 week period. Sterile electrostatic cloths were used for sampling and information pertaining to the surface sampled was recorded. MRSA isolates and C. difficile specimens were obtained from hospitalized patients.Enrichment culture was performed and spa typing or ribotyping was conducted for MRSA or C. difficile, respectively. Exact logistic regression models were constructed to examine risk factors associated with MRSA and C. difficile contamination.

RESULTS

Sixteen (41%) patient rooms had ≥ 1 surfaces contaminated with MRSA and/or C. difficile. For 218 surfaces investigated, 3.2% and 6.4% were contaminated with MRSA or C. difficile, respectively. Regression models indicated that surfaces in rooms exposed to a C. difficile patient had significantly increased odds of being contaminated with C. difficile, compared to surfaces in unexposed patient rooms. Additionally, compared to plastic surfaces, cork surfaces had significantly increased odds of being contaminated with C. difficile. For 236 samples collected from the ward environment, MRSA and C. difficile were recovered from 2.5% and 5.9% of samples, respectively. Overall, the majority of MRSA and C. difficile strains were molecularly identified as spa type 2/t002 (84.6%, n = 11) and ribotype 078 (50%, n = 14), respectively.

CONCLUSIONS

In patient rooms and the ward environment, specific materials and locations were identified as being contaminated with MRSA or C. difficile. These sites should be cleaned and disinfected with increased vigilance to help limit the transmission and dissemination of MRSA and C. difficile within the hospital.

Bacterial spore structures and their protective role in biocide resistance

The structure and chemical composition of bacterial spores differ considerably from those of vegetative cells. These differences largely account for the unique resistance properties of the spore to environmental stresses, including disinfectants and sterilants, resulting in the emergence of spore-forming bacteria such as Clostridium difficile as major hospital pathogens. Although there has been considerable work investigating the mechanisms of action of many sporicidal biocides against Bacillus subtilis spores, there is far less information available for other species and particularly for various Clostridia. This paucity of information represents a major gap in our knowledge given the importance of Clostridia as human pathogens. This review considers the main spore structures, highlighting their relevance to spore resistance properties and detailing their chemical composition, with a particular emphasis on the differences between various spore formers. Such information will be vital for the rational design and development of novel sporicidal chemistries with enhanced activity in the future.

A novel fusion protein containing the receptor binding domains of C. difficile toxin A and toxin B elicits protective immunity against lethal toxin and spore challenge in preclinical efficacy models

Antibodies targeting the Clostridium difficile toxin A and toxin B confer protective immunity to C. difficile associated disease in animal models and provided protection against recurrent C. difficile disease in human subjects. These antibodies are directed against the receptor binding domains (RBD) located in the carboxy-terminal portion of both toxins and inhibit binding of the toxins to their receptors. We have constructed a recombinant fusion protein containing portions of the RBD from both toxin A and toxin B and expressed it in Escherichia coli. The fusion protein induced high levels of serum antibodies to both toxins A and B capable of neutralizing toxin activity both in vitro and in vivo. In a hamster C. difficile infection model, immunization with the fusion protein reduced disease severity and conferred significant protection against a lethal dose of C. difficile spores. Our studies demonstrate the potential of the fusion protein as a vaccine that could provide protection from C. difficile disease in humans.

Successful combat of an outbreak due to Clostridium difficile PCR ribotype 027 and recognition of specific risk factors

In the period April-September 2005, an outbreak of Clostridium difficile infection (CDI) due to PCR ribotype 027 occurred among 50 patients in a 341-bed community hospital in Harderwijk, The Netherlands. A retrospective case-control study was performed to identify risk factors specific for CDI, using a group of patients with CDI (n = 45), a group of randomly selected control patients without diarrhoea (n = 90), and a group of patients with non-infectious diarrhoea (n = 109). Risk factors for CDI and for non-CDI diarrhoea were identified using multiple logistic regression analysis. Independent risk factors for CDI were: age above 65 years (OR 2.6; 95% CI 1.0-5.7), duration of hospitalization (OR 1.04 per additional day; 95% CI 1.0-1.1), and antibiotic use (OR 12.5; 95% CI 3.2-48.1). Of the antibiotics used, cephalosporins and fluoroquinolones were identified as the major risk factors for development of CDI. The risk of developing CDI was particularly high in people receiving a combination of a cephalosporin and a fluoroquinolone (OR 57.5; 95% CI 6.8-483.6). The main factors affecting the risk of non-CDI diarrhoea were proton-pump inhibitors, immunosuppressive drugs, underlying digestive system disease, previous surgery, and gastric tube feeding. The outbreak ended only after implementation of restricted use of cephalosporins and a complete ban on fluoroquinolones, in addition to general hygienic measures, cohorting of patients in a separate ward, education of staff, and intensified environmental cleaning. The results of this study support the importance of appropriate antimicrobial stewardship in the control of hospital outbreaks with C. difficile PCR ribotype 027.

Clinical review of the management of fulminant clostridium difficile infection

BACKGROUND

Clostridium difficile infection (CDI) is a frequent cause of morbidity and mortality among elderly hospitalized patients. A small but increasing number of patients have developed fulminant CDI, and a significant number of these patients require emergency colectomy. In this review, we discuss the risk factors, pathophysiology, diagnosis, and management of fulminant CDI.

DATA SOURCES

A literature search (Medline, Embase, Cochrane Library, Biosis, Science Citation Index, Ovid Journals) was performed from the period between January 1980 and June 2008 using the key words "Clostridium difficile,""pseudomembranous enterocolitis,""colectomy,""acute abdomen,""antibiotic-associated diarrhea," or "fulminant Clostridium difficile colitis." Articles not in English or not related to human subjects were excluded. For this review, we analyzed the articles identified in our original search and those articles cited in the original review articles. No randomized trials were found on the surgical management of fulminant CDI and only retrospective studies with a minimum of five patients were used in the review. With respect to medical treatment, we based our review on guideline articles, systematic reviews, and available randomized trials.

CONCLUSION

Both the incidence and severity of CDI are increasing. Fulminant CDI is underappreciated as a life-threatening disease because of a lack of awareness of its severity and its nonspecific clinical syndrome. Early diagnosis and treatment are essential for a good outcome, and early surgical intervention should be used in patients who are unresponsive to medical therapy. The surgical procedure of choice is a total abdominal colectomy with end ileostomy, although the mortality rate remains high.

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-associated diarrhoea

Clostridium difficile is an important nosocomial pathogen and the most frequently diagnosed cause of infectious hospital-acquired diarrhoea. Toxigenic strains usually produce toxin A and toxin B, which are the primary virulence factors of C. difficile. Some recently described strains produce an additional toxin, an adenosine-diphosphate ribosyltransferase known as binary toxin, the role of which in pathogenicity is unknown. There has been concern about the emergence of a hypervirulent fluoroquinolone-resistant strain of C. difficile in North America and Europe. The use of fluoroquinolone antimicrobials appears to be acting as a selective pressure in the emergence of this strain. In this review, we describe the current state of knowledge about C. difficile as a cause of diarrhoeal illness.

A case of recurrent Clostridium difficile diarrhea

Clostridium difficile is an important and increasingly common cause of nosocomial diarrhea. Recent epidemics of C. difficile-associated disease (CDAD) reveal a pathogen that is becoming more virulent, leading to an increase in disease severity, treatment failures, and relapses. Those of advanced age are at a particular risk of acquiring this debilitating and costly disease. This case describes CDAD recurring in an 87-year-old resident of a long-term care facility, which caused hospitalization. After five days of therapy on oral metronidazole with minimal improvement in diarrheal symptoms, the patient was switched to oral vancomycin. The patient subsequently improved and completed a 14-day course of metronidazole/vancomycin. The patient's stool was recultured shortly before finishing therapy and revealed C. difficile antigen; the patient was asymptomatic at that time, and it was therefore recommended to stop therapy after the 14-day treatment course. The patient was concurrently prescribed lactobacillus, a probiotic, for treatment of CDAD. The use of probiotics in the treatment of CDAD needs further study.

Clostridium difficile-associated disease in Oregon: increasing incidence and hospital-level risk factors

BACKGROUND

The incidence of Clostridium difficile-associated disease (CDAD) appears to be increasing. Population-based estimates of disease have been limited, and analyses of hospital-level risk factors for CDAD are lacking. We sought to determine the incidence and trends of CDAD in Oregon and to identify hospital-level factors associated with increases in disease.

METHODS

We analyzed hospital discharge data to calculate the incidence and to describe trends of CDAD in Oregon from 1995 through 2002. We administered questionnaires to hospital laboratory directors, infection control practitioners, and pharmacists to determine the status of laboratory, infection control, and pharmacy policies over time.

RESULTS

The overall incidence of CDAD in Oregon was 3.5 case patients per 10,000 residents in 2002. Incidence increased from 1.4 to 3.3 cases per 1,000 hospital discharges from 1995 to 2002. Rates of disease increased most in hospitals with licensed bed capacity of more than 250 beds and more than 5 intensive care unit beds. Few laboratories, infection control practitioners, and pharmacists were able to identify changes in specific policies over the study period.

CONCLUSIONS

This is the first study to determine a statewide population-based incidence of CDAD. Incidence of CDAD in Oregon has more than doubled over the past decade; larger hospitals experienced the greatest increase in disease rates. We did not identify hospital-level policies that could explain the increase. A study of patients with CDAD at the hospitals with the largest increases is underway to further identify risk factors.

Antimicrobial susceptibility pattern of Clostridium difficile and its relation to PCR ribotypes in a Swedish university hospital

All 238 Clostridium difficile isolates were susceptible to metronidazole and vancomycin, whereas 84% and 1% were resistant to clindamycin and fusidic acid. Etest MICs for metronidazole were lower than agar dilution MICs (P < 0.01) but without difference in susceptible-intermediate-resistant categorization. No particular PCR ribotype was associated with clindamycin or fusidic acid resistance.

Significant Absorption of Oral Vancomycin in a Patient with Clostridium difficile Colitis and Normal Renal Function

Orally-administered vancomycin is poorly absorbed in most patients, usually producing minimal or subtherapeutic serum concentrations. Bowel inflammation may enhance absorption of oral vancomycin, particularly in those with renal failure. A 77-year-old female with Clostridium difficile (C difficile) colitis and normal renal function was treated with high doses of oral vancomycin and achieved serum concentrations in the therapeutic range. To our knowledge, this is the first report of a patient with C difficile colitis and normal renal function to develop therapeutic serum concentrations following oral administration of vancomycin.

Genotypic and Phenotypic Analysis ofClostridium difficileCorrelated with Previous Antibiotic Exposure

To analyze Clostridium difficile susceptibility results and genotypes in relation to antibiotic exposures that precipitated C. difficile-associated diarrhea (CDAD), we examined 83 nosocomial C. difficile isolates recovered at a tertiary care center in Boston, Massachusetts. MICs were determined by E-test methodology using modified Brucella agar. Isolates were genotyped by pulsed-field gel electrophoresis and restriction enzyme analysis. Antibiotic susceptibilities were: ciprofloxacin (0%), clindamycin (59%), trovafloxacin (63%), ceftriaxone (73%), piperacillin/tazobactam (100%), metronidazole (100%), and vancomycin (100%). The two most common strain groups, isolated from a total of 33 patients, were much more likely to be resistant to clindamycin, erythromycin, and trovafloxacin than other strain groups [79% (26 of 33) versus 2% (1 of 50), respectively]. Clindamycin exposure was strongly associated with CDAD caused by isolates that exhibited multiple resistance to clindamycin, erythromycin, and trovafloxacin (prevalence odds ratio, 4.2; 95% confidence interval, 1.1-16.8), whereas other antimicrobials did not yield significant associations. Resistance of specific C. difficile strains to clindamycin and other antimicrobial agents may contribute to their hospital dissemination and explain, in part, the propensity of clindamycin to trigger nosocomial outbreaks.

Could hospital patients' hands constitute a missing link?

The relationship between contamination of patients' hands and transmission of healthcare-associated infection has received only limited attention, but may represent a previously overlooked but potentially significant link in the chain of infection. This paper aims critically to review the literature to determine whether this possible epidemiological relationship is worthy of further consideration. Studies that have investigated the microbiology or hand hygiene behaviours of patients and other groups are examined to establish their limitations and implications for future practice and research. Examples of healthcare-associated infections where improving patient hand hygiene may have a favourable impact on transmission, and how this might be achieved within the context of current UK health service initiatives, are discussed. It is recommended that systematic studies of the role of patients' hands in the chain of hospital infection should be undertaken.

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.

Pseudomembranous colitis in children

This review presents the microbiology, management and prevention of pseudomembranous colitis (PMC) in children. PMC is commonly associated with prior antibiotic exposure and hospitalization. It is caused almost exclusively by toxins produced by Clostridium difficile. The clinical spectrum of this disease may range from a mild, non-specific diarrhea to severe colitis with toxic megacolon, perforation, and death. PMC may affect all age groups, although a lower incidence has been noted in children. Ampicillin, amoxicillin, the second- and third-generation cephalosporins and clindamycin are the drugs most frequently associated with development of PMC, although nearly all antimicrobials have been implicated as causes of diarrhea and colitis. Discontinuation of antibiotics and supportive therapy usually lead to resolution of this disorder. Administration of oral vancomycin or other therapeutic regimens may be needed.

Rifalazil treats and prevents relapse of clostridium difficile-associated diarrhea in hamsters

Although vancomycin and metronidazole effectively treat Clostridium difficile-associated diarrhea and colitis (CDAD), their use is associated with a high incidence of relapsing C. difficile infection. Rifalazil is a new benzoxazinorifamycin that possesses activity against Mycobacterium tuberculosis and gram-positive bacteria. Here we compared rifalazil and vancomycin for effectiveness in preventing or treating clindamycin-induced cecitis in a hamster model of CDAD. Golden Syrian hamsters were injected subcutaneously with clindamycin phosphate (10 mg/kg), followed 24 h later by C. difficile gavage. Hamsters received by gavage for 5 days vehicle, vancomycin (50 mg/kg), or rifalazil (20 mg/kg) either simultaneously with (prophylactic protocol) or 24 h after C. difficile administration (treatment protocol). While all vehicle-administered animals became moribund within 48 h of C. difficile administration, no rifalazil- or vancomycin-treated animals in either protocol showed signs of morbidity after 7 days. Ceca of rifalazil-treated animals showed absence of epithelial cell damage, significantly reduced congestion and edema, and less, but not statistically significantly less, neutrophil infiltration compared to those of vehicle-treated animals. In contrast, vancomycin-treated animals demonstrated severe epithelial cell damage and mildly reduced congestion and edema. Moreover, hamsters relapsed and tested C. difficile toxin positive (by enzyme-linked immunosorbent assay) 10 to 15 days after discontinuation of vancomycin treatment. None of the rifalazil-treated hamsters showed signs of disease or presence of toxins in their feces 30 days after discontinuation of treatment. Our results indicate that once daily rifalazil may be superior to vancomycin for curative treatment of CDAD.

Mass antibiotic treatment for group A streptococcus outbreaks in two long-term care facilities

Outbreaks of invasive infections caused by group A β-hemolytic streptococcus (GAS) may occur in long-term care settings and are associated with a high case-fatality rate in debilitated adults. Targeted antibiotic treatment only to residents and staff known to be at specific risk of GAS may be an ineffective outbreak control measure. We describe two institutional outbreaks in which mass antibiotic treatment was used as a control measure. In the first instance, mass treatment was used after targeted antibiotic treatment was not successful. In the second instance, mass treatment was used to control a rapidly evolving outbreak with a high case-fatality rate. Although no further clinical cases were seen after the introduction of mass antibiotic treatment, persistence of the outbreak strain was documented in one institution >1 year after cases had ceased. Strain persistence was associated with the presence of a chronically colonized resident and poor infection control practices.

Comparison of AP-PCR typing and PCR-ribotyping for estimation of nosocomial transmission of Clostridium difficile

We recently attempted to clarify an increased incidence of Clostridium difficile-associated diarrhoea (CDAD) in our hospital by arbitrarily primed polymerase chain reaction (AP-PCR) typing of isolates from 147 consecutive patients collected during a 12 month period (Wullt et al. J Hosp Infect 1999;43:265-273). In the present study we compared the results based on previous AP-PCR data with those based on recent PCR ribotyping of the same isolates and re-analysis of a subset of isolates by AP-PCR typing. The pattern of PCR ribotypes was similar among inpatients and outpatients. A cluster of three closely related PCR ribotypes, related to those of the serogroup H and A8 type strains, dominated and comprised 31% of inpatient and 28% of outpatient C. difficile isolates. The apparent nosocomial transmission rate among inpatients with CDAD was only 9% by AP-PCR typing compared with 18 or 36% by PCR ribotyping depending on the definition used (proportion of patients sharing C. difficile type and ward within two or 12 months). Corresponding rates for all CDAD patients were 5% by AP-PCR and 11 or 21% by PCR ribotyping. Thus, most CDAD patients apparently became ill due to their endogenous strain of C. difficile. Because of the low concordance between the two typing methods the proportion of patients fulfilling the criteria for nosocomial transmission by both methods was only 1%. Re-examination of isolates from patients with recurrences revealed a reproducibility problem with AP-PCR typing. We conclude, that of these two PCR-based options for typing of C. difficile PCR ribotyping offers a superior experimental robustness compared with AP-PCR typing.

Epidemiology and molecular characterization of Clostridium difficile strains from patients with diarrhea: low disease incidence and evidence of limited cross-infection in a Swedish teaching hospital

We prospectively studied the epidemiology of Clostridium difficile-associated diarrhea (CDAD) in a 900-bed hospital over the course of 12 months by PCR-ribotyping of C. difficile isolates. A total of 304 cases were diagnosed, corresponding to an overall incidence of 7/1,000 admissions, with higher rates in nephrology, hematology, and organ transplantation wards (37, 30, and 21/1,000), and 72% were classified as hospital associated (onset in hospital or onset at home but after a hospital stay within 2 months). All 382 isolates from 227 of 304 (75%) patients available for PCR-ribotyping were typeable, yielding 70 PCR-ribotypes. The three most common types comprised 30% of hospital-associated and 34% of community-associated cases, indicating import via admitted patients as a major source of C. difficile strains occurring in the hospital. Of the 227 patients studied, 38% each contributed 2 to 13 fecal samples positive for C. difficile over the course of the study period. Repeat isolates of the same PCR-ribotype as the first isolate were found in 79% of these patients and in 95% of specimens delivered within 30 days, compared to 63% of those obtained at 31 to 204 days. Nosocomial acquisition of CDAD, defined as the proportion of cases sharing C. difficile type and admitted to the same ward within 2 or 12 months, was 20% and 32% of hospital-associated cases and 14% and 23% of all cases, respectively. Thus, most CDAD cases diagnosed over the course of the study period, including those associated with hospitalization, appeared to be caused by endogenous C. difficile strains rather than by strains truly being acquired in the hospital.

Clostridium difficile vaccine and serum immunoglobulin G antibody response to toxin A

There is a strong association between serum antibody responses to toxin A and protection against Clostridium difficile diarrhea. A parenteral C. difficile toxoid vaccine induced very-high-level responses to anti-toxin A immunoglobulin G (IgG) in the sera of healthy volunteers. After vaccination, the concentrations of anti-toxin A IgG in the sera of all 30 recipients exceeded the concentrations that were associated with protection in previous clinical studies. Furthermore, the median concentration of serum anti-toxin A IgG in the test group was 50-fold higher than the previous threshold. These findings support the feasibility of using a vaccine to protect high-risk individuals against C. difficile-associated diarrhea and colitis.

[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 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.

Underlying disease severity as a major risk factor for nosocomial Clostridium difficile diarrhea

OBJECTIVE

To determine the diagnostic accuracy of an index of underlying disease severity (Horn's index) in identifying patients with a high probability of having nosocomial Clostridium difficile diarrhea as a complication of antimicrobial therapy.

DESIGN

A prospective cohort study of 252 adult patients admitted to the hospital and receiving antibiotics. Risk facctors for C. difficile diarrhea were first determined retrospectively in a different cohort of 300 hospitalized patients (primary cohort) and then prospectively in this cohort of 252 hospitalized patients receiving antibiotics (secondary cohort). At the time of hospital admission, disease was rated by clinicians as mild (1), moderate (2), severe (3), or extremely severe (4) using a modified Horn's index. Multivariable logistic regression analysis was used to determine the odds ratio (OR) for C. difficile diarrhea associated with increasing levels of disease severity.

SETTING

An urban teaching hospital affiliated with a medical school in Boston, Massachusetts.

RESULTS

The incidence of nosocomial C. difficile diarrhea was 8.7% in the primary cohort and 11% in the secondary cohort In the prospective cohort study (secondary cohort), the OR for C. difficile diarrhea associated with extremely severe disease was 17.6 (95% confidence interval, 5.8 to 53.5). The sensitivity, specificity, and positive and negative predictive values of a Horn's index score of 3 or more (severe to extremely severe disease) as a predictor of nosocomial C. difficile diarrhea were 79%, 73%, 27%, and 96%, respectively.

CONCLUSIONS

These findings provide a means of early stratification of hospitalized patients receiving antibiotics according to their risk for nosocomial C. difficile diarrhea. Patients with severe to extremely severe disease at the time of admission may benefit from careful monitoring of antibiotic prescribing and early attention to infection control issues. In the future, these "high-risk" patients may benefit from prophylaxis studies of novel agents being developed to prevent C. difficile diarrhea.

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.

Infection in the chronically critically ill: unique risk profile in a newly defined population

Although CCI is defined as prolonged ventilatory failure with tracheotomy stemming from preceding critical illness, the contention that multisystem debilities impact on most CCI patients' care and recovery is a central thesis of this volume. Perhaps reflecting the combined debilities inherent in CCI, infectious complications take their toll in morbidity, mortality, and persistent ventilatory insufficiency. Enhanced susceptibility to infection results from a potent admixture of barrier breakdown, exposure to virulent and resistant nosocomial pathogens, and postulated "immune exhaustion" that stems from the combined impact of comorbidities and the sequellae of critical illness. Strategies to improve outcome in CCI-related infection include standard measures of support especially nutrition, reducing environmental inoculum through pulmonary hygiene measures, skin care, and limiting barrier breaches, and appropriate antimicrobials directed at likely pathogens. Future stratification of patient risk on the basis of immune phenotype or genotype and potential immunomodulatory prophylaxis may be around the corner, as new prospects in the pharmaceutical armamentarium are presently undergoing testing.

Health care costs and mortality associated with nosocomial diarrhea due to Clostridium difficile

A total of 271 patients were prospectively followed up to determine whether patients whose hospital stay is complicated by diarrhea due to Clostridium difficile experience differences in cost and length of stay and survival rates when compared with patients whose stay is not complicated by C. difficile-associated diarrhea. Forty patients (15%) developed nosocomial C. difficile-associated diarrhea. These patients incurred adjusted hospital costs of $3669--that is, 54% (95% confidence interval [CI], 17%-103%)--higher than patients whose course was not complicated by C. difficile-associated diarrhea. The extra length of stay attributable to C. difficile-associated diarrhea was 3.6 days (95% CI, 1.5-6.2). C. difficile-associated diarrhea was not associated with excess 3-month or 1-year mortality after adjustment for age, comorbidity, and disease severity. On the basis of the findings of this study, a conservative estimate of the cost of this disease in the United States exceeds $1.1 billion per year.

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.

Antibiotic prophylaxis and the risk of Clostridium difficile-associated diarrhoea

To test the hypothesis that extended antibiotic prophylaxis increases the risk of Clostridium difficile -associated diarrhoea (CDAD), we conducted a retrospective cohort study of 2641 patients under-going cardiovascular surgery. Main outcome measures were the duration of prophylaxis (< 48 h vs. > 48 h) and the occurrence of CDAD. CDAD occurred in 31 patients (1.2%), who were significantly older (70 +/- 9 y vs. 66 +/- 10 y; P = 0.03), received more therapeutic antibiotics (2.2 +/- 1.9 vs. 0.4 +/- 0.9; P = 0.001) and had a longer postoperative hospital stay (26 +/- 19 d vs. 9 +/- 8 d; P < 0.001) than non-cases. After adjusting for confounding, we did not observe an association between prolonged prophylaxis and CDAD [adjusted odds ratio (AOR), 0.8; CI, 0.4-1.8]. In contrast, three independent predictors were identified: increasing length of hospital stay (AOR per one-day-increment, 1.03; CI, 1.01-1.05), and treatment with third generation cephalosporins (AOR, 5.9; CI, 2.2-16.0) or beta-lactam-beta-lactamase inhibitor combinations (AOR, 4.6; CI, 1.7-12.3). Our results did not confirm that extended prophylaxis after clean surgery increases the risk of CDAD, which remains an uncommon postoperative complication, associated even with short antibiotic exposure.