Clostridium difficile-associated diarrhea and colitis in adults. A prospective case-controlled epidemiologic study

Clostridium difficile Infection

Clostridium difficile is an anaerobic, Gram-positive, spore-forming, toxin-secreting bacillus that has long been recognized to be the most common etiologic pathogen of antibiotic-associated diarrhea. C. difficile infection (CDI) is now the most common cause of health care-associated infections in the United States and accounts for 12% of these infections (Magill SS et al., N Engl J Med370:1198-1208, 2014). Among emerging pathogens of public health importance in the United States, CDI has the highest population-based incidence, estimated at 147 per 100,000 (Lessa FC et al., N Engl J Med372:825-834, 2015). In a report on antimicrobial resistance, C. difficile has been categorized by the Centers for Disease Control and Prevention as one of three "urgent" threats (http://www.cdc.gov/drugresistance/threat-report-2013/). Although C. difficile was first described in the late 1970s, the past decade has seen the emergence of hypertoxigenic strains that have caused increased morbidity and mortality worldwide. Pathogenic strains, host susceptibility, and other regional factors vary and may influence the clinical manifestation and approach to intervention. In this article, we describe the global epidemiology of CDI featuring the different strains in circulation outside of North America and Europe where strain NAP1/027/BI/III had originally gained prominence. The elderly population in health care settings has been disproportionately affected, but emergence of CDI in children and healthy young adults in community settings has, likewise, been reported. New approaches in management, including fecal microbiota transplantation, are discussed.

Selected Topics in Anaerobic Bacteriology

Alteration in the host microbiome at skin and mucosal surfaces plays a role in the function of the immune system, and may predispose immunocompromised patients to infection. Because obligate anaerobes are the predominant type of bacteria present in humans at skin and mucosal surfaces, immunocompromised patients are at increased risk for serious invasive infection due to anaerobes. Laboratory approaches to the diagnosis of anaerobe infections that occur due to pyogenic, polymicrobial, or toxin-producing organisms are described. The clinical interpretation and limitations of anaerobe recovery from specimens, anaerobe-identification procedures, and antibiotic-susceptibility testing are outlined. Bacteriotherapy following analysis of disruption of the host microbiome has been effective for treatment of refractory or recurrent Clostridium difficile infection, and may become feasible for other conditions in the future.

Fecal transplant in refractory Clostridium difficile colitis

BACKGROUND

Clostridium difficile infections are becoming more common, more severe, and more likely to recur. Conventional treatment with antibiotics often fails to eradicate the infection; even when it succeeds, recurrent infection is common. Complementary treatment with probiotic agents to reconstitute the physiological intestinal flora does not yield any consistent benefit. In recent years, fecal transplantation has been used in the English-speaking countries with cure rates of about 87%, but the available evidence is limited to large case series. No randomized controlled trials have been performed. We present the case of a 73-year-old woman with intractable, recurrent enterocolitis due to Clostridium difficile who was successfully treated with fecal transplantation via colonoscopy.

CASE DESCRIPTION

Upon the completion of antibiotic treatment for a second recurrence of enterocolitis, stool in liquid suspension was introduced into the patient's colon through a colonoscope. Prior testing had shown the stool donor to be free of acute infection or stool pathogens. The patient was given loperamide to prolong contact of the stool transplant with the colonic mucosa. She was also treated with Saccharomyces cerevisiae for four weeks.

COURSE

There was no clinical or microbiological evidence of a further recurrence of enterocolitis for 6 months after transplantation. Stool transplantation had no adverse effects.

CONCLUSION

This patient had a lasting remission of enterocolitis due to Clostridium difficile after the treatment described above. Fecal transplantation seems to be a safe and highly effective treatment for recurrent Clostridium difficile infection. It is unclear whether the administration of Saccharomyces cerevisiae confers any additional benefit.

Rapid diagnosis of Clostridium difficile infection by multiplex real-time PCR

The gold standards for the diagnosis of Clostridium difficile infections (CDIs) are the cytotoxicity assay and the toxigenic culture. However, both methods are time-consuming and the results are not available before 24-48 h. We developed and evaluated a multiplex in-house real-time polymerase chain reaction (PCR) assay for the simultaneous detection of toxigenic strains of C. difficile and the presumptive identification of the epidemic NAP1/027/BI strain from stools. Amplifications were performed using specific primers for tcdB and tcdC on an ABI Prism 7300 (Applied Biosystems). The detection of amplicons was done using TaqMan probes. The analytical sensitivity of the multiplex real-time PCR for detecting tcdB was estimated to 10 CFU/g of stools. This assay was assessed from 881 consecutive unformed stools from patients suspected of having CDI. The gold standard was the toxigenic culture for the diagnosis of CDI and PCR ribotyping for the identification of the NAP1/027/BI strain. The prevalence of positive toxigenic culture was 9.31%. Compared to the toxigenic culture, the sensitivity, specificity, and positive and negative predictive values were 86.59%, 97.43%, 78.02%, and 98.57%, respectively, for the real-time PCR and 70.73%, 100%, 100%, and 97.08%, respectively, for the cytotoxicity assay.

Clostridium difficile infection: epidemiology and control measurements

Clostridium difficile (C. difficile) is the most commonly recognized cause of nosocomial infection and antibiotic-associated diarrhea in healthcare settings. C. difficile infection (CDI) can result in pseudomembranous colitis. The diagnosis of CDI should be based on a combination of clinical and laboratory findings. The majority of CDIs are acquired from external sources, and healthcare facilities are the main sources of transmission. Rational use of antibiotics is the most effective method to prevent CDI. Effective control measurements for nosocomial infection should be emphasized in healthcare settings to prevent the transmission of CDI. Limited data have shown that probiotics may be effective for the prevention of CDI.

Clostridium difficile 30 years on: what has, or has not, changed and why?

The report of clindamycin-associated colitis in 1974 by Tedesco et al. [Ann Intern Med 81: 429-33] stimulated an intense search for the cause of this severe complication of antibiotic use. The search culminated in early 1978 in the publication of a series of papers within 3 months that identified the causative agent as Clostridium difficile and its accompanying toxins. Thirty years later we are in the midst of a resurgence of C. difficile infection (CDI) in North America and Europe that is greater than ever previously reported and for which morbidity and mortality appear to be higher than ever seen in the past. The purpose of this review is to highlight the discoveries of the past 30 years that, in my view, have brought us to our current level of understanding of the pathogenesis, prevention and treatment of CDI, and to suggest why a disease thought to be managed so well 30 years ago could now be causing more morbidity and mortality than ever before. In the 21st century the focus should be on better understanding the relationship between the C. difficile organism and the host at the mucosal level, so that biotherapeutic and vaccine strategies for the prevention of CDI can be developed.

Risk of Clostridium difficile infection after perioperative antibacterial prophylaxis before and during an outbreak of infection due to a hypervirulent strain

BACKGROUND

Perioperative antibacterial prophylaxis (PAP) is an important component of surgical site infection prevention but may be associated with adverse effects, such as Clostridium difficile infection (CDI). Since the emergence of a hypervirulent strain of C. difficile, the risk of development of CDI after PAP has not been evaluated. The purpose of this study was to determine the risk of PAP-induced CDI after selected surgical procedures and to compare such risk before with such risk after the emergence of the hypervirulent strain of C. difficile.

METHODS

We performed a retrospective cohort study including all patients aged > or = 18 years who underwent either abdominal hysterectomy, hip arthroplasty, craniotomy, or colon, cardiac, or vascular surgery from August 1999 through May 2005 in a tertiary care hospital in Quebec, Canada.

RESULTS

A total of 8373 surgical procedures were performed, and PAP was used in 7600 of these interventions. Of 98 CDI episodes identified, 40 occurred after patients received PAP only. The risk of CDI was 14.9 cases per 1000 surgical procedures among patients who received PAP only during the period 2003-2005, compared with 0.7 cases per 1000 surgical procedures during the period 1999-2002 (P < .001). The independent risk factors associated with CDI in patients given PAP only were older age, administration of cefoxitin (rather than cefazolin) alone or in combination with another drug, and year of surgery.

CONCLUSIONS

In the context of a large epidemic of CDI associated with the emergence of a novel strain, 1.5% of patients who received PAP as their sole antibiotic treatment developed CDI. In situations in which the only purpose of PAP is to prevent infrequent and relatively benign infections, the risks may outweigh the benefits in some elderly patients.

Antimicrobial-associated risk factors for Clostridium difficile infection

Antimicrobial therapy plays a central role in the pathogenesis of Clostridium difficile infection (CDI), presumably through disruption of indigenous intestinal microflora, thereby allowing C. difficile to grow and produce toxin. Investigations involving animal models and studies performed in vitro suggest that inhibitory activity against C. difficile and differences in the propensity to stimulate toxin production may also influence the likelihood that particular drugs may cause CDI. Although nearly all antimicrobial classes have been associated with CDI, clindamycin, third-generation cephalosporins, and penicillins have traditionally been considered to harbor the greatest risk. Recent studies have also implicated fluoroquinolones as high-risk agents, a finding that is most likely to be related in part to increasing fluoroquinolone resistance among epidemic strains (i.e., restriction-endonuclease analysis group BI/North American PFGE type 1 strains) and some nonepidemic strains of C. difficile. Restrictions in the use of clindamycin and third-generation cephalosporins have been associated with reductions in CDI. Because use of any antimicrobial has the potential to induce the onset of CDI and disease caused by other health care-associated pathogens, antimicrobial stewardship programs that promote judicious use of antimicrobials are encouraged in concert with environmental and infection control-related efforts.

Systematic review of the risk of enteric infection in patients taking acid suppression

CONTEXT

Proton pump inhibitors (PPIs) and H(2) receptor antagonists (H(2)RAs) have become the mainstay of therapy in acid-related upper gastrointestinal disorders. There have been concerns raised about the possible association of PPIs with enteric infections.

OBJECTIVE

We conducted a systematic review to evaluate any association between acid suppression and enteric infection. We also assessed differences between types of enteric infections and the type of acid suppression.

DATA SOURCES

Electronic searches of MEDLINE (1966-2005), EMBASE (1988-2005), and CINAHL (1982-2005) were undertaken using a combination of subject headings and text words related to PPI therapy, H(2)RAs, and enteric infections.

STUDY SELECTION

All observational studies were eligible, including cross-sectional, case control, and cohort studies that evaluated risk of enteric infection associated with antisecretory therapy. Eligibility assessment was made by two independent researchers.

DATA EXTRACTION

Information on study design, patient population, type of acid suppression, type of infection, and outcomes was collected. The odds ratio (OR) of taking acid suppression therapy in cases and controls was calculated and results were synthesized using a random effects model (DerSimonian and Laird, Stats direct version 2.4.4).

DATA SYNTHESIS

A total of 12 papers evaluating 2,948 patients with Clostridium difficile were included in the review. There was an increased risk of taking antisecretory therapy in those infected with C. difficile (pooled OR 1.94, 95% CI 1.37-2.75). There was significant heterogeneity between the studies (P= 0.0006) that was not explained by planned subgroup analysis. The association was greater for PPI use (OR 1.96, 95% CI 1.28-3.00) compared with H(2)RA use (OR 1.40, 95% CI 0.85-2.29). A total of six studies evaluated Salmonella, Campylobacter, and other enteric infections in 11,280 patients. There was an increased risk of taking acid suppression in those with enteric infections (OR 2.55, 95% CI 1.53-4.26). There was significant heterogeneity between the studies (P < 0.0001) that was not explained by subgroup analysis. The association was greater for PPI use (OR 3.33, 95% CI 1.84-6.02) compared with H(2)RA use (OR 2.03, 95% CI 1.05-3.92).

CONCLUSION

There is an association between acid suppression and an increased risk of enteric infection. Further prospective studies on patients taking long-term acid suppression are needed to establish whether this association is causal.

Is It Clostridium difficile Infection or Something Else? A Case-control Study of 352 Hospitalized Patients With New-onset Diarrhea

BACKGROUND

Clostridium difficile-associated diarrhea (CDAD) is a leading cause of nosocomial diarrhea in the United States, and may be associated with significant morbidity and occasional mortality. Diarrhea is also very common among hospitalized patients and is often related to a variety of factors not related to C difficile infection.

METHODS

We performed a retrospective case-control study at a tertiary care community medical center to delineate factors that are predictive of CDAD among hospitalized patients with new-onset diarrhea (ie, not present at the time of admission). Controls were selected based on negative C difficile toxin test(s) (CDTTs) (> 95% by cytotoxic assay), presence on the same ward as the patients with first positive CDTT, and hospitalization around the same period as the positive cases.

RESULTS

The study involved 352 patients (88 cases and 264 controls). In univariate analysis, age 75 years or greater, exposure to cefazolin or levofloxacin during the 4-week period preceding CDTT, and hospitalization for 7 days or greater before CDTT were significantly associated with a positive test; male gender and prior ceftriaxone exposure nearly reached statistical significance. Multivariate logistic regression analysis revealed age 75 years or greater (odds ratio [OR] 2.2, 95% confidence interval [CI] 1.3-3.7), hospitalization for 7 days or more (OR 2.3, 95% CI 1.3-3.8], and prior exposure to cefazolin (OR 3.5, 95% CI 1.6-7.5) or levofloxacin (OR 2.1, 95% CI 1.2-3.7) as independent predictors of a positive CDTT; male gender nearly achieved statistical significance (OR 1.6, 95% CI 0.9-2.7).

CONCLUSIONS

Among hospitalized patients with diarrhea who underwent testing for C difficile toxin, age 75 years or older, hospitalization for 7 days or greater, and recent exposure to cefazolin or levofloxacin were important predictors of a positive CDTT. These findings may help in the initiation of early presumptive treatment for CDAD, and appropriate isolation of higher risk patients before results become available. In addition, consideration of these risk factors may help in deciding whether a CDTT should be repeated when the first test is negative. Our study also supports more judicious use of antibiotics, particularly cefazolin and levofloxacin, in reducing the risk of CDAD in hospitalized patients.

Failure of dietary oligofructose to prevent antibiotic-associated diarrhoea

BACKGROUND

Oligofructose is metabolized by bifidobacteria, increasing their numbers in the colon. High bifidobacteria concentrations are important in providing 'colonization resistance' against pathogenic bacteria.

AIM

To reduce the incidence of antibiotic-associated diarrhoea in elderly patients.

METHODS

Patients over the age of 65 taking broad-spectrum antibiotics received either oligofructose or placebo. A baseline stool sample was cultured for Clostridium difficile and tested for C. difficile toxin. A further stool sample was analysed for C. difficile if diarrhoea developed.

RESULTS

No difference was seen in the baseline characteristics, incidence of diarrhoea, C. difficile infection or hospital stay between the two groups (n = 435). Oligofructose increased bifidobacterial concentrations (P < 0.001, 95% CI: 0.69-1.72). A total of 116 (27%) patients developed diarrhoea of which 49 (11%) were C. difficile-positive and were more likely to be taking a cephalosporin (P = 0.006), be female (P < 0.001), to have lost more weight (P < 0.001, 95% CI: 0.99-2.00) and stayed longer in hospital (P < 0.001, 95% CI: 0.10-1.40). Amoxicillin (amoxycillin) and clavulanic acid increased diarrhoea not caused by C. difficile (P = 0.006).

CONCLUSION

Oligofructose does not protect elderly patients receiving broad-spectrum antibiotics from antibiotic-associated diarrhoea whether caused by C. difficile or not. Oligofructose was well-tolerated and increased faecal bifidobacterial concentrations.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Epidemiology and outcome of Clostridium difficile infection and diarrhea in HIV infected inpatients

Clostridium difficile causes diarrhea in HIV infected patients but reports of prevalence, risk factors, and outcome vary. We studied the impact of C. difficile in 161 HIV infected inpatients admitted to Cook County Hospital. Patients with C. difficile had more hospital admissions in the previous 6 months (p =.04), spent more days in the hospital in the previous 3 months (p =.02), more often had previously received H2 blockers or treatment for Pneumocystis carinii (p <.05), and had a more frequent history of herpesvirus (p =.03) or opportunistic infections (p =.04). C. difficile associated diarrhea (CDAD) was the etiology in 32% of all study patients with diarrhea. Patients with CDAD were hospitalized for longer periods (p =.02) and received more antibiotics (p =.002). C. difficile was frequently present in our HIV infected patients, especially those with advanced HIV disease, but appeared to have little impact on morbidity or mortality.

Conditions associated with leukocytosis in a tertiary care hospital, with particular attention to the role of infection caused by clostridium difficile

Few modern studies have enumerated the conditions associated with leukocytosis. Our clinical experience has implicated Clostridium difficile infection in a substantial proportion of patients with leukocytosis. In a prospective, observational study of 400 inpatients with WBC counts of >/=15,000 cells/mm(3), we documented >/=1 infection in 207 patients (53%). Of these 207 patients, 97 (47%) had pneumonia, 60 (29%) had urinary tract infection, 34 (16%) had soft-tissue infection, and 34 (16%) had C. difficile infection. C. difficile infection was present in 25% of patients with WBC counts of >30,000 cells/mm(3) who did not have hematological malignancy. Other causes of leukocytosis in the 400 patients included physiological stress, in 152 patients (38%); medications or drugs, in 42 (11%); hematological disease, in 22 (6%); and necrosis or inflammation, in 22 (6%). C. difficile infection is a prominent cause of leukocytosis and this diagnosis should be considered for patients with WBC counts of >/=15,000 cells/mm(3), even in the absence of diarrheal symptoms.

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 infection: risk factors, medical and surgical management

BACKGROUND

Clostridium difficile has become recognized as a cause of nosocomial infection which may progress to a fulminant disease.

METHODS

Literature review using electronic literature research back to 1966 utilizing Medline and Current Contents. All publications on antibiotic-associated diarrhea, antibiotic-associated colitis, and pseudomembranous colitis as well as C. difficile infection were included. We addressed established and potential risk factors for C. difficile disease such as an impaired immune system and cost benefits of different diagnostic tests. An algorithm is outlined for diagnosis and both medical and surgical management of mild, moderate and severe C. difficile disease.

RESULTS

Diagnosis of C. difficile infection should be suspected in patients with diarrhea, who have received antibiotics within 2 months or whose symptoms started after hospitalization. A stool specimen should be tested for the presence of leukocytes and C. difficile toxins. If this is negative and symptoms persist, stool should be tested with 'rapid' enzyme immunoabsorbent and stool cytotoxin assays, which are the most cost-effective tests. Endoscopy and other imaging studies are reserved for severe and rapidly progressive courses. Oral metronidazole or vancomycin are the antibiotics of choice. Surgery is rarely required for selected patients refractory to medical treatment. The threshold for surgery in severe cases with risk factors including an impaired immune system should be low.

CONCLUSION

C. difficile infection has been recognized with increased frequency as a nosocomial infection. Early diagnosis with immunoassays of the stool and prompt medical therapy have a high cure rate. Metronidazole has supplanted oral vancomycin as the drug of first choice for treating C. difficile infections.

Environmental control to reduce transmission of Clostridium difficile

Restrictive antibiotic policies and infection control measures have been shown to reduce the incidence of Clostridium difficile-associated diarrhea (CDAD) among hospitalized patients. To date, the role of environmental disinfectants in reducing nosocomial CDAD rates has not been well studied. In a before-and-after intervention study, patients in 3 units were evaluated to determine if unbuffered 1:10 hypochlorite solution is effective as an environmental disinfectant in reducing the incidence of CDAD. Among 4252 patients, the incidence rate of CDAD for bone marrow transplant patients decreased significantly, from 8.6 to 3.3 cases per 1000 patient-days (hazard ratio, 0.37; 95% confidence interval, 0.19-0.74), after the environmental disinfectant was switched from quaternary ammonium to 1:10 hypochlorite solution in the rooms of patients with CDAD. Reverting later to quaternary ammonium solution increased the CDAD rate to 8.1 cases per 1000 patient-days. No reduction in CDAD rates was seen among neurosurgical intensive care unit and general medicine patients, for whom baseline rates were 3.0 and 1.3 cases per 1000 patient-days, respectively. Unbuffered 1:10 hypochlorite solution is effective in decreasing patients' risk of developing CDAD in areas where CDAD is highly endemic. Presumed mechanisms include reducing the environmental burden and the potential for C. difficile transmission among susceptible patients.

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.

Pseudomembranous colitis: causes and cures

Clostridium difficile is the most common nosocomial pathogen of the gastrointestinal tract and has increased in frequency over time. Typical symptoms of C. difficile infection include diarrhea, which is usually nonbloody, or colitis associated with severe abdominal pain, fever and/or gross or occult blood in the stools. Pseudomembranous colitis (PMC), the severest form of this disease, occurs as a result of a severe inflammatory response to the C. difficile toxins. This review focuses on PMC, as this severe form is associated with the greatest medical concern. Diagnosis rests on detection of C. difficile in the stool, either by culture, tissue culture assay for cytotoxin B or detection of antigens in the stool by rapid enzyme immunoassays. Oral therapy with metronidazole 250 mg 4 times a day for 10 days is the recommended first-line therapy. Vancomycin is also effective, but its use must be limited to decrease the development of vancomycin-resistant organisms such as enterococci. Vancomycin (125-500 mg 4 times a day for 10 days) should be limited to those who cannot tolerate or have not responded to metronidazole, or when metronidazole use is contraindicated, as in the first trimester of pregnancy. A therapeutic response within a few days is usual. Recurrence of symptoms after antibiotics occurs in 20% of cases and is associated with persistence of C. difficile in the stools. Further recurrences then become more likely. Therapy with antibiotics in a pulsed or tapered regimen is often effective as are efforts to normalize the fecal flora. The yeast Saccharomyces boulardii has been proven in controlled trials to reduce recurrences when given as an adjunct to antibiotic therapy. Careful hand washing and environmental decontamination are necessary to prevent epidemics.

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.

Risk factors for Clostridium difficile infection

A systematic review of the literature to identify risk factors associated with Clostridium difficile infection was conducted. Two main outcomes were considered: C. difficile diarrhoea and C. difficile carriage. A qualitative assessment, based on a set of defined and consistently applied criteria, appeared to be the best approach for risk factors other than antibiotic use, as an approach based on meta-analysis would have utilized only the information provided by a minority of the studies. Risk factors for which there was evidence suggestive or consistent with an association with C. difficile diarrhoea were: increasing age (excluding infancy), severity of underlying diseases, non-surgical gastrointestinal procedures, presence of a nasogastric tube, anti-ulcer medications, stay on ITU, duration of hospital stay, duration of antibiotic course, administration of multiple antibiotics. For malignant haematological disorders there was evidence of an association only with C. difficile carriage, but there were no suitable studies to explore a possible association of this risk factor with symptomatic infection. Antibiotic use lent itself to quantitative assessment with meta-analysis using logistic regression. Exposure to an antibiotic was shown to be statistically significantly associated with both C. difficile diarrhoea and C. difficile carriage. The meta-analysis approach enabled the ranking of individual antibiotics in relation to the risk of C. difficile infection, though the 95% confidence intervals were often wide and overlapping. Antibiotics associated with a lower risk of C. difficile diarrhoea should be considered, especially when attempting to control a C. difficile outbreak or when prescribing for a patient with other C. difficile risk factors. This systematic review of the literature enabled the identification of features it would be desirable to consider in future epidemiological studies.

Epidemiology, risk factors and treatments for antibiotic-associated diarrhea

Antibiotic-associated diarrhea (AAD) is a common complication of antibiotics and recent findings on the epidemiology, etiologies and treatment strategies are reviewed. Rates of AAD vary from 5 to 39% depending upon the specific type of antibiotic. The severity of AAD may include uncomplicated diarrhea, colitis or pseudomembranous colitis. The pathogenesis of AAD may be mediated through the disruption of the normal flora and overgrowth of pathogens or through metabolic imbalances. The impact of AAD is reflected by increased hospital stays, higher medical costs and increased rates of comorbidity. The key to decreasing these consequences is prompt diagnosis followed by effective treatment and institution of control measures.

Hospital-acquired infection in elderly patients

Increasing numbers of elderly people are being treated in hospitals and are at particular risk of acquiring infections. The incidence, risk factors and types of hospital-acquired infection (HAI) in the elderly are reviewed. Special reference is made to urinary tract infections, respiratory tract infections, gastrointestinal infections including Clostridium difficile, bacteraemia, skin and soft tissue infections and infections with antibiotic-resistant organisms.

Laboratory surveillance method for nosocomial Clostridium difficile diarrhea

BACKGROUND

Clostridium difficile is the most common infectious cause of endemic nosocomial diarrhea, but traditional surveillance methods for this infection can be time-consuming. The purpose of this article is to (1) describe a laboratory surveillance method for nosocomial diarrhea and nosocomial Clostridium difficile diarrhea (CDD) that does not require chart review and (2) describe some of the epidemiology of these infections at a university-affiliated, public hospital by using this surveillance method.

METHODS

The main assumption underlying the surveillance method is that all patients with nosocomial diarrhea have a C. difficile stool toxin assay performed. On the basis of this assumption, the frequency of testing stool samples for toxin is considered a surrogate for the occurrence of nosocomial diarrhea; it is also assumed that the results of the stool toxin assay distinguish between those with (positive assay) and without (negative assay) CDD. During the study period (January 1, 1993, to August 30, 1996) surveillance for nosocomial CDD was performed by monitoring results of C. difficile stool toxin assays done with the Cytoclone A and B enzyme immunoassay. Each month a list of results of all assays performed was reviewed and patients were excluded on the basis of the following criteria. First, patients with assays done within the first 4 days of admission were assumed to have community-acquired diarrhea and excluded. Among patients with assays done > 4 days after admission, patients with two or more assays done within a 7-day period were counted only once; repeated assays (positive or negative) in the 14 days after an initial positive assay (indicating nosocomial CDD) were excluded, but assays done more than 14 days after a positive or a negative assay were counted separately (representing a relapse or new episode of diarrhea). Patients remaining on the list after all the exclusion criteria were applied represented those with nosocomial diarrhea.

RESULTS

The mean (+/- SD) frequency of episodes of nosocomial diarrhea per month for each study year (1993, 1994, 1995, and first 8 months of 1996) was 52.6 +/- 16.2, 51.4 +/- 10.5, 49.2 +/- 9.3, 57.8 +/- 11.6, respectively (p = 0.48 by ANOVA); the mean frequency of nosocomial diarrhea per 1000 admissions per month was 48.4 +/- 14.5, 47.7 +/- 10.9, 44.0 +/- 9.6, and 51.6 +/- 9.3, respectively (p = 0.52); and the mean frequency of nosocomial CDD episodes per 100 episodes of nosocomial diarrhea was 24.7 +/- 8.5, 18.9 +/- 4.8, 17.4 +/- 5.7, and 12.2 +/- 7.2, respectively (p = 0.003). The median time (days) after admission to the onset of nosocomial CDD (first positive assay) for each study year was 14.5, 13.0, 12.0, and 13.0, respectively.

CONCLUSIONS

Although not all of the underlying assumptions of the method have been verified, the similarity of the findings in the present study to those of previously published studies of nosocomial CDD suggests that the method is valid. Alternatives to traditional methods of performing nosocomial infection surveillance need to be developed so that infection control practitioners can focus more of their efforts on prevention activities.

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 in HIV-infected patients: epidemiology and risk factors

A retrospective analysis of all the cases of Clostridium difficile-associated diarrhea (CDAD) in hospitalized patients infected with HIV was performed over a 52-month period to assess the incidence, epidemiology, and risk factors of CDAD. A case of CDAD was defined as a patient with diarrhea and a positive stool cytotoxin B assay. Sixty-seven cases of CDAD were recorded in HIV-infected patients between January 1991 and April 1995. The annual incidence of CDAD ranged from 1.7 to 6.4 per 100 HIV-infected patients discharged from hospital. The 67 CDAD cases included 48 (72%) first episodes and 19 (28%) relapses. Serogroup C accounted for 69% of strains from initial episodes of CDAD. To identify risk factors for CDAD, 34 HIV-infected patients with a first episode were compared with 66 HIV-infected controls matched for the length of hospital stay. Three independent factors remained significantly associated with CDAD among HIV-infected patients: CD4+ cell counts <50/mm3 (OR = 5.2; 95% CI = 1.4-19.3; p = 0.01), clindamycin use (OR = 5.0; 95% CI = 1.3-18.3; p = 0.02) and penicillin use (OR = 4.6; 95% CI = 1.1-18.8; p = 0.03). C. difficile is a common enteric pathogen responsible for nosocomial diarrhea in HIV-infected patients. Clinicians should keep this pathogen in mind when searching for the cause of diarrhea in these patients, especially those who are severely immunocompromised or have received clindamycin or penicillin.

Gastrointestinal pathology in HIV-infected patients

Specific pathologic processes, particularly oral, esophageal, and intestinal infections, are common in the alimentary tract of AIDS patients. Many of these diseases are adequately assessed only by biopsy with histologic examination. Most are rare or unreported in immunocompetent hosts and are easily missed by those not familiar with them. This article describes the gross or endoscopic and histologic appearances and the diagnostic criteria for enteric pathologic processes seen in HIV-infected individuals.

Arbitrary primed PCR rules out Clostridium difficile cross-infection among patients in a haematology unit

Eight out of 20 (40%) patients with haematological malignancies hospitalized in the same unit of our hospital from 24 January to 24 April 1995, suffered from diarrhoea due to Clostridium difficile. The C. difficile isolates were characterized by serotyping and by arbitrary primed polymerase chain reaction (AP-PCR) using three different 10-mer oligonucleotides. It was found by serotyping that five patients had non-typeable isolates and three had serogroup H isolates. The AP-PCR typed all the isolates and yielded various patterns suggesting that there had been no cross-transmission between the patients. Control faecal sample cultures showed that two patients were still carrying the same isolates after specific treatment with vancomycin or metronidazole, and that one patient had acquired an isolate with a new AP-PCR type. AP-PCR was found to be a rapid, effective discriminative method for the immediate epidemiological tracking of hospital-acquired infections due to C difficile.

Risk of diarrhoea, Clostridium difficile and cefotaxime in the elderly

Clostridium difficile diarrhoea is an increasingly important nosocomial infection. Clostridium difficile infection is associated with antibiotic use. The elderly are at greatest risk. We reported an outbreak associated with the use of cefotaxime, a third-generation cephalosporin. We review the extent of this association, putative causal mechanisms and suggest an integrated approach to the control of C difficile infection which focuses on both limiting environmental contamination and reducing patient susceptibility. Future developments are also considered, especially the potential for vaccination.

Financial burden of hospital-acquired Clostridium difficile infection

Clostridium difficile infection has become endemic in many hospitals and yet few data on the associated costs of such cases are available. We prospectively followed 50 consecutive cases of C. difficile infection and 92 control patients, who were admitted to the same geriatric wards within 72 h of the cases. Cases and controls had similar age, sex and major diagnosis distributions. Cases stayed significantly longer (mean 21.3 days, median 20.5 days; P < 0.001) in hospital than controls, including an average 14 days in a side room. Diarrhoea developed in cases on average 10.8 days after admission, which, when compared with a mean duration of stay for controls of 25.2 days, implies that C. difficile infection caused an increased duration of stay, as opposed to infection occurring because of longer residence. There was a significantly higher death rate in cases compared with controls (P < 0.01). Antibiotic treatment of C. difficile infection cost an average of Pounds 47 per case. The average number of laboratory investigations per day was similar for cases and controls, but the increased length of stay meant an extra cost for tests of approximately Pounds 210 per case. Assuming hotel costs of Pounds 150 (Pounds 200) per day stay (in a side room), 94% of the additional costs associated with C. difficile infection were due to increased duration of stay (Pounds 3850). The total identifiable increased cost of C. difficile infection was, therefore, in excess of Pounds 4000 per case. Such high costs can be used to justify expenditure on personnel and/or other control measures to reduce the incidence of this hospital-acquired infection.

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.

Ten years of prospective Clostridium difficile-associated disease surveillance and treatment at the Minneapolis VA Medical Center, 1982-1991

OBJECTIVES

To understand the epidemiology, risks, and management of Clostridium difficile-associated disease (CDAD) and to establish and evaluate reliable methods of surveillance.

DESIGN

Case finding was done by daily ward and laboratory rounds. The criteria for CDAD diagnosis were: at least four unformed stools per day for 2 days and a positive culture or cytotoxin for C difficile, or positive endoscopy or autopsy for pseudomembranes.

SETTING

The surveillance covered all patients from 1982 through 1991 in the 820-bed Minneapolis Veterans Affairs Medical Center.

PARTICIPANTS

The criteria were met by 908 patients. Medical service patients numbered 488; surgical patients, 420. Frequencies ranged from a high of 149 cases in 1982 to a low of 50 cases in 1989.

RESULTS

Stool specimens were obtained on 898 (99%) of the 908 CDAD patients. Stools were culture-positive in 864 (96%) of 898, cytotoxin-positive in 569 (63%) of 898. Endoscopy was performed on 196 (22%) of the 908 patients, and 80 (41%) of 196 patients had pseudomembranes. Ten (1%) of the 908 patients were diagnosed by endoscopy without a stool specimen, or at autopsy. No treatment was needed for 135 (15%) of the 908 CDAD patients, and 19 (2%) of the 908 died before treatment was started. Oral metronidazole was the treatment for 632 (70%) of 908 patients (1% intolerance, 2% failure, 7% relapse) and oral vancomycin was given to 122 (13%) of 908 patients (1% intolerance, 1% failure, 10% relapse). Twelve patients had pseudomembranous colitis at autopsy, and it was the primary cause of death in 5 (0.6%) of 908.

CONCLUSIONS

CDAD usually responds to oral metronidazole or vancomycin but is nonetheless responsible for a high morbidity and occasional mortality in patients even when the diagnosis and treatment are pursued aggressively.

Medical technologists using molecular epidemiology as part of the infection control team

Two medical technologists were appointed as permanent members of a new epidemiology section in the diagnostic microbiology laboratory of a large Veterans Administration Medical Center in the fall of 1989. These positions accounted for 9% of the total microbiology staff and were created on a temporary basis 2 years earlier from a need to have dedicated technical expertise for use in the culture, isolation, and typing of nosocomial organisms. The technologists have evaluated outbreaks due to Clostridium difficile, methicillin-susceptible Staphylococcus aureus, and Serratia marcescens, and have begun work on a methicillin-resistant Staphylococcus aureus (MRSA)-typing scheme. Their major responsibility has been the development and application of molecular biology techniques for the typing of nosocomial isolates, including restriction enzyme analysis of genomic DNA, plasmid profiling with and without restriction enzyme analysis, ribosomal RNA probing of restricted genomic DNA, and selected DNA sequencing of target organisms. Medical supervision rests jointly between the directors of the infection control program and the microbiology laboratory. During their tenure, infections due to C. difficile have dropped from 95 cases per year to 57 cases annually, treatment of MRSA colonization with systemic agents has been curtailed, and a case control investigation involving S. marcescens was avoided. The inclusion of medical technologists in the infection control practice of large medical care facilities, particularly with the availability of molecular epidemiologic techniques and the emergence of increasing numbers of multiply-drug-resistant pathogens, will become an essential component of these programs.

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.

Risk factors for the development of Clostridium difficile-associated diarrhea during a hospital outbreak

OBJECTIVE

To evaluate the risk factors associated with a nosocomial outbreak of Clostridium difficile-associated diarrhea.

DESIGN

Case-control study with two control groups.

SETTING

University-affiliated urban hospital.

PATIENTS

A convenience sample of 26 patients was chosen out of a total of 78 hospitalized patients with C difficile-associated diarrhea, defined as the presence of diarrhea and a positive C difficile cytotoxin assay or stool culture. Twenty-six controls were matched for age, gender, ward, and date of admission; 18 additional controls were matched to surgical patients for date and ward of admission, as well as for the type of surgical procedure performed.

RESULTS

Significant risk factors for the development of C difficile-associated diarrhea were gastrointestinal surgery (exposure odds ratio [EOR] = 7.9, p = .004, 95% confidence interval [CI] = 1.9, 35), use of neomycin (EOR = 15.6, p = .012, 95% CI = 1.7, 92), clindamycin (EOR = 15.6, p = .005, 95% CI = 1.7, 92), metronidazole (EOR = 5.7, p = .02, 95% CI = 1.4, 25), and excess antibiotic use (mean number of antibiotics = 4.2 versus 1.4, p less than .00005). The presence of systemic disease and the use of antacids or immunosuppressive drugs were similar in cases and controls. In surgical patients, no specific antibiotic could be linked to C difficile-associated diarrhea because of uniform perioperative antibiotic use. There was a significant difference in the number of antibiotics administered to cases and controls (mean = 3.1 versus 1.9, p less than .005).

CONCLUSIONS

The results suggest that control of nosocomial C difficile-associated diarrhea may be attained by minimizing the administration of antibiotics, avoidance of high-risk antibiotics, and having a high index of suspicion of C difficile-associated diarrhea in patients who develop diarrhea after gastrointestinal surgery. Perioperative administration of metronidazole, when given with other antibiotics, failed to protect against the development of C difficile-associated diarrhea.

Nosocomial Clostridium difficile colonisation and disease

To assess the risk of acquiring Clostridium difficile diarrhoea or colitis in patients colonised with C difficile, rectal swabs taken weekly for 9 weeks from patients with long-term (at least 7 days) hospital stays on three wards were cultured for C difficile. 60 (21%) of 282 patients were culture-positive for C difficile during their hospital stay, of whom 51 were symptom-free faecal excretors. C difficile diarrhoea developed in the other 9 patients; 2 were culture-positive for C difficile and had diarrhoea at the time of first culture, and 7 had diarrhoea or pseudomembranous colitis after 1-6 previously negative weekly rectal cultures. All patients with diarrhoea were on one ward, but symptom-free, excretors were found on all wards. HindIII chromosomal restriction endonuclease analysis (REA) of the C difficile isolates revealed 18 distinct types. All isolates from the patients with diarrhoea were one of two nearly identical REA types, B or B2. 26 of the 29 total B/B2 isolates were from patients on the same ward, which points to a nosocomial outbreak. The symptom-free excretors were not at increased risk of subsequent clinical illness.