Control of an outbreak of infection with the hypervirulent Clostridium difficile BI strain in a university hospital using a comprehensive "bundle" approach

Clostridium difficile infection in children: a comprehensive review

OBJECTIVE

To provide a comprehensive review of the literature relating to Clostridium difficile (C. difficile) infection (CDI) in the pediatric population.

METHODS

Two investigators conducted independent searches of PubMed, Web of Science, and Scopus until March 31st, 2013. All databases were searched using the terms 'Clostridium difficile infection', 'Clostridium difficile associated diarrhea' 'antibiotic associated diarrhea', 'C. difficile', in combination with 'pediatric' and 'paediatric'. Articles which discussed pediatric CDI were reviewed and relevant cross references also read and evaluated for inclusion. Selection bias could be a possible limitation of this approach.

FINDINGS

There is strong evidence for an increased incidence of pediatric CDI. Increasingly, the infection is being acquired from the community, often without a preceding history of antibiotic use. The severity of the disease has remained unchanged. Several medical conditions may be associated with the development of pediatric CDI. Infection prevention and control with antimicrobial stewardship are of paramount importance. It is important to consider the age of the child while testing for CDI. Traditional therapy with metronidazole or vancomycin remains the mainstay of treatment. Newer antibiotics such as fidaxomicin appear promising especially for the treatment of recurrent infection. Conservative surgical options may be a life-saving measure in severe or fulminant cases.

CONCLUSIONS

Pediatric providers should be cognizant of the increased incidence of CDI in children. Early and judicious testing coupled with the timely institution of therapy will help to secure better outcomes for this disease.

Use of multilocus variable number of tandem repeats analysis genotyping to determine the role of asymptomatic carriers in Clostridium difficile transmission

BACKGROUND

Previous studies have suggested that asymptomatic carriers of toxigenic Clostridium difficile are a source of hospital-associated (HA) infections. Multilocus variable number of tandem repeats analysis (MLVA) is a highly discriminatory molecular subtyping tool that helps to determine possible transmission sources.

METHODS

Clostridium difficile isolates were recovered from perirectal swabs collected for vancomycin-resistant Enterococcus (VRE) surveillance as well as from clinical C. difficile toxin-positive stool samples from July to November 2009 at the University of Pittsburgh Medical Center Presbyterian (UPMC). MLVA was performed to determine the genetic relationships between isolates from asymptomatic carriers and patients with HA C. difficile infection (HA-CDI). Asymptomatic carriage and HA-CDI isolates were considered to be associated if the carriage isolate was collected before the HA-CDI isolate and if the MLVA genotypes had a summed tandem-repeat difference of ≤ 2.

RESULTS

Of 3006 patients screened, 314 (10.4%) were positive for toxigenic C. difficile, of whom 226 (7.5%) were detected only by VRE surveillance cultures. Of 56 incident cases of CDI classified as HA at UPMC during the study with available isolates, 17 (30%) cases were associated with CDI patients, whereas 16 (29%) cases were associated with carriers. Transmission events from prior bed occupants with CDI (n = 2) or carriers (n = 2) were identified in 4 of 56 cases.

CONCLUSIONS

In our hospital with an established infection control program designed to contain transmission from symptomatic CDI patients, asymptomatic carriers appear to have played an important role in transmission. Identification and isolation of carriers may be necessary to further reduce transmission of C. difficile in such settings.

Novel strategies for enhanced removal of persistent Bacillus anthracis surrogates and Clostridium difficile spores from skin

Background

Removing spores of Clostridium difficile and Bacillus anthracis from skin is challenging because they are resistant to commonly used antimicrobials and soap and water washing provides only modest efficacy. We hypothesized that hygiene interventions incorporating a sporicidal electrochemically generated hypochlorous acid solution (Vashe^®) would reduce the burden of spores on skin.

Methods

Hands of volunteers were inoculated with non-toxigenic C. difficile spores or B. anthracis spore surrogates to assess the effectiveness of Vashe solution for reducing spores on skin. Reduction in spores was compared for Vashe hygiene interventions versus soap and water (control). To determine the effectiveness of Vashe solution for removal of C. difficile spores from the skin of patients with C. difficile infection (CDI), reductions in levels of spores on skin were compared for soap and water versus Vashe bed baths.

Results

Spore removal from hands was enhanced with Vashe soak (>2.5 log₁₀ reduction) versus soap and water wash or soak (~2.0 log₁₀ reduction; P<0.05) and Vashe wipes versus alcohol wipes (P<0.01). A combined approach of soap and water wash followed by soaking in Vashe removed >3.5 log₁₀ spores from hands (P<0.01 compared to washing or soaking alone). Bed baths using soap and water (N =26 patients) did not reduce the percentage of positive skin cultures for CDI patients (64% before versus 57% after bathing; P =0.5), whereas bathing with Vashe solution (N =21 patients) significantly reduced skin contamination (54% before versus 8% after bathing; P =0.0001). Vashe was well-tolerated with no evidence of adverse effects on skin.

Conclusions

Vashe was safe and effective for reducing the burden of B. anthracis surrogates and C. difficile spores on hands. Bed baths with Vashe were effective for reducing C. difficile on skin. These findings suggest a novel strategy to reduce the burden of spores on skin.

Easily modified factors contribute to delays in diagnosis of Clostridium difficile infection: a cohort study and intervention

Although rapid laboratory tests are available for diagnosis of Clostridium difficile infection (CDI), delays in completion of CDI testing are common in clinical practice. We conducted a cohort study of 242 inpatients tested for CDI to determine the timing of different steps involved in diagnostic testing and to identify modifiable factors contributing to delays in diagnosis. The average time from test order to test result was 1.8 days (range, 0.2 to 10.6), with time from order to stool collection accounting for most of the delay (mean, 1.0 day; range, 0 to 10). Several modifiable factors contributed to delays, including not providing stool collection supplies to patients in a timely fashion, rejection of specimens due to incorrect labeling or leaking from the container, and holding samples in the laboratory for batch processing. Delays in testing contributed to delays in initiation of treatment for patients diagnosed with CDI and to frequent prescription of empirical CDI therapy for patients with mild to moderate symptoms whose testing was ultimately negative. An intervention that addressed several easily modified factors contributing to delays resulted in a significant decrease in the time required to complete CDI testing. These findings suggest that health care facilities may benefit from a review of their processes for CDI testing to identify and address modifiable factors that contribute to delays in diagnosis and treatment of CDI.

Preventing clostridium difficile infection in the intensive care unit

Clostridium difficile is a formidable problem in the twenty-first century. Because of injudicious use of antibiotics, the emergence of the hypervirulent epidemic strain of this organism has been difficult to contain. The NAP1/BI/027 strain causes more-severe disease than other widely prevalent strains and affects patients who were not traditionally thought to be at risk for Clostridium difficile infection. Critically ill patients remain at high risk for this pathogen, and preventive measures, such as meticulous contact precautions, hand hygiene, environmental disinfection, and, most importantly, antibiotic stewardship, are the cornerstones of mitigation in the intensive care unit.

Does improving surface cleaning and disinfection reduce health care-associated infections?

Contaminated environmental surfaces provide an important potential source for transmission of health care-associated pathogens. In recent years, a variety of interventions have been shown to be effective in improving cleaning and disinfection of surfaces. This review examines the evidence that improving environmental disinfection can reduce health care-associated infections.

Calcineurin inhibitors and Clostridium difficile infection in adult lung transplant recipients: the effect of cyclosporine versus tacrolimus

BACKGROUND

Tacrolimus (FK506) has a superior immunosuppressive effect compared with cyclosporine (CSA) without a significant increase in generalized infectious complications. Differences in specific infections such as Clostridium difficile (CDI) have not been reported. We investigated the relationship between calcineurin inhibitors and CDI, hypothesizing that choice of calcineurin inhibitor (CSA or FK506) after lung transplantation would have no effect on the incidence of CDI.

METHODS

We performed a retrospective chart review of lung transplant recipients between June 1, 2000, and December 31, 2005, at a single institution. Positive CDI assays through December 11, 2011, were also recorded. We used Student's t- and chi-squared tests (α = 0.05) to compare CSA and FK506 groups. We calculated adjusted hazard ratios for CDI using Cox proportional hazard models.

RESULTS

We identified 217 lung transplant recipients: 106 patients in the CSA group and 111 patients in the FK506 group. A total of 31 patients (27.9%) in the FK506 group developed CDI postoperatively compared with 20 patients (18.9%) in the CSA group (P = 0.16). The adjusted hazard ratio for CDI in the FK506 group was not significantly higher (1.53; 95% confidence interval, 0.78-2.98). There was no significant difference in the intensive care unit or total length of stay, in-hospital incidence rate, time to first CDI episode, or recurrence rate between groups.

CONCLUSIONS

The CDI rates were not significantly higher in the FK506 group than the CSA group in our study. These data are consistent with previous studies on FK506 that show no increase in infectious complications over CSA, and demonstrate its continued safety in lung transplantation.

Guidelines for diagnosis, treatment, and prevention of Clostridium difficile infections

Clostridium difficile infection (CDI) is a leading cause of hospital-associated gastrointestinal illness and places a high burden on our health-care system. Patients with CDI typically have extended lengths-of-stay in hospitals, and CDI is a frequent cause of large hospital outbreaks of disease. This guideline provides recommendations for the diagnosis and management of patients with CDI as well as for the prevention and control of outbreaks while supplementing previously published guidelines. New molecular diagnostic stool tests will likely replace current enzyme immunoassay tests. We suggest treatment of patients be stratified depending on whether they have mild-to-moderate, severe, or complicated disease. Therapy with metronidazole remains the choice for mild-to-moderate disease but may not be adequate for patients with severe or complicated disease. We propose a classification of disease severity to guide therapy that is useful for clinicians. We review current treatment options for patients with recurrent CDI and recommendations for the control and prevention of outbreaks of CDI.

Knowledge, attitudes and practice regarding Clostridium difficile: a survey of physicians in an academic medical center

Using current guidelines, we surveyed physicians at our hospital to ascertain knowledge, attitudes, and practice regarding Clostridium difficile infection. The survey identified significant gaps in knowledge and practice. Infection control professionals should include physician education on Clostridium difficile infection diagnosis, isolation precautions, and treatment as part of a comprehensive control program.

Local formularies

The widespread availability of authoritative guidance on prescribing from a wide variety of international and national bodies calls into question the need for additional local formulary advice. This article describes contemporary local formulary management in the United Kingdom and discusses the areas where local decision making remains valuable. Local formularies can fulfil important roles which justify their continued existence, including ensuring local ownership and acceptance of advice, rapid dissemination of information, responsiveness to local circumstances and service design, sensitivity to local pricing arrangements and close professional links with commissioners, pharmacists and prescribers.

Impact of an antimicrobial stewardship program comprehensive care bundle on management of candidemia

STUDY OBJECTIVE

To analyze the impact of a comprehensive care bundle directed by an antimicrobial stewardship team (AST) on the management of candidemia.

DESIGN

Single-center, quasi-experimental study.

SETTING

A 930-bed academic hospital.

PATIENTS

Seventy-eight patients with candidemia were evaluated; 41 patients received the candidemia care bundle (AST group), and 37 did not (historical control group).

MEASUREMENTS AND MAIN RESULTS

A candidemia care bundle was developed by an interdisciplinary AST, incorporating key elements from the Infectious Diseases Society of America's Clinical Practice Guidelines for the Management of Candidemia. The AST made prospective recommendations in accordance with the care bundle. Bundle elements were utilization of appropriate antifungal agents with appropriate duration of use, removal of intravenous catheters, repeat blood cultures, monitoring of time until clearance of candidemia, and performance of ophthalmologic examinations. Compliance with all candidemia care bundle elements was significantly higher in the AST group versus the control group (78.0% vs 40.5%, p=0.0016). Implementation of the care bundle significantly improved rates of ophthalmologic examination (97.6% vs 75.7%, p=0.0108), selection of appropriate antifungal therapy (100% vs 86.5%, p=0.0488), and compliance with an appropriate duration of therapy (97.6% vs 67.7%, p=0.0012). In addition, the AST group had fewer excess total days of therapy beyond the recommended duration than the control group (5 vs 83 total antifungal days). Length of hospitalization (20 vs 21 days, p=0.9184), time until clearance of candidemia (3 vs 3 days p=0.610), rate of persistent candidemia (22% vs 40.5%, p=0.126), and rate of recurrent candidemia (4.9% vs 5.4%, p=0.916) were similar in the AST group versus the control group.

CONCLUSION

A comprehensive candidemia care bundle directed by our institution's AST improved the management of patients with candidemia. We encourage further exploration into the use of care bundles by ASTs as part of their multifaceted approach to promoting appropriate antimicrobial utilization and optimizing the management of patients with infectious diseases.

Prevention of hospital-onset Clostridium difficile infection in the New York metropolitan region using a collaborative intervention model

The incidence, severity, and associated costs of Clostridium difficile (C. difficile) infection (CDI) have dramatically increased in hospitals over the past decade, indicating an urgent need for strategies to prevent transmission of C. difficile. This article describes a multifaceted collaborative approach to reduce hospital-onset CDI rates in 35 acute care hospitals in the New York metropolitan region. Hospitals participated in a comprehensive CDI reduction intervention and formed interdisciplinary teams to coordinate their efforts. Standardized clinical infection prevention and environmental cleaning protocols were implemented and monitored using checklists. Monthly data reports were provided to hospitals for facility-specific performance evaluation and comparison to aggregate data from all participants. Hospitals also participated in monthly teleconferences to review data and highlight successes, challenges, and strategies to reduce CDI. Incidence of hospital-onset CDI per 10,000 patient days was the primary outcome measure. Additionally, the incidence of nonhospital-associated, community-onset, hospital-associated, and recurrent CDIs were measured. The use of a collaborative model to implement a multifaceted infection prevention strategy was temporally associated with a significant reduction in hospital-onset CDI rates in participating New York metropolitan regional hospitals.

Using a dog's superior olfactory sensitivity to identify Clostridium difficile in stools and patients: proof of principle study

OBJECTIVE

To investigate whether a dog's superior olfactory sensitivity can be used to detect Clostridium difficile in stool samples and hospital patients.

DESIGN

Proof of principle study, using a case-control design.

SETTING

Two large Dutch teaching hospitals.

PARTICIPANTS

A 2 year old beagle trained to identify the smell of C difficile and tested on 300 patients (30 with C difficile infection and 270 controls).

INTERVENTION

The dog was guided along the wards by its trainer, who was blinded to the participants' infection status. Each detection round concerned 10 patients (one case and nine controls). The dog was trained to sit or lie down when C difficile was detected.

MAIN OUTCOME MEASURES

Sensitivity and specificity for detection of C difficile in stool samples and in patients.

RESULTS

The dog's sensitivity and specificity for identifying C difficile in stool samples were both 100% (95% confidence interval 91% to 100%). During the detection rounds, the dog correctly identified 25 of the 30 cases (sensitivity 83%, 65% to 94%) and 265 of the 270 controls (specificity 98%, 95% to 99%).

CONCLUSION

A trained dog was able to detect C difficile with high estimated sensitivity and specificity, both in stool samples and in hospital patients infected with C difficile.

Fidaxomicin versus vancomycin for Clostridium difficile infection: meta-analysis of pivotal randomized controlled trials

Two recently completed phase 3 trials (003 and 004) showed fidaxomicin to be noninferior to vancomycin for curing Clostridium difficile infection (CDI) and superior for reducing CDI recurrences. In both studies, adults with active CDI were randomized to receive blinded fidaxomicin 200 mg twice daily or vancomycin 125 mg 4 times a day for 10 days. Post hoc exploratory intent-to-treat (ITT) time-to-event analyses were undertaken on the combined study 003 and 004 data, using fixed-effects meta-analysis and Cox regression models. ITT analysis of the combined 003/004 data for 1164 patients showed that fidaxomicin reduced persistent diarrhea, recurrence, or death by 40% (95% confidence interval [CI], 26%–51%; P < .0001) compared with vancomycin through day 40. A 37% (95% CI, 2%–60%; P = .037) reduction in persistent diarrhea or death was evident through day 12 (heterogeneity P = .50 vs 13–40 days), driven by 7 (1.2%) fidaxomicin versus 17 (2.9%) vancomycin deaths at <12 days. Low albumin level, low eosinophil count, and CDI treatment preenrollment were risk factors for persistent diarrhea or death at 12 days, and CDI in the previous 3 months was a risk factor for recurrence (all P < .01). Fidaxomicin has the potential to substantially improve outcomes from CDI.

Association of relapse of Clostridium difficile disease with BI/NAP1/027

Recurrent Clostridium difficile infection (CDI) occurs in up to 35% of patients. Recurrences can be due to either relapse with the same strain or reinfection with another strain. In this study, multilocus variable-number tandem-repeat analysis (MLVA) was performed on C. difficile isolates from patients with recurrent CDI to distinguish relapse from reinfection. In addition, univariate and multivariate analyses were performed to identify risk factors associated with relapse. Among patients with a single recurrence, relapse due to the original infecting strain was more prevalent than reinfection and the interval between episodes was shorter than among patients who had reinfections. Among patients with >1 recurrence, equal distributions of relapse and reinfection or a combination of the two episode types were observed. Initial infection with the BI/NAP1/027 epidemic clone was found to be a significant risk factor for relapse. This finding may have important implications for patient therapy. Classification of recurrent CDI episodes by MLVA can be utilized to make informed patient care decisions and to accurately define new CDI cases for infection control and reimbursement purposes.

Clostridium difficile outbreaks: prevention and treatment strategies

The incidence and severity of Clostridium difficile infection (CDI) have increased dramatically over the past decade. Its treatment, however, has largely remained the same with the exception of oral vancomycin use as a first-line agent in severe disease. From 1999 to 2004, 20,642 deaths were attributed to CDI in the United States, almost 7 times the rate of all other intestinal infections combined. Worldwide, several major CDI outbreaks have occurred, and many of these were associated with the NAP1 strain. This ‘epidemic’ strain has contributed to the rising incidence and mortality of CDI. The purpose of this article is to review the current management, treatment, infection control, and prevention strategies that are needed to combat this increasingly morbid disease.

Detection, treatment, and prevention of Clostridium difficile infection

Clostridium difficile is a gram-positive anaerobic bacillus responsible for approximately 1 of 5 cases of antibiotic-associated diarrhea. C difficile infection (CDI) is defined by at least 3 unformed stools in a 24-hour period and stool, endoscopic, or histopathologic test results that indicate the presence of this bacteria. The history of CDI research can be divided into early (before 2000) and modern eras (after 2000). C difficile was first described in 1935, and the characteristics and causes of CDI as well as therapies were identified during the early era of research. During the modern era, CDI has become a more common, aggressive nosocomial infection. Our understanding of the epidemiology, diagnosis, treatment, and prevention of CDI has increased at a rapid pace. We review features of CDI diagnosis, treatment, and prevention.

Bundling hand hygiene interventions and measurement to decrease health care-associated infections

Proper performance of hand hygiene at key moments during patient care is the most important means of preventing health care-associated infections (HAIs). With increasing awareness of the cost and societal impact caused by HAIs has come the realization that hand hygiene improvement initiatives are crucial to reducing the burden of HAIs. Multimodal strategies have emerged as the best approach to improving hand hygiene compliance. These strategies use a variety of intervention components intended to address obstacles to complying with good hand hygiene practices, and to reinforce behavioral change. Although research has substantiated the effectiveness of the multimodal design, challenges remain in promoting widespread adoption and implementation of a coordinated approach. This article reviews elements of a multimodal approach to improve hand hygiene and advocates the use of a "bundled" strategy. Eight key components of this bundle are proposed as a cohesive program to enable the deployment of synergistic, coordinated efforts to promote good hand hygiene practice. A consistent, bundled methodology implemented at multiple study centers would standardize processes and allow comparison of outcomes, validation of the methodology, and benchmarking. Most important, a bundled approach can lead to sustained infection reduction.

Strategies for prevention of Clostridium difficile infection

Infection control is the most essential component of an effective overall management strategy for prevention of nosocomial Clostridium difficile infection (CDI). The cornerstones of CDI prevention are appropriate contact precautions and strict hand hygiene. Other important tactics are effective environmental cleaning, identification and removal of environmental sources of C. difficile, and antibiotic stewardship. Hospitalists, as coordinators of care for each patient and advocates for quality care, can spearhead these efforts.

Epidemiology of Klebsiella oxytoca-associated diarrhea detected by Simmons citrate agar supplemented with inositol, tryptophan, and bile salts

We studied the clinical and epidemiological characteristics of Klebsiella oxytoca-associated diarrhea in hospitalized patients in Hong Kong. Between 1 November 2009 and 30 April 2011, all inositol-fermenting colonies found on Simmons citrate agar supplemented with inositol, tryptophan, and bile salts (SCITB agar) used for the culturing of diarrheal stool samples were screened by a spot indole test for K. oxytoca. The overall sensitivity of SCITB agar plus the spot indole test (93.3%) for the detection of K. oxytoca in stool samples was superior to that of MacConkey agar (63.3%), while the specificities were 100% and 60.4%, respectively. The former achieved a 23-fold reduction in the workload and cost of subsequent standard biochemical identifications. Cytotoxin production and the clonality of K. oxytoca were determined by a cell culture cytotoxicity neutralization assay using HEp-2 cells and pulsed-field gel electrophoresis (PFGE), respectively. Of 5,581 stool samples from 3,537 patients, K. oxytoca was cultured from 117/5,581 (2.1%) stool samples from 104/3,537 (2.9%) patients. Seventy-six of 104 (73.1%) patients with K. oxytoca had no copathogens in their diarrheal stool samples. Twenty-four (31.6%) of 76 patients carried cytotoxin-producing strains, which were significantly associated with antibiotic therapy after hospital admission (50% versus 21.2%; P = 0.01). Health care-associated diarrhea was found in 44 (42%) of 104 patients with K. oxytoca, but there was no epidemiological linkage suggestive of a nosocomial outbreak, and PFGE showed a diverse pattern. None of the patients with cytotoxin-producing K. oxytoca developed antibiotic-associated hemorrhagic colitis, suggesting that K. oxytoca can cause a mild disease manifesting as uncomplicated antibiotic-associated diarrhea with winter seasonality.

Characterisation of Clostridium difficile hospital ward-based transmission using extensive epidemiological data and molecular typing

BACKGROUND

Clostridium difficile infection (CDI) is a leading cause of antibiotic-associated diarrhoea and is endemic in hospitals, hindering the identification of sources and routes of transmission based on shared time and space alone. This may compromise rational control despite costly prevention strategies. This study aimed to investigate ward-based transmission of C. difficile, by subdividing outbreaks into distinct lineages defined by multi-locus sequence typing (MLST).

METHODS AND FINDINGS

All C. difficile toxin enzyme-immunoassay-positive and culture-positive samples over 2.5 y from a geographically defined population of ~600,000 persons underwent MLST. Sequence types (STs) were combined with admission and ward movement data from an integrated comprehensive healthcare system incorporating three hospitals (1,700 beds) providing all acute care for the defined geographical population. Networks of cases and potential transmission events were constructed for each ST. Potential infection sources for each case and transmission timescales were defined by prior ward-based contact with other cases sharing the same ST. From 1 September 2007 to 31 March 2010, there were means of 102 tests and 9.4 CDIs per 10,000 overnight stays in inpatients, and 238 tests and 15.7 CDIs per month in outpatients/primary care. In total, 1,276 C. difficile isolates of 69 STs were studied. From MLST, no more than 25% of cases could be linked to a potential ward-based inpatient source, ranging from 37% in renal/transplant, 29% in haematology/oncology, and 28% in acute/elderly medicine to 6% in specialist surgery. Most of the putative transmissions identified occurred shortly (≤ 1 wk) after the onset of symptoms (141/218, 65%), with few >8 wk (21/218, 10%). Most incubation periods were ≤ 4 wk (132/218, 61%), with few >12 wk (28/218, 13%). Allowing for persistent ward contamination following ward discharge of a CDI case did not increase the proportion of linked cases after allowing for random meeting of matched controls.

CONCLUSIONS

In an endemic setting with well-implemented infection control measures, ward-based contact with symptomatic enzyme-immunoassay-positive patients cannot account for most new CDI cases.

Clostridium difficile in the ICU: the struggle continues

Clostridium difficile infection (CDI) management has become more daunting over the past decade because of alarming increases in CDI incidence and severity both in the hospital and in the community. This increase has concomitantly caused significant escalation of the health-care economic burden caused by CDI, and it will likely be translated to increased ICU admission and attributable mortality. Some possible causes for difficulty in management of CDI are as follows: (1) inability to predict and prevent development of severe/complicated or relapsing CDI in patients who initially present with mild symptoms; (2) lack of a method to determine who would have benefited a priori from initiating vancomycin treatment first instead of treatment with metronidazole; (3) lack of sensitive and specific CDI diagnostics; (4) changing epidemiology of CDI, including the emergence of a hypervirulent, epidemic C difficile strain associated with increased morbidity and mortality; (5) association of certain high-usage nonantimicrobial medications with CDI; and (6) lack of treatment regimens that leave the normal intestinal flora undisturbed while treating the primary infection. The objective of this article is to present current management and prevention guidelines for CDI based on recommendations by the Society for Healthcare Epidemiology of America and Infectious Diseases Society of America and potential new clinical management strategies on the horizon.

Antibiotic policy

There is a clear association between antibiotic use and resistance both on individual and population levels. In the European Union, countries with large antibiotic consumption have higher resistance rates. Antibiotic resistance leads to failed treatments, prolonged hospitalisations, increased costs and deaths. With few new antibiotics in the Research & Development pipeline, prudent antibiotic use is the only option to delay the development of resistance. Antibiotic policy consists of prescribing strategies to optimise the indication, selection, dosing, route of administration, duration and timing of antibiotic therapy to maximise clinical cure or prevention of infection whilst limiting the unintended consequences of antibiotic use, including toxicity and selection of resistant microorganisms. A secondary goal is to reduce healthcare costs without adversely affecting the quality of care. The purpose of this paper is to provide the evidence base of prudent antibiotic policy. Special emphasis is placed on urinary tract infections. The value and support of antibiotic committees, guidelines, ID consultants and/or antimicrobial stewardship teams to prolong the efficacy of available antibiotics will be discussed.

A targeted strategy to wipe out Clostridium difficile

This study evaluated daily cleaning with germicidal bleach wipes on wards with a high incidence of hospital-acquired Clostridium difficile infection (CDI). The intervention reduced hospital-acquired CDI incidence by 85%, from 24.2 to 3.6 cases per 10,000 patient-days, and prolonged the median time between hospital-acquired CDI cases from 8 to 80 days.

Development and validation of a Clostridium difficile infection risk prediction model

OBJECTIVE

To develop and validate a risk prediction model that could identify patients at high risk for Clostridium difficile infection (CDI) before they develop disease.

DESIGN AND SETTING

Retrospective cohort study in a tertiary care medical center.

PATIENTS

Patients admitted to the hospital for at least 48 hours during the calendar year 2003.

METHODS

Data were collected electronically from the hospital's Medical Informatics database and analyzed with logistic regression to determine variables that best predicted patients' risk for development of CDI. Model discrimination and calibration were calculated. The model was bootstrapped 500 times to validate the predictive accuracy. A receiver operating characteristic curve was calculated to evaluate potential risk cutoffs.

RESULTS

A total of 35,350 admitted patients, including 329 with CDI, were studied. Variables in the risk prediction model were age, CDI pressure, times admitted to hospital in the previous 60 days, modified Acute Physiology Score, days of treatment with high-risk antibiotics, whether albumin level was low, admission to an intensive care unit, and receipt of laxatives, gastric acid suppressors, or antimotility drugs. The calibration and discrimination of the model were very good to excellent (C index, 0.88; Brier score, 0.009).

CONCLUSIONS

The CDI risk prediction model performed well. Further study is needed to determine whether it could be used in a clinical setting to prevent CDI-associated outcomes and reduce costs.

The emergence of Clostridium difficile infection among peripartum women: a case-control study of a C. difficile outbreak on an obstetrical service

OBJECTIVE

An outbreak of 20 peripartum Clostridium difficile infections (CDI) occurred on the obstetrical service at the University of Washington Medical Center (UWMC) between April 2006 and June 2007. In this report, we characterize the clinical manifestations, describe interventions that appeared to reduce CDI, and determine potential risk factors for peripartum CDI.

METHODS

An investigation was initiated after the first three peripartum CDI cases. Based on the findings, enhanced infection control measures and a modified antibiotic regimen were implemented. We conducted a case-control study of peripartum cases and unmatched controls.

RESULTS

During the outbreak, there was an overall incidence of 7.5 CDI cases per 1000 deliveries. Peripartum CDI infection compared to controls was significantly associated with cesarean delivery (70% versus 34%; P=0.03), antibiotic use (95% versus 56%; P=0.001), chorioamnionitis (35% versus 5%; P=0.001), and the use of the combination of ampicillin, gentamicin, and clindamycin (50% versus 3%; P<0.001). Use of combination antibiotics remained a significant independent risk factor for CDI in the multivariate analysis.

CONCLUSIONS

The outbreak was reduced after the implementation of multiple infection control measures and modification of antibiotic use. However, sporadic CDI continued for 8 months after these measures slowed the outbreak. Peripartum women appear to be another population susceptible to CDI.

Antimicrobial stewardship: attempting to preserve a strategic resource

Antimicrobials hold a unique place in our drug armamentarium. Unfortunately the increase in resistance among both gram-positive and gram-negative pathogens coupled with a lack of new antimicrobial agents is threatening our ability to treat infections. Antimicrobial use is the driving force behind this rise in resistance and much of this use is suboptimal. Antimicrobial stewardship programs (ASP) have been advocated as a strategy to improve antimicrobial use. The goals of ASP are to improve patient outcomes while minimizing toxicity and selection for resistant strains by assisting in the selection of the correct agent, right dose, and best duration. Two major strategies for ASP exist: restriction/pre-authorization that controls use at the time of ordering and audit and feedback that reviews ordered antimicrobials and makes suggestions for improvement. Both strategies have some limitations, but have been effective at achieving stewardship goals. Other supplemental strategies such as education, clinical prediction rules, biomarkers, clinical decision support software, and institutional guidelines have been effective at improving antimicrobial use. The most effective antimicrobial stewardship programs have employed multiple strategies to impact antimicrobial use. Using these strategies stewardship programs have been able to decrease antimicrobial use, the spread of resistant pathogens, the incidence of C. difficile infection, pharmacy costs, and improved patient outcomes.

Implementing quality initiatives using a bundled approach

Critical care has been criticised for its inconsistency in implementing and evaluating evidence based practice both at national and international level. A review of the critical care literature by Berenholtz et al. (2002) identified interventions that might help prevent morbidity or mortality in the intensive care unit; from this four elements were developed into the initial ventilator care bundle. The aim of this bundle was to improve the quality of care for mechanically ventilated patients by improving compliance with relevant evidence based practice; implementation of this or an adapted cluster of interventions has been shown consistently to reduce the incidence of ventilator-associated pneumonias across countries. There are now numerous care bundles and the bundle approach to quality improvement has been proven to be effective across a number of problems, international boundaries and in a wide variety of ICU's. The bundle approach recognises that core clinical interventions, are not always consistently applied across all appropriate patients, the range of interventions within a bundle tackles the problem from a variety of different angles. Other strengths include its adaptability to the wide variety of environments and working practices of intensive care units across the world. The bundle and the method of implementation can be adapted to suit individual teams and units; however, this can also be a weakness of this approach as it limits comparability across centres. The bundle approach to quality improvement requires significant multidisciplinary engagement and resources to be effective.

Clostridium difficile isolates with increased sporulation: emergence of PCR ribotype 002 in Hong Kong

We identified a predominant clone of Clostridium difficile PCR ribotype 002, which was associated with an increased sporulation frequency. In 2009, 3,528 stool samples from 2,440 patients were tested for toxigenic C. difficile in a healthcare region in Hong Kong. A total of 345 toxigenic strains from 307 (13.3%) patients were found. Ribotype 002 was the predominant ribotype, which constituted 35 samples from 29 (9.4%) patients. The mean sporulation frequency of ribotype 002 was 20.2%, which was significantly higher than that of the 56 randomly selected ribotypes other than 002 as concurrent controls (3.7%, p < 0.001). Patients carrying toxigenic ribotype 002 were more frequently admitted from an elderly home (p = 0.01) and received more β-lactam antibiotics in the preceding 3 months compared with the controls (p = 0.04) . The identification of toxigenic ribotype 002 in 2009 was temporally related to a significant increase in both the incidence of toxigenic C. difficile from 0.53 to 0.95 per 1,000 admissions (p < 0.001) and the rate of positive detection from 4.17% to 6.28% (p < 0.001) between period 1 (2004–2008) and period 2 (2009). This finding should alert both the physician and the infection control team to the establishment of and possible outbreaks by ribotype 002 in our hospitals, as in the case of ribotype 027.

Comparison of strain typing results for Clostridium difficile isolates from North America

Accurate strain typing is critical for understanding the changing epidemiology of Clostridium difficile infections. We typed 350 isolates of toxigenic C. difficile from 2008 to 2009 from seven laboratories in the United States and Canada. Typing was performed by PCR-ribotyping, pulsed-field gel electrophoresis (PFGE), and restriction endonuclease analysis (REA) of whole-cell DNA. The Cepheid Xpert C. difficile test for presumptive identification of 027/NAP1/BI isolates was also tested directly on original stool samples. Of 350 isolates, 244 (70%) were known PCR ribotypes, 224 (68%) were 1 of 8 common REA groups, and 187 (54%) were known PFGE types. Eighty-four isolates typed as 027, NAP1, and BI, and 83 of these were identified as presumptive 027/NAP1/BI by Xpert C. difficile. Eight additional isolates were called presumptive 027/NAP1/BI by Xpert C. difficile, of which three were ribotype 027. Five PCR ribotypes contained multiple REA groups, and three North American pulsed-field (NAP) profiles contained both multiple REA groups and PCR ribotypes. There was modest concordance of results among the three methods for C. difficile strains, including the J strain (ribotype 001 and PFGE NAP2), the toxin A-negative 017 strain (PFGE NAP9 and REA type CF), the 078 animal strain (PFGE NAP7 and REA type BK), and type 106 (PFGE NAP11 and REA type DH). PCR-ribotyping, REA, and PFGE provide different but overlapping patterns of strain clustering. Unlike the other methods, the Xpert C. difficile 027/NAP1/BI assay gave results directly from stool specimens, required only 45 min to complete, but was limited to detection of a single strain type.

Update on Clostridium difficile infection

PURPOSE OF REVIEW

This review summarizes the most recent epidemiological data and advances in research into the pathogenesis, diagnosis and treatment of Clostridium difficile infection (CDI).

RECENT FINDINGS

The epidemiology of CDI has changed with the emergence of hypervirulent strains. CDI rates have increased in the community, in children and in patients with inflammatory bowel disease. Although the North American pulsed-field gel electrophoresis type 1, restriction endonuclease analysis group BI, PCR ribotype 027 (NAP1/BI/027) strain remains prevalent in North America, surveillance suggests that it is decreasing in Europe. A similar strain, PCR ribotype 078, is emerging which is associated with community-associated CDI and has been isolated in animals and food products. The Society for Healthcare Epidemiology of America and the Infectious Diseases Society of America have published new guidelines on the epidemiology, diagnosis, treatment, infection control and environmental management of C. difficile. Several novel therapies for CDI are at different stages of development. There have been promising trial results with fidaxomicin, a novel antibiotic for the treatment of CDI and monoclonal antibodies against toxins A and B, which have been shown to significantly reduce CDI recurrence rates.

SUMMARY

Major advances have been made in our understanding of the spread and pathogenesis of C. difficile and new treatment options are becoming available.

Epidemiology of clostridium difficile and vancomycin-resistant Enterococcus colonization in patients on a spinal cord injury unit

BACKGROUND/OBJECTIVE

Patients with spinal cord injury (SCI) are at risk of acquiring colonization with Clostridium difficile and vancomycin-resistant Enterococcus (VRE) due to prolonged hospitalization and frequent antimicrobial use. We examined the frequency of stool, skin, and environmental contamination with C. difficile and VRE in hospitalized patients with SCl.

METHODS

We performed a cross-sectional study of 22 hospitalized patients with SCI with no symptoms of C. difficile infection. Stool samples, skin, and environmental sites were cultured for C. difficile and VRE, and polymerase chain reaction ribotyping was performed for C. difficile isolates. Fisher's exact test was used to compare the proportions of skin and environmental contamination among stool carriers and non-carriers. Univariate analysis was used to assess factors associated with asymptomatic carriage of C. difficile.

RESULTS

Of 22 asymptomatic patients, 11 (50%) were asymptomatic carriers of toxigenic C. difficile and 12 (55%) were carriers of VRE. In comparison with non-carriers, asymptomatic carriers of toxigenic C. difficile had higher rates of skin (45 versus 9%) (P = 0.07) and environmental contamination (55 versus 9%) (P = 0.03) and longer length of stay (median, 57 versus 6 days; P = 0.04). A majority of skin and environmental C. difficile isolates from individuals were identical to isolates from stool. In comparison with non-carriers, patients with VRE stool colonization had non-significant trends toward more frequent skin (27 versus 9%) and environmental (18 versus 9%) contamination.

CONCLUSION

Asymptomatic stool carriage of toxigenic C. difficile and VRE was common on an acute-care SCI unit. Asymptomatic carriers of toxigenic C. difficile had frequent skin and environmental contamination, suggesting the potential to contribute to transmission.

Importance and Impact of Antimicrobial Stewardship

The landscape of health care is rapidly changing. With health care reform on the horizon, institutions are examining many practices to determine the best way to provide optimal care while minimizing economic burden. Antimicrobial stewardship is one method many institutions are implementing to achieve this balance. Antimicrobial stewardship encompasses a wide range of services aimed at improving patient outcomes and minimizing the untoward effects of antimicrobial agents including side effects as well as induction of resistance. These programs have been shown to decrease both the development of resistance as well as expenditures on antimicrobial agents. Recently, computerized decision support software has been implemented at many institutions. This technology has greatly improved the productivity of antimicrobial stewardship programs. Combining available technology with expert knowledge in infectious diseases is necessary to ensure the continued efficacy of current antimicrobial agents.

The changing epidemiology of Clostridium difficile infections

The epidemiology of Clostridium difficile infection (CDI) has changed dramatically during this millennium. Infection rates have increased markedly in most countries with detailed surveillance data. There have been clear changes in the clinical presentation, response to treatment, and outcome of CDI. These changes have been driven to a major degree by the emergence and epidemic spread of a novel strain, known as PCR ribotype 027 (sometimes referred to as BI/NAP1/027). We review the evidence for the changing epidemiology, clinical virulence and outcome of treatment of CDI, and the similarities and differences between data from various countries and continents. Community-acquired CDI has also emerged, although the evidence for this as a distinct new entity is less clear. There are new data on the etiology of and potential risk factors for CDI; controversial issues include specific antimicrobial agents, gastric acid suppressants, potential animal and food sources of C. difficile, and the effect of the use of alcohol-based hand hygiene agents.

The ecology and pathobiology of Clostridium difficile infections: an interdisciplinary challenge

Clostridium difficile is a well recognized pathogen of humans and animals. Although C. difficile was first identified over 70 years ago, much remains unknown in regards to the primary source of human acquisition and its pathobiology. These deficits in our knowledge have been intensified by dramatic increases in both the frequency and severity of disease in humans over the last decade. The changes in C. difficile epidemiology might be due to the emergence of a hypervirulent stain of C. difficile, ageing of the population, altered risk of developing infection with newer medications, and/or increased exposure to C. difficile outside of hospitals. In recent years, there have been numerous reports documenting C. difficile contamination of various foods, and reports of similarities between strains that infect animals and strains that infect humans as well. The purposes of this review are to highlight the many challenges to diagnosing, treating, and preventing C. difficile infection in humans, and to stress that collaboration between human and veterinary researchers is needed to control this pathogen.

Risk Factors for Treatment Failure and Recurrence after Metronidazole Treatment for Clostridium difficile-associated Diarrhea

BACKGROUND/AIMS

The incidence of treatment failure or recurrence of Clostridium difficile-associated diarrhea (CDAD) following metronidazole treatment has increased recently. We studied the treatment failure, recurrence rate, and risk factors predictive of treatment failure and recurrence after metronidazole treatment for CDAD.

METHODS

We retrospectively identified consecutive patients who were admitted and treated for CDAD at a single tertiary institution in Korea over a recent 10-year period (i.e., 1998-2008).

RESULTS

Metronidazole was administered as the initial treatment to 111 of 117 patients (94.9%) with CDAD. Fourteen patients (12.6%) had no clinical response to the metronidazole treatment, and in 13 patients (13.4%) CDAD recurred after successful metronidazole treatment. Diabetes mellitus (p=0.014) and sepsis (p=0.002) were independent risk factors for metronidazole treatment failure. Patients who had received surgery within 1 month before CDAD developed were more likely to experience a recurrence after metronidazole treatment (p=0.032). Vancomycin exhibited a higher response rate after treatment failure, and metronidazole showed a reasonable response rate in the treatment of recurrence. Treatment failure and recurrence rates increased with time after metronidazole treatment for CDAD over the 10-year study period.

CONCLUSIONS

Our data suggest that diabetes mellitus and sepsis are independent risk factors for metronidazole treatment failure, and that operation history within 1 month of development of CDAD is a predictor of a recurrence after metronidazole treatment.

Interventions to improve hand hygiene compliance in patient care

BACKGROUND

Health care-associated infection is a major cause of morbidity and mortality. Hand hygiene is regarded as an effective preventive measure.

OBJECTIVES

To update the review done in 2007, to assess the short and longer-term success of strategies to improve hand hygiene compliance and to determine whether a sustained increase in hand hygiene compliance can reduce rates of health care-associated infection.

SEARCH STRATEGY

We conducted electronic searches of: the Cochrane Central Register of Controlled Trials; the Cochrane Effective Practice and Organisation of Care Group specialised register of trials; MEDLINE; PubMed; EMBASE; CINAHL; and the BNI. Originally searched to July 2006, for the update databases were searched from August 2006 until November 2009.

SELECTION CRITERIA

Randomised controlled trials, controlled clinical trials, controlled before and after studies, and interrupted time series analyses meeting explicit entry and quality criteria used by the Cochrane Effective Practice and Organisation of Care Group were eligible for inclusion. Studies reporting indicators of hand hygiene compliance and proxy indicators such as product use were considered. Self-reported data were not considered a valid measure of compliance. Studies to promote hand hygiene compliance as part of a care bundle approach were included, providing data relating specifically to hand hygiene were presented separately. Studies were excluded if hand hygiene was assessed in simulations, non-clinical settings or the operating theatre setting.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed data quality.

MAIN RESULTS

Four studies met the criteria for the review: two from the original review and two from the update. Two studies evaluated simple education initiatives, one using a randomized clinical trial design and the other a controlled before and after design. Both measured hand hygiene compliance by direct observation. The other two studies were both interrupted times series studies. One study presented three separate interventions within the same paper: simple substitutions of product and two multifaceted campaigns, one of which included involving practitioners in making decisions about choice of hand hygiene products and the components of the hand hygiene program. The other study also presented two separate multifaceted campaigns, one of which involved application of social marketing theory. In these two studies follow-up data collection continued beyond twelve months, and a proxy measure of hand hygiene compliance (product use) was recorded. Microbiological data were recorded in one study. Hand hygiene compliance increased for one of the studies where it was measured by direct observation, but the results from the other study were not conclusive. Product use increased in the two studies in which it was reported, with inconsistent results reported for one initiative. MRSA incidence decreased in the one study reporting microbiological data.

AUTHORS' CONCLUSIONS

The quality of intervention studies intended to increase hand hygiene compliance remains disappointing. Although multifaceted campaigns with social marketing or staff involvement appear to have an effect, there is insufficient evidence to draw a firm conclusion. There remains an urgent need to undertake methodologically robust research to explore the effectiveness of soundly designed and implemented interventions to increase hand hygiene compliance.

Clostridium difficile

Clostridium difficile has re-emerged as a major hospital-acquired infection since 2001. Despite development of polymerase chain reaction-based testing, no single clinical diagnostic test has emerged with sufficient sensitivity, specificity, and turnaround time to be entirely reliable for disease diagnosis. The importance of C difficile acquired outside the hospital environment remains an unknown factor and awaits further epidemiologic investigation. This article discusses the changing epidemiology, clinical presentation, and pathogenesis of C difficile infection and highlights the ongoing challenges of laboratory diagnosis, treatment, and disease relapse.

Managing antimicrobial resistance in intensive care units

The challenges in managing patients with infection in the intensive care unit are increased in an era where there are dwindling antimicrobial choices for multidrug-resistant pathogens. Clinicians in the intensive care unit must balance between choosing appropriate antimicrobial treatment for patients with suspected infection and utilizing antimicrobials in a judicious fashion. Improving antimicrobial utilization is a critical component to reducing antimicrobial resistance. Although providing effective antimicrobial therapy and improving antimicrobial utilization may seem to be competing goals, there are effective strategies to accomplish both. Antimicrobial stewardship programs provide an organized way to implement these strategies and can enhance the intensive care unit physician's success in improving patient outcomes and combating antimicrobial resistance in the intensive care unit.

Impact of strain type on detection of toxigenic Clostridium difficile: comparison of molecular diagnostic and enzyme immunoassay approaches

A multicenter clinical trial assessed the performance of the Cepheid Xpert C. difficile assay on stool specimens collected from patients suspected of having Clostridium difficile infection (CDI). A total of 2,296 unformed stool specimens, collected from seven study sites, were tested by Xpert C. difficile enrichment culture followed by cell culture cytotoxicity testing of the isolates (i.e., toxigenic culture with enrichment) and the study sites' standard C. difficile test methods. The methods included enzyme immunoassay (EIA), direct cytotoxin testing, and two- and three-step algorithms using glutamate dehydrogenase (GDH) screening followed by either EIA or EIA and an in-house PCR assay. All C. difficile strains were typed by PCR-ribotyping. Compared to results for toxigenic culture with enrichment, the sensitivity, specificity, and positive and negative predictive values of the Xpert assay were 93.5, 94.0, 73.0, and 98.8%, respectively. The overall sensitivity of the EIAs compared to that of enrichment culture was 60.0%, and the sensitivity of combined GDH algorithms was 72.9%; both were significantly lower than that of Xpert C. difficile (P < 0.001 and P = 0.03, respectively). The sensitivity of the EIA was significantly lower than that of the Xpert C. difficile assay for detection of ribotypes 002, 027, and 106 (P < 0.0001, P < 0.0001, and P = 0.004, respectively, Fisher's exact test), and the sensitivity of GDH algorithms for ribotypes other than 027 was lower than that for Xpert C. difficile (P < 0.001). The Xpert C. difficile assay is a simple, rapid, and accurate method for detection of toxigenic C. difficile in unformed stool specimens and is minimally affected by strain type compared to EIA and GDH-based methods.