Asymptomatic carriage of toxigenic Clostridium difficile by hospitalized patients

Heterogeneity of Clostridioides difficile asymptomatic colonization prevalence: a systematic review and meta-analysis

BACKGROUND

Asymptomatic carriers significantly influence the transmission dynamics of C. difficile. This study aimed to assess the prevalence of toxigenic C. difficile asymptomatic colonization (tCDAC) and investigate its heterogeneity across different populations. We searched MEDLINE, Web of Science, and Scopus for articles published between 2000 and 2023 on tCDAC. Studies including asymptomatic adults with laboratory-confirmed tCDAC were eligible. We performed a random-effects meta-analysis to estimate the pooled prevalence by clinical characteristics, settings, and geographic areas. In addition, we used outlier analyses and meta-regression to explore sources of prevalence variability.

RESULTS

Fifty-one studies involving 39,447 patients were included. The tCDAC prevalence ranged from 0.5 to 51.5%. Among pooled estimates, a high prevalence was observed in patients with cystic fibrosis, outbreak settings, and cancer patients, whereas the lowest rates were found in healthy individuals and healthcare workers. Similar colonization rates were observed between admitted and hospitalized patients. Our meta-regression analysis revealed lower rates in healthy individuals and higher rates in cystic fibrosis patients and studies from North America. Additionally, compared with that among healthy individuals, the prevalence significantly increased by 15-47% among different populations and settings.

CONCLUSION

Our study revealed that tCDAC is a common phenomenon. We found high prevalence estimates that showed significant variability across populations. This heterogeneity could be partially explained by population characteristics and settings, supporting their role in the pathogenesis and burden of this disease. This highlights the need to identify high-risk groups to improve infection control strategies, decrease transmission dynamics, and better understand the natural history of this disease.

Hand and environmental hygiene: respective roles for MRSA, multi-resistant gram negatives, Clostridioides difficile, and Candida spp

Healthcare-associated infections (HAIs) caused by multidrug-resistant organisms (MDROs) represent a global threat to human health and well-being. Because transmission of MDROs to patients often occurs via transiently contaminated hands of healthcare personnel (HCP), hand hygiene is considered the most important measure for preventing HAIs. Environmental surfaces contaminated with MDROs from colonized or infected patients represent an important source of HCP hand contamination and contribute to transmission of pathogens. Accordingly, facilities are encouraged to adopt and implement recommendations included in the World Health Organization hand hygiene guidelines and those from the Society for Healthcare Epidemiology of America/Infectious Diseases Society of America/Association for Professionals in Infection Control and Epidemiology. Alcohol-based hand rubs are efficacious against MDROs with the exception of Clostridiodes difficile, for which soap and water handwashing is indicated. Monitoring hand hygiene adherence and providing HCP with feedback are of paramount importance. Environmental hygiene measures to curtail MDROs include disinfecting high-touch surfaces in rooms of patients with C. difficile infection daily with a sporicidal agent such as sodium hypochlorite. Some experts recommend also using a sporicidal agent in rooms of patients colonized with C. difficile, and for patients with multidrug-resistant Gram-negative bacteria. Sodium hypochlorite, hydrogen peroxide, or peracetic acid solutions are often used for daily and/or terminal disinfection of rooms housing patients with Candida auris or other MDROs. Products containing only a quaternary ammonium agent are not as effective as other agents against C. auris. Portable medical equipment should be cleaned and disinfected between use on different patients. Detergents are not recommended for cleaning high-touch surfaces in MDRO patient rooms, unless their use is followed by using a disinfectant. Facilities should consider using a disinfectant instead of detergents for terminal cleaning of floors in MDRO patient rooms. Education and training of environmental services employees is essential in assuring effective disinfection practices. Monitoring disinfection practices and providing personnel with performance feedback using fluorescent markers, adenosine triphosphate assays, or less commonly cultures of surfaces, can help reduce MDRO transmission. No-touch disinfection methods such as electrostatic spraying, hydrogen peroxide vapor, or ultraviolet light devices should be considered for terminal disinfection of MDRO patient rooms. Bundles with additional measures are usually necessary to reduce MDRO transmission.

Disinfection and sterilization: New technologies

BACKGROUND

Adherence to professional guidelines and/or manufacturer's instructions for use regarding proper disinfection and sterilization of medical devices is crucial to preventing cross transmission of pathogens between patients. Emerging pathogens (e.g., Candida auris) and complex medical devices provide new challenges.

METHODS

A search for published English articles on new disinfection and sterilization technologies was conducted by Google, Google scholar and PubMed.

RESULTS

Several new disinfection methods or products (e.g., electrostatic spraying, new sporicides, colorized disinfectants, "no touch" room decontamination, continuous room decontamination) and sterilization technologies (e.g., new sterilization technology for endoscopes) were identified.

CONCLUSIONS

These technologies should reduce patient risk.

Environmental approaches to controlling Clostridioides difficile infection in healthcare settings

As today's most prevalent and costly healthcare-associated infection, hospital-onset Clostridioides difficile infection (HO-CDI) represents a major threat to patient safety world-wide. This review will discuss how new insights into the epidemiology of CDI have quantified the prevalence of C. difficile (CD) spore contamination of the patient-zone as well as the role of asymptomatically colonized patients who unavoidable contaminate their near and distant environments with resilient spores. Clarification of the epidemiology of CD in parallel with the development of a new generation of sporicidal agents which can be used on a daily basis without damaging surfaces, equipment, or the environment, led to the research discussed in this review. These advances underscore the potential for significantly mitigating HO-CDI when combined with ongoing programs for optimizing the thoroughness of cleaning as well as disinfection. The consequence of this paradigm-shift in environmental hygiene practice, particularly when combined with advances in hand hygiene practice, has the potential for significantly improving patient safety in hospitals globally by mitigating the acquisition of CD spores and, quite plausibly, other environmentally transmitted healthcare-associated pathogens.

Prevalence and risk factors of toxigenic Clostridioides difficile asymptomatic carriage in 11 French hospitals

Clostridioides difficile infection (CDI) incidence has increased over the last 20 years. Studies suggest that asymptomatic carriers may be an important reservoir of C. difficile in healthcare settings. We conducted a point prevalence study to estimate the toxigenic C. difficile asymptomatic carriage rate and the associated risk factors in patients >3 years old. Between September 16, 2019 and January 15, 2020, all patients hospitalized in 11 healthcare facilities in the Paris urban area were included in the study. They were screened on the day of the survey for toxigenic C. difficile carriage by rectal swab and interviewed. Isolates were characterized by PCR ribotyping and multiplex PCR targeting toxin genes. A logistic regression model was used to determine the risk factors associated with toxigenic C. difficile asymptomatic carriage using uni- and multivariate analysis in the subpopulation of patients >3 years old. During the study period, 2,389 patients were included and screened. The median age was 62 years (interquartile range 35-78 years) and 1,153 were male (48.3%). Nineteen patients had a previous CDI (0.9%). Overall, 185/2389 patients were positive for C. difficile (7.7%), including 93 toxigenic strains (3.9%): 77 (82.8%) were asymptomatic (prevalence 3.2%) whereas 12 (12.9%) were diarrheic. Prevalences of toxigenic C. difficile were 3.5% in patients >3 years old and 7.0% in ≤3 years old subjects, respectively. Toxigenic strains mainly belonged to PCR ribotypes 106 (n = 14, 15.0%), 014 (n = 12, 12.9%), and 020 (n = 10, 10.8%). Among toxigenic strains, 6 (6.4%) produced the binary toxin. In multivariate analysis, two factors were positively associated with toxigenic C. difficile asymptomatic carriage in patients >3 years old: multidrug-resistant organisms co-carriage [adjusted Odd Ratio (aOR) 2.3, CI 95% 1.2-4.7, p = 0.02] and previous CDI (aOR 5.8, CI 95% 1.2-28.6, p = 0.03). Conversely, consumption of raw milk products were associated with reduced risk of toxigenic C. difficile colonization (aOR 0.5, CI 95% 0.2-0.9, p = 0.01). We showed that there was a low prevalence of asymptomatic toxigenic C. difficile carriage in hospitalized patients. Consumption of raw milk prevents toxigenic C. difficile colonization, probably due to the barrier effect of milk-associated bacteria.

Impact of testing on Clostridioides difficile infection in hospitals across Europe: a mathematical model

OBJECTIVES

The prevalence of Clostridioides difficile infection (CDI) has been shown to vary markedly between European countries, both in hospitals and in the community. Determining the true prevalence has proven challenging. Without systematic testing in hospitals, the unchecked transmission of CDI can lead to large outbreaks in more susceptible cohorts. We investigate the success of CDI surveillance and control measures across Europe, by examining the dynamics of disease spread from the community into a hospital setting. We focus on national differences, such as variability in testing and sampling, disease prevalence in communities and hospitals, and antimicrobial usage.

METHODS

We developed a stochastic, compartmental, dynamic mathematical model parameterized using sampling and testing rate data from COMBACTE-CDI, a multicountry study in which all diarrhoeal stool samples (N = 3163) from European laboratories were tested for CDI, and data for antimicrobial usage and incidence of hospital cases sourced from the European Centre for Disease Prevention and Control.

RESULTS

The framework estimates the prevalence of CDI among hospital patients across European countries and explores how national differences impact the dynamics, transmission, and relative incidence of CDI within the hospital setting. The model illustrates the mechanisms influencing these national differences, namely, antimicrobial usage rates, national sampling and testing rates, and community prevalence of CDI.

DISCUSSION

Differential costs for testing and practicalities of scaling up testing mean every country needs to consider balancing CDI testing costs against the costs of treatment and care of patients with CDI.

Trends in Clostridioides difficile infection across a public health hospital system in New York City 2019-2021: A cautionary note

Contrary to national reports, rates of healthcare facility-onset Clostridioides difficile infection across an 11-hospital system rose after the spring of 2020, when New York City was the epicenter for the COVID-19 pandemic. Antibiotic pressure from an escalation in cephalosporin usage correlated with this increase. The majority of cases of Clostridioides difficile were in patients without COVID-19, suggesting the pandemic has adversely impacted the healthcare of other inpatients.

Genomic Determination of Relative Risks for Clostridioides difficile Infection From Asymptomatic Carriage in Intensive Care Unit Patients

BACKGROUND

Clostridioides difficile infections (CDIs) are among the most prevalent hospital-associated infections (HAIs), particularly for intensive care unit (ICU) patients. The risks for developing active CDI from asymptomatic carriage of C. difficile are not well understood.

METHODS

We identified asymptomatic C. difficile carriage among 1897 ICU patients using rectal swabs from an existing ICU vancomycin-resistant enterococci (VRE) surveillance program. C. difficile isolates from VRE swabs, and from C. difficile-positive stool samples, were genome sequenced. Spatial-temporal data from hospital records assessed genomically identified clusters for potential transmission events.

RESULTS

Genomic analyses identified a diverse set of strains in infected patients and asymptomatic carriers. A total of 7.4% of ICU patients asymptomatically carried C. difficile; 69% of isolates carried an intact toxin locus. In contrast, 96% of C. difficile stool isolates were toxin encoding. CDI rates in asymptomatic carriers of toxin-encoding strains were 5.3% versus 0.57% in noncarriers. The relative risk for CDI with asymptomatic carriage of a toxin-encoding strain was 9.32 (95% confidence interval, 3.25-26.7). Genomic identification of clonal clusters supported analyses for asymptomatic transmission events, with spatial-temporal overlaps identified in 13 of 28 cases.

CONCLUSIONS

Our studies provide the first genomically confirmed assessments of CDI relative risk from asymptomatic carriage of toxin-encoding strains and highlight the complex dynamics of asymptomatic transmission in ICUs. Asymptomatic carriers are an active reservoir of C. difficile in the nosocomial environment. C. difficile screening can be implemented within existing HAI surveillance programs and has the potential to support infection-control efforts against this pathogen.

Prevalence of Detection of Clostridioides difficile Among Asymptomatic Children: A Systematic Review and Meta-analysis

IMPORTANCE

Detection of Clostridioides difficile has frequently been described in asymptomatic infants and children, but accurate estimates across the age spectrum are unavailable.

OBJECTIVE

To assess the prevalence of C difficile detection among asymptomatic children across the age spectrum.

DATA SOURCES

This systematic review and meta-analysis included a search of the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, CINAHL, Scopus, and Web of Science for articles published from January 1, 1990, to December 31, 2020. Search terms included Clostridium difficile, Peptoclostridium difficile, Clostridioides difficile, CDF OR CDI OR c diff OR c difficile, Clostridium infections OR cd positive diarrhea OR cd positive diarrhea OR Clostridium difficile OR Peptoclostridium difficile OR pseudomembranous colitis OR pseudomembranous enterocolitis, enterocolitis, and pseudomembranous. These were combined with the following terms: bacterial colonization and colonization OR colonized OR colonizing OR epidemiology OR prevalence OR seroprevalence.

STUDY SELECTION

Studies were screened independently by 2 authors. Studies were included if they reported testing for C difficile among asymptomatic children (ie, children without diarrhea) younger than 18 years.

DATA EXTRACTION AND SYNTHESIS

Data were extracted independently and in duplicate by 2 reviewers. Preferred Reporting Items for a Systematic Review and Meta-analysis (PRISMA) guidelines were used. Data were pooled using a random-effects model.

MAIN OUTCOMES AND MEASURES

The primary outcome was prevalence of C difficile detection among asymptomatic children. Secondary outcomes included prevalence of toxigenic vs nontoxigenic strains of C difficile and prevalence of C difficile detection stratified by geographic region, income status, testing method, and year of testing.

RESULTS

A total of 95 studies with 19 186 participants were included. Rates of detection of toxigenic or nontoxigenic C difficile were greatest among infants aged 6 to 12 months (41%; 95% CI, 32%-50%) and decreased to 12% (95% CI, 7%-18%) among children aged 5 to 18 years. The prevalence of toxigenic C difficile colonization was lower, peaking at 14% (95% CI, 8%-21%) among infants aged 6 to 12 months and decreasing to 6% (95% CI, 2%-11%) among children older than 5 years. Although prevalence differed by geographic region (ie, North and South America vs Europe: β, -0.151, P = .001; North and South America vs Western Pacific: β, 0.136, P = .007), there was no difference by testing method (ie, culture vs polymerase chain reaction: β, 0.069, P = .052; culture vs enzyme immunoassay: β, -0.178, P = .051), income class (low-middle income vs high income: β, -0.144, P = .23; upper-middle vs high income: β, -0.020, P = .64), or period (before 1990 vs 2010-2020: β, -0.125, P = .19; 1990-1999 vs 2010-2020: β, -0.037, P = .42; 2000-2009 vs 2010-2020: β, -0.006, P = .86).

CONCLUSIONS AND RELEVANCE

In this systematic review and meta-analysis, C difficile colonization rates among children were greatest at 6 to 12 months of age and decreased thereafter. These estimates may provide context for interpreting C difficile test results among young children.

Health Care Environmental Hygiene: New Insights and Centers for Disease Control and Prevention Guidance

Recent research has significantly clarified the impact of optimizing patient-zone environmental hygiene. New insights into the environmental microbial epidemiology of many hospital-associated pathogens, especially Clostridioides difficile, have clarified and quantified the role of ongoing occult pathogen transmission from the near-patient environment. The recent development of safe, broadly effective surface chemical disinfectants has led to new opportunities to broadly enhance environmental hygiene in all health care settings. The Centers for Disease Control and Prevention has recently developed a detailed guidance to assist all health care settings in implementing optimized programs to mitigate health care-associated pathogen transmission from the near-patient surfaces.

Colonization with Gastrointestinal Pathogens Prior to Hematopoietic Cell Transplantation and Associated Clinical Implications

Infectious diarrhea following hematopoietic cell transplantation (HCT) significantly contributes to morbidity and mortality. Most HCT recipients experience diarrhea in the post-transplantation period, and infectious pathogens are frequently detected during diarrheal episodes. However, little is known about how frequently these patients are colonized with gastrointestinal (GI) pathogens before their transplantation and whether colonization predicts future diarrheal illness. We sought to determine how frequently HCT recipients are colonized with GI pathogens before HCT and the degree to which pre-HCT colonization predicts post-transplantation infectious diarrheal illness. We conducted a prospective cohort study of allogeneic and autologous HCT recipients at a single center between December 2016 and January 2019. Stool samples were collected during the week before HCT, and formed samples were evaluated for the presence of 22 diarrheal pathogens using the BioFire FilmArray GI panel. We determined the frequency with which participants were colonized with each pathogen and identified factors associated with colonization. We then determined how frequently pretransplantation colonization led to post-transplantation diarrheal infections due to the colonizing pathogen and whether colonization was associated with increased number of days of post-transplantation diarrhea during the transplant hospitalization. We enrolled 112 asymptomatic patients (allogeneic, 61%; autologous, 39%) who had a formed stool specimen before HCT, of whom 41 (37%) had a GI pathogen detected. The most commonly detected organisms were Clostridioides difficile (n = 21; 19%), Yersinia enterocolitica (n = 9; 8%), enteropathogenic Escherichia coli (EPEC) (n = 6; 6%), and norovirus (n = 5; 4%). Female sex and previous C. difficile infection were associated with C. difficile colonization, and having non-Hodgkin lymphoma was associated with being colonized with a diarrheal pathogen other than C. difficile. Thirteen of 21 patients (62%) with pretransplantation C. difficile colonization developed a clinical C. difficile infection post-transplantation, and 8 of 10 patients (80%) colonized with EPEC or enteroaggregative E. coli developed post-transplantation infections due to their colonizing pathogen. Pretransplantation C. difficile colonization was also associated with an increased duration of post-transplantation diarrhea (P = .048). Conversely, none of the 9 patients with pretransplantation Yersinia enterocolitica colonization developed a post-transplantation Y. enterocolitica infection. Patients admitted for HCT are frequently colonized with a diverse range of GI pathogens. Colonization with C. difficile colonization and diarrheagenic E. coli is frequently associated with post-transplantation diarrheal infections caused by these organisms, but the clinical significance of colonization with other GI pathogens is not clear.

Clostridioides difficile Infection, Still a Long Way to Go

Clostridioides difficile is an increasingly common pathogen both within and outside the hospital and is responsible for a large clinical spectrum from asymptomatic carriage to complicated infection associated with a high mortality. While diagnostic methods have considerably progressed over the years, the optimal diagnostic algorithm is still debated and there is no single diagnostic test that can be used as a standalone test. More importantly, the heterogeneity in diagnostic practices between centers along with the lack of robust surveillance systems in all countries and an important degree of underdiagnosis due to lack of clinical suspicion in the community, hinder a more accurate evaluation of the burden of disease. Our improved understanding of the physiopathology of CDI has allowed some significant progress in the treatment of CDI, including a broader use of fidaxomicine, the use of fecal microbiota transplantation for multiples recurrences and newer approaches including antibodies, vaccines and new molecules, already developed or in the pipeline. However, the management of CDI recurrences and severe infections remain challenging and the main question remains: how to best target these often expensive treatments to the right population. In this review we discuss current diagnostic approaches, treatment and potential prevention strategies, with a special focus on recent advances in the field as well as areas of uncertainty and unmet needs and how to address them.

Risk factors for Clostridioides difficile colonization among hospitalized adults: A meta-analysis and systematic review

OBJECTIVE

To identify risk factors for asymptomatic Clostridioides difficile colonization among hospitalized adults utilizing a meta-analysis, which may enable early identification of colonized patients at risk of spreading C. difficile.

DESIGN

Meta-analysis and systematic review.

METHODS

We systematically searched MEDLINE, Scopus, Web of Science, and EMBASE from January 1, 1975, to February 15, 2020, for articles related to C. difficile colonization among hospitalized adults. Studies with multivariable analyses evaluating risk factors for asymptomatic colonization were eligible.

RESULTS

Among 5,506 studies identified in the search, 19 studies met the inclusion criteria. Included studies reported 20,334 adult patients of whom 1,588 were asymptomatically colonized with C. difficile. Factors associated with an increased risk of colonization were hospitalization in the previous 6 months (OR, 2.18; 95% CI, 1.86-2.56; P < .001), use of gastric acid suppression therapy within the previous 8 weeks (OR, 1.42; 95% CI, 1.17-1.73; P < .001), tube feeding (OR, 2.02; 95% CI, 1.06-3.85; P = .03), and corticosteroid use in the previous 8 weeks (OR, 1.58; 95% CI, 1.14-2.17; P = .006). Receipt of antibiotics in the previous 3 months (OR, 1.37; 95% CI, 0.94-2.01; P = .10) was not associated with statistically significant effects on risk of colonization.

CONCLUSIONS

C. difficile colonization was significantly associated with previous hospitalization, gastric acid suppression, tube feeding, and corticosteroid use. Recognition of these risk factors may assist in identifying asymptomatic carriers of C. difficile and taking appropriate measures to reduce transmission.

Modeling the potential impact of administering vaccines against Clostridioides difficile infection to individuals in healthcare facilities

BACKGROUND

A vaccine against Clostridioides difficile infection (CDI) is in development. While the vaccine has potential to both directly protect those vaccinated and mitigate transmission by reducing environmental contamination, the impact of the vaccine on C. difficile colonization remains unclear. Consequently, the transmission-reduction effect of the vaccine depends on the contribution of symptomatic CDI to overall transmission of C. difficile.

METHODS

We designed a simulation model of CDI among patients in a network of 10 hospitals and nursing homes and calibrated the model using estimates of transmissibility from whole genome sequencing studies that estimated the fraction of CDI attributable to transmission from other CDI patients. We assumed the vaccine reduced the rate of progression to CDI among carriers by 25-95% after completion of a 3-dose vaccine course administered to randomly chosen patients at facility discharge. We simulated the administration of this vaccination campaign and tallied effects over 5 years.

RESULTS

We estimated 30 times higher infectivity of CDI patients compared to other carriers. Simulations of the vaccination campaign produced an average reduction of 3-16 CDI cases per 1000 vaccinated patients, with 2-11 of those cases prevented among those vaccinated and 1-5 prevented among unvaccinated patients.

CONCLUSIONS

Our findings demonstrate potential for a vaccine against CDI to reduce transmissions in healthcare facilities, even with no direct effect on carriage susceptibility. The vaccine's population impact will increase if received by individuals at risk for CDI onset in high-transmission settings.

Longitudinal investigation of carriage rates and genotypes of toxigenic Clostridium difficile in hepatic cirrhosis patients

Toxigenic Clostridium difficile (C. difficile) carriers represent an important source in the transmission of C. difficile infection (CDI) during hospitalisation, but its prevalence and mode in patients with hepatic cirrhosis are not well established. We investigated longitudinal changes in carriage rates and strain types of toxigenic C. difficile from admission to discharge among hepatic cirrhosis patients. Toxigenic C. difficile was detected in 104 (19.8%) of 526 hepatic cirrhosis patients on admission, and the carriage status changed in a portion of patients during hospitalisation. Approximately 56% (58/104) of patients lost the colonisation during their hospital stay. Among the remaining 48 patients who remained positive for toxigenic C. difficile, the numbers of patients who were positive at one, two, three and four isolations were 10 (55.6%), three (16.7%), two (11.1%) and three (16.7%), respectively. Twenty-eight patients retained a particular monophyletic strain at multiple isolations. The genotype most frequently identified was the same as that frequently identified in symptomatic CDI patients. A total of 25% (26/104) of patients were diagnosed with CDI during their hospital stay. Conclusions: Colonisation with toxigenic C. difficile strains occurs frequently in cirrhosis patients and is a risk factor for CDI.

Hospital Infection Control: Clostridioides difficile

Clostridioides difficile remains a leading cause of healthcare-associated infection. Efforts at C. difficile prevention have been hampered by an increasingly complex understanding of transmission patterns and a high degree of heterogeneity among existing studies. Effective prevention of C. difficile infection requires multimodal interventions, including contact precautions, hand hygiene with soap and water, effective environmental cleaning, use of sporicidal cleaning agents, and antimicrobial stewardship. Roles for probiotics, avoidance of proton pump inhibitors, and isolation of asymptomatic carriers remain poorly defined.

Screening of Clostridioides difficile carriers in an urban academic medical center: Understanding implications of disease

OBJECTIVE

Efforts to reduce Clostridioides difficile infection (CDI) have targeted transmission from patients with symptomatic C. difficile. However, many patients with the C. difficile organism are carriers without symptoms who may serve as reservoirs for spread of infection and may be at risk for progression to symptomatic C. difficile. To estimate the prevalence of C. difficile carriage and determine the risk and speed of progression to symptomatic C. difficile among carriers, we established a pilot screening program in a large urban hospital.

DESIGN

Prospective cohort study.

SETTING

An 800-bed, tertiary-care, academic medical center in the Bronx, New York.

PARTICIPANTS

A sample of admitted adults without diarrhea, with oversampling of nursing facility patients.

METHODS

Perirectal swabs were tested by polymerase chain reaction for C. difficile within 24 hours of admission, and patients were followed for progression to symptomatic C. difficile. Development of symptomatic C. difficile was compared among C. difficile carriers and noncarriers using a Cox proportional hazards model.

RESULTS

Of the 220 subjects, 21 (9.6%) were C. difficile carriers, including 10.2% of the nursing facility residents and 7.7% of the community residents (P = .60). Among the 21 C. difficile carriers, 8 (38.1%) progressed to symptomatic C. difficile, but only 4 (2.0%) of the 199 noncarriers progressed to symptomatic C. difficile (hazard ratio, 23.9; 95% CI, 7.2-79.6; P < .0001).

CONCLUSIONS

Asymptomatic carriage of C. difficile is prevalent among admitted patients and confers a significant risk of progression to symptomatic CDI. Screening for asymptomatic carriers may represent an opportunity to reduce CDI.

Environmental shedding of toxigenic Clostridioides difficile by asymptomatic carriers: A prospective observational study

OBJECTIVES

The aim was to compare the burden of environmental shedding of toxigenic Clostridioides difficile among asymptomatic carriers, C. difficile-infected (CDI) patients and non-carriers in an inpatient non-epidemic setting.

METHODS

C. difficile carriage was determined by positive toxin-B PCR from rectal swabs of asymptomatic patients. Active CDI was defined as a positive two-step enzyme immunoassay/polymerase chain reaction (EIA/PCR) test in patients with more than three unformed stools/24 hr. C. difficile environmental contamination was assessed by obtaining specimens from ten sites in the patients' rooms. Toxigenic strains were identified by PCR. We created a contamination scale to define the overall level of room contamination that ranged from clean to heavy contamination.

RESULTS

One hundred and seventeen rooms were screened: 70 rooms inhabited by C. difficile carriers, 30 rooms by active CDI patients and 17 rooms by non C. difficile -carriers (control). In the carrier rooms 29 (41%) had more than residual contamination, from which 17 (24%) were heavily contaminated. In the CDI rooms 12 (40%) had more than residual contamination from which three (10%) were heavily contaminated, while in the control rooms, one room (6%) had more than residual contamination and none were heavily contaminated. In a multivariate analysis, the contamination score of rooms inhabited by carriers did not differ from rooms of CDI patients, yet both were significantly more contaminated than those of non-carriers odd ratio 12.23 and 11.16 (95% confidence interval 1.5-99.96 p 0.0195, and 1.19-104.49 p 0.035), respectively.

DISCUSSION

Here we show that the rooms of C. difficile carriers are as contaminated as those of patients with active CDI and significantly more than those of non-carriers.

Epidemiologic Trends in Clostridioides difficile Infections in a Regional Community Hospital Network

IMPORTANCE

Clostridioides difficile infection (CDI) remains a leading cause of health care facility-associated infection. A greater understanding of the regional epidemiologic profile of CDI could inform targeted prevention strategies.

OBJECTIVES

To assess trends in incidence of health care facility-associated and community-acquired CDI among hospitalized patients over time and to conduct a subanalysis of trends in the NAP1 strain of CDI over time.

DESIGN, SETTING, AND PARTICIPANTS

This long-term multicenter cohort study reviewed records of patients (N = 2 025 678) admitted to a network of 43 regional community hospitals primarily in the southeastern United States from January 1, 2013, through December 31, 2017. Generalized linear mixed-effects models were used to adjust for potential clustering within facilities and changing test method (nucleic acid amplification testing or toxin enzyme immunoassay) over time.

MAIN OUTCOMES AND MEASURES

Clostridioides difficile infection incidence rates were counted as cases per 1000 admissions for community-acquired and total CDI cases or cases per 10 000 patient-days for health care facility-associated CDI. Long-term trends in the proportion of cases acquired in the community and in NAP1 strain incidence were also evaluated.

RESULTS

A total of 2 025 678 admissions and 21 254 CDI cases were included (12 678 [59.6%] female; median [interquartile range] age, 69 [55-80] years). Median (interquartile range) total CDI incidence increased slightly from 7.9 (3.5-12.4) cases per 1000 admissions in 2013 to 9.3 (4.9-13.7) cases per 1000 admissions in 2017. After adjustment, the overall incidence of health care facility-associated CDI declined (incidence rate ratio [IRR], 0.995; 95% CI, 0.990-0.999; P = .03), whereas insufficient evidence was found for either an increase or a decrease in community-acquired CDI (IRR, 1.004; 95% CI, 0.999-1.009; P = .14). The proportion of cases classified as community acquired increased over time from a mean (SD) of 0.49 (0.28) in 2013 to 0.61 (0.26) in 2017 (odds ratio, 1.010 per month; 95% CI, 1.006-1.015; P < .001). Rates of the NAP1 strain of CDI varied widely between facilities, with no statistically significant change in NAP1 strain incidence over time in the community setting (IRR, 1.007; 95% CI, 0.994-1.021) or health care facility setting (IRR, 1.011; 95% CI, 0.990-1.032).

CONCLUSIONS AND RELEVANCE

The findings suggest that, despite the modest improvement in health care facility-associated CDI rates, a better understanding of community-acquired CDI incidence is needed for future infection prevention efforts.

Management of Clostridioides (formerly Clostridium) difficile infection (CDI) in solid organ transplant recipients: Guidelines from the American Society of Transplantation Community of Practice

These updated guidelines from the American Society of Transplantation Infectious Diseases Community of Practice address the prevention and management of Clostridium difficile infection in solid organ transplant (SOT) recipients. Clostridioides (formerly Clostridium) difficile infection (CDI) is among the most common hospital acquired infections. In SOT recipients, the incidence of CDI varies by type and number or organs transplanted. While a meta-analysis of published literature found the prevalence of postoperative CDI in the general surgical population to be approximately 0.51%, the prevalence of CDI that is seen in the solid organ transplant population ranges from a low of 3.2% in the pancreatic transplant population to 12.7% in those receiving multiple organ transplants. There are no randomized, controlled trials evaluating the management of CDI in the SOT population. Herein is a review and summary of the currently available literature that has been synthesized into updated treatment guidelines for the management of CDI in the SOT population.

Impact of routine use of a spray formulation of bleach on Clostridium difficile spore contamination in non-C difficile infection rooms

The frequency of recovery of Clostridium difficile spores from surfaces after postdischarge cleaning of non-C difficile infection rooms was significantly reduced from 24%-5% after a commercial spray formulation of bleach was substituted for a quaternary ammonium disinfectant. These results suggest that routine use of a sporicidal disinfectant in all postdischarge rooms could potentially be beneficial in reducing the risk for C difficile transmission from contaminated surfaces.

Modeling Clostridium difficile in a hospital setting: control and admissions of colonized and symptomatic patients

BACKGROUND

Clostridium difficile (C. difficile) infection is an important cause of healthcare-associated diarrhea. Several factors such as admission of colonized patients, levels of serum antibodies in patients, and control strategies may involve in determining the prevalence and the persistence of C. difficile in a hospital unit.

METHODS

We develop mathematical models based on deterministic and stochastic frameworks to investigate the effects of control strategies for colonized and symptomatic patients and admissions of colonized and symptomatic patients on the prevalence and the persistence of C. difficile.

RESULTS

Our findings suggest that control strategies and admissions of colonized and symptomatic patients play important roles in determining the prevalence and the persistence of C. difficile. Improving control of C. difficile in colonized and symptomatic patients may generally help reduce the prevalence and the persistence of C. difficile. However, if admission rates of colonized and symptomatic patients are high, the prevalence of C. difficile may remain high in a patient population even though strict control policies are applied.

CONCLUSION

Control strategies and admissions of colonized and symptomatic patients are important determinants of the prevalence and the persistence of C. difficile.

Fluoroquinolone Prophylaxis Is Highly Effective for the Prevention of Central Line-Associated Bloodstream Infections in Autologous Stem Cell Transplant Patients

Patients undergoing stem cell transplant (SCT) for the treatment of hematologic malignancy are at increased risk for central line-associated bloodstream infections (CLABSIs). The use of prophylactic antibiotics to prevent CLABSIs in the setting of autologous SCT is of unclear benefit. We aimed to evaluate the impact of levofloxacin prophylaxis on reducing CLABSIs in this high-risk population. Patients undergoing autologous SCT at a tertiary care hospital received levofloxacin prophylaxis from January 13, 2016 to January 12, 2017. Levofloxacin was administered from autologous SCT (day 0) until day 13, absolute neutrophil count > 500/mm³, or neutropenic fever, whichever occurred first. Clinical outcomes were compared with a baseline group who underwent autologous SCT but did not receive antibacterial prophylaxis during the previous year. The primary endpoint was incidence of CLABSIs assessed using Cox proportional hazards regression. A total of 324 patients underwent autologous SCT during the entire study period, with 150 receiving levofloxacin prophylaxis during the intervention period. The rate of CLABSIs was reduced from 18.4% during the baseline period to 6.0% during the intervention period. On multivariable analysis levofloxacin prophylaxis significantly reduced CLABSI incidence (hazard ratio, .33; 95% confidence interval [CI], .16 to .69; P = .003). There was also a reduction in the risk of neutropenic fever (odds ratio [OR], .23; 95% CI, .14 to .39; P < .001) and a trend toward a reduction in intensive care unit transfer for sepsis (OR, .33; 95% CI, .09 to 1.24; P = .10) in patients receiving levofloxacin prophylaxis. Notably, there was no increase in Clostridium difficile infection in the levofloxacin group (OR, .66; 95% CI, .29 to 1.49; P = .32). Levofloxacin prophylaxis was effective in reducing CLABSIs and neutropenic fever in patients undergoing autologous SCT. Further studies are needed to identify specific patient groups who will benefit most from antibiotic prophylaxis.

Transmission of Clostridium difficile from asymptomatically colonized or infected long-term care facility residents

OBJECTIVE

To test the hypothesis that long-term care facility (LTCF) residents with Clostridium difficile infection (CDI) or asymptomatic carriage of toxigenic strains are an important source of transmission in the LTCF and in the hospital during acute-care admissions.

DESIGN

A 6-month cohort study with identification of transmission events was conducted based on tracking of patient movement combined with restriction endonuclease analysis (REA) and whole-genome sequencing (WGS).

SETTING

Veterans Affairs hospital and affiliated LTCF.ParticipantsThe study included 29 LTCF residents identified as asymptomatic carriers of toxigenic C. difficile based on every other week perirectal screening and 37 healthcare facility-associated CDI cases (ie, diagnosis >3 days after admission or within 4 weeks of discharge to the community), including 26 hospital-associated and 11 LTCF-associated cases.

RESULTS

Of the 37 CDI cases, 7 (18·9%) were linked to LTCF residents with LTCF-associated CDI or asymptomatic carriage, including 3 of 26 hospital-associated CDI cases (11·5%) and 4 of 11 LTCF-associated cases (36·4%). Of the 7 transmissions linked to LTCF residents, 5 (71·4%) were linked to asymptomatic carriers versus 2 (28·6%) to CDI cases, and all involved transmission of epidemic BI/NAP1/027 strains. No incident hospital-associated CDI cases were linked to other hospital-associated CDI cases.

CONCLUSIONS

Our findings suggest that LTCF residents with asymptomatic carriage of C. difficile or CDI contribute to transmission both in the LTCF and in the affiliated hospital during acute-care admissions. Greater emphasis on infection control measures and antimicrobial stewardship in LTCFs is needed, and these efforts should focus on LTCF residents during hospital admissions.

BaiCD gene cluster abundance is negatively correlated with Clostridium difficile infection

BACKGROUND

Clostridium difficile infection (CDI) is a major cause of hospital-acquired diarrhea. Secondary bile acids were shown to confer resistance to colonization by C. difficile. 7α-dehydroxylation is a key step in transformation of primary to secondary bile acids and required genes have been located in a single bile acid-inducible (bai) operon in C. scindens as well as in C. hiranonis, two Clostridium sp. recently reported to protect against C. difficile colonization.

AIM

To analyze baiCD gene abundance in C. difficile positive and negative fecal samples.

MATERIAL & METHODS

A species-specific qPCR for detecting baiCD genes was established. Fecal samples of patients with CDI, asymptomatic toxigenic C. difficile colonization (TCD), non-toxigenic C. difficile colonization (NTCD), of C. difficile negative (NC) patients, and of two patients before and after fecal microbiota transplantation (FMT) for recurrent CDI (rCDI) were tested for the presence of the baiCD genes.

RESULTS

The prevalence of the baiCD gene cluster was significantly higher in C. difficile negative fecal samples than in samples of patients diagnosed with CDI (72.5% (100/138) vs. 35.9% (23/64; p<0.0001). No differences in baiCD gene cluster prevalence were seen between NC and NTCD or NC and TCD samples. Both rCDI patients were baiCD-negative at baseline, but one of the two patients turned positive after successful FMT from a baiCD-positive donor.

CONCLUSION

Fecal samples of CDI patients are less frequently baiCD-positive than samples from asymptomatic carriers or C. difficile-negative individuals. Furthermore, we present a case of baiCD positivity observed after successful FMT for rCDI.

Clostridium difficile - From Colonization to Infection

Clostridium difficile is the most frequent cause of nosocomial antibiotic-associated diarrhea. The incidence of C. difficile infection (CDI) has been rising worldwide with subsequent increases in morbidity, mortality, and health care costs. Asymptomatic colonization with C. difficile is common and a high prevalence has been found in specific cohorts, e.g., hospitalized patients, adults in nursing homes and in infants. However, the risk of infection with C. difficile differs significantly between these cohorts. While CDI is a clear indication for therapy, colonization with C. difficile is not believed to be a direct precursor for CDI and therefore does not require treatment. Antibiotic therapy causes alterations of the intestinal microbial composition, enabling C. difficile colonization and consecutive toxin production leading to disruption of the colonic epithelial cells. Clinical symptoms of CDI range from mild diarrhea to potentially life-threatening conditions like pseudomembranous colitis or toxic megacolon. While antibiotics are still the treatment of choice for CDI, new therapies have emerged in recent years such as antibodies against C. difficile toxin B and fecal microbial transfer (FMT). This specific therapy for CDI underscores the role of the indigenous bacterial composition in the prevention of the disease in healthy individuals and its role in the pathogenesis after alteration by antibiotic treatment. In addition to the pathogenesis of CDI, this review focuses on the colonization of C. difficile in the human gut and factors promoting CDI.

Understanding Clostridium difficile Colonization

Clostridium difficile is the main causative agent of antibiotic-associated and health care-associated infective diarrhea. Recently, there has been growing interest in alternative sources of C. difficile other than patients with Clostridium difficile infection (CDI) and the hospital environment. Notably, the role of C. difficile-colonized patients as a possible source of transmission has received attention. In this review, we present a comprehensive overview of the current understanding of C. difficile colonization. Findings from gut microbiota studies yield more insights into determinants that are important for acquiring or resisting colonization and progression to CDI. In discussions on the prevalence of C. difficile colonization among populations and its associated risk factors, colonized patients at hospital admission merit more attention, as findings from the literature have pointed to their role in both health care-associated transmission of C. difficile and a higher risk of progression to CDI once admitted. C. difficile colonization among patients at admission may have clinical implications, although further research is needed to identify if interventions are beneficial for preventing transmission or overcoming progression to CDI.

Clostridium difficile - From Colonization to Infection

Clostridium difficile is the most frequent cause of nosocomial antibiotic-associated diarrhea. The incidence of C. difficile infection (CDI) has been rising worldwide with subsequent increases in morbidity, mortality, and health care costs. Asymptomatic colonization with C. difficile is common and a high prevalence has been found in specific cohorts, e.g., hospitalized patients, adults in nursing homes and in infants. However, the risk of infection with C. difficile differs significantly between these cohorts. While CDI is a clear indication for therapy, colonization with C. difficile is not believed to be a direct precursor for CDI and therefore does not require treatment. Antibiotic therapy causes alterations of the intestinal microbial composition, enabling C. difficile colonization and consecutive toxin production leading to disruption of the colonic epithelial cells. Clinical symptoms of CDI range from mild diarrhea to potentially life-threatening conditions like pseudomembranous colitis or toxic megacolon. While antibiotics are still the treatment of choice for CDI, new therapies have emerged in recent years such as antibodies against C. difficile toxin B and fecal microbial transfer (FMT). This specific therapy for CDI underscores the role of the indigenous bacterial composition in the prevention of the disease in healthy individuals and its role in the pathogenesis after alteration by antibiotic treatment. In addition to the pathogenesis of CDI, this review focuses on the colonization of C. difficile in the human gut and factors promoting CDI.

Point-prevalence survey of healthcare facility-onset healthcare-associated Clostridium difficile infection in Greek hospitals outside the intensive care unit: The C. DEFINE study

BACKGROUND

The correlation of Clostridium difficile infection (CDI) with in-hospital morbidity is important in hospital settings where broad-spectrum antimicrobial agents are routinely used, such as in Greece. The C. DEFINE study aimed to assess point-prevalence of CDI in Greece during two study periods in 2013.

METHODS

There were two study periods consisting of a single day in March and another in October 2013. Stool samples from all patients hospitalized outside the ICU aged ≥18 years old with diarrhea on each day in 21 and 25 hospitals, respectively, were tested for CDI. Samples were tested for the presence of glutamate dehydrogenase antigen (GDH) and toxins A/B of C. difficile; samples positive for GDH and negative for toxins were further tested by culture and PCR for the presence of toxin genes. An analysis was performed to identify potential risk factors for CDI among patients with diarrhea.

RESULTS

5,536 and 6,523 patients were screened during the first and second study periods, respectively. The respective point-prevalence of CDI in all patients was 5.6 and 3.9 per 10,000 patient bed-days whereas the proportion of CDI among patients with diarrhea was 17% and 14.3%. Logistic regression analysis revealed that solid tumor malignancy [odds ratio (OR) 2.69, 95% confidence interval (CI): 1.18-6.15, p = 0.019] and antimicrobial administration (OR 3.61, 95% CI: 1.03-12.76, p = 0.045) were independent risk factors for CDI development. Charlson's Comorbidity Index (CCI) >6 was also found as a risk factor of marginal statistical significance (OR 2.24, 95% CI: 0.98-5.10). Median time to CDI from hospital admission was shorter with the presence of solid tumor malignancy (3 vs 5 days; p = 0.002) and of CCI >6 (4 vs 6 days, p = 0.009).

CONCLUSIONS

The point-prevalence of CDI in Greek hospitals was consistent among cases of diarrhea over a 6-month period. Major risk factors were antimicrobial use, solid tumor malignancy and a CCI score >6.

The Impact of a Computerized Clinical Decision Support Tool on Inappropriate Clostridium difficile Testing

OBJECTIVE

To evaluate the effectiveness of a computerized clinical decision support intervention aimed at reducing inappropriate Clostridium difficile testing

DESIGN

Retrospective cohort study

SETTING

University of Pennsylvania Health System, comprised of 3 large tertiary-care hospitals

PATIENTS

All adult patients admitted over a 2-year period

INTERVENTION

Providers were required to use an order set integrated into a commercial electronic health record to order C. difficile toxin testing. The order set identified patients who had received laxatives within the previous 36 hours and displayed a message asking providers to consider stopping laxatives and reassessing in 24 hours prior to ordering C. difficile testing. Providers had the option to continue or discontinue laxatives and to proceed with or forgo testing. The primary endpoint was the change in inappropriate C. difficile testing, as measured by the number of patients who had C. difficile testing ordered while receiving laxatives.

RESULTS

Compared to the 1-year baseline period, the intervention resulted in a decrease in the proportion of inappropriate C. difficile testing (29.6% vs 27.3%; P=.02). The intervention was associated with an increase in the number of patients who had laxatives discontinued and did not undergo C. difficile testing (5.8% vs 46.4%; P<.01) and who had their laxatives discontinued and underwent testing (5.4% vs 35.2%; P<.01). We observed a nonsignificant increase in the proportion of patients with C. difficile related complications (5.0% vs 8.9%; P=.11).

CONCLUSIONS

A C. difficile order set was successful in decreasing inappropriate C. difficile testing and improving the timely discontinuation of laxatives.

Infect Control Hosp Epidemiol 2017;38:1204–1208

A mathematical model of Clostridium difficile transmission in medical wards and a cost-effectiveness analysis comparing different strategies for laboratory diagnosis and patient isolation

BACKGROUND

Clostridium difficile infection (CDI) is a common and potentially fatal healthcare-associated infection. Improving diagnostic tests and infection control measures may prevent transmission. We aimed to determine, in resource-limited settings, whether it is more effective and cost-effective to allocate resources to isolation or to diagnostics.

METHODS

We constructed a mathematical model of CDI transmission based on hospital data (9 medical wards, 350 beds) between March 2010 and February 2013. The model consisted of three compartments: susceptible patients, asymptomatic carriers and CDI patients. We used our model results to perform a cost-effectiveness analysis, comparing four strategies that were different combinations of 2 test methods (the two-step test and uniform PCR) and 2 infection control measures (contact isolation in multiple-bed rooms or single-bed rooms/cohorting). For each strategy, we calculated the annual cost (of CDI diagnosis and isolation) for a decrease of 1 in the average daily number of CDI patients; the strategy of the two-step test and contact isolation in multiple-bed rooms was the reference strategy.

RESULTS

Our model showed that the average number of CDI patients increased exponentially as the transmission rate increased. Improving diagnosis by adopting uniform PCR assay reduced the average number of CDI cases per day per 350 beds from 9.4 to 8.5, while improving isolation by using single-bed rooms reduced the number to about 1; the latter was cost saving.

CONCLUSIONS

CDI can be decreased by better isolation and more sensitive laboratory methods. From the hospital perspective, improving isolation is more cost-effective than improving diagnostics.

Detection of Clostridium difficile in Feces of Asymptomatic Patients Admitted to the Hospital

Recent evidence shows that patients asymptomatically colonized with Clostridium difficile may contribute to the transmission of C. difficile in health care facilities. Additionally, these patients may have a higher risk of developing C. difficile infection. The aim of this study was to compare a commercially available PCR directed to both toxin A and B (artus C. difficile QS-RGQ kit CE; Qiagen), an enzyme-linked fluorescent assay to glutamate dehydrogenase (GDH ELFA) (Vidas, bioMérieux), and an in-house-developed PCR to tcdB, with (toxigenic) culture of C. difficile as the gold standard to detect asymptomatic colonization. Test performances were evaluated in a collection of 765 stool samples obtained from asymptomatic patients at admission to the hospital. The C. difficile prevalence in this collection was 5.1%, and 3.1% contained toxigenic C. difficile Compared to C. difficile culture, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the C. difficile GDH ELFA were 87.2%, 91.2%, 34.7%, and 99.3%, respectively. Compared with results of toxigenic culture, the sensitivity, specificity, PPV, and NPV of the commercially available PCR and the in-house PCR were 95.8%, 93.4%, 31.9%, 99.9%, and 87.5%, 98.8%, 70%, and 99.6%, respectively. We conclude that in a low-prevalence setting of asymptomatically colonized patients, both GDH ELFA and a nucleic acid amplification test can be applied as a first screening test, as they both display a high NPV. However, the low PPV of the tests hinders the use of these assays as stand-alone tests.

Asymptomatic and yet C. difficile-toxin positive? Prevalence and risk factors of carriers of toxigenic Clostridium difficile among geriatric in-patients

Background

Clostridium difficile infections (CDI) are the most frequent cause of diarrhoea in hospitals. Geriatric patients are more often affected by the condition, by a relapse and complications. Therefore, a crucial question is how often colonization with toxigenic Clostridium difficile strains occurs in elderly patients without diarrhoea and whether there is a “risk pattern” of colonized patients that can be defined by geriatric assessment. Furthermore, the probability for those asymptomatic carriers to develop a symptomatic infection over time has not been sufficiently explored.

Methods

We performed a cohort study design to assess the association of clinical variables with Clostridium difficile colonization. The first stool sample of 262 consecutive asymptomatic patients admitted to a geriatric unit was tested for toxigenic Clostridium difficile using PCR (GeneXpert, Cepheid). A comprehensive geriatric assessment (CGA) including Barthel Index, Mini Mental State Examination (MMSE) and hand grip-strength was performed. In addition, Charlson Comorbidity Index, body mass index, number and length of previous hospital stays, previous treatment with antibiotics, institutionalization, primary diagnoses and medication were recorded and evaluated as possible risk factors of colonization by means of binary logistic regression. Secondly, we explored the association of C. difficile colonization with subsequent development of CDI during hospital stay.

Results

At admission, 43 (16.4%) patients tested positive for toxin B by PCR. Seven (16.3%) of these colonized patients developed clinical CDI during hospital stay, compared to one out of 219 patients with negative or invalid PCR testing (Odds ratio 12,3; Fisher’s exact test: p = 0.000). Overall, 7 out of 8 (87.5%) CDI patients had been colonized at admission. Risk factors of colonization with C. difficile were a history of CDI, previous antibiotic treatment and hospital stays. The parameters of the CGA were not significantly associated with colonization.

Conclusion

Colonization with toxigenic Clostridium difficile strains occurs frequently in asymptomatic patients admitted to a geriatric unit. Previous CDI, antibiotic exposure and hospital stay, but not clinical variables such as CGA, are the main factors associated with asymptomatic Clostridium difficile carriage. Colonization is a crucial risk factor for subsequent development of symptomatic CDI.

Isolation of C. difficile Carriers Alone and as Part of a Bundle Approach for the Prevention of Clostridium difficile Infection (CDI): A Mathematical Model Based on Clinical Study Data

Clostridium difficile infection is the most common hospital-acquired infection. Besides infected patients, carriers have emerged as a key player in C. difficile epidemiology. In this study, we evaluated the impact of identifying and isolating carriers upon hospital admission on the incidence of CDI incidence and hospital-acquired C. difficile colonization, as a single policy and as part of bundle approaches. We simulated C. difficile transmission using a stochastic mathematical approach, considering the contribution of carriers based on published literature. In the baseline scenario, CDI incidence was 6.18/1,000 admissions (95% CI, 5.72–6.65), simulating reported estimates from U.S. hospital discharges. The acquisition rate of C. difficile carriage was 9.72/1,000 admissions (95% CI, 9.15–10.31). Screening and isolation of colonized patients on admission to the hospital decreased CDI incidence to 4.99/1,000 admissions (95% CI, 4.59–5.42; relative reduction (RR) = 19.1%) and led to 36.2% reduction in the rate of hospital-acquired colonization. Simulating an antimicrobial stewardship program reduced CDI rate to 2.35/1,000 admissions (95% CI, 2.07–2.65). In sensitivity analysis, CDI incidence was less than 2.32/1,000 admissions (RR = 62.4%) in 95% of 1,000 simulations. The combined bundle, focusing on reducing C. difficile transmission from colonized patients and the individual risk of these patients to develop CDI, decreased significantly the incidence of both CDI and hospital-acquired colonization. Implementation of this bundle to current practice is expected to have an important impact in containing CDI.

Asymptomatic Clostridium difficile colonization: epidemiology and clinical implications

BACKGROUND

The epidemiology of Clostridium difficile infection (CDI) has changed over the past decades with the emergence of highly virulent strains. The role of asymptomatic C. difficile colonization as part of the clinical spectrum of CDI is complex because many risk factors are common to both disease and asymptomatic states. In this article, we review the role of asymptomatic C. difficile colonization in the progression to symptomatic CDI, describe the epidemiology of asymptomatic C. difficile colonization, assess the effectiveness of screening and intensive infection control practices for patients at risk of asymptomatic C. difficile colonization, and discuss the implications for clinical practice.

METHODS

A narrative review was performed in PubMed for articles published from January 1980 to February 2015 using search terms 'Clostridium difficile' and 'colonization' or 'colonisation' or 'carriage'.

RESULTS

There is no clear definition for asymptomatic CDI and the terms carriage and colonization are often used interchangeably. The prevalence of asymptomatic C. difficile colonization varies depending on a number of host, pathogen, and environmental factors; current estimates of asymptomatic colonization may be underestimated as stool culture is not practical in a clinical setting.

CONCLUSIONS

Asymptomatic C. difficile colonization presents challenging concepts in the overall picture of this disease and its management. Individuals who are colonized by the organism may acquire protection from progression to disease, however they also have the potential to contribute to transmission in healthcare settings.

Pitfalls in Diagnosis of Pediatric Clostridium difficile Infection

The incidence of Clostridium difficile infection (CDI) has risen among children and C difficile is increasingly recognized as an important cause of healthcare-associated diarrhea among pediatric patients. Still, increased identification of CDI in healthy children in the community and increased testing among infants requires cautious interpretation, given the high prevalence of asymptomatic colonization in young infants and frequent detection of viruses and other co-pathogens in stool specimens in these age groups. The significance of CDI among infants and the implications of positive C difficile testing among healthy children in the community are areas in need of further study.

Practical Guidance for Clinical Microbiology Laboratories: Diagnosis of Bacterial Gastroenteritis

Bacterial gastroenteritis is a disease that is pervasive in both the developing and developed worlds. While for the most part bacterial gastroenteritis is self-limiting, identification of an etiological agent by bacterial stool culture is required for the management of patients with severe or prolonged diarrhea, symptoms consistent with invasive disease, or a history that may predict a complicated course of disease. Importantly, characterization of bacterial enteropathogens from stool cultures in clinical laboratories is one of the primary means by which public health officials identify and track outbreaks of bacterial gastroenteritis. This article provides guidance for clinical microbiology laboratories that perform stool cultures. The general characteristics, epidemiology, and clinical manifestations of key bacterial enteropathogens are summarized. Information regarding optimal specimen collection, transport, and processing and current diagnostic tests and testing algorithms is provided. This article is an update of Cumitech 12A (P. H. Gilligan, J. M. Janda, M. A. Karmali, and J. M. Miller, Cumitech 12A, Laboratory diagnosis of bacterial diarrhea, 1992).

Optimizing the Laboratory Diagnosis of Clostridium difficile Infection

The best laboratory diagnostic approach to detect Clostridium difficile infection (CDI) is the subject of ongoing debate. In the United States, nucleic acid amplification tests (NAAT) have become the most widely used tests for making this diagnosis. Detection of toxin in stool may be a better predictor of CDI disease and severity. Laboratories that have switched from toxin-based to NAAT-based methods have significantly higher CDI detection rates. The important issue is whether all NAAT-positive patients have CDI or at least some of those patients are excretors of the organism and do not have clinical disease.

Colonization with toxinogenic C. difficile upon hospital admission, and risk of infection: a systematic review and meta-analysis

OBJECTIVES

It has been suggested that colonization with C. difficile protects from infection. Nevertheless, the association between carriage of toxinogenic strains and ensuing C. difficile infections (CDIs) has not been studied.

METHODS

We searched PubMed and EMBASE databases up to 20 June 2014, using the term "difficile". Our primary outcomes of interest included the prevalence of isolation of toxinogenic C. difficile or its toxins from asymptomatic patients on hospital admission through stool or rectal swab testing and the risk of ensuing infection among colonized and noncolonized patients. Data on previous hospitalization, antibiotic, and proton pump inhibitor (PPI) use and prior CDIs among colonized and noncolonized patients were also extracted.

RESULTS

Nineteen out of 26,081 studies on 8,725 patients were included. The pooled prevalence of toxinogenic C. difficile colonization was 8.1% (95% confidence interval (CI) 5.7-11.1%), with an increasing trend over time (P=0.003), and 10.0% (95% CI 7.1-13.4%) among North American studies. Patients colonized upon hospital admission had a 5.9 times higher risk of subsequent CDIs compared with noncolonized patients (relative risk (RR) 5.86; 95% CI 4.21-8.16). The risk of CDI for colonized patients was 21.8% (95% CI 7.9-40.1%), which was significantly higher than that of noncolonized patients (3.4%; 95% CI 1.5-6.0%; P=0.03), with an attributable risk of 18.4%. History of hospitalization during the previous 3 months was associated with a higher risk of colonization (RR 1.63; 95% CI 1.13-2.34), as opposed to previous antibiotic (RR 1.07; 95% CI 0.75-1.53) and PPI use (RR 1.44; 95% CI 0.94-2.23), as well as history of CDI (RR 1.45; 95% CI 0.66-3.18) that had no impact.

CONCLUSIONS

Over 8% of admitted patients are carriers of toxinogenic C. difficile with an almost 6 times higher risk of infection. These findings update current knowledge regarding the contribution of colonization in CDI epidemiology and stress the importance of preventive measures toward colonized patients.

Clostridium difficile in the Long-Term Care Facility: Prevention and Management

Residents of long-term care facilities are at high risk for Clostridium difficile infection due to frequent antibiotic exposure in a population already rendered vulnerable to infection due to advanced age, multiple comorbid conditions and communal living conditions. Moreover, asymptomatic carriage of toxigenic C. difficile and recurrent infections are prevalent in this population. Here, we discuss epidemiology and management of C. difficile infection among residents of long-term care facilities. Also, recognizing that both the population and culture differs significantly from that of hospitals, we also address prevention strategies specific to LTCFs.

Colonization versus carriage of Clostridium difficile

Asymptomatic carriage of toxigenic strains of Clostridium difficile is common in health care facilities and the community. However, infection control efforts have traditionally focused almost entirely on symptomatic patients. There is now growing concern that asymptomatic carriers may be an underappreciated source of transmission. This article provides an overview of the pathogenesis and epidemiology of C difficile colonization, reviews the evidence that asymptomatic carriers shed spores and contribute to transmission, and examines practical issues related to prevention of transmission from carriers.

Whole genome sequencing reveals potential spread of Clostridium difficile between humans and farm animals in the Netherlands, 2002 to 2011

Farm animals are a potential reservoir for human Clostridium difficile infection (CDI), particularly PCR ribotype 078 which is frequently found in animals and humans. Here, whole genome single-nucleotide polymorphism (SNP) analysis was used to study the evolutionary relatedness of C. difficile 078 isolated from humans and animals on Dutch pig farms. All sequenced genomes were surveyed for potential antimicrobial resistance determinants and linked to an antimicrobial resistance phenotype. We sequenced the whole genome of 65 C. difficile 078 isolates collected between 2002 and 2011 from pigs (n = 19), asymptomatic farmers (n = 15) and hospitalised patients (n = 31) in the Netherlands. The collection included 12 pairs of human and pig isolates from 2011 collected at 12 different pig farms. A mutation rate of 1.1 SNPs per genome per year was determined for C. difficile 078. Importantly, we demonstrate that farmers and pigs were colonised with identical (no SNP differences) and nearly identical (less than two SNP differences) C. difficile clones. Identical tetracycline and streptomycin resistance determinants were present in human and animal C. difficile 078 isolates. Our observation that farmers and pigs share identical C. difficile strains suggests transmission between these populations, although we cannot exclude the possibility of transmission from a common environmental source.

Clostridium difficile carriage in hospitalized cancer patients: a prospective investigation in eastern China

BACKGROUND

Clostridium difficile carriage has been considered as a potential source for the deadly infection, but its role in cancer patients is still unclear. We aimed to identify the clinical and immunological factors that are related to C. difficile carriage in Chinese cancer patients.

METHODS

A total of 400 stool samples were collected from cancer patients who received chemotherapy in three hospitals of eastern China. Bacterial genomic DNA was extracted and two toxin genes (tcdA and tcdB) were detected. PCR ribotyping was performed using capillary gel electrophoresis. Concentrations of prostaglandin E2 (PGE2), transforming growth factor beta (TGF-β) and interleukin-10 (IL-10) were measured using enzyme-linked immunosorbent assay (ELISA) kits.

RESULTS

Eighty-two (20.5%) samples were confirmed to be C. difficile-positive and positive for tpi, tcdA, and tcdB genes. The C. difficile-positive rates in patients with diarrhea and no diarrhea were 35% and 19.7%, respectively (p = 0.09). Patients who were younger than 50 years old and were hospitalized for at least 10 days had a C. difficile-positive rate as high as 35%. In contrast, patients who were older than 50 years old and were hospitalized for less than 10 days had a C. difficile-positive rate of only 12.7% (p = 0.0009). No association was found between C. difficile carriage and chemotherapy regimen, antibiotic drug use, or immunosuppressive mediators, such as prostaglandin E2 (PGE2), transforming growth factor beta (TGF-β), or interleukin-10 (IL-10). Twelve ribotypes of C. difficile were identified, but none of them belonged to ribotype 027.

CONCLUSIONS

We conclude that younger patients and those with longer hospitalization stays may be more prone to C. difficile carriage. Studies of larger populations are warranted to clarify the exact role of C. difficile carriage in hospitalized cancer patients in China.

Point-of-Care Testing for Clostridium Difficile Infection: A Real-World Feasibility Study of a Rapid Molecular Test in Two Hospital Settings

Introduction

In the developed world, Clostridium difficile infection (CDI) is the most important cause of nosocomial infectious diarrhea. In addition to providing epidemiological data and helping to indicate that a local outbreak may be occurring, laboratory tests are used to augment clinical decisions on individual patients. Very rarely do diagnostic tests provide results at the point of decision making; in the intervening period between requesting investigations on a patient with suspected CDI and return of the laboratory result, decisions must be made regarding patient isolation and treatment.

Methods

A 22-month, real-world feasibility study was conducted in patients with clinically significant diarrhea, in a London Hospital between March 2011 and January 2013, in three older persons’ wards and two intensive care units (ICUs) to determine acceptability, ease of use, change in turnaround time and clinical utility of a rapid, polymerase chain reaction (PCR)-based point-of-care test (POCT) (Cepheid GeneXpert^®, Sunnyvale, California, USA) for diagnosis of Clostridium difficile. Nurses in the older persons’ ward and laboratory technicians in the ICU were trained to perform the test. Residual samples were sent to the centralized laboratory for parallel testing using a two-step algorithm.

Results

A total of 335 samples were tested using the POCT with a median turnaround time of 1.85 h compared with 18 h for the centralized laboratory test. Overall agreement with centralized laboratory testing was 98.1%. Discrepant samples were more frequent on elderly wards than ICU. Overall 20/335 (6%) processing errors were encountered and were highest in the first few months of the study. Significantly more processing errors occurred on the older persons’ wards 13/102 (12.7%) than on ICU 7/271 (2.6%). Older persons’ patients who had POCT were significantly less likely to have a test requested for bacterial stool culture (3.1% vs. 10.9% p = 0.044). This difference was not observed in the ICU patients. No other differences in ancillary test requesting, mortality or length of stay were observed.

Conclusions

The majority of users reported that the POCT was easy to perform and was an acceptable part of their job. POCT using this system is feasible and acceptable to nursing staff and technicians working within these two hospital-based settings.

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-014-0038-6) contains supplementary material, which is available to authorized users.