The rise in Clostridium difficile infection incidence among hospitalized adults in the United States: 2001-2010

BACKGROUND

Clostridium difficile infection (CDI) incidence is a growing concern. This study provides national estimates of CDI over 10 years and identifies trends in mortality and hospital length of stay (LOS) among hospitalized adults with CDI.

METHODS

We conducted a retrospective analysis of the US National Hospital Discharge Surveys from 2001-2010. Eligible cases included adults aged ≥ 18 years discharged from a hospital with an ICD-9-CM diagnosis code for CDI (008.45). Data weights were used to derive national estimates. CDI incidence rates were depicted as CDI discharges per 1,000 total adult discharges.

RESULTS

These data represent 2.2 million adult hospital discharges for CDI over the study period. CDI incidence increased from 4.5 CDI discharges per 1,000 total adult discharges in 2001 to 8.2 CDI discharges per 1,000 total adult discharges in 2010. The overall in-hospital mortality rate was 7.1% for the study period. Mortality increased slightly over the study period, from 6.6% in 2001 to 7.2% in 2010. Median hospital LOS was 8 days (interquartile range, 4-14 days), and remained stable over the study period.

CONCLUSIONS

The incidence of CDI among hospitalized adults in the United States nearly doubled from 2001-2010. Furthermore, there is little evidence of improvement in patient mortality or hospital LOS.

Multi-institution case-control and cohort study of risk factors for the development and mortality of Clostridium difficile infections in Japan

OBJECTIVE

To examine risk factors for Clostridium difficile infection (CDI) morbidity and mortality in Japan.

DESIGN

Multimethod investigation including a case-control study and cohort study.

SETTING

47 participating facilities of the National Hospital Organization (NHO).

PARTICIPANTS

1026 patients with CDI and 878 patients in the control group over the age of 18 years admitted to the subject NHO facilities from November 2010 to October 2011.

MAIN OUTCOME MEASURES

In a case-control study, we identify risk factors for CDI development. Next, in a cohort study, we identify risk factors for all-cause mortality within 30 days following CDI onset.

RESULTS

A total of 1026 cases of CDI meeting the definitions of this investigation were identified, encompassing 878 patients at 42 of the 47 subject facilities. In the case-control study, we identified, compared with no antibiotics use, use of first-generation and second-generation cephem antibiotics (OR 1.44; 95% CI 1.10 to 1.87), use of third-generation and fourth-generation cephem antibiotics (OR 1.86; 95% CI 1.48 to 2.33) and use of carbapenem antibiotics (OR 1.87; 95% CI 1.44 to 2.42) the risk factors for CDI development. However, use of penicillin was not identified as a risk factor. In the cohort study, sufficient data for analysis was available for 924 CDI cases; 102 of them (11.0%) resulted in death within 30 days of CDI onset. Compared with no anti-CDI drug use, use of vancomycin was associated with reduced risk of mortality (OR 0.43; 95% CI 0.25 to 0.75) whereas metronidazole was not.

CONCLUSIONS

The findings mirror those of previous studies from Europe and North America, identifying the administration of broad-spectrum antibiotics as a risk factor for CDI development. The use of vancomycin is associated with a decreased risk of mortality.

Clostridium difficile infection and inflammatory bowel disease: what gastroenterologists and surgeons should know

Over the past two decades there has been a dramatic increase worldwide in both incidence and severity of Clostridium difficile infection (CDI). Paralleling the rising incidence of CDI in the general population, there has been an even higher increase in the incidence of CDI among patients with inflammatory bowel disease (IBD). CDI may mimic a flare of IBD as symptoms and laboratory parameters are often similar, and therefore, screening for CDI is recommended at every flare in such patients. Enzyme immunoassay to detect Clostridium difficile toxin A and B in stool is still the most widely used test for CDI diagnosis despite its low sensitivity. Metronidazole for mild/moderate CDI,and vancomycin for severe CDI are the preferred agents for the treatment of infection. CDI has a negative impact both on short- and long- term IBD outcomes, increasing the need for surgery, as well as the mortality rate and healthcare costs. All gastroenterologists and surgeons should have a high index of suspicion for CDI when evaluating a patient with IBD flare, as prompt diagnosis and adequate treatment of infection improve outcomes. Measures must be taken to prevent spreading of infection in gastroenterology /surgery settings.

The magnitude and duration of Clostridium difficile infection risk associated with antibiotic therapy: a hospital cohort study

Antibiotic therapy is the principal risk factor for Clostridium difficile infection (CDI), but little is known about how risks cumulate over the course of therapy and abate after cessation. We prospectively identified CDI cases among adults hospitalized at a tertiary hospital between June 2010 and May 2012. Poisson regression models included covariates for time since admission, age, hospitalization history, disease pressure, and intensive care unit stay. Impacts of antibiotic use through time were modeled using 4 measures: current antibiotic receipt, time since most recent receipt, time since first receipt during a hospitalization, and duration of receipt. Over the 24-month study period, we identified 127 patients with new onset nosocomial CDI (incidence rate per 10,000 patient days [IR] = 5.86). Of the 4 measures, time since most recent receipt was the strongest independent predictor of CDI incidence. Relative to patients with no prior receipt of antibiotics in the last 30 days (IR = 2.95), the incidence rate of CDI was 2.41 times higher (95% confidence interval [CI] 1.41, 4.13) during antibiotic receipt and 2.16 times higher when patients had receipt in the prior 1–5 days (CI 1.17, 4.00). The incidence rates of CDI following 1–3, 4–6 and 7–11 days of antibiotic exposure were 1.60 (CI 0.85, 3.03), 2.27 (CI 1.24, 4.16) and 2.10 (CI 1.12, 3.94) times higher compared to no prior receipt. These findings are consistent with studies showing higher risk associated with longer antibiotic use in hospitalized patients, but suggest that the duration of increased risk is shorter than previously thought.

Development and validation of a recurrent Clostridium difficile risk-prediction model

BACKGROUND

Recurrent Clostridium difficile infection (rCDI) affects 10% to 25% of patients with initial CDI (iCDI). Initiation of new therapies that reduce recurrences rests on identifying patients at high risk for rCDI at iCDI onset.

OBJECTIVE

To develop a predictive model for rCDI based on factors present at iCDI onset.

DESIGN

Retrospective cohort study.

SETTING

Large urban academic medical center.

PATIENTS

All adult patients with an inpatient iCDI from January 1, 2003 to December 31, 2009.

INTERVENTION

None.

MEASUREMENTS

Positive toxin assay for C difficile with no C difficile infection in the previous 60 days constituted iCDI. Repeat positive toxin within 42 days of stopping iCDI treatment defined rCDI. Three demographic, 13 chronic, and 12 acute disease characteristics, and 7 processes of care prior to or at the onset of iCDI, were assessed for association with rCDI. A logistic regression model to identify predictors for rCDI was developed and cross-validated.

RESULTS

Among the 4196 patients enrolled, 425 (10.1%) developed rCDI. Six factors (case status as community-onset healthcare-associated, ≥2 hospitalizations in the prior 60 days, new gastric acid suppression, fluoroquinolone and high-risk antibiotic use at the onset of iCDI, age) predicted rCDI in multivariate analyses, whereas intensive care unit stay appeared protective. The model achieved moderate discrimination (C statistic 0.643) and calibration (Brier score 0.089). Its negative predictive value was 90% or higher across a wide range of risk.

CONCLUSIONS

Among patients hospitalized with rCDI, multiple factors present at the onset of iCDI increased the risk for rCDI. Recognizing patients at high-risk for rCDI can help clinicians tailor early treatment and prevention.

[Diarrhea associated with Clostridium difficile in the elderly: new perspectives]

Infection due to Clostridium difficile is currently the main cause of hospital acquired gastrointestinal disease. Its prevalence in the elderly population is higher due to there being many associated risk factors in this age group, such as comorbidity, frequent exposure to the healthcare or residential home setting, immunosenescence, greater consumption of antibiotics, and antiacids. The diagnostic techniques have notably improved in the last few years, which could also account for an increase in its diagnosis. The new expert consensus recommendations propose stratifying the clinical situation of the patient in order to choose the treatment option. Therapeutic options have recently been included in the new Clinical Guidelines, such as flidaxomicin or fecal transplants, with encouraging results, particularly for the control of frequent recurrences.

A population-based spatio-temporal analysis of Clostridium difficile infection in Queensland, Australia over a 10-year period

OBJECTIVES

To identify the spatio-temporal patterns and environmental factors associated with Clostridium difficile infection (CDI) in Queensland, Australia.

METHODS

Data from patients tested for CDI were collected from 392 postcodes across Queensland between May 2003 and December 2012. A binomial logistic regression model, with CDI status as the outcome, was built in a Bayesian framework, incorporating fixed effects for sex, age, source of the sample (healthcare facility or community), elevation, rainfall, land surface temperature, seasons of the year, time in months and spatially unstructured random effects at the postcode level.

RESULTS

C. difficile was identified in 13.1% of the samples, the proportion significantly increased over the study period from 5.9% in 2003 to 18.8% in 2012. CDI peaked in summer (14.6%) and was at its lowest in autumn (10.1%). Other factors significantly associated with CDI included female sex (OR: 1.08; 95%CI: 1.01-1.14), community source samples (OR: 1.12; 95%CI: 1.05-1.20), and higher rainfall (OR: 1.09; 95%CI: 1.02-1.17). There was no significant spatial variation in CDI after accounting for the fixed effects in the model.

CONCLUSIONS

There was an increasing annual trend in CDI in Queensland from 2003 to 2012. Peaks of CDI were found in summer (December-February), which is at odds with the current epidemiological pattern described for northern hemisphere countries. Epidemiologically plausible explanations for this disparity require further investigation.

[Epidemiology of Clostridium difficile-associated disease (CDAD) in Salamanca]

INTRODUCTION

Clostridium difficile infection is considered a major cause of nosocomial diarrhoea in developed countries and is increasingly becoming more important as an etiologic agent of community diarrhoea, also in patients without risk factors.

METHOD

Beginning in May 2011, the aim of our study is to know the characteristics of patients suffering from C. difficile Associated Disease in Salamanca University Hospital, collecting their data in a survey conducted for this purpose. A case was defined as a patient with compatible clinical and positive microbiological diagnosis.

RESULTS

After 18 months of study, 41 cases had been documented representing an incidence of 1.15 cases per 10,000 patient-days. Patients were hospitalized (37) or health care associated (4), females (54%), age ≥ 65 years (56%) with prior antibiotic treatment (80%), most had diarrhea after the third day of admission, less than three weeks and without blood. Most were treated with metronidazole alone (78%), 19% with metronidazole and vancomycin, and the remaining percentage was resolved without treatment. Recurrences were about 20% and 7 (17%) died.

CONCLUSIONS

The characteristics of our patients with C. difficile - associated disease are the same as those reported by other authors. Local surveillance is important in order to study the endemic and epidemic C. difficile infection. According to published epidemiological changes, we should be able to develop strategies from the Microbiology laboratories that will improve diagnosis of the disease.

Antibiotic resistance of Clostridium perfringens isolates from broiler chickens in Egypt

The use of antibiotic feed additives in broiler chickens results in a high prevalence of resistance among their enteric bacteria, with a consequent emergence of antibiotic resistance in zoonotic enteropathogens. Despite growing concerns about the emergence of antibiotic-resistant strains, which show varying prevalences in different geographic regions, little work has been done to investigate this issue in the Middle East. This study provides insight into one of the world's most common and financially crippling poultry diseases, necrotic enteritis caused by Clostridium perfringens. The study was designed to determine the prevalence of antibiotic resistance in C. perfringens isolates from clinical cases of necrotic enteritis in broiler chickens in Egypt. A total of 125 isolates were obtained from broiler flocks in 35 chicken coops on 17 farms and were tested using the disc diffusion method. All 125 isolates were resistant to gentamicin, streptomycin, oxolinic acid, lincomycin, erythromycin and spiramycin. The prevalence of resistance to other antibiotics was also high: rifampicin (34%), chloramphenicol (46%), spectinomycin (50%), tylosin-fosfomycin (52%), ciprofloxacin (58%), norfloxacin (67%), oxytetracycline (71%), flumequine (78%), enrofloxacin (82%), neomycin (93%), colistin (94%), pefloxacin (94%), doxycycline (98%) and trimethoprim-sulfamethoxazole (98%). It is recommended that C. perfringens infections in Egypt should be treated with antibiotics for which resistant isolates are rare at present; namely, amoxicillin, ampicillin, cephradine, fosfomycin and florfenicol.

Clinical characteristics of Clostridium difficile infection in hospitalized patients with antibiotic-associated diarrhea in a university hospital in China

The purpose of this study was to identify clinical characteristics of Clostridium difficile infection (CDI) in patients with antibiotic-associated diarrhea (AAD). A prospective study was conducted among patients hospitalized in Fudan University Hospital Huashan from August 1, 2012 to July 31, 2013. Toxigenic C. difficile isolates were characterized by PCR ribotyping and multilocus sequence typing. AAD developed in 1.0 % (206/20437) of the antibiotic-treated hospitalized patients and toxigenic C. difficile was isolated from 30.6 % (63/206) of patients with AAD. The frequency of AAD was highest in the intensive care unit (10.7 %); however the proportion of CDI in AAD was highest in the Geriatric Unit (38 %). AAD ranged in severity from mild to moderate. One case with pseudomembranous colitis was identified. Use of carbapenems was found to significantly increase the risk of CDI (OR, 2.31; 95 % CI, 1.22-4.38; p = 0.011). Patient demographics, presumed risk factors, clinical manifestations and laboratory findings revealed no significant difference between patients with CDI and non-C. difficile AAD. Over 90 % of the patients with CDI or non-C. difficile AAD were cured. Two patients had CDI recurrence. Ribotype H was the dominant (18.8 %) genotype, followed by ribotype 012 and ribotype 017. C. difficile plays a significant role in AAD in our setting in China. Because the severity of diarrhea ranges from mild to moderate, it is difficult for Chinese clinicians to identify CDI from AAD patients, therefore CDI should be included in the routine differential diagnoses for hospitalized patients presenting with AAD.

Detection of Clostridium difficile infection clusters, using the temporal scan statistic, in a community hospital in southern Ontario, Canada, 2006-2011

BACKGROUND

In hospitals, Clostridium difficile infection (CDI) surveillance relies on unvalidated guidelines or threshold criteria to identify outbreaks. This can result in false-positive and -negative cluster alarms. The application of statistical methods to identify and understand CDI clusters may be a useful alternative or complement to standard surveillance techniques. The objectives of this study were to investigate the utility of the temporal scan statistic for detecting CDI clusters and determine if there are significant differences in the rate of CDI cases by month, season, and year in a community hospital.

METHODS

Bacteriology reports of patients identified with a CDI from August 2006 to February 2011 were collected. For patients detected with CDI from March 2010 to February 2011, stool specimens were obtained. Clostridium difficile isolates were characterized by ribotyping and investigated for the presence of toxin genes by PCR. CDI clusters were investigated using a retrospective temporal scan test statistic. Statistically significant clusters were compared to known CDI outbreaks within the hospital. A negative binomial regression model was used to identify associations between year, season, month and the rate of CDI cases.

RESULTS

Overall, 86 CDI cases were identified. Eighteen specimens were analyzed and nine ribotypes were classified with ribotype 027 (n = 6) the most prevalent. The temporal scan statistic identified significant CDI clusters at the hospital (n = 5), service (n = 6), and ward (n = 4) levels (P ≤ 0.05). Three clusters were concordant with the one C. difficile outbreak identified by hospital personnel. Two clusters were identified as potential outbreaks. The negative binomial model indicated years 2007-2010 (P ≤ 0.05) had decreased CDI rates compared to 2006 and spring had an increased CDI rate compared to the fall (P = 0.023).

CONCLUSIONS

Application of the temporal scan statistic identified several clusters, including potential outbreaks not detected by hospital personnel. The identification of time periods with decreased or increased CDI rates may have been a result of specific hospital events. Understanding the clustering of CDIs can aid in the interpretation of surveillance data and lead to the development of better early detection systems.

NAP1 strain type predicts outcomes from Clostridium difficile infection

BACKGROUND

Studies are conflicting regarding the importance of the fluoroquinolone-resistant North American pulsed-field gel electrophoresis type 1 (NAP1) strain in Clostridium difficile infection (CDI) outcome. We describe strain types causing CDI and evaluate their association with patient outcomes.

METHODS

CDI cases were identified from population-based surveillance. Multivariate regression models were used to evaluate the associations of strain type with severe disease (ileus, toxic megacolon, or pseudomembranous colitis within 5 days; or white blood cell count ≥15 000 cells/µL within 1 day of positive test), severe outcome (intensive care unit admission after positive test, colectomy for C. difficile infection, or death within 30 days of positive test), and death within 14 days of positive test.

RESULTS

Strain typing results were available for 2057 cases. Severe disease occurred in 363 (17.7%) cases, severe outcome in 100 (4.9%), and death within 14 days in 56 (2.7%). The most common strain types were NAP1 (28.4%), NAP4 (10.2%), and NAP11 (9.1%). In unadjusted analysis, NAP1 was associated with greater odds of severe disease than other strains. After controlling for patient risk factors, healthcare exposure, and antibiotic use, NAP1 was associated with severe disease (adjusted odds ratio [AOR], 1.74; 95% confidence interval [CI], 1.36-2.22), severe outcome (AOR, 1.66; 95% CI, 1.09-2.54), and death within 14 days (AOR, 2.12; 95% CI, 1.22-3.68).

CONCLUSIONS

NAP1 was the most prevalent strain and a predictor of severe disease, severe outcome, and death. Strategies to reduce NAP1 prevalence, such as antibiotic stewardship to reduce fluoroquinolone use, might reduce CDI morbidity.

Clostridium difficile infection among children across diverse US geographic locations

OBJECTIVE

Little is known about the epidemiology of Clostridium difficile infection (CDI) among children, particularly children ≤3 years of age in whom colonization is common but pathogenicity uncertain. We sought to describe pediatric CDI incidence, clinical presentation, and outcomes across age groups.

METHODS

Data from an active population- and laboratory-based CDI surveillance in 10 US geographic areas during 2010-2011 were used to identify cases (ie, residents with C difficile-positive stool without a positive test in the previous 8 weeks). Community-associated (CA) cases had stool collected as outpatients or ≤3 days after hospital admission and no overnight health care facility stay in the previous 12 weeks. A convenience sample of CA cases were interviewed. Demographic, exposure, and clinical data for cases aged 1 to 17 years were compared across 4 age groups: 1 year, 2 to 3 years, 4 to 9 years, and 10 to 17 years.

RESULTS

Of 944 pediatric CDI cases identified, 71% were CA. CDI incidence per 100,000 children was highest among 1-year-old (66.3) and white (23.9) cases. The proportion of cases with documented diarrhea (72%) or severe disease (8%) was similar across age groups; no cases died. Among the 84 cases interviewed who reported diarrhea on the day of stool collection, 73% received antibiotics during the previous 12 weeks.

CONCLUSIONS

Similar disease severity across age groups suggests an etiologic role for C difficile in the high rates of CDI observed in younger children. Prevention efforts to reduce unnecessary antimicrobial use among young children in outpatient settings should be prioritized.

Common questions about Clostridium difficile infection

Clostridium difficile infection is a common cause of antibiotic-associated diarrhea. It causes no symptoms in more than one-half of infected patients, but can also cause a wide spectrum of illnesses and death. The incidence and severity have increased in recent years. The most important modifiable risk factor for C. difficile infection is antibiotic exposure; this risk is dose-related and higher with longer courses and combination therapy. C. difficile infection is also associated with older age, recent hospitalization, multiple comorbidities, use of gastric acid blockers, inflammatory bowel disease, and immunosuppression. It has become more common in younger, healthier patients in community settings. The most practical testing options are rapid testing with nucleic acid amplification or enzyme immunoassays to detect toxin, or a two-step strategy. Treatment includes discontinuing the contributing antibiotic, if possible. Mild C. difficile infection should be treated with oral metronidazole; severe infection should be treated with oral vancomycin. Fidaxomicin may be an effective alternative. Recurrences of the infection should be treated based on severity. Tapering and the pulsed-dose method of oral vancomycin therapy for second recurrences are effective. Prevention includes responsible antibiotic prescribing and vigilant handwashing. Probiotics prevent antibiotic-associated diarrhea, but are not recommended specifically for preventing C. difficile infection.

[Successful measures to combat Clostridium difficile at Herlev Hospital]

Clostridium difficile is a common cause of health-care associated diarrhoea. We describe the supplementary measures taken at Herlev Hospital to combat a concerning rise in number of cases. The measures taken involve implementation of antibiotic stewardship; meetings every two weeks between the cleaning department, head nurses, infection control nurse and a clinical microbiologist with plans for near future actions; prompt isolation of patients with diarrhoea; rapid, PCR-based diagnostics; room disinfection. Comparing 2011 with 2012 shows a total decline of 32.9%.

[Clostridium difficile ribotype 027 is a challenge]

Infection with Clostridium difficile is the primary infective cause of antibiotic-associated diarrhoea. In 2008, a major outbreak of CD027 took place in North Zealand, Denmark. We described this infection in a single medical department. Patients positive for C. difficile enlisted at Medical Department O, Herlev Hospital, in 2009 were included and demographic data were recorded. In total, 69 patients were included, average age 83 years, Charlson Comorbidity Score 4. Of all patients 24 died. Further studies are needed in order to treat and minimize infection with C. difficile.

[Antibiotic stewardship has been established at Herlev Hospital]

A high incidence of Clostridium difficile and multiresistant organisms and increasing consumption of cephalosporins and quinolones have required an antibiotic stewardship programme, and antibiotic audits with feedback, revised guidelines and stringent prescription rules have been successful. The hospital intervention was managed by an antibiotic team combined with contact persons in all departments, a pocket edition of the guideline was available, and monthly commented reports about antibiotic consumption in each department were presented on the intranet. Significant declining use of restricted antibiotics was observed.

A cluster of fulminant Clostridium difficile colitis in an intensive care unit in Italy

We describe, for the first time, a cluster of lethal fulminant health-care associated Clostridium difficile (CD) colitis in Italy, observed in the intensive care unit (ICU) of an Italian tertiary care hospital in Rome. For all cases the cause of ICU admission was CD-related septic shock. Three out of seven patients were residents in a long-term care facility in Rome, and the others had been transferred to the ICU from different medical wards of the same hospital. Five patients died within 96 h of ICU admission. Because of a clinical deterioration after 4 days of adequate antibiotic therapy, two patients underwent subtotal colectomy: both of them died within 30 days of surgical intervention. In four cases, ribotyping assay was performed and ribotype 027 was recognized. This high mortality rate could be attributable to three findings: the extent of disease severity induced by the strain 027, the delay in antimicrobial therapy administration, and the lack of efficacy of the standard antibiotic treatment for fulminant CD colitis compared to an earlier surgical approach. In order to contain a CD infection epidemic, control and surveillance measures should be implemented, and empirical therapy should be administered. Because of potential 027 ribotype CD spread in Italy, CDI should be regarded with a high index of suspicion in all patients presenting with shock and signs or symptoms suggesting abdominal disease, and an early surgical approach should be considered.

The prolongation of length of stay because of Clostridium difficile infection

BACKGROUND

Clostridium difficile infection (CDI) possibly extends hospital length of stay (LOS); however, the current evidence does not account for the time-dependent bias, ie, when infection is incorrectly analyzed as a baseline covariate. The aim of this study was to determine whether CDI increases LOS after managing this bias.

METHODS

We examined the estimated extra LOS because of CDI using a multistate model. Data from all persons hospitalized >48 hours over 4 years in a tertiary hospital in Australia were analyzed. Persons with health care-associated CDIs were identified. Cox proportional hazards models were applied together with multistate modeling.

RESULTS

One hundred fifty-eight of 58,942 admissions examined had CDI. The mean extra LOS because of infection was 0.9 days (95% confidence interval: -1.8 to 3.6 days, P = .51) when a multistate model was applied. The hazard of discharge was lower in persons who had CDI (adjusted hazard ratio, 0.42; P < .001) when a Cox proportional hazard model was applied.

CONCLUSION

This study is the first to use multistate models to determine the extra LOS because of CDI. Results suggest CDI does not significantly contribute to hospital LOS, contradicting findings published elsewhere. Conversely, when methods prone to result in time-dependent bias were applied to the data, the hazard of discharge significantly increased. These findings contribute to discussion on methods used to evaluate LOS and health care-associated infections.

Carriage of Clostridium difficile by wild urban Norway rats (Rattus norvegicus) and black rats (Rattus rattus)

Clostridium difficile is an important cause of enteric infections in humans. Recently, concerns have been raised regarding whether animals could be a source of C. difficile spores. Although colonization has been identified in a number of domestic species, the ability of commensal pests to serve as a reservoir for C. difficile has not been well investigated. The objective of this study was to determine whether urban rats (Rattus spp.) from Vancouver, Canada, carry C. difficile. Clostridium difficile was isolated from the colon contents of trapped rats and was characterized using ribotyping, toxinotyping, and toxin gene identification. Generalized linear mixed models and spatial analysis were used to characterize the ecology of C. difficile in rats. Clostridium difficile was isolated from 95 of 724 (13.1%) rats, although prevalence differed from 0% to 46.7% among city blocks. The odds of being C. difficile positive decreased with increasing weight (odds ratio [OR], 0.67; 95% confidence interval [CI], 0.53 to 0.87), suggesting that carriage is more common in younger animals. The strains isolated included 9 ribotypes that matched recognized international designations, 5 identified by our laboratory in previous studies, and 21 "novel" ribotypes. Some strains were clustered geographically; however, the majority were dispersed throughout the study area, supporting environmental sources of exposure and widespread environmental contamination with a variety of C. difficile strains. Given that urban rats are the source of a number of other pathogens responsible for human morbidity and mortality, the potential for rats to be a source of C. difficile for humans deserves further consideration.

Clostridium difficile infection: a worldwide disease

Clostridium difficile, an anaerobic toxigenic bacterium, causes a severe infectious colitis that leads to significant morbidity and mortality worldwide. Both enhanced bacterial toxins and diminished host immune response contribute to symptomatic disease. C. difficile has been a well-established pathogen in North America and Europe for decades, but is just emerging in Asia. This article reviews the epidemiology, microbiology, pathophysiology, and clinical management of C. difficile. Prompt recognition of C. difficile is necessary to implement appropriate infection control practices.