Incidence of and risk factors for community-associated Clostridium difficile infection: a nested case-control study

BACKGROUND

Clostridium difficile is the most common cause of nosocomial infectious diarrhea in the United States. However, recent reports have documented that C. difficile infections (CDIs) are occurring among patients without traditional risk factors. The purpose of this study was to examine the epidemiology of CA-CDI, by estimating the incidence of CA-CDI and HA-CDI, identifying patient-related risk factors for CA-CDI, and describing adverse health outcomes of CA-CDI.

METHODS

We conducted a population-based, retrospective, nested, case-control study within the University of Iowa Wellmark Data Repository from January 2004 to December 2007. We identified persons with CDI, determined whether infection was community-associated (CA) or hospital-acquired (HA), and calculated incidence rates. We collected demographic, clinical, and pharmacologic information for CA-CDI cases and controls (i.e., persons without CDI). We used conditional logistic regression to estimate the odds ratios (ORs) for potential risk factors for CA-CDI.

RESULTS

The incidence rates for CA-CDI and HA-CDI were 11.16 and 12.1 cases per 100,000 person-years, respectively. CA-CDI cases were more likely than controls to receive antimicrobials (adjusted OR, 6.09 [95% CI 4.59-8.08]) and gastric acid suppressants (adjusted OR, 2.30 [95% CI 1.56-3.39]) in the 180 days before diagnosis. Controlling for other covariates, increased risk for CA-CDI was associated with use of beta-lactam/beta-lactamase inhibitors, cephalosporins, clindamycin, fluoroquinolones, macrolides, and penicillins. However, 27% of CA-CDI cases did not receive antimicrobials in the 180 days before their diagnoses, and 17% did not have any traditional risk factors for CDI.

CONCLUSIONS

Our study documented that the epidemiology of CDI is changing, with CA-CDI occurring in populations not traditionally considered "high-risk" for the disease. Clinicians should consider this diagnosis and obtain appropriate diagnostic testing for outpatients with persistent or severe diarrhea who have even remote antimicrobial exposure.

Incidence of and risk factors for community-associated Clostridium difficile infection: a nested case-control study

Background

Clostridium difficile is the most common cause of nosocomial infectious diarrhea in the United States. However, recent reports have documented that C. difficile infections (CDIs) are occurring among patients without traditional risk factors. The purpose of this study was to examine the epidemiology of CA-CDI, by estimating the incidence of CA-CDI and HA-CDI, identifying patient-related risk factors for CA-CDI, and describing adverse health outcomes of CA-CDI.

Methods

We conducted a population-based, retrospective, nested, case-control study within the University of Iowa Wellmark Data Repository from January 2004 to December 2007. We identified persons with CDI, determined whether infection was community-associated (CA) or hospital-acquired (HA), and calculated incidence rates. We collected demographic, clinical, and pharmacologic information for CA-CDI cases and controls (i.e., persons without CDI). We used conditional logistic regression to estimate the odds ratios (ORs) for potential risk factors for CA-CDI.

Results

The incidence rates for CA-CDI and HA-CDI were 11.16 and 12.1 cases per 100,000 person-years, respectively. CA-CDI cases were more likely than controls to receive antimicrobials (adjusted OR, 6.09 [95% CI 4.59-8.08]) and gastric acid suppressants (adjusted OR, 2.30 [95% CI 1.56-3.39]) in the 180 days before diagnosis. Controlling for other covariates, increased risk for CA-CDI was associated with use of beta-lactam/beta-lactamase inhibitors, cephalosporins, clindamycin, fluoroquinolones, macrolides, and penicillins. However, 27% of CA-CDI cases did not receive antimicrobials in the 180 days before their diagnoses, and 17% did not have any traditional risk factors for CDI.

Conclusions

Our study documented that the epidemiology of CDI is changing, with CA-CDI occurring in populations not traditionally considered "high-risk" for the disease. Clinicians should consider this diagnosis and obtain appropriate diagnostic testing for outpatients with persistent or severe diarrhea who have even remote antimicrobial exposure.

Impact of clinical symptoms on interpretation of diagnostic assays for Clostridium difficile infections

Asymptomatic Clostridium difficile colonization is common in hospitalized patients. Existing C. difficile assay comparisons lack data on severity of diarrhea or patient outcomes, limiting the ability to interpret their results in regard to the diagnosis of C. difficile infection (CDI). The objective of this study was to measure how including patient presentation with the C. difficile assay result impacted assay performance to diagnose CDI. Stool specimens from 150 patients that met inclusion and exclusion criteria were selected. Nine methods to detect C. difficile in stool were evaluated. All patients were interviewed prospectively to assess diarrhea severity. We then assessed how different reference standards, with and without the inclusion of patient presentation, impact the sensitivity, specificity, and positive and negative predictive values of the assays to diagnose CDI. There were minimal changes in sensitivity; however, specificity was significantly lower for the assays Tox A/B II, C. diff Chek-60, BD GeneOhm Cdiff, Xpert C. difficile, and Illumigene C. difficile and for toxigenic culture (P was <0.01 for all except Tox A/B II from fresh stool, for which the P value was 0.016) when the reference standard was recovery of toxigenic C. difficile from stool plus the presence of clinically significant diarrhea compared to when the reference standard was having at least four assays positive while ignoring diarrhea severity. There were 15 patients whose assay result was reported as negative but subsequently found to be positive by at least four assays in the comparison. None suffered from any CDI-related adverse events. In conclusion, clinical presentation is important when interpreting C. difficile diagnostic assays.

A case-control study of community-associated Clostridium difficile infection: no role for proton pump inhibitors

BACKGROUND

The epidemiology of community-associated Clostridium difficile infection is not well known. We performed a multicenter, case-control study to further describe community-associated C. difficile infection and assess novel risk factors.

METHODS

We conducted this study at 5 sites from October 2006 through November 2007. Community-associated C. difficile infection included individuals with diarrhea, a positive C. difficile toxin, and no recent (12 weeks) discharge from a health care facility. We selected controls from the same clinics attended by cases. We collected clinical and exposure data at the time of illness and cultured residual stool samples and performed ribotyping.

RESULTS

Of 1041 adult C. difficile infections, 162 (15.5%) met criteria for community-associated: 66 case and 114 control patients were enrolled. Case patients were relatively young (median 64 years), female (56%), and frequently required hospitalization (38%). Antimicrobials, malignancy, exposure to high-risk persons, and remote health care exposure were independently associated with community-associated C. difficile infection. In 40% of cases, we could not confirm recent antibiotic exposure. Stomach-acid suppressants were not associated with community-associated infection, and 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors appeared protective. Prevalence of the hypervirulent NAP-1/027 strain was infrequent (17%).

CONCLUSIONS

Community-associated C. difficile infection resulted in a substantial health care burden. Antimicrobials are a significant risk factor for community-associated infection. However, other unique factors also may contribute, including person-to-person transmission, remote health care exposures, and 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors. A role for stomach-acid suppressants in community-associated C. difficile infection is not supported.

Clostridium difficile infection in an endemic setting in the Netherlands

The purpose of this investigation was to study risk factors for Clostridium difficile infection (CDI) in an endemic setting. In a 34-month prospective case-control study, we compared the risk factors and clinical characteristics of all consecutively diagnosed hospitalised CDI patients (n = 93) with those of patients without diarrhoea (n = 76) and patients with non-CDI diarrhoea (n = 64). The incidence of CDI was 17.5 per 10,000 hospital admissions. C. difficile polymerase chain reaction (PCR) ribotype 014 was the most frequently found type (15.9%), followed by types 078 (12.7%) and 015 (7.9%). Independent risk factors for endemic CDI were the use of second-generation cephalosporins, previous hospital admission and previous stay at the intensive care unit (ICU). The use of third-generation cephalosporins was a risk factor for diarrhoea in general. We found no association of CDI with the use of fluoroquinolones or proton pump inhibitors (PPIs). The overall 30-day mortality among CDI patients, patients without diarrhoea and patients with non-CDI diarrhoea was 7.5%, 0% and 1.6%, respectively. In this endemic setting, risk factors for CDI differed from those in outbreak situations. Some risk factors that have been ascribed to CDI earlier were, in this study, not specific for CDI, but for diarrhoea in general. The 30-day mortality among CDI patients was relatively high.

The changing epidemiology of Clostridium difficile infections

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

Recognition and prevention of hospital-associated enteric infections in the intensive care unit

The objectives of this article were to review the causes and extent of hospital-associated infectious diarrhea and associated risks in the general hospital ward and intensive care unit (ICU), to compare microorganisms with similar symptoms to aid in recognition that will lead to timely and appropriate treatment and control measures, and to propose infection prevention protocols that could decrease human process errors in the ICU. This literature review describes epidemiology, comparison of microbial characteristics for potential hospital-associated enteric pathogens, diagnosis, and prevention, especially if important in the ICU, and particularly in regard to Clostridium difficile. Enteric organisms that most commonly cause hospital-associated infectious diarrhea in acute care settings and the ICU are C. difficile, rotavirus, and norovirus, although others may also be important, particularly in developing countries. To recognize and control infectious diarrhea successfully in the ICU, intensivists should be aware that epidemiology, risks, and prevention measures may differ between these microorganisms. In addition, intensivists should be ready to implement systems changes related to notification, isolation precautions and prevention, and environmental cleaning in the ICU.

The changing epidemiology of Clostridium difficile infections

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

Clostridium difficile PCR ribotype 027: assessing the risks of further worldwide spread

Highly virulent strains of Clostridium difficile have emerged since 2003, causing large outbreaks of severe, often fatal, colitis in North America and Europe. In 2008–10, virulent strains spread between continents, with the first reported cases of fluoroquinolone-resistant C difficile PCR ribotype 027 in three Asia-Pacific countries and Central America. We present a risk assessment framework for assessing risks of further worldwide spread of this pathogen. This framework first requires identification of potential vehicles of introduction, including international transfers of hospital patients, international tourism and migration, and trade in livestock, associated commodities, and foodstuffs. It then calls for assessment of the risks of pathogen release, of exposure of individuals if release happens, and of resulting outbreaks. Health departments in countries unaffected by outbreaks should assess the risk of introduction or reintroduction of C difficile PCR ribotype 027 using a structured risk-assessment approach.

Correlations between bed occupancy rates and Clostridium difficile infections: a time-series analysis

A time-series analysis was performed to identify the impact of bed occupancy rates and length of hospital stay on the incidence of Clostridium difficile infections (CDI). Between January 2003 and July 2008, a mean incidence of 0·5 CDI cases/1000 patient days was recorded. Application of a multivariate model (R2=0·50) showed that bed occupancy rates on general wards (P<0·01) and length of stay in intensive care units (ICUs) (P<0·01) influenced the incidence of CDI. Overcrowding on general wards and long periods in ICUs were identified as being positively associated with the incidence of CDI.

Safety of the long-term use of proton pump inhibitors

The proton pump inhibitors (PPIs) as a class are remarkably safe and effective for persons with peptic ulcer disorders. Serious adverse events are extremely rare for PPIs, with case reports of interstitial nephritis with omeprazole, hepatitis with omeprazole and lansoprazole, and disputed visual disturbances with pantoprazole and omeprazole. PPI use is associated with the development of fundic gland polyps (FGP); stopping PPIs is associated with regression of FGP. In the absence of Helicobacter pylori infection, the long-term use of PPIs has not been convincingly proven to cause or be associated with the progression of pre-existing chronic gastritis or gastric atrophy or intestinal metaplasia. Mild/modest hypergastrinemia is a physiological response to the reduction in gastric acid secretion due to any cause. The long-term use of PPIs has not been convincingly proven to cause enterochromaffin-like cell hyperplasia or carcinoid tumors. PPIs increase the risk of community acquired pneumonia, but not of hospital acquired (nosocomial) pneumonia. There is no data to support particular care in prescribing PPI therapy due to concerns about risk of hip fracture with the long-term use of PPIs. Long-term use of PPIs does not lead to vitamin B12 deficiencies, except possibly in the elderly, or in persons with Zollinger-Ellison Syndrome who are on high doses of PPI for prolonged periods of time. There is no convincingly proven data that PPIs increase the risk of Clostridium difficile-associated diarrhea in persons in the community. The discontinuation of PPIs may result in rebound symptoms requiring further and even continuous PPI use for suppression of symptoms. As with all medications, the key is to use PPIs only when clearly indicated, and to reassess continued use so that long-term therapy is used judiciously. Thus, in summary, the PPIs are a safe class of medications to use long-term in persons in whom there is a clear need for the maintenance of extensive acid inhibition.

A time-series analysis of clostridium difficile and its seasonal association with influenza

OBJECTIVE

To characterize the temporal progression of the monthly incidence of Clostridium difficile infections (CDIs) and to determine whether the incidence of CDI is related to the incidence of seasonal influenza.

DESIGN

A retrospective study of patients in the Nationwide Inpatient Sample during the period from 1998 through 2005.

METHODS

We identified all hospitalizations with a primary or secondary diagnosis of CDI with use of International Classification of Diseases, 9th Revision, Clinical Modification codes, and we did the same for influenza. The incidence of CDI was modeled as an autoregression about a linear trend. To investigate the association of CDI with influenza, we compared national and regional CDI and influenza series data and calculated cross-correlation functions with data that had been prewhitened (filtered to remove temporal patterns common to both series). To estimate the burden of seasonal CDI, we developed a proportional measure of seasonal CDI.

RESULTS

Time-series analysis of the monthly number of CDI cases reveals a distinct positive linear trend and a clear pattern of seasonal variation (R2 = 0.98). The cross-correlation functions indicate that influenza activity precedes CDI activity on both a national and regional basis. The average burden of seasonal (ie, winter) CDI is 23%.

CONCLUSIONS

The epidemiologic characteristics of CDI follow a pattern that is seasonal and associated with influenza, which is likely due to antimicrobial use during influenza seasons. Approximately 23% of average monthly CDI during the peak 3 winter months could be eliminated if CDI remained at summer levels.

Clostridium difficile infections in outpatient dialysis cohort

We examined the Clostridium difficile infection rate and risk factors in an outpatient dialysis cohort. The Cox proportional hazard for developing C. difficile infection was significantly higher with high comorbidity index and low serum albumin level. Conversely, it was lower for patients who had frequent bloodstream and dialysis access-related infections.

Clostridium difficile in solid organ transplant recipients

Clostridium difficile infection (CDI) is a common problem encountered in solid organ transplant (SOT) recipients and the incidence is increasing. Generally, SOT recipients have an incidence of CDI that is similar to other post-operative patients, but this group has several unique risk factors that may contribute to more severe disease. Recent studies in non-transplant patients have indicated that treatment choices should be based on the severity of the illness. Although there continues to be a lack of well designed, randomized, controlled trials to support the management decisions that must be made for SOT recipients with CDI, the available evidence is reviewed and summarized for these treatment guidelines.

Impact of an intervention to control Clostridium difficile infection on hospital- and community-onset disease; an interrupted time series analysis

Strategies to reduce rates of Clostridium difficile infection (CDI) generally recommend isolation or cohorting of active cases and the reduced use of cephalosporin and quinolone antibiotics. Data supporting these recommendations come predominantly from the setting of epidemic disease caused by ribotype 027 strains. We introduced an initiative involving a restrictive antibiotic policy and a CDI-cohort ward at an acute, 820-bed teaching hospital where ribotype 027 strains account for only one quarter of all CDI cases. Antibiotic use and monthly CDI cases in the 12 months before and the 15 months after the initiative were compared using an interrupted time series analysis and segmented regression analysis. The initiative resulted in a reduced level of cephalosporin and quinolone use (22.0% and 38.7%, respectively, both p <0.001) and changes in the trends of antibiotic use such that cephalosporin use decreased by an additional 62.1 defined daily doses (DDD) per month (p <0.001) and antipseudomonal penicillin use increased by 20.7 DDD per month (p = 0.011). There were no significant changes in doxycycline or carbapenem use. Although the number of CDI cases each month was falling before the intervention, there was a significant increase in the rate of reduction after the intervention from 3% to 8% per month (0.92, 95% CI 0.86-0.99, p = 0.03). During the study period, there was no change in the proportion of cases having their onset in the community, nor in the proportion of ribotype 027 cases. CDI cohorting and restriction of cephalosporin and quinolone use are effective in reducing CDI cases in a setting where ribotype 027 is endemic.

Evaluation of the performance of CURB-65 with increasing age

There has been concern about the performance of CURB-65 in older patients with community-acquired pneumonia (CAP) and that younger patients who subsequently die are initially misclassified as having non-severe CAP. The purpose of this study was to evaluate the effect of age on the performance of CURB-65. We analysed data prospectively, collected in two UK hospitals. Patients were stratified into four age cohorts. Mortality in each cohort was then stratified by CURB-65 score. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and area under the receiver operating curve (AUROC) were calculated. Four hundred and twenty-eight patients were included. Misclassification of patients who subsequently died as non-severe CAP patients (CURB-65 score of < or =2) increased with increasing age (from 3% in the <65-year cohort to 27% in those aged >85 years). There were no deaths (0/105) in those aged <65 years who had a CURB-65 score of 0 or 1. At the British Thoracic Society cut-off for severe CAP (CURB-65 score of > or =3), CURB-65 performed best in 16-64-year-olds (PPV 0.4, NPV 0.97). The AUROC was significantly higher for the <65-year cohort in comparison with older patients (0.93 vs. 0.7, p <0.05). Clinicians should interpret the CURB-65 score with care in older patients referred to hospital with CAP. In those aged <65 years, however, CURB-65 appears to be able to identify a cohort of patients (CURB-65 score of 0 or 1) with very low mortality.

Clostridium difficile infection in the intensive care unit

Clostridium difficile infection (CDI) is becoming more common worldwide. The morbidity and mortality associated with C difficile is also increasing at an alarming rate. Critically ill patients are at particularly high risk for CDI because of the prevalence of multiple risk factors in this patient population. Treatment of C difficile continues to be a difficult problem in patients with severe or recurrent disease. This article seeks to provide a broad understanding of CDI in the intensive care unit, with special emphasis on risk factor identification, treatment options, and disease prevention.

Multicenter study of the impact of community-onset Clostridium difficile infection on surveillance for C. difficile infection

OBJECTIVE

To evaluate the impact of cases of community-onset, healthcare facility (HCF)-associated Clostridium difficile infection (CDI) on the incidence and outbreak detection of CDI.

DESIGN

A retrospective multicenter cohort study.

SETTING

Five university-affiliated, acute care HCFs in the United States.

METHODS

We collected data (including results of C. difficile toxin assays of stool samples) on all of the adult patients admitted to the 5 hospitals during the period from July 1, 2000, through June 30, 2006. CDI cases were classified as HCF-onset if they were diagnosed more than 48 hours after admission or as community-onset, HCF-associated if they were diagnosed within 48 hours after admission and if the patient had recently been discharged from the HCF. Four surveillance definitions were compared: cases of HCF-onset CDI only (hereafter referred to as HCF-onset CDI) and cases of HCF-onset and community-onset, HCF-associated CDI diagnosed within 30, 60, and 90 days after the last discharge from the study hospital (hereafter referred to as 30-day, 60-day, and 90-day CDI, respectively). Monthly CDI rates were compared. Control charts were used to identify potential CDI outbreaks.

RESULTS

The rate of 30-day CDI was significantly higher than the rate of HCF-onset CDI at 2 HCFs (P < .01). The rates of 30-day CDI were not statistically significantly different from the rates of 60-day or 90-day CDI at any HCF. The correlations between each HCF's monthly rates of HCF-onset CDI and 30-day CDI were almost perfect (rho range, 0.94-0.99; P < .001). Overall, 12 time points had a CDI rate that was more than 3 standard deviations above the mean, including 11 time points identified using the definition for HCF-onset CDI and 9 time points identified using the definition for 30-day CDI, with discordant results at 4 time points ((kappa = 0.794; P < .001).

CONCLUSIONS

Tracking cases of both community-onset and HCF-onset, HCF-associated CDI captures significantly more CDI cases, but surveillance of HCF-onset, HCF-associated CDI alone is sufficient to detect an outbreak.

Clostridium difficile in retail meat products, USA, 2007

To determine the presence of Clostridium difficile, we sampled cooked and uncooked meat products sold in Tucson, Arizona. Forty-two percent contained toxigenic C. difficile strains (either ribotype 078/toxinotype V [73%] or 027/toxinotype III [NAP1 or NAP1-related; 27%]). These findings indicate that food products may play a role in interspecies C. difficile transmission.

Complete restriction of fluoroquinolone use to control an outbreak of Clostridium difficile infection at a community hospital

OBJECTIVE

To review the effect of interventions, including a complete restriction in the use of fluoroquinolones (FQs), used to control an outbreak of hospital-onset Clostridium difficile infection (HO-CDI) caused primarily by the epidemic North American pulsed-field gel electrophoresis type 1 strain.

DESIGN

Retrospective cohort and case-control study of all episodes of HO-CDI both before and after 2 interventions.

SETTING

Community hospital; January 1, 2005, through March 31, 2007. Interventions. Complete, 5-month, facility-wide restriction of fluoroquinolone use, during which a change in the environmental-services contractor occurred.

RESULTS

During a 27-month period, 319 episodes of HO-CDI occurred. The hospital-wide mean defined daily doses of antimicrobials decreased 22% after restricting FQ use, primarily because of a 66% decrease in the use of FQs. The interventions were also associated with a significant change in the HO-CDI incidence trends and with an absolute decrease of 22% in HO-CDI cases caused by the epidemic strain (from 66% before the intervention period to 44% during and after the intervention period; P=.02). Univariate analysis revealed that case patients with HO-CDI due to the epidemic strain were more likely than control patients, who did not have diarrhea, to receive a FQ, whereas case patients with HO-CDI due to a nonepidemic strain were not. However, FQ use was not significantly associated with HO-CDI in multivariable analysis.

CONCLUSIONS

An outbreak of epidemic-strain HO-CDI was controlled at a community hospital after an overall decrease in antimicrobial use, primarily because of a restriction of FQ use and a change in environmental-services contractors. The restriction of FQ use may be useful as an adjunct control measure in a healthcare facilities during outbreaks of epidemic-strain HO-CDI.

Clostridium difficile-associated diarrhoea, a frequent complication in patients with acute myeloid leukaemia

Diarrhoea occurs frequently in neutropenic patients with acute leukaemia receiving chemotherapy and may be caused by either infection- or drug-induced cytotoxicity. Since Clostridium difficile is the most common cause of nosocomial infectious diarrhoea in non-haematologic patients, we were interested in its incidence in patients with acute myeloid leukaemia (AML). In this retrospective study, we analysed 134 patients with AML receiving a total of 301 chemotherapy courses. Diarrhoea occurred during 33% of all courses in 58 patients. C. difficile-associated diarrhoea (CDAD) occurred in 18% of all patients and 9% of all treatment courses. Almost one third of diarrhoea episodes were caused by C. difficile. CDAD was associated with older age (58 vs. 50 years), number of antibiotics administered (2 vs. 1), duration of antibiotic therapy (7 vs. 4 days), ceftazidime as the antibiotic of choice (75% vs. 54%) and duration of neutropenia (12 vs. 7 days) prior to onset of diarrhoea. An increased risk for CDAD was seen for prolonged neutropenia. CDAD responded well to oral metronidazole and/or vancomycin and no patient died of this complication. In conclusion, CDAD is common in patients with AML receiving chemotherapy. C. difficile enterotoxin testing of stool specimens should be included in all symptomatic patients.

The clinical safety of long-term lansoprazole for the maintenance of healed erosive oesophagitis

BACKGROUND

The clinical safety of long-term lansoprazole therapy for the maintenance of healed erosive oesophagitis has not been extensively studied in clinical trials.

AIM

To assess the long-term clinical safety of dose-titrated lansoprazole as maintenance therapy for up to 82 months in subjects with healed erosive oesophagitis.

METHODS

Clinical safety was assessed by monitoring adverse events (AEs), laboratory data including serum gastrin levels, and endoscopy.

RESULTS

Mean duration (+/- s.d.) of lansoprazole treatment during the titrated open-label period was 56 +/- 24 months (range <1-82 months). Overall, 189 of 195 (97%) subjects experienced a total of 2825 treatment-emergent AEs. Most AEs occurred during the first year of treatment, were mild-to-moderate in severity and resolved while on treatment. Of 155 serious AEs (in 74 subjects), only two (colitis and rectal haemorrhage in one subject) were considered treatment-related. Sixty-nine of 195 subjects (35%) experienced 187 treatment-related AEs, with diarrhoea (10%), headache (8%) and abdominal pain (6%) being the most common. Gastrin levels > or = 400 pg/mL were seen in 9% of subjects; hypergastrinemia was not associated with gastro-intestinal AEs or nodules/polyps.

CONCLUSIONS

Lansoprazole maintenance therapy for up to 6 years is safe and well tolerated in subjects with healed erosive oesophagitis.

Incidence, prevalence, and analysis of risk factors for surgical site infection following adult spinal surgery

STUDY DESIGN

A retrospective cohort study to identify rates and analyze the risk factors for postoperative spinal wound infection.

OBJECTIVE

To determine significant risk factors for postoperative spinal wound infection by comparing those patients who developed a postoperative wound infection with the rest of the cohort.

SUMMARY OF BACKGROUND DATA

A surgical site infection (SSI) is a common complication after spinal surgery. SSI leads to higher morbidity, mortality, and healthcare costs. To develop strategies to reduce the risk for SSI, independent risk factors for SSI should be identified.

METHODS

The electronic patient record of all 3174 patients who underwent orthopedic spinal surgery at out institution were abstracted. Individual patient and perioperative characteristics were stored in an electronic database.

RESULTS

In total, 132 (4.2%) patients were found to have an SSI with 84 having deep based infection. Estimated blood loss over 1 liter (P = 0.017), previous SSI (P = 0.012) and diabetes (P = 0.050) were found to be independent statistically significant risk factors for SSI. Obesity (P = 0.009) was found to significantly increase the risk of superficial infection, whereas anterior spinal approach decreased the risk (P = 0.010). Diabetes (P = 0.033), obesity (P = 0.047), previous SSI (P = 0.009), and longer surgeries (2-5 hours [P = 0.023] and 5 or more hours [P = 0.009]) were found to be independent significant risk factors for deep SSI.

CONCLUSION

SSI is commonly seen after spinal surgery. In our study, we identified independent risk factors for both deep and superficial SSI. Identification of these risk factors should allow us to design protocols to decrease the risk of SSE in future patients.

Hospital-associated Clostridium difficile infection: is it necessary to track community-onset disease?

OBJECTIVES

To compare Clostridium difficile infection (CDI) rates determined with use of a traditional definition (ie, with healthcare-onset CDI defined as diagnosis of CDI more than 48 hours after hospital admission) with rates determined with use of expanded definitions, including both healthcare-onset CDI and community-onset CDI, diagnosed within 48 hours after hospital admission in patients who were hospitalized in the previous 30 or 60 days, and to determine whether differences exist between patients with CDI onset in the community and those with CDI onset in a healthcare setting.

DESIGN

Prospective cohort.

SETTING

Tertiary acute care facility.

PATIENTS

General medicine patients who received a diagnosis of CDI during the period January 1, 2004, through December 31, 2005.

METHODS

CDI was classified as healthcare-onset CDI, healthcare facility-associated CDI after hospitalization within the previous 30 days, and/or healthcare facility-associated CDI after hospitalization within the previous 60 days. Patient demographic characteristics and medication exposures were obtained. The CDI incidence with use of each definition, CDI rate variability, patient demographic characteristics, and medication exposures were compared.

RESULTS

The healthcare-onset CDI rate (1.6 cases per 1,000 patient-days) was significantly lower than the 30-day healthcare facility-associated CDI rate (2.4 cases per 1,000 patient-days; P< .01) and the 60-day healthcare facility-associated CDI rate (2.6 cases per 1,000 patient-days; P< .01). There was good correlation between the healthcare-onset CDI rate and both the 30-day (correlation, 0.69; P< .01) and 60-day (correlation, 0.70; P< .01) healthcare facility-associated CDI rates. There were no months in which the CDI rate was more than 3 standard deviations from the mean. Compared with patients with healthcare-onset CDI, patients with community-onset CDI were less likely to have received a fourth-generation cephalosporin (P= .02) or intravenous vancomycin (P+ .01) during hospitalization.

CONCLUSIONS

Compared with the traditional definition, expanded definitions identify more patients with CDI. There is good correlation between traditional and expanded CDI definitions; therefore, it is unclear whether expanded surveillance is necessary to identify an abnormal change in CDI rates. Cases that met the expanded definitions were less likely to have occurred in patients with fourth-generation cephalosporin and vancomycin exposure.

Proton pump inhibitors increase significantly the risk of Clostridium difficile infection in a low-endemicity, non-outbreak hospital setting

BACKGROUND

Proton pump inhibitors (PPI) have been linked to higher risk of Clostridium difficile infection (CDI). The relevance of this association in hospitals with low disease activity, where an outbreak strain is nondominant, has been assessed in relatively few studies.

AIM

To assess the association of PPI and CDI in a setting of low disease activity.

METHODS

A retrospective cohort study was conducted at two hospitals. Patients admitted for > or = 7 days receiving antibiotics were included. Demographics, exposure to PPI, antibiotics and other drugs in relation to diagnosis of CDI were assessed by univariate and multivariate analyses.

RESULTS

Of 14 719 patients, 149 (1%) first episode CDI were documented; PPI co-exposure increased CDI [1.44 cases/100 patients vs. 0.74 cases/100 non-exposed (OR: 1.96, 95% CI: 1.42-2.72)]. By logistic regression, PPI days (adjusted OR: 1.01 per day, 95% CI: 1.00-1.02), histamine-2 blockers, antidepressants, antibiotic days, exposure to medications, age, admission service and length of admission were significant predictors.

CONCLUSIONS

A statistically significant increase in CDI was observed in antibiotic recipients who received PPI, but the absolute risk increase is modest. In settings of with low rates of CDI, the benefit of PPI therapy outweighs the risk of developing CDI. These data support programmes to decrease inappropriate use of PPI in hospitalized patients.

Proton pump inhibitor use and enteric infections

Proton pump inhibitors (PPIs) and H2 receptor antagonists (H2RAs) are very commonly prescribed drugs and are routinely used in the chronic management of gastro-esophageal reflux disease. Concerns have been raised about the possible association of PPIs with enteric infections. This article reviews the studies that have examined the associations of proton pump inhibitors in particular, and enteric infections.

Clostridium difficile infection in solid organ transplant recipients

PURPOSE OF REVIEW

To provide a general understanding of Clostridium difficile infection with a focus on recent publications that evaluate the disease in solid organ transplant recipients.

RECENT FINDINGS

The incidence of C. difficile infection is increasing worldwide. Epidemics due to a hypervirulent C. difficile strain are associated with an escalating severity of disease. New evidence further supports basing initial treatment choice on disease severity.

SUMMARY

C. difficile is a significant pathogen in solid organ transplant recipients. Multiple risk factors are found in this population that may result in more severe disease. A high index of suspicion is necessary for the early diagnosis and treatment of C. difficile infection in transplant recipients. Metronidazole and vancomycin show equivalent efficacy in the treatment for mild-to-moderate disease, but vancomycin has demonstrated superiority in the treatment of severe disease. Surgical intervention is also an important consideration in the treatment of solid organ transplant recipients with severe colitis. Rigorous infection control practices are essential for preventing the spread of C. difficile within the hospital environment.

Review of current literature on the economic burden of Clostridium difficile infection

Clostridium difficile is well recognized as the most common infectious cause of healthcare-associated diarrhea. Since 2000, this pathogen has demonstrated an increased propensity to cause more frequent and virulent illness that is often refractory to treatment. An analysis by the Centers for Disease Control and Prevention revealed that, in the United States, the number of patients discharged from hospitals who received the International Classification of Diseases, Ninth Revision discharge diagnosis code for C. difficile infection (CDI) more than doubled from 2000 to 2003. Unpublished data indicate that this trend has continued and that more than 250,000 US hospitalizations were associated with CDI in 2005. A previously uncommon hypervirulent strain of C. difficile is thought to contribute, in part, to the dramatic increase in the incidence and severity of the infection. Although the economic impact of the disease is believed to be profound and is expected to increase, data on the costs associated with CDI are scarce. To more completely assess its economic burden, we performed a review of available literature that reported costs associated with the infection.

The management of Clostridium difficile infection

INTRODUCTION/BACKGROUND

Clostridium difficile is the commonest cause of nosocomial diarrhoea. The epidemiology and clinical phenotype of the disease has dramatically changed with the global emergence of a virulent strain of C. difficile.

SOURCE

This review was compiled using data from individual studies and review articles identified from PubMed. The retrieved articles were also examined for additional references.

AREAS OF AGREEMENT

Appropriate and timely infection control measures are required to control C. difficile infection (CDI) in the hospital environment, and either oral metronidazole or vancomycin remains the mainstay of treatment depending on the severity of infection.

AREAS OF CONTROVERSY

The optimal method for diagnosing CDI remains unclear, as does the best therapeutic strategy for the management of multiple relapses. GROWING POINTS/AREAS TIMELY FOR DEVELOPING RESEARCH: Studies of new antimicrobial agents with activity against C. difficile are required to improve the management of multiply relapsing disease. The use of novel therapeutic approaches that do not require antimicrobials requires urgent research, including the use of immunological or vaccine-based regimen, bacteriotherapy or C. difficile-specific bacteriophages.

Antibiotic-associated diarrhea: epidemiology, trends and treatment

A common complication of antibiotic use is the development of gastrointestinal disease. This complication ranges from mild diarrhea to pseudomembranous colitis. Outbreaks of antibiotic-associated diarrhea (AAD) may also occur in healthcare settings, usually caused by Clostridium difficile. AAD typically occurs in 5-35% of patients taking antibiotics and varies depending upon the specific type of antibiotic, the health of the host and exposure to pathogens. The pathogenesis of AAD may be mediated through the disruption of the normal microbiota resulting in pathogen overgrowth or metabolic imbalances. The key to addressing AAD is prompt diagnosis followed by effective treatment and institution of control measures. Areas of active research include the search for other etiologies and more effective treatments.

Meta-analysis to assess risk factors for recurrent Clostridium difficile infection

SUMMARY

Clostridium difficile infection (CDI) is the most common cause of hospital-acquired diarrhoea. It is estimated that 15-20% of patients experience recurrence of CDI. A limited number of studies have looked at the risk factors for recurrent CDI. We conducted a meta-analysis of observational studies and randomised controlled trials (RCTs) to assess risk factors for recurrent CDI. Studies were identified using the PubMed database and search terms 'Clostridium difficile associated diarrhoea' or 'pseudomembranous colitis'. Both observational studies and RCTs were included. In all, 1215 studies were identified of which 48 met the inclusion criteria. Twelve studies involving 1382 patients with CDI met the complete eligibility requirements. Odds ratios and information on study quality were abstracted by two investigators independently. To be included in the analysis, each risk factor was required to be evaluated by at least three separate studies. Continued use of non-C. difficile antibiotics after diagnosis of CDI (OR: 4.23; 95% CI: 2.10-8.55; P<0.001), concomitant receipt of antacid medications (OR: 2.15; 95% CI: 1.13-4.08; P=0.019), and older age (OR: 1.62; 95% CI: 1.11-2.36; P=0.0012) were significantly associated with increased risk of recurrent CDI. Significant prognostic risk factors were identified as risk factors for CDI recurrence. Additional or novel interventions may be required for these patients to prevent CDI recurrence.

A clinical risk index for Clostridium difficile infection in hospitalised patients receiving broad-spectrum antibiotics

Identification of a population at high risk for Clostridium difficile infection (CDI) would enable CDI prevention strategies to be designed. The purpose of this study was to create a clinical risk index that would predict those at risk for CDI. A CDI risk index was therefore developed, based on a cohort of hospital patients given broad-spectrum antibiotics, and divided into a development and validation cohort. Logistic regression equations helped identify significant predictors of CDI. A scoring algorithm for CDI risk was created using identified risk factors and collapsed to create four categories of CDI risk. The area under the receiver operating characteristic (aROC) curve was used to measure goodness-of-fit. Among 54 226 patients, 392 tested positive for C. difficile. Age 50-80 years [odds ratio (OR: 0.5; P<0.0116)], age >80 years (OR: 2.5; P<0.0001), haemodialysis (OR: 1.5; P=0.0227), non-surgical admission (OR: 2.2; P<0.0001) and increasing length of stay in the intensive care unit (OR: 2.1; P<0.0001) were significantly associated with CDI. A simple risk index using presence of significant variables was significantly associated with increasing risk for CDI in both development (OR: 3.57; P<0.001; aROC: 0.733) and validation (OR: 3.31; P<0.001; aROC: 0.712) cohorts. An OR-derived risk index did not perform as well as the simple risk index. This easily implemented risk index should allow stratification of patients into risk group categories for development of CDI and help fashion preventive strategies.

Effects of exposure of Clostridium difficile PCR ribotypes 027 and 001 to fluoroquinolones in a human gut model

The incidence of Clostridium difficile infection is increasing, with reports implicating fluoroquinolone use. A three-stage chemostat gut model was used to study the effects of three fluoroquinolones (ciprofloxacin, levofloxacin, and moxifloxacin) on the gut microbiota and two epidemic C. difficile strains, strains of PCR ribotypes 027 and 001, in separate experiments. C. difficile total viable counts, spore counts, and cytotoxin titers were determined. The emergence of C. difficile isolates with reduced antibiotic susceptibility was monitored with fluoroquinolone-containing medium, and molecular analysis of the quinolone resistance-determining region was performed. C. difficile spores were quiescent in the absence of fluoroquinolones. Instillation of each fluoroquinolone led to C. difficile spore germination and high-level cytotoxin production. High-level toxin production occurred after detectable spore germination in all experiments except those with C. difficile PCR ribotype 027 and moxifloxacin, in which marked cytotoxin production preceded detectable germination, which coincided with isolate recovery on fluoroquinolone-containing medium. Three C. difficile PCR ribotype 027 isolates and one C. difficile PCR ribotype 001 isolate from fluoroquinolone-containing medium exhibited elevated MICs (80 to > or =180 mg/liter) and possessed mutations in gyrA or gyrB. These in vitro results suggest that all fluoroquinolones have the propensity to induce C. difficile infection, regardless of their antianaerobe activities. Resistant mutants were seen only following moxifloxacin exposure.

Effect of telephoned notification of positive Clostridium difficile test results on the time to the ordering of antimicrobial therapy

The time between electronic-medical-record reporting of a positive result of a test for Clostridium difficile toxin in stool and the ordering of antimicrobial therapy was compared during consecutive periods when results were not telephoned (n = 274) and when results were telephoned (n = 90) to the clinical service. The mean times to the ordering of antimicrobial therapy were 11.9 and 3.6 hours, respectively (P < .001).