Recurrent Clostridium difficile infections: The importance of the intestinal microbiota

Clostridium difficile infections (CDI) are a leading cause of antibiotic-associated and nosocomial diarrhea. Despite effective antibiotic treatments, recurrent infections are common. With the recent emergence of hypervirulent isolates of C. difficile, CDI is a growing epidemic with higher rates of recurrence, increasing severity and mortality. Fecal microbiota transplantation (FMT) is an alternative treatment for recurrent CDI. A better understanding of intestinal microbiota and its role in CDI has opened the door to this promising therapeutic approach. FMT is thought to resolve dysbiosis by restoring gut microbiota diversity thereby breaking the cycle of recurrent CDI. Since the first reported use of FMT for recurrent CDI in 1958, systematic reviews of case series and case report have shown its effectiveness with high resolution rates compared to standard antibiotic treatment. This article focuses on current guidelines for CDI treatment, the role of intestinal microbiota in CDI recurrence and current evidence about FMT efficacy, adverse effects and acceptability.

Risk factors for recurrent Clostridium difficile infection (CDI) hospitalization among hospitalized patients with an initial CDI episode: a retrospective cohort study

Background

Recurrent Clostridium difficile infection (rCDI) is observed in up to 25% of patients with an initial CDI episode (iCDI). We assessed risk factors for rCDI among patients hospitalized with iCDI.

Methods

We performed a retrospective cohort study at Barnes-Jewish Hospital from 1/1/03 to 12/31/09. iCDI was defined as a positive toxin assay for C. difficile with no CDI in previous 60 days, and rCDI as a repeat positive toxin ≤42 days of stopping iCDI treatment. Three demographic, 13 chronic and 12 acute disease characteristics, and 21 processes of care were assessed for association with rCDI. Cox modeling identified independent risk factors for rCDI.

Results

425 (10.1%) of 4,200 patients enrolled developed rCDI. Of the eight risk factors for rCDI on multivariate analyses, the strongest three were 1) high-risk antimicrobials following completion of iCDI treatment (HR 2.95, 95% CI 2.25-3.86), 2) community-onset healthcare-associated iCDI (HR 1.80, 95% CI 1.41-2.29) and 3) fluoroquinolones after completion of iCDI treatment (HR 1.56, 95% CI 1.63-2.08). Other risk factors included gastric acid suppression, ≥2 hospitalizations within prior 60 days, age, and IV vancomycin after iCDI treatment ended.

Conclusions

The rCDI rate was 10.1%. Recognizing such modifiable risk factors as certain antimicrobial treatments and gastric acid suppression may help optimize prevention efforts.

Cefpodoxime for antimicrobial prophylaxis in neutropenia: a retrospective case series

BACKGROUND

Antimicrobial prophylaxis in select neutropenic patients has reduced fever, infection rates, hospital length of stay, and hospitalization rates. Guidelines from the Infectious Diseases Society of America recommend the consideration of prophylaxis with a fluoroquinolone in patients at high risk for infection after chemotherapy. The use of fluoroquinolones has been associated with many adverse events, and there is limited evidence on alternative antimicrobial prophylaxis in patients intolerant of fluoroquinolones.

OBJECTIVES

Our study describes a single-center experience of cefpodoxime as an alternative to fluoroquinolones for antibacterial prophylaxis during neutropenia after chemotherapy and represents a retrospective evaluation of an oral cephalosporin in adult patients for this purpose.

METHODS

This retrospective case series analyzed data from the electronic medical records of 41 patients having hematologic malignancies and given cefpodoxime for neutropenic prophylaxis.

RESULTS

The rate of febrile neutropenia was 85%, with 60% culture-positive infections. Gram-positive organisms were identified in 52% of positive cultures, and gram-negative organisms represented 40% of positive cultures. Antimicrobial resistance to guideline-recommended empiric treatment regimens was not seen in breakthrough infections.

CONCLUSIONS

Cefpodoxime can be utilized for prophylaxis, without adversely affecting resistance to broad-spectrum agents, and maintains a high level of appropriateness of guideline-recommended empiric regimens. This study of cefpodoxime prophylaxis in adult patients intolerant to fluoroquinolones adds to the literature of potential alternative agents for prophylaxis in neutropenic patients.

Variations in virulence and molecular biology among emerging strains of Clostridium difficile

Clostridium difficile is a Gram-positive, spore-forming organism which infects and colonizes the large intestine, produces potent toxins, triggers inflammation, and causes significant systemic complications. Treating C. difficile infection (CDI) has always been difficult, because the disease is both caused and resolved by antibiotic treatment. For three and a half decades, C. difficile has presented a treatment challenge to clinicians, and the situation took a turn for the worse about 10 years ago. An increase in epidemic outbreaks related to CDI was first noticed around 2003, and these outbreaks correlated with a sudden increase in the mortality rate of this illness. Further studies discovered that these changes in CDI epidemiology were associated with the rapid emergence of hypervirulent strains of C. difficile, now collectively referred to as NAP1/BI/027 strains. The discovery of new epidemic strains of C. difficile has provided a unique opportunity for retrospective and prospective studies that have sought to understand how these strains have essentially replaced more historical strains as a major cause of CDI. Moreover, detailed studies on the pathogenesis of NAP1/BI/027 strains are leading to new hypotheses on how this emerging strain causes severe disease and is more commonly associated with epidemics. In this review, we provide an overview of CDI, discuss critical mechanisms of C. difficile virulence, and explain how differences in virulence-associated factors between historical and newly emerging strains might explain the hypervirulence exhibited by this pathogen during the past decade.

Spread of epidemic Clostridium difficile NAP1/027 in Latin America: case reports in Panama

The rate and severity of Clostridium difficile infection (CDI) have been linked to the emergence and spread of the hypervirulent toxigenic strain NAP1/027. This strain has been responsible for large outbreaks in healthcare facilities in North America and Europe and most recently in Latin America. This is the first report of the NAP1 strain in Panama. It suggests that the spread of C. difficile NAP1 throughout Latin America could be a possibility as evidenced in the following case reports. Five isolates typed as NAP1 had tcdA, tcdB, binary toxin gene cdtB and tcdC deletion. All isolates were resistant to clindamycin, fluoroquinolones and rifampicin. Under this scenario, surveillance programmes for CDI should be implemented in public health facilities in Latin America and diagnosis of CDI should be considered, especially in patients with predisposing factors.

Is obesity a risk factor for Clostridium difficile infection?

BACKGROUND

The epidemiology of Clostridium difficile infection (CDI) has become an important area of investigation, especially in light of the global increase in both hospital-acquired (HA) and community-acquired (CA) CDI. Recently, obesity was found to be associated with CDI and was suggested to represent an independent risk factor for it.

OBJECTIVE

We undertook a case-control study to examine obesity as an exposure for both HA and CA cases in adults (age ≥ 18 years) admitted to a tertiary, university-affiliated, acute care medical facility in the northeastern United States.

METHODS

During the period January 2012-July 2013, we examined cross-sectional BMI data on 189 cases of CDI and 189 contemporaneous age and gender-matched controls.

RESULTS

We were unable to detect a statistically significant difference between the two groups; in fact, the BMI values for both groups were substantially equivalent (cases: median=26.5 kg/m, IQR: 22.1-32.5; controls: median=26.0, IQR: 22.7-31.0; p=0.696). Odds ratios (and 95% confidence intervals), evaluated at BMI of 25, 30 and 35 kg/m(2), did not demonstrate statistical significance.

CONCLUSION

These data suggest that obesity, as described by BMI, may not be a risk factor for CDI in all populations.

The changing epidemiology of Clostridium difficile infection

PURPOSE OF REVIEW

Clostridium difficile infection (CDI) is a growing concern and has a substantial impact on morbidity and mortality. Epidemiology of CDI has dramatically changed over the last decade. Diagnostic and treatment strategies are even more complicated given the wide variety of available diagnostic methods and the emergence of refractory or recurrent CDI. This review is intended to provide information on current CDI epidemiology and guidance for evidence-based diagnosis and management strategies.

RECENT FINDINGS

Various studies from the United States, Europe, and Canada revealed increased incidence of CDI since 2000. Although CDI has long been associated with healthcare settings, recent studies indicate it is more common in the community than previously recognized. For diagnostic strategies, newer testing methods, including nucleic acid amplification tests, have enhanced sensitivity compared with toxin testing, but at the expense of decreased specificity. New agents for treating CDI are being developed and higher quality data to support fecal microbiota transplantation for treating recurrent CDI are emerging.

SUMMARY

CDI epidemiology continues to evolve. Prompt recognition and an evidence-based treatment approach is the key to successfully manage CDI. Further, studies on diagnostic and therapeutic strategies are needed to further improve patient outcomes.

Enteric infections

Cancer patients, particularly those with neutropenia, are at risk for enteric and intra-abdominal infections. Specific infections and infectious syndromes in this setting include neutropenic enterocolitis, bacterial infections such as Clostridium difficile infection (CDI), viral infections such as CMV colitis, and parasitic infections such as strongyloidiasis. Diagnosing and gauging the severity of CDI presents challenges, as chemotherapy may produce symptoms that mimic CDI and laboratory findings such as leukocytosis are not reliable in this population. Treatment for enteric infections should be pathogen specific, although broad-spectrum antibiotics are often required as initial empiric therapy in patients with neutropenia.

Medication risk factors associated with healthcare-associated Clostridium difficile infection: a multilevel model case-control study among 64 US academic medical centres

OBJECTIVES

The main objective of this study was to determine patient- and hospital-level medication risk factors associated with Clostridium difficile infection (CDI) occurrence among patients clustered within hospitals using a multilevel model.

METHODS

Patients with healthcare-associated (HA)-CDI were identified from among 64 academic medical centres in 2009. A frequency match was conducted; for each case, up to two controls were selected, matched on similar pre-infection length of stay and clinical service line. Patient- and hospital-level medication use, including antibacterial and gastric acid-suppressant agents, was assessed using a two-level logistic regression model.

RESULTS

A total of 5967 CDI cases and 8167 controls were included in the analysis. The odds of acquiring HA-CDI increased with the following medications [OR (95% CI)]: anti-methicillin-resistant Staphylococcus aureus agents [1.38 (1.22-1.56)]; third- or fourth-generation cephalosporins [1.75 (1.62-1.89)]; carbapenems [1.60 (1.44-1.79)]; β-lactam/β-lactamase inhibitor combinations [1.49 (1.36-1.64)]; vancomycin [1.73 (1.57-1.89)]; and proton pump inhibitors [1.43 (1.30-1.57)]. The odds of acquiring HA-CDI decreased with the following medications: clindamycin [0.74 (0.63-0.87)]; and macrolides [0.88 (0.77-0.99)]. Controlling for patient-level covariates, no hospital-level medication covariates that we analysed had statistically significant effects on HA-CDI. The odds of acquiring HA-CDI increased with the hospital proportion of patients aged ≥ 65 years [1.01 (1.00-1.02)].

CONCLUSIONS

We found several medications that were associated with the risk of patients developing HA-CDI, including β-lactam/β-lactamase inhibitor combinations, third- or fourth-generation cephalosporins, carbapenems, vancomycin, proton pump inhibitors and anti-methicillin-resistant S. aureus agents. There were no medication effects significant at the hospital level.

Viral co-infections are common and are associated with higher bacterial burden in children with clostridium difficile infection

Clostridium difficile infections in children are increasing. In this cohort study, we enrolled 62 children with diarrhea and C difficile. We performed polymerase chain reaction assays to detect viral agents of gastroenteritis and quantify C difficile burden. Fifteen (24%) children diagnosed as having C difficile infection had a concomitant viral co-infection. These patients tended to be younger and had a higher C difficile bacterial burden than children with no viral co-infections (median difference = 565,957 cfu/mL; P = 0.011), but were clinically indistinguishable. The contribution of viral co-infection to C difficile disease in children warrants future investigation.

Clinical significance of methicillin-resistant Staphylococcus aureus colonization on hospital admission: one-year infection risk

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization among inpatients is a well-established risk factor for MRSA infection during the same hospitalization, but the long-term risk of MRSA infection is uncertain. We performed a retrospective cohort study to determine the one-year risk of MRSA infection among inpatients with MRSA-positive nasal polymerase chain reaction (PCR) tests confirmed by positive nasal culture (Group 1), patients with positive nasal PCR but negative nasal culture (Group 2), and patients with negative nasal PCR (Group 3).

METHODOLOGY/PRINCIPAL FINDINGS

Subjects were adults admitted to a four-hospital system between November 1, 2006 and March 31, 2011, comprising 195,255 admissions. Patients underwent nasal swab for MRSA PCR upon admission; if positive, nasal culture for MRSA was performed; if recovered, MRSA was tested for Panton-Valentine Leukocidin (PVL). Outcomes included MRSA-positive clinical culture and skin and soft tissue infection (SSTI). Group 1 patients had a one-year risk of MRSA-positive clinical culture of 8.0% compared with 3.0% for Group 2 patients, and 0.6% for Group 3 patients (p<0.001). In a multivariable model, the hazard ratios for future MRSA-positive clinical culture were 6.52 (95% CI, 5.57 to 7.64) for Group 1 and 3.40 (95% CI, 2.70 to 4.27) for Group 2, compared with Group 3 (p<0.0001). History of MRSA and concurrent MRSA-positive clinical culture were significant risk factors for future MRSA-positive clinical culture. Group 1 patients colonized with PVL-positive MRSA had a one-year risk of MRSA-positive clinical culture of 10.1%, and a one-year risk of MRSA-positive clinical culture or SSTI diagnosis of 21.7%, compared with risks of 7.1% and 12.5%, respectively, for patients colonized with PVL-negative MRSA (p = 0.04, p = 0.005, respectively).

CONCLUSIONS/SIGNIFICANCE

MRSA nasal colonization is a significant risk factor for future MRSA infection; more so if detected by culture than PCR. Colonization with PVL-positive MRSA is associated with greater risk than PVL-negative MRSA.

The impact of cefepime as first line therapy for neutropenic fever on Clostridium difficile rates among hematology and oncology patients

After changing empiric treatment of febrile neutropenia from meropenem to cefepime, the effect on Clostridium difficile infection (CDI) was investigated. The change was assessed using an autoregressive model. A significant increase in CDI rates occurred following the introduction of cefepime. There may be an association between increased cefepime usage and CDI.

Risk factors, preemptive therapy, and antiperistaltic agents for Clostridium difficile infection in cancer patients

BACKGROUND

Clostridium difficile infection (CDI) is a serious complication of chemotherapy including high-dose regimens with autologous stem cell transplantation (ASCT). Antiperistaltic agents are contraindicated in CDI and preemptive CDI therapy is not recommended. We assessed the incidence, risk factors, and outcomes of CDI in patients with newly diagnosed multiple myeloma (MM) receiving similar antineoplastic therapy and supportive care including antiperistaltic agents and preemptive CDI antibiotics for significant diarrhea.

METHODS

A total of 303 consecutive MM patients (2004-2007) were enrolled in a protocol consisting of induction chemotherapy, tandem melphalan (MEL)-ASCT, and consolidation. Patients with grade 2-4 diarrhea were simultaneously tested for CDI, and initiated on antiperistaltic agents (loperamide) and preemptive anti-CDI therapy. Risk factors, including prior CDI and MM immunoglobulin (Ig) isotype, were evaluated. Multinomial logistic regression was used to compute the relative risk ratio (RRR) and 95% confidence intervals (CIs).

RESULTS

There were 43 cases of CDI (14.2%) during 1529 chemotherapy courses (536 ASCT). IgA MM protected against CDI (RRR 0.35; 95% CI 0.13-0.93, P = 0.04) whereas CDI during first induction markedly increased the risk of recurrence during second induction (RRR = 10.94; 95% CI 1.90, 62.92, P = 0.01) and following MEL-ASCT (RRR = 6.63; 95% CI 1.51, 29.12, P = 0.01). No CDI-related surgical intervention or death ensued despite use of antiperistaltic agents.

CONCLUSIONS

CDI was not uncommon in cancer patients receiving chemotherapy. IgA myeloma appears to be protective. Concurrent antiperistaltic (loperamide) and preemptive CDI therapies were associated with excellent outcomes. Prior CDI history increased the risk for recurrence during successive chemotherapy courses.

Influence of cohorting patients with Clostridium difficile infection on risk of symptomatic recurrence

BACKGROUND

Cohorting of patients with Clostridium difficile infection (CDI) is recommended when single side-rooms are unavailable. Although patients may remain infectious after cessation of diarrhoea, continued cohorting may place them at increased risk of reinfection.

AIM

To identify risk factors for CDI recurrence and to determine whether cohorting of patients is associated with increased risk of recurrence.

METHODS

Data describing patient demographics, comorbidity, CDI severity and treatment were collected for 248 CDI patients at our hospital between October 2008 and June 2011. The primary outcome was symptomatic recurrence within 30 days of diagnosis.

FINDINGS

One hundred and thirty-eight (55.6%) CDI patients were admitted to the cohort ward. These patients were more likely to have severe CDI (odds ratio: 1.95; 95% confidence interval: 1.10-3.46; P = 0.022) and receive vancomycin (1.59; 0.94-2.68; P = 0.083) than patients who were not cohorted. Twenty-six patients (10.5%) suffered recurrence (21 cohorted and five not cohorted). Urinary infection on admission (5.16; 2.10-12.64; P < 0.001), cohorting (3.77; 1.37-10.35; P = 0.01) and concomitant antibiotics (2.07; 0.91-4.72; P = 0.083) were associated with increased risk of recurrence. On multivariate analysis, cohorting (3.94; 1.23-12.65; P = 0.021) and urinary infection (4.27; 1.62-11.24; P = 0.003) were significant predictors of recurrence.

CONCLUSION

Patients admitted to a C. difficile cohort ward may be at increased risk of recurrence because they are at increased risk of reinfection. Hospitals using cohort wards to control C. difficile should manage patient flow through the cohort to minimize this risk.

Clostridium difficile infection in older adults

Clostridium difficile infection, the most frequent cause of nosocomial diarrhea, disproportionately affects older adults. The two most important risk factors for developing C. difficile infection are antimicrobial exposure and age >65 years old. Risk factors specific to older adults are frequent interactions with healthcare systems and age-related changes in physiology, including immune senescence and changes to the gut microbiome. Metronidazole and oral vancomcyin are the mainstays of conventional treatment for C. difficile infection. Alternative therapies include fidaxomicin, a narrow-spectrum macrocyclic antibiotic, and fectal bacteriotherapy, which offers an excellent therapeutic outcome. Strategies to prevent C. difficile infections include enhanced infection control measures and reducing inappropriate antimicrobial use through stewardship.

Excess risk of Clostridium difficile infection in ovarian cancer is related to exposure to broad-spectrum antibiotics

PURPOSE

The purpose of the study was to determine if a diagnosis of ovarian cancer is independently associated with an increased risk of Clostridium difficile infection (CDI).

METHODS

The University HealthSystem Consortium database was queried to perform a retrospective cohort study of women with and without ovarian cancer who were diagnosed with CDI. Inpatients undergoing total hysterectomy from 2008 to 2012 were studied. Ovarian cancer patients were compared to non-ovarian cancer patients to evaluate relative risk (RR) of CDI. Adjustment was made for known or suspected CDI risk factors to determine RR of CDI independent of these variables.

RESULTS

In this study, 115,203 patients were included. CDI was reported in 0.80 % of ovarian cancer patients and in 0.31 % of non-ovarian cancer patients (RR = 2.50; 95 % confidence interval (CI) = 2.02 to 3.35). Stratification by age, presence of other comorbidities, or administration of antineoplastic drugs did not significantly modify the elevated risk associated with ovarian cancer. Significantly increased risk in ovarian cancer patients was no longer observed after controlling for broad-spectrum antibiotic administration (RR = 1.28, 95 % CI = 0.39 to 4.13). Compared to non-ovarian cancer patients, ovarian cancer patients were more frequently treated with broad-spectrum antibiotics, had a 39 % longer mean duration of therapy, and had 2.5-fold greater mean total exposure to broad-spectrum antibiotics.

CONCLUSIONS

After adjustment for antibiotic use, ovarian cancer patients are not at excess risk of CDI. Additional studies are needed to understand the patterns of broad-spectrum antibiotic prescription for ovarian cancer patients leading to increased exposure. If feasible, reduction of this exposure may decrease morbidity in this population.

Clostridium difficile as a cause of acute diarrhea: a prospective study in a tertiary care center

INTRODUCTION

Clostridium difficile-associated diarrhea (CDAD) is an increasing problem. Recent reports suggest presence of community acquired CDAD (CA CDAD). Studies in India have shown varied results.

AIMS

The following are the aims of this study: (a) the prevalence of CDAD and CA CDAD in patients with acute diarrhea; (b) the incremental yield of second stool sample for the diagnosis of C. difficile infection (CDI); and (c) the risk factors for CDI.

PATIENTS AND METHODS

Patients with acute diarrhea (<4 weeks) between April 2009 and December 2010 had two stool sample tested for C. difficile toxin (CDT) by enzyme-linked immunofluorescent assay. Demographic, clinical data, risk factors, clinical course, complications, treatment, and response were noted.

RESULTS

Of 150 patients (mean age, 47.3 years; 76 males), 12 (8 %) had their first stool sample positive for CDT. Two patients (1.3 %) had community acquired CDI. The study group was compared with 138 patients ("control group", stool samples negative for CDT). Compared to the controls, the study group were more likely to have had intensive care unit (ICU) stay (p = 0.018) and tube feeding (p = 0.035). Eleven patients were treated with metronidazole. One patient did not respond to metronidazole and was treated with vancomycin. No patient developed complications of CDAD.

CONCLUSIONS

The prevalence of CDAD in our population was 8 % and of CA CDAD was 1.3 %. There was no advantage of testing two samples. ICU stay and tube feeding were major risk factors for the CDAD. Metronidazole was an effective first-line therapy.

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

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

Adjuvant vancomycin for antibiotic prophylaxis and risk of Clostridium difficile infection after coronary artery bypass graft surgery

OBJECTIVE

The incidence of hospital-acquired Clostridium difficile infection (CDI) has increased rapidly over the past decade; patients undergoing major surgery, including coronary artery bypass grafting (CABG), are at particular risk. Intravenous vancomycin exposure has been identified as an independent risk factor for CDI, but this is controversial. It is not known whether vancomycin administered for surgical site infection prophylaxis increases the risk of CDI.

METHODS

Using data from the Premier Perspective Comparative Database, we assembled a cohort of 69,807 patients undergoing CABG surgery between 2004 and 2010 who received either a cephalosporin alone (65.1%) or a cephalosporin plus vancomycin (34.9%) on the day of surgery. Patients were observed for CDI until discharge from the index hospitalization. In these groups, we evaluated the comparative rate of postoperative CDI with Cox models; confounding was addressed using propensity scores.

RESULTS

In all, 77 (0.32%) of the 24,393 patients receiving a cephalosporin plus vancomycin and 179 (0.39%) of the 45,414 patients receiving a cephalosporin alone had postoperative CDI (unadjusted hazard ratio [HR], 0.73; 95% confidence interval [CI], 0.56-0.95). After adjusting for confounding variables with either propensity score matching or stratification, there was no meaningful association between adjuvant vancomycin exposure and postoperative CDI (HR, 0.85; 95% CI, 0.61-1.19; and HR, 0.85; 95% CI, 0.63-1.15, respectively). Results of multiple sensitivity analyses were similar to the main findings.

CONCLUSIONS

After adjustment for patient and surgical characteristics, a short course of prophylactic vancomycin was not associated with an increased risk of CDI among patients undergoing CABG surgery.

Validation of the chronic disease score-infectious disease (CDS-ID) for the prediction of hospital-associated clostridium difficile infection (CDI) within a retrospective cohort

Background

Aggregate comorbidity scores are useful for summarizing risk and confounder control in studies of hospital-associated infections. The Chronic Disease Score – Infectious Diseases (CDS-ID) was developed for this purpose, but it has not been validated for use in studies of Clostridium difficile Infection (CDI). The aim of this study was to assess the discrimination, calibration and potential for confounder control of CDS-ID compared to age alone or individual comorbid conditions.

Methods

Secondary analysis of a retrospective cohort study of adult inpatients with 2 or more days of antibiotic exposure at a tertiary care facility during 2005. Logistic regression models were used to predict the development of CDI up to 60 days post-discharge. Model discrimination and calibration were assessed using the c-statistic and Hosmer-Lemeshow (HL) tests, respectively. C-statistics were compared using chi-square tests.

Results

CDI developed in 185 out of 7,792 patients. The CDS-ID was a better standalone predictor of CDI than age (c-statistic 0.653 vs 0.609, P=0.04). The best discrimination was observed when CDS-ID and age were both used to predict CDI (c-statistic 0.680). All models had acceptable calibration (P>0.05).

Conclusion

The CDS-ID is a valid tool for summarizing risk of CDI associated with comorbid conditions.

Markers of intestinal inflammation, not bacterial burden, correlate with clinical outcomes in Clostridium difficile infection

BACKGROUND

Clostridium difficile is a leading hospital-acquired infection. Many patients remain symptomatic for several days on appropriate antibiotic therapy. To assess the contribution of ongoing infection vs persistent inflammation, we examined the correlation between fecal cytokine levels, fecal C. difficile burden, and disease outcomes in C. difficile infection (CDI).

METHODS

We conducted a prospective cohort study in Barnes Jewish Hospital between June 2011 and May 2012 of hospitalized adults with CDI. We determined fecal interleukin 8 (IL-8) and lactoferrin protein concentrations by enzyme immunoassay. We used real-time polymerase chain reaction (PCR) to measure relative fecal IL-8 and CXCL-5 RNA transcript abundances, and quantitative PCR to enumerate C. difficile burden.

RESULTS

Of 120 study subjects, 101 (84%) were started on metronidazole, and 33 of those (33%) were subsequently given vancomycin. Sixty-two (52%) patients had diarrhea persistent for 5 or more days after starting CDI therapy. Initial fecal CXCL-5 messenger RNA (mRNA), IL-8 mRNA, and IL-8 protein correlated with persistent diarrhea and use of vancomycin. Time to diarrhea resolution was longer in patients with elevated fecal cytokines at diagnosis. Fecal cytokines were more sensitive than clinical severity scores in identifying patients at risk of treatment failure. Clostridium difficile burden did not correlate with any measure of illness or outcome at any point, and decreased equally with metronidazole and vancomycin.

CONCLUSIONS

Persistent diarrhea in CDI correlates with intestinal inflammation and not fecal pathogen burden. These findings suggest that modulation of host response, rather than adjustments to antimicrobial regimens, might be a more effective approach to patients with unremitting disease.

The association between histamine 2 receptor antagonist use and Clostridium difficile infection: a systematic review and meta-analysis

BACKGROUND

Clostridium difficile infection (CDI) is a major health problem. Epidemiological evidence suggests that there is an association between acid suppression therapy and development of CDI.

PURPOSE

We sought to systematically review the literature that examined the association between histamine 2 receptor antagonists (H2RAs) and CDI.

DATA SOURCE

We searched Medline, Current Contents, Embase, ISI Web of Science and Elsevier Scopus from 1990 to 2012 for all analytical studies that examined the association between H2RAs and CDI.

STUDY SELECTION

Two authors independently reviewed the studies for eligibility.

DATA EXTRACTION

Data about studies characteristics, adjusted effect estimates and quality were extracted.

DATA SYNTHESIS

Thirty-five observations from 33 eligible studies that included 201834 participants were analyzed. Studies were performed in 6 countries and nine of them were multicenter. Most studies did not specify the type or duration of H2RAs therapy. The pooled effect estimate was 1.44, 95% CI (1.22-1.7), I(2) = 70.5%. This association was consistent across different subgroups (by study design and country) and there was no evidence of publication bias. The pooled effect estimate for high quality studies was 1.39 (1.15-1.68), I2 = 72.3%. Meta-regression analysis of 10 study-level variables did not identify sources of heterogeneity. In a speculative analysis, the number needed to harm (NNH) with H2RAs at 14 days after hospital admission in patients receiving antibiotics or not was 58, 95% CI (37, 115) and 425, 95% CI (267, 848), respectively. For the general population, the NNH at 1 year was 4549, 95% CI (2860, 9097).

CONCLUSION

In this rigorous systematic review and meta-analysis, we observed an association between H2RAs and CDI. The absolute risk of CDI associated with H2RAs is highest in hospitalized patients receiving antibiotics.

A methodological, systematic review of evidence-based independent risk factors for surgical site infections after spinal surgery

OBJECTIVE

To identify the independent risk factors, based on available evidence in the literature, for patients developing surgical site infections (SSI) after spinal surgery.

METHODS

Non-interventional studies evaluating the independent risk factors for patients developing SSI following spinal surgery were searched in Medline, Embase, Sciencedirect and OVID. The quality of the included studies was assessed by a modified quality assessment tool that had been previously designed for observational studies. The effects of studies were combined with the study quality score using a best-evidence synthesis model.

RESULTS

Thirty-six observational studies involving 2,439 patients with SSI after spinal surgery were identified. The included studies covered a wide range of indications and surgical procedures. These articles were published between 1998 and 2012. According to the quality assessment criteria for included studies, 15 studies were deemed to be high-quality studies, 5 were moderate-quality studies, and 16 were low-quality studies. A total of 46 independent factors were evaluated for risk of SSI. There was strong evidence for six factors, including obesity/BMI, longer operation times, diabetes, smoking, history of previous SSI and type of surgical procedure. We also identified 8 moderate-evidence, 31 limited-evidence and 1 conflicting-evidence factors.

CONCLUSION

Although there is no conclusive evidence for why postoperative SSI occurs, these data provide evidence to guide clinicians in admitting patients who will have spinal operations and to choose an optimal prophylactic strategy. Further research is still required to evaluate the effects of these above risk factors.

Outcomes of health care-associated pneumonia empirically treated with guideline-concordant regimens versus community-acquired pneumonia guideline-concordant regimens for patients admitted to acute care wards from home

BACKGROUND

The introduction of the health care-associated pneumonia (HCAP) categorization expanded recommendations for broad-spectrum empiric antibiotics to pneumonia patients presenting from the community with recent health care-system exposure. However, the efficacy of such regimens in improving clinical outcomes in these patients has not been well established.

OBJECTIVE

To compare the clinical outcomes of HCAP patients treated initially with HCAP guideline-concordant antibiotic regimens to those treated initially with community-acquired pneumonia (CAP) guideline-concordant antibiotic regimens.

METHODS

This retrospective study included HCAP patients presenting from home and admitted to general medical wards. HCAP regimen patients were treated empirically with at least 1 antipseudomonal agent. All other patients were assigned to the CAP regimen group. The primary end point was clinical cure at 30 days postdischarge. Subgroup analysis was performed in patients hospitalized 1-30 days and 31-90 days before the HCAP admission.

RESULTS

Of 228 HCAP admissions, 122 patients received CAP regimens and 106 received HCAP regimens. The 2 groups were similar at baseline, including Pneumonia Severity Index scores. Attributable clinical cure occurred in 75.4% of CAP regimen patients and 69.8% of HCAP regimen patients (p = 0.34). Overall clinical cure occurred in 59.8% of CAP regimen patients and 54.7% of HCAP regimen patients (p = 0.44). The CAP regimen group used fewer days of intravenous antibiotics (4.39 vs 7.75, p < 0.0001) and had shorter lengths of stay (6.36 vs 8.58 days, p < 0.0001). For patients hospitalized 31-90 days earlier, clinical cure was higher in the CAP regimen group (attributable, 82.9% vs 60.0%, p = 0.0090; overall, 67.1% vs 47.5%, p = 0.044).

CONCLUSIONS

Compared to CAP guideline-concordant regimens, treatment of HCAP with HCAP guideline-concordant regimens did not increase clinical cure rates and was associated with lower clinical cure rates in patients hospitalized 31-90 days prior to the HCAP admission. This study suggests that broad-spectrum empiric antibiotics may not be necessary in all HCAP patient groups.

MAPK-activated protein kinase 2 contributes to Clostridium difficile-associated inflammation

Clostridium difficile infection (CDI) results in toxin-induced epithelial injury and marked intestinal inflammation. Fecal markers of intestinal inflammation correlate with CDI disease severity, but regulation of the inflammatory response is poorly understood. Previous studies demonstrated that C. difficile toxin TcdA activates p38 kinase in tissue culture cells and mouse ilium, resulting in interleukin-8 (IL-8) release. Here, we investigated the role of phosphorylated mitogen-activated protein kinase (MAPK)-activated protein kinase (MK2 kinase, pMK2), a key mediator of p38-dependent inflammation, in CDI. Exposure of cultured intestinal epithelial cells to the C. difficile toxins TcdA and TcdB resulted in p38-dependent MK2 activation. Toxin-induced IL-8 and GROα release required MK2 activity. We found that p38 and MK2 are activated in response to other actin-disrupting agents, suggesting that toxin-induced cytoskeleton disruption is the trigger for kinase-dependent cytokine response. Phosphorylated MK2 was detected in the intestines of C. difficile-infected hamsters and mice, demonstrating for the first time that the pathway is activated in infected animals. Furthermore, we found that elevated pMK2 correlated with the presence of toxigenic C. difficile among 100 patient stool samples submitted for C. difficile testing. In conclusion, we find that MK2 kinase is activated by TcdA and TcdB and regulates the expression of proinflammatory cytokines. Activation of p38-MK2 in infected animals and humans suggests that this pathway is a key driver of intestinal inflammation in patients with CDI.

Unnecessary antimicrobial use in patients with current or recent Clostridium difficile infection

OBJECTIVE

To determine the fraction of unnecessary antimicrobial use among patients with current and/or recent Clostridium difficile infection (CDI).

DESIGN

Retrospective review from January 2004 through December 2006.

SETTING

Minneapolis Veterans Affairs Medical Center (MVAMC).

PARTICIPANTS

Patients with new-onset CDI diagnosed at the MVAMC without another CDI diagnosis in the prior 30 days.

METHODS

Pharmacy and medical records were reviewed to identify incident CDI cases, non-CDI antimicrobial use during and up to 30 days after completion of CDI treatment, and patient characteristics. Two infectious disease physicians independently assessed non-CDI antimicrobial use, which was classified as unnecessary if not fully indicated. Factors associated with only unnecessary use were identified through univariable and multivariable analysis.

RESULTS

Of 246 patients with new-onset CDI, 141 (57%) received non-CDI antimicrobials during and/or after their CDI treatment, totaling 2,147 antimicrobial days and 445 antimicrobial courses. The two reviewers agreed regarding the necessity of antimicrobials in more than 99% of antimicrobial courses (85% initially, 14% after discussion). Seventy-seven percent of patients received at least 1 unnecessary antimicrobial dose, 26% of patients received only unnecessary antimicrobials, and 45% of total non-CDI antimicrobial days included unnecessary antimicrobials. The leading indications for unnecessary antimicrobial use were putative urinary tract infection and pneumonia. Drug classes frequently used unnecessarily were fluoroquinolones and β-lactams.

CONCLUSIONS

Twenty-six percent of patients with recent CDI received only unnecessary (and therefore potentially avoidable) antimicrobials. Heightened awareness and caution are needed when antimicrobial therapy is contemplated for patients with recent CDI.

Clostridium difficile infection and limitations of markers for severity in patients with hematologic malignancy

OBJECTIVE

To describe characteristics of Clostridium difficile infection (CDI) and markers of severe CDI among patients with hematologic malignancies.

DESIGN

Case-control study.

SETTING

Tertiary care teaching hospital.

PATIENTS AND METHODS

Inpatients with hematologic malignancies and CDI were age and time matched with 2 control inpatients without hematologic malignancies. Chart reviews were performed, and C. difficile isolates were strain typed.

RESULTS

Case patients (n = 41) and control patients (n = 82) patients were different in respect to receipt of immunosuppressive agents within 2 months (92.7% vs 25.6%; P < .0001); neutropenia within 2 months (75.6% vs 3.7%; P < .0001) and mean (± standard deviation) white blood cell (WBC) count at diagnosis (vs 4.9 ± 14.1 vs 11.8 ± 6.8 x 10(3) cells/mL; P <.0001); baseline mean creatinine level (0.89 ± 0.1 vs 1.6 ± 2.4 mg/dL; P = .003), mean creatinine level at diagnosis (0.83 ± 0.4 vs 1.85 ± 1.9 mg/dL; P = .004), and creatinine increases of 1.5 times over baseline (2.4% vs 15.1%; P = .02). Immunosuppressive agents and creatinine level remained significant in multivariable analysis (P = .03 for both variables). Severity correlated with mortality when measured by alternate severity criteria but not when measured by the Society for Healthcare Epidemiology of America/Infectious Diseases Society of America criteria, which are based solely on WBC count and creatinine elevation. The prevalence of the epidemic BI/NAP1/027 strain was similar in both groups.

CONCLUSIONS

Patients with hematologic malignancies had lower creatinine levels at the time of CDI diagnosis compared with control patients. WBC counts also tended to be lower in case patients. CDI severity criteria based on WBC count and creatinine level may not be applicable to patients with hematologic malignancies.

Burden of Clostridium difficile on the healthcare system

There are few high-quality studies of the costs of Clostridium difficile infection (CDI), and the majority of studies focus on the costs of CDI in acute-care facilities. Analysis of the best available data, from 2008, indicates that CDI may have resulted in $4.8 billion in excess costs in US acute-care facilities. Other areas of CDI-attributable excess costs that need to be investigated are costs of increased discharges to long-term care facilities, of CDI with onset in long-term care facilities, of recurrent CDI, and of additional adverse events caused by CDI.

Association of decreased serum protein fractions with Clostridium difficile infection in the acute care setting: a case–control study

Aim: This study examines the association of decreased levels of serum proteins with the occurrence of Clostridium difficile-associated diarrhea (CDAD) in hospitalized patients. Materials & methods: This is a retrospective case–control study using a case cohort (n = 171) that had been described in an earlier study and a cohort of 332 contemporaneous controls. Results: Patients with CDAD had significantly lower serum levels of albumin, total protein and globulins, and decreased albumin/globulin ratio (p < 0.0001 for all parameters). After adjustment for confounders, hypoproteinemia was more closely associated with CDAD than either hypoalbuminemia or albumin/globulin ratio. Hypoproteinemia exhibited an odds ratios of 10.6 (95% CI: 6.62–17.0) after adjustment for race, and 11.0 (95% CI: 6.88–17.1) after adjustment for age. Conclusion: Decreased total serum protein is more closely associated with CDAD than hypoalbuminemia.

Gastric acid suppression and outcomes in Clostridium difficile infection: a population-based study

OBJECTIVE

To evaluate the association of gastric acid suppression medications, including proton pump inhibitors and histamine type 2 blockers, with outcomes in patients with Clostridium difficile infection (CDI) in a population-based cohort.

PATIENTS AND METHODS

To understand the association between acid suppression and outcomes in patients with CDI, we conducted a population-based study in Olmsted County, Minnesota, from January 1, 1991, through December 31, 2005. We compared demographic data and outcomes, including severe, severe-complicated, and recurrent CDI and treatment failure, in a cohort of patients with CDI who were treated with acid suppression medications with these outcomes in a cohort with CDI that was not exposed to acid-suppressing agents.

RESULTS

Of 385 patients with CDI, 36.4% were undergoing acid suppression (23.4% with proton pump inhibitors, 13.5% with histamine type 2 blockers, and 0.5% with both). On univariate analysis, patients taking acid suppression medications were significantly older (69 vs 56 years; P<.001) and more likely to have severe (34.2% vs 23.6%; P=.03) or severe-complicated (4.4% vs 2.6% CDI; P=.006) infection than patients not undergoing acid suppression. On multivariable analyses, after adjustment for age and comorbid conditions, acid suppression medication use was not associated with severe or severe-complicated CDI. In addition, no association between acid suppression and treatment failure or CDI recurrence was found.

CONCLUSION

In this population-based study, after adjustment for age and comorbid conditions, patients with CDI who underwent acid suppression were not more likely to experience severe or severe-complicated CDI, treatment failure, or recurrent infection.

Clostridium difficile-associated diarrhea and proton pump inhibitor therapy: a meta-analysis

OBJECTIVES

Clostridium difficile-associated diarrhea (CDAD) is a major cause of morbidity and increasing health-care costs among hospitalized patients. Although exposure to antibiotics remains the most documented risk factor for CDAD, attention has recently been directed toward a plausible link with proton pump inhibitors (PPIs). However, the results of studies on the association between CDAD and PPIs remain controversial. We have conducted a meta-analysis to summarize the association between PPIs and CDAD among hospitalized patients.

METHODS

A systematic search of published literature on studies that investigated the association between PPIs and CDAD from 1990 to 2010 was conducted on Medline and PubMed. The identified articles were reviewed for additional references. The most adjusted risk estimates were extracted by two authors and summarized using random effects meta-analysis. We also conducted a subgroup analysis by study design. Publication bias was evaluated using the Begg and Egger tests. A sensitivity analysis using the Duval and Tweedie "trim-and-fill" method has also been performed.

RESULTS

Twenty-three studies including close to 300,000 patients met the inclusion criteria. There was a 65% (summary risk estimate 1.69 with a 95% confidence interval (CI) from 1.395 to 1.974; P<0.000) increase in the incidence of CDAD among patients on PPIs. By study design, whether case-control study (17) or cohort study (6), there was still a significant increase in the incidence of CDAD among PPI users. The risk estimates were 2.31 (95% CI from 1.72 to 3.10; P<0.001) and 1.48 (95% CI from 1.25 to 1.75; P<0.001) for cohort and case-control studies, respectively.

CONCLUSIONS

There is sufficient evidence to suggest that PPIs increase the incidence of CDAD. Our meta-analysis shows a 65% increase in the incidence of CDAD among PPI users. We recommend that the routine use of PPIs for gastric ulcer prophylaxis should be more prudent. Establishing a guideline for the use of PPI may help in the future with the judicious use of PPIs. Further studies, preferably prospective, are needed to fully explore the association between PPIs and CDAD.

Epidemiology of Clostridium difficile infections in a tertiary-care hospital in Korea

To survey healthcare-associated Clostridium difficile infection (HA-CDI) in a 900-bed tertiary-care hospital, we prospectively investigated the epidemiology of CDI and distribution of PCR-ribotypes. From February 2009 through January 2010, all patients with HA-CDI were enrolled. Epidemiological information and prescription records for antibiotics were collected. The C. difficile isolates were characterized using reference strains and were tested for antibiotic susceptibility. During the survey, incidence of HA-CDI was 71.6 per 100 000 patient-days. In total, 140 C. difficile isolates were obtained from 166 patients with HA-CDI. The PCR-ribotyping yielded 38 distinct ribotypes. The three most frequently found ribotypes made up 56.4% of all isolates; they comprised 37 isolates (26.4%) of PCR-ribotype 018, 22 (15.7%) of toxin A-negative PCR-ribotype 017, and 20 (14.3%) of PCR-ribotype 001. Clostridium difficile PCR-ribotype 018 was present in all departments throughout the hospital during the 11 months, whereas ribotype 017 and ribotype 001 appeared mostly in the pulmonary department. Hypervirulent C. difficile PCR-ribotype 027 was detected in 1 month on two wards. The incidence of CDI in each department showed a seven-fold difference, which correlated significantly with the amount of prescribed clindamycin (R = 0.783, p 0.013) or moxifloxacin (R = 0.733, p 0.025) in the departments. The rates of resistance of the three commonest ribotypes to clindamycin and moxifloxacin were significantly higher than those of other strains (92.1% versus 38.2% and 89.5% versus 27.3%, respectively). CDI is an important nosocomially acquired infection and this study emphasizes the importance of implementing country-wide surveillance to detect and control CDI in Korea.

Clostridium difficile infection in a patient with Crohn disease

Crohn disease is a chronic inflammatory disorder, which is rare in pediatric patients. The definite etiology and mechanism to induce an acute exacerbation of Crohn disease remains mostly unknown. The authors report on a 14-year-old girl with Crohn disease who has acute gastrointestinal symptoms caused by toxin A-producing Clostridium difficile, which mimicked a flare-up of Crohn disease. There was no preceding antibiotic prescription before the episode. The disease activity did not improve after steroid treatment, which is unusual for Crohn disease. However, all symptoms were dramatically relieved after eradication of C difficile, and led to a symptom-free period for more than 3 years. This case report aims to address the unusual presentation of a usual pathogen, C difficile, in a pediatric patient with Crohn disease.

Proton pump inhibitor use and recurrent Clostridium difficile-associated disease: a case-control analysis matched by propensity score

BACKGROUND AND AIM

Clostridium difficile has been increasingly diagnosed in hospitalized patients. An association between proton pump inhibitors (PPIs) use and Clostridium difficile-associated disease (CDAD) and between recurrent CDAD has been suggested. The aim of this study is to investigate whether PPI use is associated with the development of recurrent CDAD.

METHODS

This was a retrospective case-control study of patients with CDAD at Yeungnam University Medical Center, seen from January 2004 to December 2008. C. difficile infection was diagnosed by the presence of C. difficile toxin in the stool. Those with recurrent disease were matched with nonrecurrent controls using multivariate matched sampling methods that incorporated the propensity score.

RESULTS

Recurrent CDAD developed in 28 (14.1%) of the 198 patients with diarrhea and positive C. difficile stool toxin assays. Multivariate analysis of the total population of recurrent versus nonrecurrent CDAD revealed that additional use of non-C. difficile antimicrobial therapy (concomitant with the treatment or after or both), poor response to therapy with metronidazole or vancomycin, and recent gastrointestinal surgery were risk factors for recurrent CDAD. We were able to match 21 recurrent CDAD subjects with 21 without recurrent CDAD. Among the matched patients only PPI use was associated with recurrent CDAD (ie, 47.6% vs. 4.8%, P=0.004 for recurrent vs. nonrecurrent CDAD, respectively).

CONCLUSIONS

Among the matched patient groups, only PPI therapy was associated with recurrent CDAD. Prospective studies are needed to clarify whether avoidance of PPIs or specific cotherapies will reduce the incidence of recurrent C. difficile-associated diarrhea.

Risk factors for Clostridium difficile toxin-positive diarrhea: a population-based prospective case-control study

Increased incidence and severity of Clostridium difficile infections (CDIs) is of major concern. However, by minimizing known risk factors, the incidence can be decreased. The aim of this investigation was to calculate the incidence and assess risk factors for CDI in our population. A 1-year prospective population-based nationwide study in Iceland of CDIs was carried out. For risk factor evaluation, each case was matched with two age- and sex-matched controls that tested negative for C. difficile toxin. A total of 128 CDIs were identified. The crude incidence was 54 cases annually per 100,000 population >18 years of age. Incidence increased exponentially with older age (319 per 100,000 population >86 years of age). Community-acquired origin was 27 %. Independent risk factors included: dicloxacillin (odds ratio [OR]: 7.55, 95 % confidence interval [CI]: 1.89-30.1), clindamycin (OR: 6.09, 95 % CI: 2.23-16.61), ceftriaxone (OR: 4.28, 95 % CI: 1.59-11.49), living in a retirement home (OR: 3.9, 95 % CI: 1.69-9.16), recent hospital stay (OR: 2.3, 95 % CI: 1.37-3.87). Proton pump inhibitors (PPIs) were used by 60/111 (54 %) versus 91/222 (41 %) (p = 0.026) and ciprofloxacin 19/111 (17 %) versus 19/222 (9 %) (p = 0.027) for cases and controls, respectively. In all, 75 % of primary CDIs treated with metronidazole recovered from one course of treatment. CDI was mostly found among elderly patients. The most commonly identified risk factors were broad-spectrum antibiotics and recent contact with health care institutions. PPI use was significantly more prevalent among CDI patients.

Association between proton pump inhibitor therapy and Clostridium difficile infection in a meta-analysis

BACKGROUND & AIMS

In the past decade, there has been a growing epidemic of Clostridium difficile infection (CDI). During this time, use of proton pump inhibitors (PPIs) has increased exponentially. We evaluated the association between PPI therapy and the risk of CDI by performing a meta-analysis.

METHODS

We searched MEDLINE and 4 other databases for subject headings and text words related to CDI and PPI in articles published from 1990 to 2010. All observational studies that investigated the risk of CDI associated with PPI therapy and used CDI as an end point were considered eligible. Two investigators screened articles independently for inclusion criteria, data extraction, and quality assessment; disagreements were resolved based on consensus with a third investigator. Data were combined by means of a random-effects model and odds ratios were calculated. Subgroup and sensitivity analyses were performed based on study design and antibiotic use.

RESULTS

Thirty studies (25 case-control and 5 cohort) reported in 29 articles met the inclusion criteria (n = 202,965). PPI therapy increased the risk for CDI (odds ratio, 2.15, 95% confidence interval, 1.81-2.55), but there was significant heterogeneity in results among studies (P < .00001). This association remained after subgroup and sensitivity analyses, although significant heterogeneity persisted among studies.

CONCLUSIONS

PPI therapy is associated with a 2-fold increase in risk for CDI. Because of the observational nature of the analyzed studies, we were not able to study the causes of this association. Further studies are needed to determine the mechanisms by which PPI therapy might increase risk for CDI.

Infections in spinal instrumentation

Surgical-site infection (SSI) in the spine is a serious postoperative complication. Factors such as posterior surgical approach, arthrodesis, use of spinal instrumentation, age, obesity, diabetes, tobacco use, operating-room environment and estimated blood loss are well established in the literature to affect the risk of infection. Infection after spine surgery with instrumentation is becoming a common pathology. The reported infection rates range from 0.7% to 11.9%, depending on the diagnosis and complexity of the procedure. Besides operative factors, patient characteristics could also account for increased infection rates. These infections after instrumented spinal fusion are particularly difficult to manage due to the implanted, and possibly infected, instrumentation. Because the medical, economic and social costs of SSI after spinal instrumentation are enormous, any significant reduction in risks will pay dividends. The goal of this literature review was to analyse risk factors, causative organisms, diagnostic elements (both clinical and biological), different treatment options and their efficiency and consequences and the means of SSI prevention.

Systematic review: the use of proton pump inhibitors and increased susceptibility to enteric infection

The use of proton pump inhibitors (PPIs) is increasing worldwide. Suppression of gastric acid alters the susceptibility to enteric bacterial pathogens. AIM  This systematic review was undertaken to examine the relationship between PPI use and susceptibility to enteric infections by a specific pathogen based on published literature and to discuss the potential mechanisms of PPI enhanced pathogenesis of enteric infections. METHODS  PubMed, OVID Medline Databases were searched. Search terms included proton pump inhibitors and mechanisms of, actions of, gastric acid, enteric infections, diarrhoea, Clostridium difficile, Salmonella, Shigella and Campylobacter. RESULTS The use of PPIs increases gastric pH, encourages growth of the gut microflora, increases bacterial translocation and alters various immunomodulatory and anti-inflammatory effects. Enteric pathogens show variable gastric acid pH susceptibility and acid tolerance levels. By multiple mechanisms, PPIs appear to increase susceptibility to the following bacterial enteropathogens: Salmonella, Campylobacter jejuni, invasive strains of Escherichia coli, vegetative cells of Clostridium difficile, Vibrio cholerae and Listeria. We describe the available evidence for enhanced susceptibility to enteric infection caused by Salmonella, Campylobacter and C. difficile by PPI use, with adjusted relative risk ranges of 4.2-8.3 (two studies); 3.5-11.7 (four studies); and 1.2-5.0 (17 of 27 studies) for the three respective organisms. CONCLUSIONS Severe hypochlorhydria generated by PPI use leads to bacterial colonisation and increased susceptibility to enteric bacterial infection. The clinical implication of chronic PPI use among hospitalized patients placed on antibiotics and travellers departing for areas with high incidence of diarrhoea should be considered by their physicians.

Cumulative antibiotic exposures over time and the risk of Clostridium difficile infection

BACKGROUND

Clostridium difficile infection (CDI) is a major cause of hospital-acquired diarrhea and is most commonly associated with changes in normal intestinal flora caused by administration of antibiotics. Few studies have examined the risk of CDI associated with total dose, duration, or number of antibiotics while taking into account the complex changes in exposures over time.

METHODS

A retrospective cohort study conducted from 1 January to 31 December 2005 among hospitalized patients 18 years or older receiving 2 or more days of antibiotics.

RESULTS

The study identified 10,154 hospitalizations for 7,792 unique patients and 241 cases of CDI, defined as the detection of C. difficile toxin in a diarrheal stool sample within 60 days of discharge. We observed dose-dependent increases in the risk of CDI associated with increasing cumulative dose, number of antibiotics, and days of antibiotic exposure. Compared to patients who received only 1 antibiotic, the adjusted hazard ratios (HRs) for those who received 2, 3 or 4, or 5 or more antibiotics were 2.5 (95% confidence interval [CI] 1.6-4.0), 3.3 (CI 2.2-5.2), and 9.6 (CI 6.1-15.1), respectively. The receipt of fluoroquinolones was associated with an increased risk of CDI, while metronidazole was associated with reduced risk.

CONCLUSIONS

Cumulative antibiotic exposures appear to be associated with the risk of CDI. Antimicrobial stewardship programs that focus on the overall reduction of total dose as well as number and days of antibiotic exposure and the substitution of high-risk antibiotic classes for lower-risk alternatives may reduce the incidence of hospital-acquired CDI.

Development and validation of a Clostridium difficile infection risk prediction model

OBJECTIVE

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

DESIGN AND SETTING

Retrospective cohort study in a tertiary care medical center.

PATIENTS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Differential risk of Clostridium difficile infection with proton pump inhibitor use by level of antibiotic exposure

PURPOSE

Clostridium difficile infection (CDI) is a major cause of hospital-acquired diarrhea worldwide. We examined the risk of CDI associated with the use of acid-suppressive agents (proton pump inhibitors [PPI] and histamine-2 receptor blockers) and determined whether this risk varied by number or type of antibiotic (high or low CDI risk) received during hospitalization.

METHODS

We conducted a retrospective cohort study of hospitalizations among adult patients at an academic teaching hospital in Rochester, New York, during which two or more days of antibiotics were prescribed. Multivariable marginal Cox proportional hazards models with time-varying exposures were used to examine time to the development of CDI.

RESULTS

A total of 10 154 hospitalizations and 241 cases of CDI, defined as detection of C. difficile toxin in a diarrheal stool sample within 60 days of discharge, were identified. PPI use was independently associated with an increased risk of CDI (adjusted hazard ratio = 4.5; 95% confidence interval [CI] = 2.3-9.0). Among hospitalizations during which one, two, three or four, and five or more antibiotics were prescribed, the adjusted hazard ratios for PPI use were 15.7 (CI = 6.4-38.8), 4.9 (CI = 2.2-11.2), 4.3 (CI = 1.9-9.9), and 2.7 (CI = 1.2-5.9), respectively (p for interaction = .002).

CONCLUSIONS

The use of PPI is common among patients receiving antibiotics during hospitalization. The greater risk of CDI in relation to PPI among hospitalizations during which fewer or low-risk antibiotics were prescribed suggests a potentially clinically relevant interaction between antibiotics and PPI. Further study is needed to elucidate possible mechanisms for the observed effect.

Systematic review of measurement and adjustment for colonization pressure in studies of methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and clostridium difficile acquisition

OBJECTIVE

Colonization pressure is an important infection control metric. The aim of this study was to describe the definition and measurement of and adjustment for colonization pressure in nosocomial-acquisition risk factor studies of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and Clostridium difficile.

METHODS

We performed a computerized search of studies of nosocomial MRSA, VRE, and C. difficile acquisition published before July 1, 2009, through MEDLINE. Studies were included if a study outcome was MRSA, VRE, or C. difficile acquisition; the authors identified risk factors associated with MRSA, VRE, or C. difficile acquisition; and the study measured colonization pressure.

RESULTS

The initial MEDLINE search yielded 505 articles. Sixty-six of these were identified as studies of nosocomial MRSA, VRE, or C. difficile acquisition; of these, 18 (27%) measured colonization pressure and were included in the final review. The definition of colonization pressure varied considerably between studies: the proportion of MRSA- or VRE-positive patients (5 studies), the proportion of MRSA- or VRE-positive patient-days (6 studies), or the total or mean number of MRSA-, VRE-, or C. difficile-positive patients or patient-days (7 studies) in the unit over periods of varying length. In 10 of 13 studies, colonization pressure was independently associated with MRSA, VRE, or C. difficile acquisition.

CONCLUSION

There is a need for a simple and consistent method to quantify colonization pressure in both research and routine clinical care to accurately assess the effect of colonization pressure on cross-transmission of antibiotic-resistant bacteria.

Evaluation of hospital room assignment and acquisition of Clostridium difficile infection

BACKGROUND AND OBJECTIVE

Clostridium difficile spores persist in hospital environments for an extended period. We evaluated whether admission to a room previously occupied by a patient with C. difficile infection (CDI) increased the risk of acquiring CDI.

DESIGN

Retrospective cohort study.

SETTING

Medical intensive care unit (ICU) at a tertiary care hospital.

METHODS

Patients admitted from January 1, 2005, through June 30, 2006, were evaluated for a diagnosis of CDI 48 hours after ICU admission and within 30 days after ICU discharge. Medical, ICU, and pharmacy records were reviewed for other CDI risk factors. Admitted patients who did develop CDI were compared with admitted patients who did not.

RESULTS

Among 1,844 patients admitted to the ICU, 134 CDI cases were identified. After exclusions, 1,770 admitted patients remained for analysis. Of the patients who acquired CDI after admission to the ICU, 4.6% had a prior occupant without CDI, whereas 11.0% had a prior occupant with CDI (P = .002). The effect of room on CDI acquisition remained a significant risk factor (P = .008) when Kaplan-Meier curves were used. The prior occupant's CDI status remained significant (p = .01; hazard ratio, 2.35) when controlling for the current patient's age, Acute Physiology and Chronic Health Evaluation III score, exposure to proton pump inhibitors, and antibiotic use.

CONCLUSIONS

A prior room occupant with CDI is a significant risk factor for CDI acquisition, independent of established CDI risk factors. These findings have implications for room placement and hospital design.

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.