Quinolone use as a risk factor for nosocomial Clostridium difficile-associated diarrhea

Empiric aztreonam is associated with increased mortality compared to beta-lactams in septic shock

PURPOSE

To determine if aztreonam as initial empiric treatment of adult septic shock is associated with increased mortality compared to the use of anti-pseudomonal beta-lactam agents.

METHODS

This was a multicenter, retrospective cohort study of 582 adult emergency department patients admitted to 12 acute care facilities within a single health system from January 2014 to December 2017 with septic shock receiving either aztreonam or an anti-pseudomonal beta-lactam for empiric treatment and discharged with an infection-related ICD-9 or ICD-10 code. The primary endpoint was in-hospital mortality.

RESULTS

Initial exposure to aztreonam was associated with increased hospital mortality compared to treatment with an anti-pseudomonal beta-lactam agent (22.7% vs. 12.9%, OR = 1.98, 95% CI: 1.27-3.11). When adjusted for APACHE II score, the treatment group effect on mortality remained statistically significant (OR = 1.74, 95% CI: 1.08-2.80). Aztreonam use was also associated with increased utilization of aminoglycosides (28.9% vs. 12.4%, p < 0.0001) and fluoroquinolones (50.5% vs. 25.8%, p < 0.01). There was no difference in hospital or intensive care unit length of stay in surviving patients between the two groups.

CONCLUSIONS

Compared to anti-pseudomonal beta-lactams, empiric treatment with aztreonam is associated with increased mortality and greater antibiotic exposure among patients with acute septic shock. These findings suggest that treatment with anti-pseudomonal beta-lactams should be prioritized over allergy avoidance whenever feasible.

Infections in Older Adults

Infections in elderly patients can prove diagnostically challenging. Age-related factors affecting the immune system in older individuals contribute to nonspecific presentations. Other age-related factors and chronic conditions have symptoms that may or may not point to an infectious diagnosis. Delay in administration of antimicrobials can lead to poor outcomes; however, unnecessary administration of antimicrobials can lead to increased morbidity and contribute to the emergence of multidrug-resistant organisms. Careful clinical assessment and consideration of patient history and risk factors is crucial. When necessary, antimicrobials should be chosen that are appropriate for the diagnosis and deescalated as soon as possible.

Healthcare facility-onset, healthcare facility-associated Clostridioides difficile infection in Veterans with spinal cord injury and disorder

Objective: To describe the burden and risk of healthcare facility-onset, healthcare facility-associated (HO-HCFA) Clostridioides difficile infection (CDI) in Veterans with spinal cord injury and disorder (SCI/D). Design: Retrospective, longitudinal cohort study from October 1, 2001-September 30, 2010. Setting: Ninety-four acute care Veterans Affairs facilities. Participants: Patients with SCI/D. Outcomes: Incidence rate of HO-HCFA CDI. Methods: Rates of CDI were determined, and crude unadjusted incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were calculated. Multivariable Poisson random-effects regression analyses were used to assess factors independently associated with the rate of CDI. Results: 1,409 cases of HO-HCFA CDI were identified. CDI rates in 2002 were 13.9/10,000 person-days and decreased to 5.5/10,000 person-days by 2010. Multivariable regression analyses found that antibiotic (IRR = 18.79, 95% CI 14.09-25.07) and proton-pump inhibitor (PPI) or H2 blocker use (IRR = 7.71, 95% CI 5.47-10.86) were both independently associated with HO-HCFA CDI. Exposure to both medications demonstrated a synergistic risk (IRR = 37.55, 95% CI 28.39-49.67). Older age, Northeast region, and invasive respiratory procedure in the prior 30 days were also independent risk factors, while longer SCI duration and care at a SCI center were protective. Conclusion: Although decreasing, CDI rates in patients with SCI/D remain high. Targeted antimicrobial stewardship and pharmacy interventions that reduce antibiotic and PPI/H2 blocker use could have profound benefits in decreasing HO-HCFA CDI in this high-risk population.

Incidence of healthcare-associated Clostridioides difficile infections and association with ward-level antibiotic consumption in a German university hospital: an ecological study

OBJECTIVES

Clostridioides difficile infection (CDI) is one of the most important healthcare-associated infections. We aimed to describe the incidence density of healthcare-associated CDI (HA-CDI) in Germany's largest hospital and to identify associations with ward-level antimicrobial consumption.

METHODS

We used surveillance data on CDI and antimicrobial consumption from 2014 to 2017 and analysed a potential association by means of multivariable regression analysis.

RESULTS

We included 77 wards with 404998 admitted patients and 1850862 patient-days. Six hundred and seventy-one HA-CDI cases were identified, resulting in a pooled mean incidence density of 0.36/1000 patient-days (IQR = 0.34-0.39). HA-CDI incidence density on ICU and haematological-oncological wards was about three times higher than on surgical wards [incidence rate ratio (IRR) = 3.00 (95% CI = 1.96-4.60) and IRR = 2.78 (95% CI = 1.88-4.11), respectively]. Ward-level consumption of third-generation cephalosporins was the sole antimicrobial risk factor for HA-CDI. With each DDD/100 patient-days administered, a ward's HA-CDI incidence density increased by 2% [IRR = 1.02 (95% CI = 1.01-1.04)]. Other risk factors were contemporaneous community-associated CDI cases [IRR = 1.32 (95% CI = 1.07-1.63)] and CDI cases in the previous month [IRR = 1.27 (95% CI = 1.07-1.51)]. Furthermore, we found a significant decrease in HA-CDI in 2017 compared with 2014 [IRR = 0.68 (95% CI = 0.54-0.86)].

CONCLUSIONS

We confirmed that ward-level antimicrobial use influences HA-CDI and specifically identified third-generation cephalosporin consumption as a risk factor.

Treatment of Helicobacter pylori Is Not Associated With Future Clostridium difficile Infection

INTRODUCTION

Helicobacter pylori (HP) infection is associated with many gastrointestinal disorders, including gastric cancer, and consensus guidelines recommend eradication after detection. There is a theoretical, yet uninvestigated, concern that HP treatment could increase the risk of Clostridium difficile infection (CDI). Using the data from a large cohort of patients with HP, we investigated whether HP eradication is associated with CDI.

METHODS

A retrospective cohort study within the Veterans Health Administration on 38,535 patients (median age 61.8 years; 91.8% men) with detected HP between January 1, 1994, and December 31, 2018 was conducted. Primary outcome was a positive laboratory test for CDI within 3 months of HP detection. Multivariable logistic regression evaluated the following: patient demographics, previous CDI, recent hospitalization, and whether the patient received HP eradication therapy (by antibiotic and regimen, and including proton pump therapy). Secondary analysis of those treated evaluated whether eradication of HP was associated with CDI.

RESULTS

Among 38,535 patients, 28,818 (74.8%) were treated for HP and 284 (0.74%) developed CDI. In multivariable analysis, prominent factors included hospital discharge within 12 weeks (odds ratio [OR] 2.15; 95% confidence interval [CI]: 1.22-3.77) and 4 weeks (OR 3.46; 95% CI: 2.18-5.48), P < 0.001, and previous CDI (OR 12.5; 95% CI: 9.21-17.0, P < 0.001). Treatment of HP was not associated with future CDI. In secondary analysis of those treated, confirmation of eradication was not associated with future CDI (OR 1.49; 95% CI: 0.67-3.29).

DISCUSSION

In a large study of US patients with HP, we demonstrate that neither treatment nor eradication of HP is associated with CDI. Previous C. difficile infection and recent hospital discharge, established risk factors for CDI, are strongly associated. These findings suggest that treatment should be continued to be prescribed when HP is detected (http://links.lww.com/AJG/B507).

Fuzzy Comprehensive Evaluation Assistant 3D-QSAR of Environmentally Friendly FQs to Reduce ADRs

Most studies on adverse drug reactions (ADRs) of fluoroquinolones (FQs) have focused on the mechanisms of single ADRs, and no quantitative structure–activity relationship (QSAR) method studies have been carried out that combine several ADRs of FQs. In this study, an improved three-dimensional (3D) QSAR method was established using fuzzy comprehensive evaluation. This method could simultaneously consider three common ADRs of FQs using molecular parameters. The improved method could comprehensively predict three ADRs of FQs and provide direction for the development of new drugs with lower ADRs than the originals. According to the improved method, 48 derivatives with lower ADRs (decreased by 4.86% to 50.92%) were designed from pazufloxacin. Three derivatives with a higher genotoxicity, higher photodegradation, and lower bioconcentration than pazufloxacin were selected using the constructed QSAR methods of the FQs. Finally, three traditional 3D-QSAR methods of single ADR were constructed to validate the improved method. The improved method was reasonable, with a relative error range of 0.96% to 4.30%. This study provides valuable reference data and will be useful for the development of strategies to produce new drugs with few ADRs. In the absence of complementary biological studies of these adverse drug reactions, the results reported here may be quite divergent from those found in humans or experimental animals in vivo. One major reason for this is that many adverse drug reactions are dependent upon enzyme-catalyzed metabolic activation (toxication) or on non-enzymatic conversion to toxic products and are not due to the parent drug moiety.

Enteral tolerance in critically ill patients

Enteral nutrition (EN) can maintain the structure and function of the gastrointestinal mucosa better than parenteral nutrition. In critically ill patients, EN must be discontinued or interrupted, if gastrointestinal complications, particularly vomiting and bowel movement disorders, do not resolve with appropriate management. To avoid such gastrointestinal complications, EN should be started as soon as possible with a small amount of EN first and gradually increased. EN itself may also promote intestinal peristalsis. The measures to decrease the risk of reflux and aspiration include elevation the head of the bed (30° to 45°), switch to continuous administration, administration of prokinetic drugs or narcotic antagonists to promote gastrointestinal motility, and switch to jejunal access (postpyloric route). Moreover, the control of bowel movement is also important for intensive care and management. In particular, prolonged diarrhea can cause deficiency in nutrient absorption, malnutrition, and increase in mortality. In addition, diarrhea may cause a decrease the circulating blood volume, metabolic acidosis, electrolyte abnormalities, and contamination of surgical wounds and pressure ulcers. If diarrhea occurs in critically ill patients on EN management, it is important to determine whether diarrhea is EN-related or not. After ruling out the other causes of diarrhea, the measures to prevent EN-related diarrhea include switch to continuous infusion, switch to gastric feeding, adjustment of agents that improve gastrointestinal peristalsis or laxative, administration of antidiarrheal drugs, changing the type of EN formula, and semisolidification of EN formula. One of the best ways to success for EN management is to continue as long as possible without interruption and discontinuation of EN easily by appropriate measures, even if gastrointestinal complications occur.

Predictors of Mortality Among a National Cohort of Veterans With Recurrent Clostridium difficile Infection

Background

Though recurrent Clostridium difficile infection (CDI) is common and poses a major clinical concern, data are lacking regarding mortality among patients who survive their initial CDI and have subsequent recurrences. Risk factors for mortality in patients with recurrent CDI are largely unknown.

Methods

Veterans Affairs patients with a first CDI (stool sample with positive C. difficile toxin(s) and ≥2 days CDI treatment) were included (2010-2014). Subsequent recurrences were defined as additional CDI episodes ≥14 days after the stool test date and within 30 days of the end of treatment. A matched (1:4) case-control analysis was conducted using multivariable conditional logistic regression to identify predictors of all-cause mortality within 30 days of the first recurrence.

Results

Crude 30-day all-cause mortality rates were 10.6% for the initial CDI episode, 8.3% for the first recurrence, 4.2% for the second recurrence, and 5.9% for the third recurrence. Among 110 cases and 440 controls, 6 predictors of mortality were identified: use of proton pump inhibitors (PPIs; odds ratio [OR], 3.86; 95% confidence interval [CI], 2.14-6.96), any antibiotic (OR, 3.33; 95% CI, 1.79-6.17), respiratory failure (OR, 8.26; 95% CI, 1.71-39.92), congitive dysfunction (OR, 2.41; 95% CI, 1.02-5.72), nutrition deficiency (OR, 2.91; 95% CI, 1.37-6.21), and age (OR, 1.04; 95% CI, 1.01-1.07).

Conclusions

In our national cohort of Veterans, crude mortality decreased by 44% from the initial episode to the third recurrence. Treatment with antibiotics, use of PPIs, and underlying comorbidities were important predictors of mortality in recurrent CDI. Our study assists health care providers in identifying patients at high risk of death after CDI recurrence.

Proton pump inhibitors therapy and risk of Clostridium difficile infection: Systematic review and meta-analysis

AIM

To perform a systematic review and meta-analysis on proton pump inhibitors (PPIs) therapy and the risk of Clostridium difficile infection (CDI).

METHODS

We conducted a systematic search of MEDLINE/PubMed and seven other databases through January 1990 to March 2017 for published studies that evaluated the association between PPIs and CDI. Adult case-control and cohort studies providing information on the association between PPI therapy and the development of CDI were included. Pooled odds ratios (ORs) estimates with 95% confidence intervals (CIs) were calculated using the random effect. Heterogeneity was assessed by I² test and Cochran’s Q statistic. Potential publication bias was evaluated via funnel plot, and quality of studies by the Newcastle-Otawa Quality Assessment Scale (NOS).

RESULTS

Fifty-six studies (40 case-control and 16 cohort) involving 356683 patients met the inclusion criteria and were analyzed. Both the overall pooled estimates and subgroup analyses showed increased risk for CDI despite substantial statistical heterogeneity among studies. Meta-analysis of all studies combined showed a significant association between PPI users and the risk of CDI (pooled OR = 1.99, CI: 1.73-2.30, P < 0.001) as compared with non-users. The association remained significant in subgroup analyses: by design-case-control (OR = 2.00, CI: 1.68-2.38, P < 0.0001), and cohort (OR = 1.98, CI: 1.51-2.59, P < 0.0001); adjusted (OR = 1.95, CI: 1.67-2.27, P < 0.0001) and unadjusted (OR = 2.02, CI: 1.41-2.91, P < 0.0001); unicenter (OR = 2.18, CI: 1.72-2.75, P < 0.0001) and multicenter (OR = 1.82, CI: 1.51-2.19, P < 0.0001); age ≥ 65 years (OR = 1.93, CI: 1.40-2.68, P < 0.0001) and < 65 years (OR = 2.06, CI: 1.11-3.81, P < 0.01). No significant differences were found in subgroup analyses (test for heterogeneity): P = 0.93 for case-control vs cohort, P = 0.85 for adjusted vs unadjusted, P = 0.24 for unicenter vs multicenter, P = 0.86 for age ≥ 65 years and < 65 years. There was significant heterogeneity across studies (I² = 85.4%, P < 0.001) as well as evidence of publication bias (funnel plot asymmetry test, P = 0.002).

CONCLUSION

This meta-analysis provides further evidence that PPI use is associated with an increased risk for development of CDI. Further high-quality, prospective studies are needed to assess whether this association is causal.

Updated meta-analysis of controlled observational studies: proton-pump inhibitors and risk of Clostridium difficile infection

Attention has recently been directed toward a plausible link between Clostridium difficile infection (CDI) and proton-pump inhibitors (PPIs). However, the results of studies on the association between CDI and PPI remain controversial. We searched the literature databases from their inception to December 2016, without restriction of language, including all controlled observational studies examining the association between acid-suppressive therapy and CDI. Pooled analysis of 50 studies showed a significant association between PPI use and risk of developing CDI (odds ratio: 1.26; 95% confidence interval: 1.12-1.39) as compared with non-users. When stratified by study patients, the relative risk of hospital-acquired CDI and community-associated CDI were 1.29 (1.14-1.44) and 1.17 (0.74-1.59). After restricting the studies according to hospital department, the relative risks of hospital-acquired CDI in ICUs and general wards were 1.43 (0.74-2.11) and 1.29 (1.13-1.45). By implementing cumulative meta-analysis, it was clear that earlier trials of CDI conducted in the early 2000s demonstrated a high degree of heterogeneity and a high percentage of negative results. Since 2011, the overall association between PPI use and risk of developing CDI has remained relatively stable within an effect size between OR 1.20 and 1.26. Our findings indicate a significant associated risk of incident CDI among PPI users, especially in general ward patients. The totality of evidence, when using cumulative meta-analysis, showed that further trials are unlikely to overturn this positive result. Therefore establishing a guideline for the use of PPIs may help in future with the control of CDI.

Assessing the Risk of Hospital-Acquired Clostridium Difficile Infection With Proton Pump Inhibitor Use: A Meta-Analysis

BACKGROUND Clostridium difficile is the principal infectious cause of antibiotic-associated diarrhea and accounts for 12% of hospital-acquired infections. Recent literature has shown an increased risk of C. difficile infection (CDI) with proton pump inhibitor (PPI) use. OBJECTIVE To conduct a systematic assessment of the risk of hospital-acquired CDI following exposure to PPI. METHODS We searched multiple databases for studies examining the relationship between PPI and hospital-acquired CDI. Pooled odds ratios were generated and assessment for heterogeneity performed. RESULTS We found 23 observational studies involving 186,033 cases that met eligibility criteria. Across studies, 10,307 cases of hospital-acquired CDI were reported. Significant heterogeneity was present; therefore, a random effects model was used. The pooled odds ratio was 1.81 (95% CI, 1.52-2.14), favoring higher risk of CDI with PPI use. Significant heterogeneity was present, likely due to differences in assessment of exposure, study population, and definition of CDI. DISCUSSION This meta-analysis suggests PPIs significantly increase the risk of hospital-acquired CDI. Given the significant health and economic burden of CDI and the risks of PPI, optimization of PPI use should be included in a multifaceted approach to CDI prevention. Infect Control Hosp Epidemiol 2016;1408-1417.

Current Trends in the Epidemiology and Outcomes of Clostridium difficile Infection

Clostridium difficile is the most frequently identified cause of nosocomial diarrhea and has been associated with epidemics of diarrhea in hospitals and long-term care facilities. The continued increase in C. difficile infection (CDI) suggests that it has surpassed other pathogens in causing healthcare-associated infections. The Centers for Disease Control and Prevention recently identified CDI as an "urgent threat" in its recent report on antibiotic resistance threats in the United States, highlighting the need for urgent and aggressive action to prevent this infection. The impact of antibiotics as a risk factor for new-onset CDI is well established; however, recognizing classes of antibiotics with the highest risks and reducing unnecessary antibiotic use are important strategies for prevention of CDI and subsequent recurrence. In addition, the recognition of the community as an important setting for onset of CDI presents a challenge and is an area for future research.

Effects of fluoroquinolone restriction (from 2007 to 2012) on Clostridium difficile infections: interrupted time-series analysis

BACKGROUND

Antimicrobial stewardship is a key component in the reduction of healthcare-associated infections, particularly Clostridium difficile infection (CDI). We successfully restricted the use of cephalosporins and, subsequently, fluoroquinolones. From an endemically high level of >280 cases per year in 2007-08, the number of CDIs reduced to 72 cases in 2011-12.

AIM

To describe the implementation and impact of fluoroquinolone restriction on CDI.

METHODS

This was an interrupted time-series analysis pre and post fluoroquinolone restriction for 60 months based on a Poisson distribution model.

FINDINGS

In June 2008, fluoroquinolone consumption halved to about 5 defined daily doses (DDD) per 100 occupied bed-days (OBD). This was followed by a significant fall in CDI number [rate ratio (RR): 0.332; 95% confidence interval (CI): 0.240-0.460] which remained low over the subsequent months. Subsequently, fluoroquinolone consumption was further reduced to about 2 DDD/100 OBD in June 2010 accompanied by further reduction in CDI rate (RR: 0.394; 95% CI: 0.199-0.781). In a univariate Poisson model the CDI rate was associated with fluoroquinolone usage (RR: 1.086; 95% CI: 1.077-1.094).

CONCLUSION

We conclude that in an environment where cephalosporin usage is already low, the reduction in fluoroquinolone usage was associated with an immediate, large, and significant reduction in CDI cases.

Impact of a clinical guideline for prescribing antibiotics to inpatients reporting penicillin or cephalosporin allergy

BACKGROUND

Self-reported penicillin allergy infrequently reflects an inability to tolerate penicillins. Inpatients reporting penicillin allergy receive alternative antibiotics that might be broader spectrum, more toxic, or less effective.

OBJECTIVE

To develop and assess a clinical guideline for the general inpatient provider that directs taking a history and prescribing antibiotics for patients with penicillin or cephalosporin allergy.

METHODS

A guideline was implemented to assist providers with assessing allergy history and prescribing antibiotics for patients with reported penicillin or cephalosporin allergy. The guideline used a standard 2-step graded challenge or test dose. A quasi-experimental study was performed to assess safety, feasibility, and impact on antibiotic use by comparing treatment 21 months before guideline implementation with 12 months after guideline implementation.

RESULTS

Significantly more test doses to β-lactam antibiotics were performed monthly after vs before guideline implementation (median 14.5, interquartile range 13-16.25, vs 2, interquartile range 1-3.25, P < .001). Seven adverse drug reactions occurred during guideline-driven test doses, with no significant difference in rate (3.9% vs 6.1%, P = .44) or severity (P > .5) between periods. Guideline-driven test doses decreased alternative antimicrobial therapy after the test dose, including vancomycin (68.3% vs 37.2%, P < .001), aztreonam (11.5% vs 0.5%, P < .001), aminoglycosides (6.0% vs 1.1%, P = .004), and fluoro quinolones (15.3% vs 3.3%, P < .001).

CONCLUSION

The implementation of an inpatient antibiotic prescribing guideline for patients with penicillin or cephalosporin allergy was associated with an almost 7-fold increase in the number of test doses to β-lactams without increased adverse drug reactions. Patients assessed with guideline-driven test doses were observed to have significantly decreased alternative antibiotic exposure.

Clostridium difficile-Associated Disease in Patients in a Small Rural Hospital

Objective.

To determine the risk factors for Clostridium difficile–associated disease (CDAD) in a 25-bed rural hospital and to compare antimicrobial use ratios at the study hospital with those at a large academic medical center.

Design.

Case-control study.

Setting.

A 25-bed rural hospital in Iowa during the period from August 2002 through January 2005.

Patients.

A total of 17 case patients with CDAD and 34 control patients matched for age (ie, within 10 years of the case patient's age), sex, and admission date (ie, within 2 weeks of the case patient's admission date).

Methods.

Retrospective medical record review was performed to obtain data on antimicrobial exposures during the 6 weeks before hospital admission for both case and control patients. Exact conditional logistic regression was used for univariable and multivariable analyses. Antimicrobial use ratios were calculated to compare the rates of antimicrobial use for case and control patients at the study hospital with the rates for patients evaluated in a study of CDAD at a nearly 700-bed teaching hospital.

Results.

Case patients had a larger cumulative number of days of antimicrobial use (P = .004), and they received a larger total number of antimicrobial agents during hospitalization (P = .001). Antimicrobial use ratios were higher for both case and control patients at the smaller hospital, compared with the larger hospital.

Conclusions.

CDAD at a small rural hospital was not associated with exposure to the antimicrobial classes that are typically associated with CDAD, but was instead related to the total number of antimicrobials used to treat patients. The rate of antimicrobial use for case and control patients was about 40% higher at the small rural hospital, compared with the corresponding rates at a large academic medical center.

A retrospective analysis of clinical characteristics, hospitalization, and functional outcomes in residents with and without Clostridium difficile infection in US long-term care facilities

OBJECTIVE

Patients in long-term care (LTC) are at increased risk for acquiring Clostridium difficile infection (CDI). We compared the characteristics and outcomes of matched cohorts with and without CDI in the LTC setting.

METHODS

Using a retrospective cohort design, demographic characteristics, Minimum Data Set (MDS 2.0) assessments (years 2007-2010), and pharmacy records of residents were analyzed. Residents were required to have a CDI diagnosis, ≥1 MDS 2.0 assessment ≤120 days pre- and post-index event, and receipt of metronidazole (MET) or vancomycin (VAN) within ±7 days of index date. Baseline characteristics were compared between cases and controls matched 1:3 on age, gender, and index year. Cox regression (CR) analysis evaluated the relationship between CDI status, and post-index mortality and hospitalization.

RESULTS

A total of 1145 CDI residents were matched with 3488 non-CDI residents. A second sample used propensity score methods. CDI vs. non-CDI residents had a higher baseline comorbidity burden (Charlson score: 3.0 ± 1.9 vs. 2.2 ± 1.8, respectively), and were more likely to have had a recent hospitalization (63% vs. 9%, respectively) and shorter mean pre-index continuous length of stay (cLOS) in the LTC (386.4 d ± 536.3 d vs. 568.3 d ± 567.4 d, respectively), all P < 0.0001. CR analyses of both samples indicated that CDI was strongly associated with shorter times to hospitalization and mortality (hazard ratio (HR) = 1.3, P = 0.023 and 2.2, P < 0.0001, respectively; propensity-matched group). Pre-index LTC cLOS also remained an important variable in the CR analysis and was the strongest predictor of post-index hospitalization and mortality (HR = 0.999 and 0.996, respectively, P < 0.0001), indicating that residents with longer pre-index LTC cLOS had longer times to post-index hospitalization and mortality. Our reliance on the MDS records for case identification was our chief limitation; misclassification was mitigated by our requirement to include CDI treatment as part of our inclusion criteria.

CONCLUSIONS

Understanding factors that put LTC patients at risk for CDI can help guide better management and improvement of patient outcomes.

Fluoroquinolone- and ceftriaxone-based therapy of community-acquired pneumonia in hospitalized patients: the risk of subsequent isolation of multidrug-resistant organisms

A retrospective cohort study was performed on 175 adult patients treated for community-acquired pneumonia with moxifloxacin or ceftriaxone/azithromycin in a nonintensive care unit. Both cohorts were very similar with regard to a wide range of characteristics including age, severity of disease, comorbidities, length of stay, and mortality. Multidrug-resistant organisms were subsequently isolated from 6 (15%) moxifloxacin-treated patients and 5 (4%) ceftriaxone/azithromycin-treated patients within 90 days after beginning of therapy (P = .026 on logistic regression analysis).

Recurrence of Clostridium difficile infection among veterans with spinal cord injury and disorder

BACKGROUND

Recurrent Clostridium difficile (CDI) infection is a growing concern; however, there are little data on impact of recurrent CDI on those with spinal cord injury and disorder (SCI/D). Therefore, the objective of this study was to identify risk factors associated with recurrence of CDI among Veterans with SCI/D.

METHODS

This was a retrospective cohort study with data from outpatient, inpatient, and extended care settings at 83 Department of Veterans Affairs facilities from 2002 to 2009.

RESULTS

Of 1,464 cases of CDI analyzed, 315 cases (21.5%) had a first recurrence of CDI. Multivariable regression demonstrated that risk factors significantly associated with increased recurrence were concomitant fluoroquinolone use (odds ratio [OR], 1.39; 95% confidence interval [CI]: 1.08-1.80), whereas concomitant tetracycline use (OR, 0.35; 95% CI: 0.14-0.90), and cerebrovascular accident (OR, 0.46; 95% CI: 0.25-0.85) were associated with decreased recurrence. A subanalysis in those with health care facility-onset CDI showed that increased length of stay postinitial CDI was a significant risk factor for recurrence as was concomitant use of fluoroquinolones and that tetracycline remained protective for recurrence.

CONCLUSION

Concomitant fluoroquinolone use was a risk factor for the recurrence of CDI. In contrast, tetracyclines and cerebrovascular accident were protective. Length of stay greater than 90 days from the initial CDI episode was also a risk factor for recurrence among those with health care facility-onset CDI. Future studies should focus on effective strategies to prevent these risk factors among the SCI/D population.

Comparison of antimicrobial susceptibility among Clostridium difficile isolated from an integrated human and swine population in Texas

Clostridium difficile can be a major problem in hospitals because the bacterium primarily affects individuals with an altered intestinal flora; this largely occurs through prolonged antibiotic use. Proposed sources of increased community-acquired infections are food animals and retail meats. The objective of this study was to compare the antimicrobial resistance patterns of C. difficile isolated from a closed, integrated population of humans and swine to increase understanding of the bacterium in these populations. Swine fecal samples were collected from a vertically flowing swine population consisting of farrowing, nursery, breeding, and grower/finisher production groups. Human wastewater samples were collected from swine worker and nonworker occupational group cohorts. Antimicrobial susceptibility testing was performed on 523 C. difficile strains from the population using the commercially available agar diffusion Epsilometer test (Etest(®)) for 11 different antimicrobials. All of the swine and human strains were susceptible to amoxicillin/clavulanic acid, piperacillin/tazobactam, and vancomycin. In addition, all of the human strains were susceptible to chloramphenicol. The majority of the human and swine strains were resistant to cefoxitin and ciprofloxacin. Statistically significant differences in antimicrobial susceptibility were found among the swine production groups for ciprofloxacin, tetracycline, amoxicillin/clavulanic acid, and clindamycin. No significant differences in antimicrobial susceptibility were found across human occupational group cohorts. We found that 8.3% of the swine strains and 13.3% of the human strains exhibited resistance to metronidazole. The finding of differences in susceptibility patterns between human and swine strains of C. difficile provides evidence that transmission between host species in this integrated population is unlikely.

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.

Antibiotic heterogeneity optimizes antimicrobial prescription and enables resistant pathogen control in the intensive care unit

BACKGROUND

Multi-drug-resistant organisms (MDRO) complicate care increasingly on the general ward and in the emergency department, operating room, and intensive care unit (ICU). Whereas barrier precautions are important in limiting transmission of MDRO between patients, few tactics have been defined that reduce the genesis of MDRO.

METHOD

Review of pertinent English-language literature.

RESULTS

Antibiotic heterogeneity practices, as part of an overall antimicrobial drug stewardship program, offer one readily deployable means to reduce selection pressure for MDRO development in the ICU. The data underpinning this approach and data derived from its use indicate that, especially in surgical ICUs, heterogeneity of antibiotic prescribing can preserve or restore microbial ecology, reduce the prevalence of MDRO and the incidence of infections caused thereby, and facilitate the implementation and effectiveness of other antibiotic-sparing tactics, such as de-escalation.

CONCLUSION

Heterogeneity of antibiotic prescribing is effective in preventing the dissemination of MDRO pathogens.

Risk of Clostridium difficile infection with acid suppressing drugs and antibiotics: meta-analysis

OBJECTIVES

Several studies have raised concern regarding the possible association between proton-pump inhibitors (PPIs) and Clostridium difficile infection (CDI). We aimed to perform a systematic review of incident and recurrent CDI in PPI users, and to evaluate the relative impact of concurrent antibiotic use, or switching acid suppression to histamine-2-receptor antagonists (H2RAs).

METHODS

We searched MEDLINE and EMBASE from inception to December 2011 for controlled observational studies that reported on the risk of CDI with and without PPI use. We performed random effects meta-analysis and assessed statistical heterogeneity using the I(2) statistic.

RESULTS

We included 42 observational studies (30 case-control, 12 cohort) totalling 313,000 participants overall. Pooled analysis of 39 studies showed a statistically significant association between PPI use and risk of developing CDI, odds ratio (OR) 1.74 (95% confidence interval (CI) 1.47-2.85, P<0.001, I(2)=85%) compared with non-users. A pooled analysis of three studies showed a significant associated risk of recurrent CDI associated with PPIs, OR 2.51 (95% CI 1.16-5.44, P=0.005, I(2)=78%). Subgroup analysis failed to fully clarify the source of the substantial statistical heterogeneity. Adjusted indirect comparison demonstrated that use of H2RAs as an alternative carried a lower-risk OR 0.71 (95% CI 0.53-0.97) compared with PPIs. Conversely, concomitant use of PPI and antibiotics conferred a greater-risk OR 1.96 (95% CI 1.03-3.70) above that of PPIs alone. For PPI and antibiotics, the Rothman's synergy index was 1.36 and attributable proportion of risk from interaction 0.19, indicating an increased risk from interaction beyond the effects of each drug alone.

CONCLUSIONS

Despite the substantial statistical and clinical heterogeneity, our findings indicate a probable association between PPI use and incident and recurrent CDI. This risk is further increased by concomitant use of antibiotics and PPI, whereas H2RAs may be less harmful.

Evaluating contemporary antibiotics as a risk factor for Clostridium difficile infection in surgical trauma patients

BACKGROUND

With most Clostridium difficile infections (CDI) occurring after exposure to antimicrobial treatment, specific antibiotics and duration of exposure were evaluated independently for increased risk of CDI in surgical patients.

METHODS

A retrospective, case-control design was used to study surgical inpatients. The case group had a positive Clostridium difficile toxin assay, whereas the control group did not.

RESULTS

Four antibiotics had a risk that was statistically significant for causing CDI in surgical patients: cefepime (odds ratio [OR], 5.7; 95% confidence interval [CI], 1.7-19.1; p = 0.0044), imipenem/cilastatin (OR, 3.2; 95% CI, 1.2-8.9; p = 0.0388), piperacillin/tazobactam (OR, 2.4; 95% CI, 1.3-4.5; p = 0.0067), and vancomycin (OR, 1.9; 95% CI, 1.0-3.5; p = 0.0439). Exposure longer than 7 days to cefepime (p = 0.0006), piperacillin/tazobactam (p = 0.0021), and imipenem/cilastatin (p = 0.0171) also increased risk for development of CDI.

CONCLUSION

The use of cefepime, imipenem/cilastatin, piperacillin/tazobactam, and vancomycin and the use of multiple classes of antibiotics for at least 7 days significantly increased the risk of CDI in surgical inpatients.

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.

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.

Prevention and treatment of urinary tract infection with probiotics: Review and research perspective

The spiralling costs of antibiotic therapy, the appearance of multiresistant bacteria and more importantly for patients and clinicians, unsatisfactory therapeutic options in recurrent urinary tract infection (RUTI) calls for alternative and advanced medical solutions. So far no sufficient means to successfully prevent painful and disabling RUTI has been found. Even though long-term oral antibiotic treatment has been used with some success as a therapeutic option, this is no longer secure due to the development of bacterial resistance. One promising alternative is the use of live microorganisms (probiotics) to prevent and treat recurrent complicated and uncomplicated urinary tract infection (UTI).

The human normal bacterial flora is increasingly recognised as an important defence to infection. Since the advent of antibiotic treatment five decades ago, a linear relation between antibiotic use and reduction in pathogenic bacteria has become established as medical conventional wisdom. But with the use of antibiotics the beneficial bacterial flora hosted by the human body is destroyed and pathogenic bacteria are selectively enabled to overgrow internal and external surfaces. The benign bacterial flora is crucial for body function and oervgrowth with pathogenic microorganisms leads to illness. Thus the concept of supporting the human body's normal flora with live microorganisms conferring a beneficial health effect is an important medical strategy.

Clostridium difficile-associated diarrhea in a tertiary care medical center

This retrospective, case-control study aimed to identify variables associated with the incidence of Clostridium difficile-associated diarrhea (CDAD) in acute care facilities and to specifically identify the relationship of fluoroquinolones and acid suppressive agents in the development of CDAD. Seventy-one symptomatic patients positive for C. difficile toxin A or B hospitalized for at least 72 hours were compared with 142 control patients hospitalized for at least 72 hours who were not positive for C. difficile toxin A or B. Two controls were matched to one case patient for age within 5 years, unit of admission, and date of admission. The mean ages for cases and controls were 63.5 and 62.7 years, respectively. After adjusting for two confounding variables-hospital stay within 3 months and Charlson Comorbidity Index-conditional multiple logistic regression identified six risk factors for development of CDAD: gastrointestinal procedures within 60 days (odds ratio [OR] 9.1, P < 0.013), levofloxacin exposure (OR 8.2, P < 0.033), moxifloxacin exposure (OR 4.1, P < 0.026), imipenem exposure (OR 14.9, P < 0.014), laxative use (OR 20.2, P < 0.0001), and immunosuppressive use (OR 20.7, P < 0.034). The risk of CDAD after exposure to levofloxacin or moxifloxacin was not significantly different. Acid suppressive therapy was not a risk factor for CDAD development.

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

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

Prevention of endemic healthcare-associated Clostridium difficile infection: reviewing the evidence

OBJECTIVES

Clostridium difficile is the most common infectious cause of healthcare-associated diarrhea. Because of the increasing incidence and severity of endemic C. difficile infection (CDI), interventions to prevent healthcare-associated CDI are essential. We undertook a systematic review of interventions to reduce healthcare-associated CDI.

METHODS

We searched multiple computerized databases, and manually searched for relevant articles to determine which interventions are useful in preventing CDI. Studies were required to be controlled in design and to report the incidence of endemic CDI as an outcome. Data on the patient population, intervention, study design, and outcomes were abstracted and reviewed using established criteria.

RESULTS

Few randomized controlled trials exist in the area of CDI prevention. The interventions with the greatest evidence for the prevention of CDI include antimicrobial stewardship, glove use, and disposable thermometers. Environmental decontamination also may decrease CDI rates, although the level of evidence is not as strong as for the other proven interventions. Treatment of asymptomatic carriage of C. difficile is not recommended. There is insufficient evidence to make a recommendation for or against the use of probiotics. In cases of known or suspected CDI, hand hygiene with soap and water is preferred over use of waterless alcohol hand rub. Many nonrandomized trials included in our analysis used multiple interventions concurrently, making the independent role of each preventive strategy difficult to determine. We chose to include only studies that focused on endemic CDI because studies of outbreaks have used multiple strategies, making it difficult to measure the relative efficacy of each strategy. Environmental disinfection and probiotics need to be studied further to evaluate their roles in the prevention of CDI. Although there have been no studies assessing the utility of isolation and cohorting for the prevention of endemic CDI specifically, it is a widely used intervention for containment of this and other similar multidrug-resistant pathogens.

CONCLUSIONS

Antimicrobial stewardship, glove use, hand hygiene, and disposable thermometers should be routinely used for the prevention of CDI. Environmental disinfection and probiotics should be studied further for their role in reducing CDI.

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.

Semi-automated risk estimation using large databases: quinolones and Clostridium difficile associated diarrhea

PURPOSE

The availability of large databases with person time information and appropriate statistical methods allow for relatively rapid pharmacovigilance analyses. A semi-automated method was used to investigate the effect of fluoroquinolones on the incidence of C. difficile associated diarrhea (CDAD).

METHODS

Two US databases, an electronic medical record (EMR) and a large medical claims database for the period 2006-2007 were evaluated using a semi-automated methodology. The raw EMR and claims datasets were subject to a normalization procedure that aligns the drug exposures and conditions using ontologies; Snowmed for medications and MedDRA for conditions. A retrospective cohort design was used together with matching by means of the propensity score. The association between exposure and outcome was evaluated using a Poisson regression model after taking into account potential confounders.

RESULTS

A comparison between quinolones as the target cohort and macrolides as the comparison cohort produced a total of 564,797 subjects exposed to a quinolone in the claims data and 233,090 subjects in the EMR. They were matched with replacement within six strata of the propensity score. Among the matched cohorts there were a total of 488 and 158 outcomes in the claims and the EMR respectively. Quinolones were found to be twice more likely to be significantly associated with CDAD than macrolides adjusting for risk factors (IRR 2.75, 95%CI 2.18-3.48).

CONCLUSIONS

Use of a semi-automated method was successfully applied to two observational databases and was able to rapidly identify a potential for increased risk of developing CDAD with quinolones.

Multihospital outbreak of Clostridium difficile infection, Cleveland, Ohio, USA

To determine whether a multihospital Clostridium difficile outbreak was associated with epidemic strains and whether use of particular fluoroquinolones was associated with increased infection rates, we cultured feces from C. difficile-infected patients. Use of fluoroquionolones with enhanced antianaerobic activity was not associated with increased infection rates.

The changing epidemiology of Clostridium difficile infections

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

The Relationship between Inpatient Fluoroquinolone Use and Clostridium difficile-Associated Diarrhea

BACKGROUND:

Limited evidence suggests there may be a link between fluoroquinolone use and Clostridium difficile-associated diarrhea (CDAD), but such an association remains unclear due to conflicting data.

OBJECTIVE:

To determine the relationship between inpatient fluoroquinolone use and CDAD; secondary objectives included the relationship between CDAD and fluoroquinolone selection, duration of therapy, and route of administration, as well as the association between fluoroquinolones and CDAD complications.

METHODS:

We conducted a retrospective, case-control study of adult inpatients diagnosed with CDAD during the period of July 2007-July 2008. In total, 174 case patients were matched on a 1:1 basis with controls. A thorough assessment of all inpatient antibiotic use was conducted, including regimens administered at our institution within the previous 8 weeks. Odds ratios were calculated using univariate logistic-regression analysis.

RESULTS:

Use of fluoroquinolones was not significantly different between patients with CDAD and matching controls (OR 1.36; 95% CI 0.09 to 2.10; p = 0.16). No relationship was found between CDAD and the individual fluoroquinolones: ciprofloxacin (OR 1.36; 95% CI 0.87 to 2.12; p = 0.18), levofloxacin (OR 1.17; 95% CI 0.62 to 2.22; p = 0.63), and moxifloxacin (OR 1.34; 95% CI 0.81 to 2.20; p = 0.25). Fluoroquinolone route of administration did not differ significantly between groups for patients receiving intravenous (OR 1.20; 95% CI 0.74 to 1.94; p = 0.46) or oral (OR 0.79; 95% CI 0.44 to 1.44; p = 0.45) therapy. Complications from CDAD were not significantly increased by fluoroquinolone use (OR 1.37; 95% CI 0.72 to 2.61; p = 0.35).

CONCLUSIONS:

Inpatient administration of fluoroquinolones was not associated with CDAD at our institution. Fluoroquinolone use in patients who developed CDAD was not related to higher incidences of CDAD-related complications.

Analysis of an outbreak of Clostridium difficile infection controlled with enhanced infection control measures

BACKGROUND

In October 2004, our Clostridium difficile infection (CDI) rate increased (relative risk, 3.51; 95% confidence interval: 2.96-4.16) from a baseline rate of 1.35 per 1000 patient-days. We describe the outbreak, the relationship between antibiotic use and CDI, and the effect of enhanced infection control measures (EICM) on CDI.

METHODS

Rates were calculated as positive C difficile toxin A or B tests among patients with nosocomial diarrhea per 1000 patient-days (duplicates removed). Antibiotic use was calculated as defined daily dose per 1000 patient-days. EICM consisted of (1) placing patients with diarrhea into empiric Contact Precautions, (2) cleaning with a bleach product in areas with CDI patients, and (3) requiring soap and water hand hygiene when caring for CDI patients. CDI rates were analyzed by chi(2) for trend. Time series methodology was used to examine the association between CDI and antibiotic use.

RESULTS

During the outbreak (October 2004-May 2005), we observed 144 excess cases of CDI. The CDI rate decreased after EICM were implemented (P < .0001) and has been maintained for 36 months beyond the outbreak. Multivariate analysis revealed positive associations between CDI rates and cefazolin use (P = .008) and levofloxacin/gatifloxacin use (P = .015).

CONCLUSION

Despite an association between some antibiotic use and CDI rates, we achieved sustained control of an outbreak using EICM without formulary changes or new antibiotic control policies. This suggests that patient-to-patient spread may be a more important cause of increased CDI rates.

Successful combat of an outbreak due to Clostridium difficile PCR ribotype 027 and recognition of specific risk factors

In the period April-September 2005, an outbreak of Clostridium difficile infection (CDI) due to PCR ribotype 027 occurred among 50 patients in a 341-bed community hospital in Harderwijk, The Netherlands. A retrospective case-control study was performed to identify risk factors specific for CDI, using a group of patients with CDI (n = 45), a group of randomly selected control patients without diarrhoea (n = 90), and a group of patients with non-infectious diarrhoea (n = 109). Risk factors for CDI and for non-CDI diarrhoea were identified using multiple logistic regression analysis. Independent risk factors for CDI were: age above 65 years (OR 2.6; 95% CI 1.0-5.7), duration of hospitalization (OR 1.04 per additional day; 95% CI 1.0-1.1), and antibiotic use (OR 12.5; 95% CI 3.2-48.1). Of the antibiotics used, cephalosporins and fluoroquinolones were identified as the major risk factors for development of CDI. The risk of developing CDI was particularly high in people receiving a combination of a cephalosporin and a fluoroquinolone (OR 57.5; 95% CI 6.8-483.6). The main factors affecting the risk of non-CDI diarrhoea were proton-pump inhibitors, immunosuppressive drugs, underlying digestive system disease, previous surgery, and gastric tube feeding. The outbreak ended only after implementation of restricted use of cephalosporins and a complete ban on fluoroquinolones, in addition to general hygienic measures, cohorting of patients in a separate ward, education of staff, and intensified environmental cleaning. The results of this study support the importance of appropriate antimicrobial stewardship in the control of hospital outbreaks with C. difficile PCR ribotype 027.

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.

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.

What have we learned about antimicrobial use and the risks for Clostridium difficile-associated diarrhoea?

Clostridium difficile is recognized as a major cause of antibiotic-associated diarrhoea and colitis. Antimicrobial agents have been repeatedly recognized as a causative risk for C. difficile-associated diarrhoea (CDAD) and more recently fluoroquinolones have been particularly implicated. Unfortunately, not all reports of antimicrobial associations with CDAD have excluded variables other than antimicrobial use. Prevention of CDAD usually involves infection control interventions and antimicrobial restriction policies may not be fully substantiated by currently available data; however, antimicrobial drug restriction seems prudent in outbreak situations.

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.

Fluoroquinolone resistance in Clostridium difficile isolates from a prospective study of C. difficile infections in Europe

The European Study Group on Clostridium difficile (ESGCD) conducted a prospective study in 2005 to monitor and characterize C. difficile strains circulating in European hospitals, collecting 411 isolates. Eighty-three of these isolates, showing resistance or intermediate resistance to moxifloxacin (MX), were selected for this study to assess susceptibility to other fluoroquinolones (FQs) and to analyse the gyr genes, encoding the DNA gyrase subunits GyrA and GyrB. Twenty MX-susceptible isolates from the surveillance study were included for comparison. Overall, one amino acid substitution in GyrA (Thr82 to Ile) and four different substitutions in GyrB (Ser416 to Ala, Asp426 to Asn, Asp426 to Val and Arg447 to Lys) were identified. A high level of resistance (MIC >or=32 microg ml(-1)) to MX, ciprofloxacin (CI), gatifloxacin (GA) and levofloxacin (LE) was found in 68 isolates showing the amino acid substitution Thr82 to Ile in GyrA, in eight isolates with the substitutions Thr82 to Ile in GyrA and Ser416 to Ala in GyrB, in two isolates showing the substitution Asp426 to Asn in GyrB and in one isolate with Asp426 to Val in GyrB. The remaining four isolates showed high MICs for CI and LE, but different MIC levels for MX and GA. In particular, intermediate levels of resistance to MX were shown by two isolates, one with the substitution Thr82 to Ile in GyrA, and one showing Asp426 to Asn in GyrB. The substitution Arg447 to Lys in GyrB was found in two strains resistant to MX, CI and LE but susceptible to GA. No substitutions in GyrA were found in the FQ-susceptible strains, whereas two strains showed the amino acid change Ser416 to Ala in GyrB. Thr82 to Ile was the most frequent amino acid change identified in the C. difficile isolates examined. In contrast to previous observations, 10% of the isolates showed this substitution in association with Ser416 to Ala in GyrB. The other amino acid changes found were characteristic of a few strains belonging to certain types and/or countries. Two new substitutions for C. difficile, Ser416 to Ala and Arg447 to Lys, were found in GyrB. Whereas the former does not seem to have a key role in resistance, since it was also detected in susceptible strains, the latter substitution occurred in the same position where other amino acid variations take place in resistant Escherichia coli and other C. difficile strains. A large number of C. difficile isolates now show an alarming pattern of resistance to the majority of FQs currently used in hospitals and outpatient settings, therefore judicious use of these antibiotics and continuous monitoring of in vitro resistance are necessary.