Real-Time Electronic Tracking of Diarrheal Episodes and Laxative Therapy Enables Verification of Clostridium difficile Clinical Testing Criteria and Reduction of Clostridium difficile Infection Rates

Health care worker perceptions toward computerized clinical decision support tools for Clostridium difficile infection reduction: A qualitative study at 2 hospitals

BACKGROUND

Clostridium difficile infection (CDI) is associated with significant morbidity and mortality. Computerized clinical decision support (CCDS) tools can aid process improvement in infection prevention and antibiotic stewardship, but implementation and health care workers (HCWs) uptake of these tools is often variable. The objective of this study was to describe HCWs' perceptions of barriers and facilitators related to uptake of CCDS tools as part of a CDI reduction bundle.

METHODS

We conducted a qualitative study among HCWs at 2 acute care hospitals in Maryland. Semi-structured interviews and structured surveys were completed by HCWs to evaluate their perception to CCDS tools at 2 different stages: predevelopment and preimplementation. Emergent themes and patterns in the data were identified and condensed.

RESULTS

Gaps in CDI-related knowledge and in communication between HCWs were identified throughout the evaluation. HCWs agreed on the potential of the tools to improve CDI diagnosis, prevention, and control. An important barrier for uptake was the perceived loss of autonomy and clinical judgment, whereas standardization and error reduction were perceived advantages.

CONCLUSIONS

These observations shaped the development and implementation of the CDI reduction bundle. Qualitative findings can provide valuable contextual information during the development stages of CCDS tools in infection prevention and antibiotic stewardship.

Fecal Host Transcriptomics for Non-Invasive Human Mucosal Immune Profiling: Proof of Concept in Clostridium Difficile Infection

Background:

Host factors play an important role in pathogenesis and disease outcome in Clostridium difficile infection (CDI), and characterization of these responses could uncover potential host biomarkers to complement existing microbe-based diagnostics.

Methods:

We extracted RNA from fecal samples of patients with CDI and profiled human mRNA using amplicon-based next-generation sequencing (NGS). We compared the fecal host mRNA transcript expression profiles of patients with CDI to controls with non-CDI diarrhea.

Results:

We found that the ratio of human actin gamma 1 (ACTG1) to 16S ribosomal RNA (rRNA) was highly correlated with NGS quality as measured by percentage of reads on target. Patients with CDI could be differentiated from those with non-CDI diarrhea based on their fecal mRNA expression profiles using principal component analysis. Among the most differentially expressed genes were ones related to immune response (IL23A, IL34) and actin-cytoskeleton function (TNNT1, MYL4, SMTN, MYBPC3, all adjusted P-values < 1 x 10^-3).

Conclusions:

In this proof-of-concept study, we used host fecal transcriptomics for non-invasive profiling of the mucosal immune response in CDI. We identified differentially expressed genes with biological plausibility based on animal and cell culture models. This demonstrates the potential of fecal transcriptomics to uncover host-based biomarkers for enteric infections.

Impact of Case-Specific Education and Face-to-Face Feedback to Prescribers and Nurses in the Management of Hospitalized Patients With a Positive Clostridium difficile Test

Background

Approaches to changing providers’ behavior around Clostridium difficile (CD) management are needed. We hypothesized that case-specific teaching points and face-to-face discussions with prescribers and nurses would improve management of patients with a positive CD test.

Methods

Charts of patients age ≥18 years with positive CD tests hospitalized July 2016 to May 2017 were prospectively reviewed to assess CD practices and generate management recommendations. The study had 4 periods: baseline (pre-intervention), intervention #1, observation, and intervention #2. Both interventions consisted of an in-person, real-time, case-based discussion and education by a CD Action Team (CDAT). Assessment occurred within 24 hours of a positive CD test for all periods; during the intervention periods, management was also assessed within 48 hours after CDAT-delivered recommendations. Outcomes included proportion of patients receiving optimized treatment and incidence rate ratios of practice changes (both CDAT-prompted and CDAT-independent).

Results

Overall, the CDAT made recommendations to 84 of 96 CD cases during intervention periods, and providers accepted 43% of CDAT recommendations. The implementation of the CDAT led to significant improvement in bowel movement (BM) documentation, use of proton pump inhibitors, and antibiotic selection for non-CD infections. Selection of CD-specific therapy improved only in the first intervention period. Laxative use and treatment of CD colonization cases remained unchanged. Only BM documentation, a nurse-driven task, was sustained independent of CDAT prompting.

Conclusions

A behavioral approach to changing the management of positive CD tests led to self-sustained practice changes among nurses but not physicians. Better understanding of prescribers’ decision-making is needed to devise enduring interventions.

Current and Future Opportunities for Rapid Diagnostics in Antimicrobial Stewardship

Rapid diagnostic testing has improved clinical care of patients with infectious syndromes when combined with antimicrobial stewardship. The authors review the current data on antimicrobial stewardship and rapid diagnostic testing in bloodstream, respiratory tract, and gastrointestinal tract infections. Evidence for the potential benefit of rapid tests in bloodstream infections seems strong, respiratory tract infections mixed, and gastrointestinal tract infections still evolving. The authors also review future directions in rapid diagnostic testing and suggest areas of focus for antimicrobial stewardship efforts.

Overreporting healthcare-associated C. difficile: A comparison of NHSN LabID with clinical surveillance definitions in the era of molecular testing

BACKGROUND

Clostridium difficile infection (CDI) is the most common healthcare-associated gastrointestinal infection. Hospitals are required to report cases of healthcare facility-onset CDI (HO-CDI) using the National Healthcare Safety Network's CDI laboratory-identified (LabID) event definition. The aim of this study was to determine the extent of potential over-reporting due to the exclusion of important clinical data within LabID reporting definitions.

METHODS

In 2015, retrospective chart review was performed on 212 HO-CDI cases reported from a large urban medical center. Cases had positive polymerase chain reaction test for the C. difficile toxin B gene from an unformed stool specimen collected >3 days after admission and >8 weeks after most recent LabID event. Cases were categorized into "clinical surveillance" groups: community-acquired infection, recurrence/relapse, asymptomatic colonization, colonization with self-limited symptoms, possible HO-CDI, and probable HO-CDI.

RESULTS

Of the infections, 13.6% were community acquired, 2.8% were recurrent/relapse, 1.9% were asymptomatic colonization, 18.4% were symptomatic colonization, 38.7% were possible HO-CDI, and 24.5% were probable HO-CDI. Within 24 hours of testing, 34.1% of patients had received a stool softener and/or laxative.

CONCLUSIONS

Laxative use and failure to identify community-onset infection may contribute to misclassification of HO-CDI. Only 62% of reported cases met clinical surveillance criteria.

Diagnostic Stewardship: Opportunity for a Laboratory-Infectious Diseases Partnership

Recent advances in microbial diagnostics are providing clinicians with information about microbes causing infections and their resistance to antimicrobial agents more rapidly than ever before. Diagnostic stewardship refers to the appropriate use of laboratory testing to guide patient management, including treatment, in order to optimize clinical outcomes and limit the spread of antimicrobial resistance. Fulfilling the promise of diagnostic stewardship requires a seamless partnership between clinical laboratories, pharmacists, and infectious diseases clinicians, so that appropriate tests are ordered and diagnostic information is translated into appropriate management in real time.

Searching for a Potential Algorithm for Clostridium difficile Testing at a Tertiary Care Hospital: Does Toxin Enzyme Immunoassay Testing Help?

Clostridium difficile is a major contributor to morbidity and mortality in the United States. Methods for identifying the organism in stool include molecular platforms, enzyme immunoassays (EIAs) for toxin, and culture. Controversy persists over whether molecular tests are too sensitive at identifying C. difficile, and there are questions about how additional laboratory information could inform clinical management and reduce over treatment. The aim of this study was to assess whether clinical factors are related to the toxin status of patients and whether information about toxin status could potentially inform clinical management of patients. A total of 201 PCR-positive C. difficile stool samples from adult patients at our institution underwent EIA toxin testing. Clinical and laboratory data were collected, and the percentage of PCR-positive/EIA-positive (PCR⁺/EIA⁺) patients and PCR⁺ and EIA-negative (PCR⁺/EIA^-) patients was calculated. Of the 201 samples, 47% were EIA positive and 53% were EIA negative. Although PCR⁺/EIA⁺ patients were more likely to have had a prior C. difficile infection (P = 0.015), there was no statistical difference between the additional data collected that correlated with a positive EIA result. We were unable to show that patients with an EIA⁺ result had worse clinical parameters than those with EIA^- results and concluded that establishing a testing algorithm that included both PCR and EIA testing would not change the clinical management of patients at our hospital.

Advances in the diagnosis and treatment of Clostridium difficile infections

Clostridium difficile is a leading cause of antibiotic-associated diarrhea worldwide. The diagnosis of C. difficile infection (CDI) requires both clinical manifestations and a positive laboratory test for C. difficile and/or its toxins. While antibiotic therapy is the treatment of choice for CDI, there are relatively few classes of effective antibiotics currently available. Therefore, the development of novel antibiotics and/or alternative treatment strategies for CDI has received a great deal of attention in recent years. A number of emerging agents such as cadazolid, surotomycin, ridinilazole, and bezlotoxumab have demonstrated activity against C. difficile; some of these have been approved for limited clinical use and some are in clinical trials. In addition, other approaches such as early and accurate diagnosis of CDI as well as disease prevention are important for clinical management. While the toxigenic culture and the cell cytotoxicity neutralization assay are still recognized as the gold standard for the diagnosis of CDI, new diagnostic approaches such as nucleic acid amplification methods have become available. In this review, we will discuss both current and emerging diagnostic and therapeutic modalities for CDI.

Feasibility and applicability of antimicrobial stewardship in immunocompromised patients

PURPOSE OF REVIEW

Antimicrobial stewardship is the primary intervention in the battle against antimicrobial resistance, but clinicians do not always apply many key antimicrobial stewardship principles to patients with significant immune defects due to lack of data and fear of bad outcomes. We review evidence regarding the application of stewardship principles to immunocompromised patients, with a focus on solid organ and hematopoietic stem cell transplant recipients.

RECENT FINDINGS

Antimicrobial stewardship programs (ASPs), targeting immunocompromised patient populations such as oncology and transplant, are gaining traction. Emerging literature suggests that several stewardship interventions can be adapted to immunocompromised hosts and improve antimicrobial utilization, but data supporting improved outcomes is very limited.

SUMMARY

The application of antimicrobial stewardship principles to immunocompromised patients is feasible, necessary, and urgent. As antimicrobial stewardship programs gain momentum across a diverse range of healthcare settings more immunocompromised patients will fall under their purview. It is imperative that centers applying antimicrobial stewardship principles share their experience and establish collaborative research efforts to advance our knowledge base in applying antimicrobial stewardship initiatives to immunocompromised host populations, both in terms of programmatic success and patient outcomes.

Toxin positivity and tcdB gene load in broad-spectrum Clostridium difficile infection

PURPOSE

This study aimed to evaluate the clinical significance of toxin positivity and toxin gene load, and the relation between them in the broad spectrum of Clostridium difficile infection (CDI) including colonization, significant diarrhea, and severe disease.

METHODS

We included 2671 fecal samples submitted for CDI diagnosis and 180 samples from healthy individuals. The clinical spectrum was categorized as category I (toxigenic C. difficile positive without clinical CDI criteria), category II (mild CDI), and category III (severe CDI). Clinical parameters were compared based on toxin EIA and tcdB C _t values. C _t values of tcdB PCR for predicting toxin EIA positivity were assessed using receiver-operating characteristic (ROC) curves.

RESULTS

The median C _t values of tcdB PCR and toxin positivity were not significantly correlated with clinical spectrum of CDI (27.5, 28.2, and 26.1 for tcdB C _t and 55.0, 56.6, and 60.9% for toxin EIA positivity in category I, II, and III, respectively, P > 0.05). There were significant differences in the tcdB C _t values between toxin EIA-positive and -negative groups (P < 0.001). Optimal cutoff for the tcdB C _t value for estimating toxin EIA positivity was 26.3 with 79.3% sensitivity and 83.6% specificity with good area under the curves (AUC, 0.848).

CONCLUSIONS

The C _t values successfully predicted toxin EIA positivity and could be used as a surrogate for toxin EIA positivity in the diagnostic algorithm and routine analysis. Further studies are needed to validate the clinical significance of tcdB PCR C _t value in toxigenic C. difficile colonization and infection.

Clostridium difficile PCR Cycle Threshold Predicts Free Toxin

There is no stand-alone Clostridium difficile diagnostic that can sensitively and rapidly detect fecal free toxins. We investigated the performance of the C. difficile PCR cycle threshold (C_T ) for predicting free toxin status. Consecutive stool samples (n = 312) positive for toxigenic C. difficile by the GeneXpert C. difficile/Epi tcdB PCR assay were tested with the rapid membrane C. Diff Quik Chek Complete immunoassay (RMEIA). RMEIA toxin-negative samples were tested with the cell cytotoxicity neutralization assay (CCNA) and tgcBIOMICS enzyme-linked immunosorbent assay (ELISA). Using RMEIA alone or in combination with CCNA and/or ELISA as the reference method, the accuracy of C_T was measured at different C_T cutoffs. Using RMEIA as the reference method, a C_T cutoff of 26.35 detected toxin-positive samples with a sensitivity, specificity, positive predictive value, and negative predictive value of 96.0% (95% confidence interval [CI], 90.2% to 98.9%), 65.9% (95% CI, 59.0% to 72.2%), 57.4% (95% CI, 52.7% to 62%), and 97.1% (95% CI, 92.8% to 98.9), respectively. Inclusion of CCNA in the reference method improved C_T specificity to 78.0% (95% CI, 70.7% to 84.2%). Intercartridge lot C_T variability measured as the average coefficient of variation was 2.8% (95% CI, 1.2% to 3.2%). Standardizing the input stool volume did not improve C_T toxin specificity. The median C_T values were not significantly different between stool samples with Bristol scores of 5, 6, and 7, between pediatric and adult samples, or between presumptive 027 and non-027 strains. In addition to sensitively detecting toxigenic C. difficile in stool, on-demand PCR may also be used to accurately predict toxin-negative stool samples, thus providing additional results in PCR-positive stool samples to guide therapy.

Strategies for Optimizing the Diagnostic Predictive Value of Clostridium difficile Molecular Diagnostics

Because nucleic acid amplification tests (NAATs) do not distinguish Clostridium difficile infection (CDI) and asymptomatic C. difficile carriage, the diagnostic predictive value of NAATs is limited when used in patients with a low probability of CDI. In this issue of the Journal of Clinical Microbiology, Truong et al. (J. Clin. Microbiol., 55:1276-1284, 2017, https://doi.org/10.1128/JCM.02319-16) report significant reductions in hospital-onset CDI and oral vancomycin utilization at their institution following implementation of a novel intervention that leveraged their clinical bioinformatics resources to prevent C. difficile testing of stools from patients without clinically significant diarrhea and in patients with recent laxative use.