Comparison of the clinical course of Clostridium difficile infection in glutamate dehydrogenase-positive toxin-negative patients diagnosed by PCR to those with a positive toxin test

Potential underreporting of treated patients using a Clostridioides difficile testing algorithm that screens with a nucleic acid amplification test

OBJECTIVE

Patients tested for Clostridioides difficile infection (CDI) using a 2-step algorithm with a nucleic acid amplification test (NAAT) followed by toxin assay are not reported to the National Healthcare Safety Network as a laboratory-identified CDI event if they are NAAT positive (+)/toxin negative (-). We compared NAAT+/toxin- and NAAT+/toxin+ patients and identified factors associated with CDI treatment among NAAT+/toxin- patients.

DESIGN

Retrospective observational study.

SETTING

The study was conducted across 36 laboratories at 5 Emerging Infections Program sites.

PATIENTS

We defined a CDI case as a positive test detected by this 2-step algorithm during 2018-2020 in a patient aged ≥1 year with no positive test in the previous 8 weeks.

METHODS

We used multivariable logistic regression to compare CDI-related complications and recurrence between NAAT+/toxin- and NAAT+/toxin+ cases. We used a mixed-effects logistic model to identify factors associated with treatment in NAAT+/toxin- cases.

RESULTS

Of 1,801 cases, 1,252 were NAAT+/toxin-, and 549 were NAAT+/toxin+. CDI treatment was given to 866 (71.5%) of 1,212 NAAT+/toxin- cases versus 510 (95.9%) of 532 NAAT+/toxin+ cases (P < .0001). NAAT+/toxin- status was protective for recurrence (adjusted odds ratio [aOR], 0.65; 95% CI, 0.55-0.77) but not CDI-related complications (aOR, 1.05; 95% CI, 0.87-1.28). Among NAAT+/toxin- cases, white blood cell count ≥15,000/µL (aOR, 1.87; 95% CI, 1.28-2.74), ≥3 unformed stools for ≥1 day (aOR, 1.90; 95% CI, 1.40-2.59), and diagnosis by a laboratory that provided no or neutral interpretive comments (aOR, 3.23; 95% CI, 2.23-4.68) were predictors of CDI treatment.

CONCLUSION

Use of this 2-step algorithm likely results in underreporting of some NAAT+/toxin- cases with clinically relevant CDI. Disease severity and laboratory interpretive comments influence treatment decisions for NAAT+/toxin- cases.

Predictive value of fecal calprotectin and lactoferrin levels for negative outcomes in Clostridioides difficile infection

PURPOSE

We investigated the role of fecal calprotectin (FC) and lactoferrin (FL) as predictive biomarkers in Clostridioides difficile infection (CDI).

METHODS

We assembled a prospective cohort including all patients with a laboratory-confirmed CDI diagnosis between January and December 2017. FL and FC levels were measured at diagnosis by commercial ELISA and EIA kits. We investigated the diagnostic accuracy of FC and FL to predict CDI recurrence and severity (study outcomes) and explored optimal cut-off values in addition to those proposed by the manufacturers (200 µg/g and 7.2 µg/mL, respectively).

RESULTS

We included 170 CDI cases (152 first episodes and 18 recurrences). The rates of recurrence (first episodes only) and severity (entire cohort) were 9.2% (14/152) and 46.5% (79/170). Both FL and FC levels were significantly higher in patients who developed study outcomes. Optimal cut-off values for FC and FL to predict CDI recurrence were 1052 µg/g and 6.0 µg/mL. The optimal cut-off value for FC yielded higher specificity (60.9%) and positive predictive value (PPV) (16.9%) than that proposed by the manufacturer. Regarding CDI severity, the optimal cut-off value for FC (439 µg/g) also provided higher specificity (43.9%) and PPV (54.1%) than that of the manufacturer, whereas the optimal cut-off value for FL (4.6 µg/mL) resulted in an improvement of PPV (57.5%).

CONCLUSION

By modifying the thresholds for assay positivity, the measurement of FC and FL at diagnosis is useful to predict recurrence and severity in CDI. Adding these biomarkers to current clinical scores may help to individualize CDI management.

Characteristics and outcomes of Clostridioides difficile infection after a change in the diagnostic testing algorithm

BACKGROUND

Polymerase chain reaction (PCR) testing for the detection of C. difficile is a highly sensitive test. Some clinical laboratories have included a 2-step testing algorithm utilizing PCR plus toxin enzyme immunoassays (EIAs) to increase specificity.

OBJECTIVE

To determine the risk factors and outcomes of C. difficile PCR-positive/toxin-positive encounters compared to PCR-positive/toxin-negative encounters.

DESIGN

Retrospective study.

SETTING

A Veterans' Affairs hospital.

METHODS

A retrospective case-control study of patient encounters with a positive C. difficile test by PCR and either a toxin EIA-positive assay (ie, cases) or toxin EIA-negative assay (ie, controls). Clinically relevant exposures and risk factors were determined to assess CDI recurrence at 30 days. Available encounter stool specimens were cultured for C. difficile and were subjected to restriction endonuclease analysis (REA) strain typing.

RESULTS

Among 130 C. difficile PCR-positive patient encounters, 80 (61.5%) were toxin EIA negative and 50 (38.5%) were toxin EIA positive. Encounters that were toxin positive were more frequently treated (96.0%) compared to toxin-negative encounters (71.3%; P < .01). A multivariable logistic regression model revealed that toxin-negative encounters were less likely to suffer a recurrent CDI episode within 30 days (odds ratio [OR], 0.20, 95% confidence interval [CI], 0.05-0.83). Additionally, a higher C. difficile PCR cycle threshold predicted a lower risk of CDI recurrence at 30 days. (OR, 0.82; 95% CI, 0.68-0.98). During the study period, the REA group Y strain accounted for most toxin-negative encounters (32.5%; P = .05), whereas REA group BI strain accounted for most toxin-positive encounters (24.3%; P = .02).

CONCLUSIONS

A testing strategy of PCR plus toxin EIA helped predict recurrent CDI.

Clinical Outcomes of Treated and Untreated C. difficile PCR-Positive/Toxin-Negative Adult Hospitalized Patients: a Quasi-Experimental Noninferiority Study

Clostridioides difficile infection (CDI) is routinely diagnosed by PCR, with or without toxin enzyme immunoassay testing. The role of therapy for positive PCR and negative toxin remains unclear. The objective of this study was to determine whether clinical outcomes of PCR+/cycle threshold-based toxin (CT-toxin)- individuals vary by result reporting and treatment strategy. We performed a quasiexperimental noninferiority study comparing clinical outcomes of PCR+/CT-toxin- individuals by reporting PCR result only (most patients treated) with reporting CT-toxin result only (most patients untreated) in a single-center, tertiary academic hospital. The primary outcome was symptomatic PCR+/CT-toxin+ conversion at 8 weeks. Secondary outcomes included 7-day diarrhea resolution, hospital length of stay, and 30-day all-cause mortality. A total of 663 PCR+/CT-toxin- test results were analyzed from 632 individuals with a median age of 61 years (interquartile range [IQR], 44 to 72) and 50.4% immunocompromised. Individuals in the preintervention group were more likely to have received CDI therapy than those in the intervention group (91.5 versus 15.1%; P < 0.001). Symptomatic toxin conversion at 8 weeks and hospital length of stay failed to establish the predefined thresholds for noninferiority. Lack of diarrhea resolution at 7 days and 30-day all-cause mortality was similar and established noninferiority (20.0 versus 13.7%; adjusted odds ratio [aOR], 0.57; 90% confidence interval [CI], 0.32 to 1.01; P = 0.1; and 8.6 versus 6.5%; aOR, 0.46; 90% CI, 0.20 to 1.04; P = 0.12). These data support the safety of withholding antibiotics for selected hospitalized individuals with suspected CDI but negative toxin.

Impact of the Introduction of a Two-Step Laboratory Diagnostic Algorithm in the Incidence and Earlier Diagnosis of Clostridioides difficile Infection

Our aim was to determine changes in the incidence of CD infection (CDI) following the introduction of a two-step diagnostic algorithm and to analyze CDI cases diagnosed in the study period. We retrospectively studied CDI (January 2009 to July 2018) in adults diagnosed by toxin enzyme immunoassay (EIA) (2009−2012) or toxin-EIA + polymerase chain reaction (PCR) algorithm (2013 onwards). A total of 443 patients with a first episode of CDI were included, 297 (67.1%) toxin-EIA-positive and 146 (32.9%) toxin-EIA-negative/PCR-positive were only identified through the two-step algorithm including the PCR test. The incidence of CDI increased from 0.9 to 4.7/10,000 patient-days (p < 0.01) and 146 (32.9%) toxin-negative CDI were diagnosed. Testing rate increased from 24.4 to 59.5/10,000 patient-days (p < 0.01) and the percentage of positive stools rose from 3.9% to 12.5% (p < 0.01). CD toxin-positive patients had a higher frequency of severe presentation and a lower rate of immunosuppressive drugs and inflammatory bowel disease. Mortality (16.3%) was significantly higher in patients with hematological neoplasm, intensive care unit admission and complicated disease. Recurrences (14.9%) were significantly higher with proton pump inhibitor exposure. The two-step diagnostic algorithm facilitates earlier diagnosis, potentially impacting patient outcomes and nosocomial spread. CD-toxin-positive patients had a more severe clinical presentation, probably due to increased CD bacterial load with higher toxin concentration. This early and easy marker should alert clinicians of potentially more severe outcomes.

Diagnostic Methods of Clostridioides difficile Infection and Clostridioides difficile Ribotypes in Studied Sample

BACKGROUND

Clostridioides (Clostridium) difficile is the most common nosocomial pathogen and antibiotic-related diarrhea in health-care facilities. Over the last few years, there was an increase in the incidence rate of C. difficile infection cases in Slovakia. In this study, the phenotypic (toxigenicity, antimicrobial susceptibility) and genotypic (PCR ribotypes, genes for binary toxins) patterns of C. difficile isolates from patients with CDI were analyzed, from July to August 2016, taken from hospitals in the Horne Povazie region of northern Slovakia. The aim of the study was also to identify hypervirulent strains (e.g., the presence of RT027 or RT176).

METHODS

The retrospective analysis of biological samples suspected of CDI were analyzed by GDH, anaerobic culture, enzyme immunoassay on toxins A/B, multiplex "real-time" PCR and PCR capillary-based electrophoresis ribotyping, and by MALDI TOF MS.

RESULTS

C. difficile isolates (n = 44) were identified by PCR ribotyping, which revealed five different ribotypes (RT001, 011, 017, 081, 176). The presence of hypervirulent RT027 was not identified. The C. difficile isolates (RT001, 011, 081, 176) were susceptible to metronidazole and vancomycin. One isolate RT017 had reduced susceptibility to vancomycin. A statistically significant difference between the most prevalent PCR ribotypes, RT001 and RT176, regarding variables such as albumin, CRP, creatinine, the length of hospitalization (p = 0.175), and glomerular filtration (p = 0.05) was not found.

CONCLUSION

The results of PCR capillary-based electrophoresis ribotyping in the studied samples showed a high prevalence of RT176 and 001.

Toxigenic Clostridium difficile-mediated Diarrhoea in Hematopoietic Stem Cell Transplantation In-Patients: Rapid Diagnosis and Efficient Treatment

Allogenic hematopoietic stem cell transplant (HSCT) recipients are susceptible to any kind of infectious agents including Clostridium difficile. We studied 86 allogenic-HSCT patients who faced diarrhoea while receiving antibiotics. DNA from stool samples were explored for the presence of C. difficile toxin genes (tcdA; tcdB) by multiplex real-time PCR. Results showed nine toxigenic C. difficile amongst which seven were positive for both toxins and two were positive for tcdB. Six of toxigenic C. difficile organisms harbouring both toxin genes were also isolated by toxigenic culture. Clostridium difficile infection was controlled successfully with oral Metronidazole and Vancomycin in the confirmed infected patients.

The Importance of Abnormal Platelet Count in Patients with Clostridioides difficile Infection

Background: Clostridium difficile infection (CDI) causes morbidity and mortality. Platelets have been increasingly recognized as an important component of innate and adaptive immunity. We aimed to assess the incidence of thrombocytopenia and thrombocytosis in CDI and the effect of an abnormal platelet count on clinical outcomes. Methods: This single-center, retrospective cohort study consisted of all adult patients hospitalized in Rabin Medical Center between 1 January 2013 and 31 December 2018 with laboratory confirmed CDI. The primary outcome was 30-day all-cause mortality. Risk factors for 30-day all-cause mortality were identified by univariable and multivariable analyses, using logistic regression. Results: A total of 527 patients with CDI were included. Among them 179 (34%) had an abnormal platelet count: 118 (22%) had thrombocytopenia and 61 (11.5%) had thrombocytosis. Patients with thrombocytosis were similar to control patients other than having a significantly higher white blood cell count at admission. Patients with thrombocytopenia were younger than control patients and were more likely to suffer from malignancies, immunosuppression, and hematological conditions. In a multivariable analysis, both thrombocytosis (OR 1.89, 95% CI 1.01–3.52) and thrombocytopenia (OR 1.70, 95% CI 1.01–2.89) were associated with 30-days mortality, as well as age, hypoalbuminemia, acute kidney injury, and dependency on activities of daily living. A sensitivity analysis restricted for patients without hematological malignancy or receiving chemotherapy revealed increased mortality with thrombocytosis but not with thrombocytopenia. Conclusions: In this retrospective study of hospitalized patients with CDI, we observed an association between thrombocytosis on admission and all-cause mortality, which might represent a marker for disease severity. Patients with CDI and thrombocytopenia also exhibited increased mortality, which might reflect their background conditions and not the severity of the CDI. Future studies should assess thrombocytosis as a severity marker with or without the inclusion of the WBC count.

Usefulness of Fecal Calprotectin in the Management of Patients with Toxigenic Clostridioides difficile

The availability of highly sensitive molecular tests for the detection of Clostridioides difficile in feces leads to overtreatment of patients who are probably only colonized. In this prospective study, the usefulness of fecal calprotectin (fCP) is evaluated in a cohort of patients with detection of toxigenic C. difficile in feces. Patients were classified by an infectious diseases consultant blinded to fCP results into three groups-group I, presumed Clostridioides difficile infection (CDI); group II, doubtful but treated CDI; and group III, presumed C. difficile colonization or self-limited CDI not needing treatment. One hundred and thirty-four patients were included. The median fCP concentrations were 410 (138-815) μg/g in group I, 188 (57-524) μg/g in group II, and 51 (26-97) μg/g in group III (26 cases); p < 0.05 for all comparisons. In forty-five out of 134 cases (33.5%), the fCP concentrations were below 100 µg/g. In conclusion, fCP is low in most patients who do not need treatment against C. difficile, and should be investigated as a potentially useful test in the management of patients with detected toxigenic C. difficile.

Real-World Experience with Bezlotoxumab for Prevention of Recurrence of Clostridioides difficile Infection

Bezlotoxumab is marketed for the prevention of recurrent Clostridioides difficile infection (rCDI). Its high cost could be determining its prescription to a different population than that represented in clinical trials. The objective of the study was to verify the effectiveness and safety of bezlotoxumab in preventing rCDI and to investigate factors related to bezlotoxumab failure in the real world. A retrospective, multicentre cohort study of patients treated with bezlotoxumab in Spain was conducted. We compared the characteristics of cohort patients with those of patients treated with bezlotoxumab in the pivotal MODIFY trials. We assessed recurrence rates 12 weeks after completion of treatment against C. difficile, and we analysed the factors associated with bezlotoxumab failure. Ninety-one patients were included in the study. The cohort presented with more risk factors for rCDI than the patients included in the MODIFY trials. Thirteen (14.2%) developed rCDI at 12 weeks of follow-up, and rCDI rates were numerically higher in patients with two or more previous episodes (25%) than in those who had fewer than two previous episodes of C. difficile infection (CDI) (10.4%); p = 0.09. There were no adverse effects attributable to bezlotoxumab. Despite being used in a more compromised population than that represented in clinical trials, we confirm the effectiveness of bezlotoxumab for the prevention of rCDI.

Clinical significance of a positive Clostridioides difficile glutamate dehydrogenase test on the outcomes of hospitalized older patients

AIM

Clostridioides difficile infection worsens the outcome of older hospitalized patients; thus, its diagnosis is necessary for the nosocomial infection control. The standard diagnostic test's limited sensitivity for Clostridioides difficile infection, an enzyme immunoassay for Clostridioides difficile toxins, is of clinical concern. Glutamate dehydrogenase detection is usually tested combined with Clostridioides difficile toxins. However, the clinical significance of a positive glutamate dehydrogenase result is unclear. We evaluated the association between positive glutamate dehydrogenase results, in-hospital mortality and hospital stay length among older patients with suspected Clostridioides difficile infection.

METHODS

In this retrospective cohort study, we examined the data of patients who received antibiotics (except for Clostridioides difficile infection treatment) after admission and tested for Clostridioides difficile infection using an enzyme immunoassay for Clostridioides difficile toxins and glutamate dehydrogenase in a secondary care hospital located in a rural region with high aging rate, between 2015 and 2018.

RESULTS

In total, 188 patients were included (83.5% of them aged >75 years). Glutamate dehydrogenase positivity was independently associated with in-hospital mortality (adjusted odds ratio 2.19, 95% confidence interval 1.14-4.21) and hospital stay length (regression coefficient 16.0, 95% confidence interval 5.15-26.9). Clostridioides difficile toxin positivity was independently associated with hospital stay duration (regression coefficient 14.5, 95% confidence interval 0.04-29.1), unlike in-hospital mortality.

CONCLUSIONS

Glutamate dehydrogenase was closely related to in-hospital mortality and prolonged hospitalization compared with Clostridioides difficile toxin. Clinicians should not neglect glutamate dehydrogenase-positive patients, even when they are Clostridioides difficile toxin-negative, and consider them as having poor prognostic potential. Geriatr Gerontol Int 2020; 20: 1138-1144.

Toxin Enzyme Immunoassays Detect Clostridioides difficile Infection With Greater Severity and Higher Recurrence Rates

BACKGROUND

Few data suggest that Clostridioides difficile infections (CDIs) detected by toxin enzyme immunoassay (EIA) are more severe and have worse outcomes than those detected by nucleic acid amplification tests (NAATs) only. We compared toxin- positive and NAAT-positive-only CDI across geographically diverse sites.

METHODS

A case was defined as a positive C. difficile test in a person ≥1 year old with no positive tests in the prior 8 weeks. Cases were detected during 2014-2015 by a testing algorithm (specimens initially tested by glutamate dehydrogenase and toxin EIA; if discordant results, specimens were reflexed to NAAT) and classified as toxin positive or NAAT positive only. Medical charts were reviewed. Multivariable logistic regression models were used to compare CDI-related complications, recurrence, and 30-day mortality between the 2 groups.

RESULTS

Of 4878 cases, 2160 (44.3%) were toxin positive and 2718 (55.7%) were NAAT positive only. More toxin-positive than NAAT-positive-only cases were aged ≥65 years (48.2% vs 38.0%; P < .0001), had ≥3 unformed stools for ≥1 day (43.9% vs 36.6%; P < .0001), and had white blood cell counts ≥15 000 cells/µL (31.4% vs 21.4%; P < .0001). In multivariable analysis, toxin positivity was associated with recurrence (adjusted odds ratio [aOR], 1.89; 95% confidence interval [CI], 1.61-2.23), but not with CDI-related complications (aOR, 0.91; 95% CI, .67-1.23) or 30-day mortality (aOR, 0.95; 95% CI, .73-1.24).

CONCLUSIONS

Toxin-positive CDI is more severe, but there were no differences in adjusted CDI-related complication and mortality rates between toxin-positive and NAAT-positive-only CDI that were detected by an algorithm that utilized an initial glutamate dehydrogenase screening test.

Discordant Clostridioides difficile diagnostic assay and treatment practice: a cross-sectional study in a tertiary care hospital, Geneva, Switzerland

OBJECTIVES

To determine the proportion of patients who received a treatment for Clostridioides difficile infection (CDI) among those presenting a discordant C. difficile diagnostic assay and to identify patient characteristics associated with the decision to treat CDI.

DESIGN

Cross-sectional study.

SETTING

Monocentric study in a tertiary care hospital, Geneva, Switzerland.

PARTICIPANTS

Among 4562 adult patients tested for C. difficile between March 2017 and March 2019, 208 patients with discordant tests' results (positive nucleic acid amplification test (NAAT+)/negative enzyme immunoassay (EIA-)) were included.

MAIN OUTCOME MEASURES

Treatment for CDI.

RESULTS

CDI treatment was administered in 147 (71%) cases. In multivariate analysis, an abdominal CT scan with signs of colitis (OR 14.7; 95% CI 1.96 to 110.8) was the only factor associated with CDI treatment.

CONCLUSIONS

The proportion of NAAT+/EIA- patients who received treatment questions the contribution of the EIA for the detection of toxin A/B after NAAT to limit overtreatment. Additional studies are needed to investigate if other factors are associated with the decision to treat.

Multicenter study of the epidemiology of Clostridioides difficile infection and recurrence in southern Brazil

Clostridioides (Clostridium) difficile is the main etiology underlying antibiotic-associated diarrhea (AAD). Still, few Brazilian data are available on this infection. The aims of this multicenter study were to identify the prevalence, clinical characteristics, and outcomes of C. difficile infection (CDI) in patients with antibiotic associated diarrhea at eight hospitals in Curitiba, southern Brazil, during the years 2017-2019. Stool samples were tested using enzyme immunoassay for glutamate dehydrogenase antigen (GDH) and A/B toxins. Positive GDH samples were further evaluated by real-time polymerase chain reaction (PCR) for the presence of genes encoding toxin B (tcdB), binary toxin (cdt), and marker of hypervirulent C. difficile strain (tcdC deletion). The prevalence of CDI in 351 patients with AAD included in the study was 17.7% (n = 62). Among the CDI cases, tcdB was positive in all 62 stool samples, while cdt was positive in 10 samples, and tcdC deletion was positive in only two. Carriage of carbapenem-resistant Gram-negative bacilli, previous hospitalization, and use of broad-spectrum cephalosporin and carbapenem were associated with CDI. Among patients with CDI, 64.5% presented with severe diarrhea, and 8% (5/62) progressed with colitis and required intensive care. The 30-day mortality was 24% (15/62), and the CDI-associated mortality was 4.8% (3/62). Overall, 83.8% (52/62) of the patients achieved primary cure, and 20.8% of the evaluated patients (10/48) presented CDI recurrence. The treatment administered was not significantly associated with the 60-day recurrence or mortality. In conclusion, we reported in this study data of prevalence and recurrence rates of CDI in patients with AAD and evaluated the number of severe cases and infection-related mortality, which were up to now unknown in Southern Brazilian hospitals.

Evaluation of Cycle Threshold, Toxin Concentration, and Clinical Characteristics of Clostridioides difficile Infection in Patients with Discordant Diagnostic Test Results

Clostridioides difficile infection (CDI) is one of the most common health care-associated infections that can cause significant morbidity and mortality. CDI diagnosis involves laboratory testing in conjunction with clinical assessment. The objective of this study was to assess the performance of various C. difficile tests and to compare clinical characteristics, Xpert C. difficile/Epi (PCR) cycle threshold (C_T ), and Singulex Clarity C. diff toxins A/B (Clarity) concentrations between groups with discordant test results. Unformed stool specimens from 200 hospitalized adults (100 PCR positive and 100 negative) were tested by cell cytotoxicity neutralization assay (CCNA), C. diff Quik Chek Complete (Quik Chek), Premier Toxins A and B, and Clarity. Clinical data, including CDI severity and CDI risk factors, were compared between discordant test results. Compared to CCNA, PCR had the highest sensitivity at 100% and Quik Chek had the highest specificity at 100%. Among clinical and laboratory data studied, prevalences of leukocytosis, prior antibiotic use, and hospitalizations were consistently higher across all subgroups in comparisons of toxin-positive to toxin-negative patients. Among PCR-positive samples, the median C_T was lower in toxin-positive samples than in toxin-negative samples; however, C_T ranges overlapped. Among Clarity-positive samples, the quantitative toxin concentration was significantly higher in toxin-positive samples than in toxin-negative samples as determined by CCNA and Quik Chek Toxin A and B. Laboratory tests for CDI vary in sensitivity and specificity. The quantitative toxin concentration may offer value in guiding CDI diagnosis and treatment. The presence of leukocytosis, prior antibiotic use, and previous hospitalizations may assist with CDI diagnosis, while other clinical parameters may not be consistently reliable.

The impact of changing reflexive to clinician-ordered Clostridioides difficile polymerase chain reaction (PCR) testing for indeterminate cases: Cost savings without associated adverse events

OBJECTIVE

To evaluate changing Clostridioides difficile infection (CDI) testing among inpatients with indeterminate enzyme immunoassay (EIA) results (antigen+/toxin-) from reflexive polymerase chain reaction (PCR) testing to clinician-ordered PCR testing.

DESIGN

Multicenter, before-and-after, quasi-experimental study.

SETTING

Four large urban tertiary-care hospitals.

METHODS

We evaluated two 6-month periods before and after an intervention. The primary study outcome was the change in the number of CDI diagnoses between periods. Secondary outcomes included the number of PCR tests performed, adverse events, and healthcare cost savings.

RESULTS

In total, 500 EIA-indeterminate C. difficile test results were evaluated: 281 before the intervention and 219 thereafter. CDI was diagnosed by PCR among EIA-indeterminate cases in 182 in the preintervention period versus 94 patients in the postintervention period (48% reduction; P < .01). PCR testing was performed in 99.6% of indeterminate cases (280 of 281; 1 not performed due to an inhibitor) in the preintervention period versus 66% (144 of 219) in the postintervention period (34% reduction; P < .01). We observed no differences between study periods in 30-day all-cause (P = .96), GI-related (P = .93), or C. difficile (P = .47) readmissions, nor in 30-day C. difficile infections (P > .99). No patient without a PCR test in the postintervention period and not treated was later diagnosed with CDI. Each reflexive PCR test not performed led to a cost savings of $4,498 per patient.

CONCLUSIONS

Applying diagnostic stewardship to C. difficile PCR testing in the inpatient setting led to significant reductions in both testing and cases. Changing the C. difficile PCR testing algorithm for EIA-indeterminate cases from reflexive to clinician-required ordering resulted in valuable cost savings without associated adverse events.

The reference method influence on the sensitivity of the Clostridium difficile enzyme immunoassays: A meta analysis

The use of enzyme immunoassays to screen for toxins A and B produced by Clostridium difficile is a common procedure in algorithms designed for its detection. Moreover, the absence of a unique test capable of providing reliable results at low cost motivates a great discussion about which algorithm is the best. Thus, several studies have evaluated the performance of these enzyme immunoassays. However, all fail to provide sufficient explanations for the different behaviours observed in different studies that evaluate the same index test against a common reference method. Our main goal was to find out which factors affect the sensitivity of these assays, since the specificity is very close to 1. In this research, we verified that sensitivity increases with the prevalence rate and with the proportion of reported cases of onset diarrhea. Therefore, its use is advisable for high prevalence rates (e.g. in an epidemic setting). As far as reference methods are concerned, nucleic acid amplification tests can be used as a reference method, with a performance similar to the well-accepted toxigenic culture. The method chosen for toxigenicity screening in a toxigenic culture also seems to affect the evaluation performance of tests and should be better studied in the future.

Prospective Evaluation of the mariPOC Test for Detection of Clostridioides difficile Glutamate Dehydrogenase and Toxins A/B

The objective of this study was to evaluate a novel automated random-access test, mariPOC CDI (ArcDia Ltd., Finland), for the detection of Clostridioides difficile glutamate dehydrogenase (GDH) and toxins A and B directly from fecal specimens. The mariPOC test was compared with both the GenomEra C. difficile PCR assay (Abacus Diagnostica Oy, Finland) and the TechLab C. diff Quik Chek Complete (Alere Inc.; now Abbot) membrane enzyme immunoassay (MEIA). Culture and the Xpert C. difficile assay (Cepheid Inc., USA) were used to resolve discrepant results. In total, 337 specimens were tested with the mariPOC CDI test and GenomEra PCR. Of these specimens, 157 were also tested with the TechLab MEIA. The sensitivity of the mariPOC test for GDH was slightly lower (95.2%) than that obtained with the TechLab assay (100.0%), but no toxin-positive cases were missed. The sensitivity of the mariPOC test for the detection of toxigenic C. difficile by analyzing toxin expression was better (81.6%) than that of the TechLab assay (71.1%). The analytical specificities for the mariPOC and the TechLab tests were 98.3% and 100.0% for GDH and 100.0% and 99.2% for toxin A/B, respectively. The analytical specificity of the GenomEra method was 100.0%. The mariPOC and TechLab GDH tests and GenomEra PCR had high negative predictive values of 99.3%, 98.3%, and 99.7%, respectively, in excluding infection with toxigenic C. difficile The mariPOC toxin A/B test and GenomEra PCR had an identical analytical positive predictive value of 100%, providing highly reliable information about toxin expression and the presence of toxin genes, respectively.

The Role of Diagnostic Stewardship in Clostridioides difficile Testing: Challenges and Opportunities

PURPOSE OF REVIEW

Accurate and timely diagnosis of Clostridioides difficile infection (CDI) is imperative to prevent C. difficile transmission and reduce morbidity and mortality due to CDI, but CDI laboratory diagnostics are complex. The purpose of this article is to review the role of laboratory tests in the diagnosis of CDI, and the role of diagnostic stewardship in optimization of C. difficile testing.

RECENT FINDINGS

Results from C. difficile diagnostic tests should be interpreted with an understanding of the strengths and limitations inherent in each testing approach. Use of highly sensitive molecular diagnostic tests without accounting for clinical signs and symptoms may lead to over-diagnosis of CDI and increased facility CDI rates. Current guidelines recommend a two-step, algorithmic approach for testing. Diagnostic stewardship interventions, such as education, order sets, order search menus, reflex orders, hard and soft stop alerts, electronic references, feedback and benchmarking, decision algorithms, and predictive analytics may help improve use of C. difficile laboratory tests and CDI diagnosis. The diagnostic stewardship approaches with the highest reported success rates include computerized clinical decision support (CCDS) interventions, face-to-face feedback, and real-time evaluations.

SUMMARY

CDI is a clinical diagnosis supported by laboratory findings. Together, clinical evaluation combined with diagnostic stewardship can optimize the accurate diagnosis of CDI.

Predictors of Clostridioides difficile Infection-Related Complications and Treatment Patterns among Nucleic Acid Amplification Test-Positive/Toxin Enzyme Immunoassay-Negative Patients

The addition of toxin enzyme immunoassay (EIA) to nucleic acid amplification tests, including PCR, creates challenges in the diagnosis and management of Clostridioides difficile infection (CDI). There are limited data in large cohorts, with discordant results, that is, PCR-positive/EIA-negative (PCR⁺/EIA^-) results. We conducted a retrospective cohort study on all PCR⁺/EIA^- adult inpatients and assessed CDI-related complications and clinical failure. We identified 240 individuals. Twenty-three (9.6%) patients experienced a CDI-related complication, including 2 cases of megacolon, 1 colectomy, and 22 intensive care unit (ICU) admissions. In multivariable logistic regression analyses, baseline severe disease by Infectious Diseases Society of America (IDSA) criteria (odds ratio [OR], 5.84; 95% confidence interval [CI], 1.88 to 18.1; P = 0.002), baseline fulminant colitis (OR, 84.7; 95% CI, 14.3 to 500; P < 0.001), fever of >38.5°C (OR, 4.61; 95% CI, 1.42 to 15.0; P = 0.011), and proton pump inhibitor (PPI) use (OR, 3.50; 95% CI, 1.19 to 10.3; P = 0.023) were associated with increased odds of CDI-related complications. For 67 PCR⁺/EIA^- patients who did not receive complete treatment, clinical failure was observed in 10 (15%) patients. A comparison of PCR⁺/EIA^- patients who received complete treatment to all 112 PCR⁺/EIA⁺ patients showed no differences in CDI-related complications (11% and 13% for PCR⁺/EIA^- and PCR⁺/EIA⁺ patients, respectively), 60-day all-cause mortality (17% and 18% for PCR⁺/EIA^- and PCR⁺/EIA⁺ patients, respectively), or recurrent CDI (7% and 9% for PCR⁺/EIA^- and PCR⁺/EIA⁺ patients, respectively). Predictors of CDI-attributable complications among PCR⁺/EIA^- patients include baseline severe disease by IDSA criteria, baseline fulminant colitis, and fever of >38.5°C. Identifying the subgroup of PCR⁺/EIA^- patients who could have true disease, and therefore allowing them to be targeted for treatment, is critical.

Comparison of Clostridioides difficile Stool Toxin Concentrations in Adults With Symptomatic Infection and Asymptomatic Carriage Using an Ultrasensitive Quantitative Immunoassay

Background

We used an ultrasensitive, quantitative single molecule array (Simoa) immunoassay to test whether concentrations of Clostridioides (formerly Clostridium) difficile toxins A and/or B in the stool of adult inpatients with C. difficile infection (CDI) were higher than in asymptomatic carriers of toxinogenic C. difficile.

Methods

Patients enrolled as CDI-NAAT had clinically significant diarrhea and a positive nucleic acid amplification test (NAAT), per US guidelines, and received CDI treatment. Potential carriers had recently received antibiotics and did not have diarrhea; positive NAAT confirmed carriage. Baseline stool samples were tested by Simoa for toxin A and B.

Results

Stool toxin concentrations in both CDI-NAAT (n = 122) and carrier-NAAT (n = 44) cohorts spanned 5 logs (0 pg/mL to >100000 pg/mL). Seventy-nine of 122 (65%) CDI-NAAT and 34 of 44 (77%) carrier-NAAT had toxin A + B concentration ≥20 pg/mL (clinical cutoff). Median toxin A, toxin B, toxin A + B, and NAAT cycle threshold (Ct) values in CDI-NAAT and carrier-NAAT cohorts were similar (toxin A, 50.6 vs 60.0 pg/mL, P = .958; toxin B, 89.5 vs 42.3 pg/mL, P = .788; toxin A + B, 197.2 vs 137.3 pg/mL, P = .766; Ct, 28.1 vs 28.6, P = .354). However, when CDI/carrier cohorts were limited to those with detectable toxin, respective medians were significantly different (A: 874.0 vs 129.7, P = .021; B: 1317.0 vs 81.7, P = .003, A + B, 4180.7 vs 349.6, P = .004; Ct, 25.8 vs 27.7, P = .015).

Conclusions

Toxin concentration did not differentiate an individual with CDI from one with asymptomatic carriage. Median stool toxin concentrations in groups with CDI vs carriage differed, but only when groups were defined by detectable stool toxin (vs positive NAAT).

Differences in Gut Microbiome in Hospitalized Immunocompetent vs. Immunocompromised Children, Including Those With Sickle Cell Disease

Background: Gut microbial diversity and composition play important roles in health. This cross-sectional study was designed to test the hypothesis that hospitalized children who may be relatively immunocompromised (IC), defined as those with cancer, sickle cell disease (SCD), transplantation, or receiving immunosuppressive therapy) would have decreased microbial diversity, increased Clostridioides difficile colonization and different species composition compared to non-immunocompromised (Non-IC) children admitted to the same pediatric unit. Methods: A stool sample was obtained within 72 h of admission to a single unit at The Children's Hospital at Montefiore, Bronx, NY from March 2016 to February 2017 and the microbiome assessed by 16S rRNA sequencing. C. difficile colonization was assessed by glutamate dehydrogenase antigen and toxin polymerase chain reaction assays. Results: Stool samples were obtained from 69 IC (32 SCD, 19 cancer, 9 transplantation and 9 other) and 37 Non-IC patients. There were no significant differences in microbial alpha diversity and C. difficile colonization comparing IC vs. non-IC patients. Lower alpha diversity, however, was independently associated with the use of proton pump inhibitors or antibiotics, including prophylactic penicillin in patients with SCD. Differences in specific species abundances were observed when comparing IC vs. non-IC patients, particularly children with SCD. Non-IC patients had increased abundance of commensals associated with health including Alistipes putredinis, Alistipes ihumii, Roseburia inulinivorans, Roseburia intestinalis, and Ruminococcus albus (p < 0.005). Conclusions: Antibiotics and proton pump inhibitors, which were more commonly used in IC children, were identified as risk factors for lower microbial diversity. Non-IC patients had higher abundance of several bacterial species associated with health. Longitudinal studies are needed to determine the clinical significance of these differences in gut microbiome.

Analysis of Routine and Integrative Data from Clostridioides difficile Infection Diagnosis and the Consequent Observations

Background:

Clostridioides difficileInfection (CDI) is an acute disease that needs a fast proper treatment. Unfortunately, the diagnosis, and above all the understanding of the results, remain arduous.

Objective:

This study analyzed routine and integrative results of all fecal samples from patients over time. Our aim was to understand the dynamics of CDI infection and the meaning of “difficult to interpret” results, to make physicians better understand the various tools they can use.

Methods:

We evaluated routine results obtained from 815 diarrheal stools with Enzyme Immunoassay (EIA) that detectsC. difficileGlutamate Dehydrogenase (GDH) antigen and toxin B. We also reanalyzed a part of samples using integrative tests: a Real-time polymerase chain reaction (RT-PCR) forC. difficiletoxin B gene (tcdB) and the automated immunoassay VIDASC. difficilesystem for GDH and toxins A/B.

Results:

EIA GDH positivity increased through multiple testing over time, with aPvalue <0.001, depicting a sort of bacterial growth curve. Eighty-five percent of GDH positive/toxin B negative,i.e., discrepant, samples PCR weretcdBpositive, 61.5% of discrepanttcdBpositive samples were VIDAS toxins A/B positive, and 44.4% of GDH EIA negative stools were VIDAS GDH positive.

Conclusion:

The results confirmed the low sensitivity of the EIA system forC. difficileGDH and toxins, questioned the use of the latter for concluding any CDI diagnostic algorithm, and led us to indicate the algorithm beginning with tcdB molecular research, and continuing in positive cases with VIDAS CD GDH method, as the most effective for CDI.

A Two-Step Approach for Diagnosing Glutamate Dehydrogenase Genes by Conventional Polymerase Chain Reaction from Clostridium difficile Isolates

BACKGROUND

Clostridium difficile is the major causative agent of nosocomial antibiotic-associated colitis. The gold standard for C. difficile detection is stool culture followed by cytotoxic assay, although it is laborious and time-consuming. We developed a screening test based on a two-step conventional polymerase chain reaction (PCR) approach to detect gluD, the glutamate dehydrogenase (GDH) enzyme gene, which is a marker for screening of C. difficile. Targeting gluD comparing to the conserved stable genetic element of pathogenicity locus (PaLoc), with an accessory gene of Cdd3, was an effective method for the detection of this pathogen from patients with enterocolitis.

METHODS

Fresh fecal samples of the patients who were clinically suspicious for antibiotic-associated colitis were collected. Stool specimens were cultured on the cycloserine-cefoxitin fructose agar (CCFA) in an anaerobic condition, following alcohol shock treatment and enrichment in Clostridium difficile Brucella broth (CDBB). On confirmed colonies, PCR was carried out for detection of PaLoc subsidiary gene, Cdd3, and toxicogenic genes, tcdA and tcdB. The gluD that is GDH gene detection was performed by conventional PCR on the extracted DNA from 578 fresh stool samples.

RESULTS

57 (9.8%) strains of C. difficile were approved by conventional PCR for gluD and Cdd3 genes, in which 37 (6.4%) colonies had tcdA+/tcdB+ genotype, 2 (0.3%) tcdA+/tcdB-, 4 (0.7%) tcdA-/ tcdB+ and the remaining 14 (2.4%) colonies were tcdA and tcdB negative.

CONCLUSION

These results demonstrate that targeting gluD by PCR is quite promising for rapid detection of C. difficile from fresh fecal samples. Furthermore, the multiple-gene analysis for tcdA and tcdB assay proved a reliable approach for diagnosing of toxigenic strains among clinical samples.

Clostridioides difficile in Outpatients: Application of a Diagnostic Algorithm Recommended by the European Society of Clinical Microbiology and Infectious Diseases

This study aimed at evaluating in outpatients an algorithm for the laboratory diagnosis of Clostridioides (Clostridium) difficile infection (CDI), i.e., enzyme immunoassays (EIAs) detecting bacterial glutamate dehydrogenase (GDH) and toxin A/B, followed by polymerase chain reaction (PCR) analyses of samples with discordant EIA results.

In total, 9802 examinations of stool samples by GDH and toxin EIAs performed in 7263 outpatients and 488 inpatients were analyzed retrospectively. Samples with discordant EIA results had been tested by a commercially available PCR assay detecting genes of the C. difficile-specific triose phosphate isomerase (tpi) and toxin B (tcdB). Concordant EIA results (686 C. difficile-positive, 8121 negative) were observed for 8807 (89.8%; 95% CI, 89.2–90.4%) samples. Of 958 samples with discordant EIA results, 895 were analyzed using PCR and 580 of 854 GDH-positive/borderline, toxin-negative samples (67.9%; 95% CI, 64.7–71.0%) were positive for tpi and tcdB, while 274 samples (32.1%; 95% CI, 29.0–35.3%) were tcdB-negative. In contrast, 35 of 41 GDH-negative, toxin-positive/borderline samples (85.4%; 95% CI, 71.2–93.5%) were tcdB-negative. Still, 6 samples (14.6%; 95% CI, 6.5–28.8%) yielded positive PCR results for both genes.

In conclusion, around 90% of the samples were analyzed appropriately by only applying EIAs. Approximately one third of the PCR-analyzed samples were tcdB-negative; thus, patients most likely did not require CDI treatment.

Prediction of poor outcome in Clostridioides difficile infection: A multicentre external validation of the toxin B amplification cycle

Classification of patients according to their risk of poor outcomes in Clostridioides difficile infection (CDI) would enable implementation of costly new treatment options in a subset of patients at higher risk of poor outcome. In a previous study, we found that low toxin B amplification cycle thresholds (C_t) were independently associated with poor outcome CDI. Our objective was to perform a multicentre external validation of a PCR-toxin B C_t as a marker of poor outcome CDI. We carried out a multicentre study (14 hospitals) in which the characteristics and outcome of patients with CDI were evaluated. A subanalysis of the results of the amplification curve of real-time PCR gene toxin B (XpertTM C. difficile) was performed. A total of 223 patients were included. The median age was 73.0 years, 50.2% were female, and the median Charlson index was 3.0. The comparison of poor outcome and non-poor outcome CDI episodes revealed, respectively, the following results: median age (years), 77.0 vs 72.0 (p = 0.009); patients from nursing homes, 24.4% vs 10.8% (p = 0.039); median leukocytes (cells/μl), 10,740.0 vs 8795.0 (p = 0.026); and median PCR-toxin B C_t, 23.3 vs 25.4 (p = 0.004). Multivariate analysis showed that a PCR-toxin B C_t cut-off <23.5 was significantly and independently associated with poor outcome CDI (p = 0.002; OR, 3.371; 95%CI, 1.565-7.264). This variable correctly classified 68.5% of patients. The use of this microbiological marker could facilitate early selection of patients who are at higher risk of poor outcome and are more likely to benefit from newer and more costly therapeutic options.

Reduced Clostridioides difficile Tests Among Solid Organ Transplant Recipients Through a Diagnostic Stewardship Bundled Intervention

BACKGROUND Clostridioides difficile infection (CDI) is a frequent complication of solid organ transplantation, especially in the early post-transplantation period. Overdiagnosis of CDI is likely common in hospitals using nucleic acid amplification testing (NAAT), potentially leading to unnecessary iatrogenesis and cost. Recently, multiple studies have shown that computerized clinical decision support (CCDS)-based interventions can significantly reduce inappropriate C. difficile testing and healthcare facility-onset CDI events across hospitals and health systems. We aimed to determine if a CCDS-based intervention could reduce C. difficile testing and surveillance infection events among recent solid organ transplant recipients, a population at high risk for CDI. We also sought to determine the safety of the CCDS intervention. MATERIAL AND METHODS Quasi-experimental census-adjusted interrupted time-series analyses were performed retrospectively to examine testing and CDI events pre- and post-intervention. Mortality and readmissions rates were also examined. RESULTS A significant 33% relative reduction in tests and a nonsignificant trend towards fewer CDI events were observed following the intervention, without significant differences in mortality or 30-day readmission. A review of patients with positive C. difficile NAATs after prevented tests revealed no specific adverse events attributable to a possible delay in CDI diagnosis. CONCLUSIONS CCDS may be a helpful and safe adjunctive strategy to reduce unnecessary testing in accordance with guideline recommendations among solid organ transplant recipients.

Toxin B PCR Amplification Cycle Threshold Adds Little to Clinical Variables for Predicting Outcomes in Clostridium difficile Infection: a Retrospective Cohort Study

The objective of the present study was to evaluate the value of the PCR cycle threshold (C_T ) for predicting the recurrence/severity of infection compared to that of toxin detection plus clinical variables. First episodes of Clostridium difficile infection (CDI) diagnosed during 2015 at our institution were included. Samples were tested for glutamate dehydrogenase (GDH) and toxin A/B by use of a single enzyme immunoassay (EIA). The Xpert C. difficile PCR assay was performed on GDH-positive samples. Medical data were reviewed by investigators blinded to diagnostic results for comparison of patients with and without recurrence or a poor outcome (severe/severe-complicated CDI episodes and all-cause death). We generated two sets of predictive models by incorporating the presence of a positive toxin EIA ("EIA-including model") or the optimal PCR C_T cutoff value ("PCR-including model") into the clinical variables. Among 227 episodes of CDI included in the study, the rates of recurrence and poor outcome were 15.8% and 30.8%, respectively. The mean PCR C_T was lower for episodes with recurrence (24.00 ± 3.28 versus 26.02 ± 4.54; P = 0.002) or a poor outcome (24.9 ± 4.24 versus 26.05 ± 4.47; P = 0.07). The optimal cutoff value for recurrence was 25.65 (sensitivity, 77.8% [95% confidence interval {CI}, 60.9 to 89.9]; and specificity, 46.6% [95% CI, 39.4 to 53.9]). The area under the receiver operator characteristics curve (auROC) for the "PCR-including model" was similar to that for the "EIA-including model" (0.785 versus 0.775, respectively). The optimal PCR C_T value for poor outcome was 27.55 (sensitivity, 78.6% [95% CI, 67.1 to 87.5]; and specificity, 35.7% [95% CI, 28.2 to 43.7]). The auROC of the "PCR-including model" was again similar to that of the "EIA-including model" (0.804 versus 0.801). Despite the inverse correlation between PCR C_T and the risk of CDI recurrence/severity, this determination does not meaningfully increase the predictive value of clinical variables plus toxin EIA.

GDH and toxin immunoassay for the diagnosis of Clostridioides (Clostridium) difficile infection is not a 'one size fit all' screening test

Diagnosing Clostridioides (Clostridium) difficile infection is challenged by lack of a clear gold standard. We sought to determine if the two-step algorithm (screening GDH and toxin lateral flow assay followed by tcdB PCR) would have adequate clinical performance at a tertiary care center. Of 486 patients, 310 (63.8%) were immunocompromised. Of 150 PCR-positive specimens, 52 (34.7%) were toxin-positive and 126 (84.0%) were GDH positive. Positive GDH or toxin results corresponded to lower PCR cycle threshold values (P < 0.01). PCR-positive patients had more frequently documented antibiotic usage (78.4% vs 66.9%, P = 0.05) and diarrhea (91.0% vs. 79.4%, P < 0.01) and less frequent alternate etiologies of diarrhea (27.3% vs. 41.1%, P = 0.004) or laxative use (24.6% vs 36.1%, P = 0.02). Toxin positivity was associated with antibiotic use (P < 0.01), but not with neutropenia, diarrhea, malignancy, or chemotherapy (P > 0.05). The application of the 2-step algorithm should be thoroughly evaluated in immunocompromised patient populations before implementation.

Clinical heterogeneity of patients with stool samples testing PCR+/Tox- from a two-step Clostridium difficile diagnostic algorithm

The clinical significance of indeterminate (PCR+/Tox-) results for patients tested with a two-step algorithm for Clostridium difficile infection (CDI) is uncertain. We aimed to evaluate the clinical presentation and 8-week outcomes of patients with indeterminate test results. Patients with stool samples testing positive by PCR and negative by toxin A/B immunoassay between February 1, 2017, and April 30, 2018, were assessed by antimicrobial stewardship program (ASP) clinicians and classified as colonized or infected. Retrospective chart review was performed to obtain outcomes occurring within 8 weeks of testing, including recurrent C. difficile diarrhea, subsequent treatment for CDI, follow-up C. difficile testing, all-cause mortality, and CDI-related complications. In total, 110 PCR+/Tox- patients were evaluated. ASP classified 54% of patients as infected and 46% as colonized. Patients assessed and classified as colonized did not have increased adverse outcomes by 8 weeks compared to those assessed as infected, despite not receiving treatment for CDI. We conclude that PCR+/Tox- patients are heterogeneous with respect to clinical presentation. Negative toxin A/B immunoassay in a two-step algorithm should not be interpreted in isolation to distinguish colonization from infection as many PCR+/Tox- results may be clinically significant for CDI.

A comprehensive approach for the patient with Clostridium difficile infection

During the last decade there have been many changes and advances in the research on Clostridium difficile infection (CDI). We have improved diagnostic and therapeutic tools and, at the same time, we have learned that the CDI implies, especially in the most vulnerable patients, an important morbidity. CDI has traditionally been undervalued and it is widely dispersed in hospitals. Surely, there is inertness in its management and there are also broad areas of improvement. If we add to this the high cost of the new drugs and the practical difficulties to implement the faecal microbiota transplant, we realize that we may not be taking full advantage of all the opportunities to improve patient's outcomes. The implementation of policies that favour the supervision of all CDI cases by an expert in infectious diseases will contribute to a better global management of this important disease.

Clinical Characteristics and Outcomes of Hematologic Malignancy Patients With Positive Clostridium difficile Toxin Immunoassay Versus Polymerase Chain Reaction Test Results

In a cohort of inpatients with hematologic malignancy and positive enzyme immunoassay (EIA) or polymerase chain reaction (PCR) Clostridium difficile tests, we found that clinical characteristics and outcomes were similar between these groups. The method of testing is unlikely to predict infection in this population, and PCR-positive results should be treated with concern.Infect Control Hosp Epidemiol 2018;863-866.