Loop-mediated isothermal amplification compared to real-time PCR and enzyme immunoassay for toxigenic Clostridium difficile detection

Rapid Isothermal Detection of Pathogenic Clostridioides difficile Using Recombinase Polymerase Amplification

Nosocomial-associated diarrhea due to Clostridioides difficile infection (CDI) is diagnosed after sample precultivation by the detection of the toxins in enzyme immunoassays or via toxin gene nucleic acid amplification. Rapid and direct diagnosis is important for targeted treatment to prevent severe cases and recurrence. We developed two singleplex and a one-pot duplex fluorescent 15 min isothermal recombinase polymerase amplification (RPA) assays targeting the toxin genes A and B (tcdA and tcdB). Furthermore, we adapted the singleplex RPA to a 3D-printed microreactor device. Analytical sensitivity was determined using a DNA standard and DNA extracts of 20 C. difficile strains with different toxinotypes. Nineteen clostridial and gastrointestinal bacteria strains were used to determine analytical specificity. Adaptation of singleplex assays to duplex assays in a 50 μL volume required optimized primer and probe concentrations. A volume reduction by one-fourth (12.4 μL) was established for the 3D-printed microreactor. Mixing of RPA was confirmed as essential for optimal analytical sensitivity. Detection limits (LOD) ranging from 119 to 1411 DNA molecules detected were similar in the duplex tube format and in the singleplex 3D-printed microreactor format. The duplex RPA allows the simultaneous detection of both toxins important for the timely and reliable diagnosis of CDI. The 3D-printed reaction chamber can be developed into a microfluidic lab-on-a-chip system use at the point of care.

Accuracy of diagnostic assays for the detection of Clostridioides difficile: A systematic review and meta-analysis

INTRODUCTION

Clostridioides difficile Infection (CDI) has been identified as one of the main causes of nosocomial infection all across the world. Rapid diagnosis of CDI is difficult and poses a significant challenge to physicians worldwide. We undertook a systematic review and meta-analysis to evaluate rapid tests' diagnostic accuracy against toxigenic culture as the reference standard for CDI.

METHOD

We searched the PubMed/MEDLINE and EMBASE databases for the relevant records. The QUADAS-2 tool was used to assess the quality of the studies. Diagnostic accuracy measures [i.e., sensitivity, specificity, diagnostic odds ratio (DOR), positive likelihood ratios (PLR), negative likelihood ratios (NLR), and the area under the curve (AUC)] were pooled with a random-effects model. All statistical analyses were performed with Meta-DiSc (Version 1.4, Cochrane Colloquium, Barcelona, Spain) and RevMan (version 5.3; The Nordic Cochrane Centre, the Cochrane Collaboration, Copenhagen, Denmark).

RESULTS

We reviewed retrieved records and identified 63 studies that met the inclusion criteria. 26 were about enzyme immunoassay (EIA) (our main index test). The sensitivity of GDH and Tox A/B EIAs were 82% (95% CI: 79-84) and 75% (95% CI: 70-79), respectively. On the other hand, the specificity of GDH EIA was 91% (95% CI: 90-92) and the specificity of Tox A/B EIA was 95% (95% CI: 94-96). Among other index tests, BD Max with 92% has the most sensitivity and cell cytotoxicity neutralization assay (CCNA) has the most specificity (100%).

CONCLUSION

This meta-analysis demonstrated that EIAs could be reliable methods for detecting CDI based on their sensitivity, specificity, time and cost-effectiveness, and simplicity in the procedure. Further work to improve rapid tests would benefit from improvements to the methodology.

The Current Knowledge on Clostridioides difficile Infection in Patients with Inflammatory Bowel Diseases

Clostridioides difficile (C. difficile) represents a major health burden with substantial economic and clinical impact. Patients with inflammatory bowel diseases (IBD) were identified as a risk category for Clostridioides difficile infection (CDI). In addition to traditional risk factors for C. difficile acquisition, IBD-specific risk factors such as immunosuppression, severity and extension of the inflammatory disease were identified. C. difficile virulence factors, represented by both toxins A and B, induce the damage of the intestinal mucosa and vascular changes, and promote the inflammatory host response. Given the potential life-threatening complications, early diagnostic and therapeutic interventions are required. The screening for CDI is recommended in IBD exacerbations, and the diagnostic algorithm consists of clinical evaluation, enzyme immunoassays (EIAs) or nucleic acid amplification tests (NAATs). An increased length of hospitalization, increased colectomy rate and mortality are the consequences of concurrent CDI in IBD patients. Selection of CD strains of higher virulence, antibiotic resistance, and the increasing rate of recurrent infections make the management of CDI in IBD more challenging. An individualized therapeutic approach is recommended to control CDI as well as IBD flare. Novel therapeutic strategies have been developed in recent years in order to manage severe, refractory or recurrent CDI. In this article, we aim to review the current evidence in the field of CDI in patients with underlying IBD, pointing to pathogenic mechanisms, risk factors for infection, diagnostic steps, clinical impact and outcomes, and specific management.

Development and Clinical Application of a Rapid and Visual Loop-Mediated Isothermal Amplification Test for tetM gene in Clostridioides difficile Strains Cultured from Feces

OBJECTIVES

To develop a rapid and visual loop-mediated isothermal amplification (LAMP) assay targeting the tetM gene in Clostridioides difficile (C. difficile) strains cultured from feces.

METHODS

Primers were designed to recognize the tetM gene in C. difficile by LAMP, using turbidity and visual detection. The sensitivity and specificity of LAMP primers was determined. Besides, We conducted both LAMP and polymerase chain reaction (PCR) for the tcdA, tcdB, cdtA, cdtB, ermB, tetM genes in 300 toxigenic C. difficile strains cultured from feces.

RESULTS

The target DNA was amplified and visualized within 60 minutes at a temperature of 62°C. A total of 26 bacterial strains were found negative for tetM, which manifested high specificity of the primers. The detection limit of LAMP was 36.1 pg/µl, which was 100-fold more sensitive than PCR. The positive rate of tetM in toxigenic C. difficile strains cultured from feces was 93.3% by both LAMP and PCR. The proportion of toxin types in those C. difficile strains was 95.7% for A+B+CDT-, 4% for A-B+CDT-, and 0.3% for A+B+CDT+, respectively.

CONCLUSIONS

This is the first study examining tetM gene in C. difficile strains cultured from feces by LAMP. Its high specificity and sensitivity, as well as visual detection, make the new assay a powerful diagnostic tool for rapid testing.

Evaluation of loop-mediated isothermal amplification assay for detection of Clostridioides difficile infection: A prospective diagnostic performance study

A novel Loop-mediated isothermal amplification (LAMP) assay, HiberGene's CD was evaluated with 82 unformed stools from patients suspected of C. difficile infection (CDI). Compared to glutamate dehydrogenase (GDH) toxins A/B test (C.diff Quik Chek®), HiberGene's LAMP showed 100% of sensitivity and 95,8% of specificity; and compared to FilmArray™ GI panel ® (BioFire), a sensitivity of 81,2% and a specificity of 100%, with 96.38% of agreement.

Establishment and evaluation of a method for efficient screening of Clostridium butyricum

At present, the traditional methods for the screening of Clostridium butyricum are not sufficiently selective and efficient. Therefore, it is necessary to establish a targeted and efficient screening method for the detection of C. butyricum. Bioinformatics was used in this study to find C. butyricum specific genes, and species-specific primers were designed based on the conserved regions of the targeted genes, followed by optimization of the PCR conditions. Methodological evaluation was carried out, and the results were compared with the traditional screening method based on Trypticase Sulfite Neomycin (TSN) selective medium. A high-efficiency PCR screening method, targeting C. butyricum species-specific primers, was established. The method was confirmed to have high specificity and sensitivity towards C. butyricum cut-off CFU 10³. Compared with the traditional method, the screening success rate of C. butyricum strains increased from 0.61 to 81.91%. The PCR screening method could quickly and accurately detect C. butyricum in samples and dramatically improve screening efficiency.

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.

Recommendations for the diagnosis and treatment of Clostridioides difficile infection: An official clinical practice guideline of the Spanish Society of Chemotherapy (SEQ), Spanish Society of Internal Medicine (SEMI) and the working group of Postoperative Infection of the Spanish Society of Anesthesia and Reanimation (SEDAR)

This document gathers the opinion of a multidisciplinary forum of experts on different aspects of the diagnosis and treatment of Clostridioides difficile infection (CDI) in Spain. It has been structured around a series of questions that the attendees considered relevant and in which a consensus opinion was reached. The main messages were as follows: CDI should be suspected in patients older than 2 years of age in the presence of diarrhea, paralytic ileus and unexplained leukocytosis, even in the absence of classical risk factors. With a few exceptions, a single stool sample is sufficient for diagnosis, which can be sent to the laboratory with or without transportation media for enteropathogenic bacteria. In the absence of diarrhoea, rectal swabs may be valid. The microbiology laboratory should include C. difficile among the pathogens routinely searched in patients with diarrhoea. Laboratory tests in different order and sequence schemes include GDH detection, presence of toxins, molecular tests and toxigenic culture. Immediate determination of sensitivity to drugs such as vancomycin, metronidazole or fidaxomycin is not required. The evolution of toxin persistence is not a suitable test for follow up. Laboratory diagnosis of CDI should be rapid and results reported and interpreted to clinicians immediately. In addition to the basic support of all diarrheic episodes, CDI treatment requires the suppression of antiperistaltic agents, proton pump inhibitors and antibiotics, where possible. Oral vancomycin and fidaxomycin are the antibacterials of choice in treatment, intravenous metronidazole being restricted for patients in whom the presence of the above drugs in the intestinal lumen cannot be assured. Fecal material transplantation is the treatment of choice for patients with multiple recurrences but uncertainties persist regarding its standardization and safety. Bezlotoxumab is a monoclonal antibody to C. difficile toxin B that should be administered to patients at high risk of recurrence. Surgery is becoming less and less necessary and prevention with vaccines is under research. Probiotics have so far not been shown to be therapeutically or preventively effective. The therapeutic strategy should be based, rather than on the number of episodes, on the severity of the episodes and on their potential to recur. Some data point to the efficacy of oral vancomycin prophylaxis in patients who reccur CDI when systemic antibiotics are required again.

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.

Performance Evaluation of the Luminex Aries C. difficile Assay in Comparison to Two Other Molecular Assays within a Multihospital Health Care Center

Clostridioides difficile infection (CDI) remain a serious issue in the United States. Fast and accurate diagnosis of CDI is paramount to achieve immediate infection control initiation, triaging, and isolation, as well as appropriate antibiotic treatment. However, both, over- and underdiagnosis can lead to adverse patient outcomes, such as unnecessary administration of antibiotics or unwanted spread of spores in any hospital setting, respectively.

Clostridioides difficile infection (CDI) remain a serious issue in the United States. Fast and accurate diagnosis of CDI is paramount to achieve immediate infection control initiation, triaging, and isolation, as well as appropriate antibiotic treatment. However, both, over- and underdiagnosis can lead to adverse patient outcomes, such as unnecessary administration of antibiotics or unwanted spread of spores in any hospital setting, respectively. In this prospective study, we evaluated the FDA-cleared Aries C. difficile assay and compared its performance and workflow characteristics to those of the BD Max Cdiff and Xpert C. difficile/Epi assays. Out of 302 samples tested, 55 (18.2%) samples were positive, and 234 (77.5%) samples were negative for C. difficile by all three testing methods. Comparison results showed a positive and negative percent agreement (PPA and NPA, respectively) between the Aries and Xpert assays of 95.2% (59/62) and 99.2% (238/240), respectively. The PPA and NPA between the Aries and BD Max assays were 91.8% (56/61) and 96.6% (230/238), respectively. Invalid result rates were determined to be 2.6% for the BD Max assay, 1.0% for the Aries assay, and 0% for the Xpert assay. Hands-on time (HoT) and total turnaround time (TAT) varied considerably depending on the sample number and instrument throughput. The HoT ranged from 1.2 to 3.5 min per sample, and the TAT was 1 to 2.3 h. Overall, the results demonstrated that the Aries assay is a rapid and sensitive method for the diagnosis of CDI in clinical laboratories.

A Laboratory Medicine Best Practices Systematic Review and Meta-analysis of Nucleic Acid Amplification Tests (NAATs) and Algorithms Including NAATs for the Diagnosis of Clostridioides (Clostridium) difficile in Adults

The evidence base for the optimal laboratory diagnosis of Clostridioides (Clostridium) difficile in adults is currently unresolved due to the uncertain performance characteristics and various combinations of tests. This systematic review evaluates the diagnostic accuracy of laboratory testing algorithms that include nucleic acid amplification tests (NAATs) to detect the presence of C. difficile The systematic review and meta-analysis included eligible studies (those that had PICO [population, intervention, comparison, outcome] elements) that assessed the diagnostic accuracy of NAAT alone or following glutamate dehydrogenase (GDH) enzyme immunoassays (EIAs) or GDH EIAs plus C. difficile toxin EIAs (toxin). The diagnostic yield of NAAT for repeat testing after an initial negative result was also assessed. Two hundred thirty-eight studies met inclusion criteria. Seventy-two of these studies had sufficient data for meta-analysis. The strength of evidence ranged from high to insufficient. The uses of NAAT only, GDH-positive EIA followed by NAAT, and GDH-positive/toxin-negative EIA followed by NAAT are all recommended as American Society for Microbiology (ASM) best practices for the detection of the C. difficile toxin gene or organism. Meta-analysis of published evidence supports the use of testing algorithms that use NAAT alone or in combination with GDH or GDH plus toxin EIA to detect the presence of C. difficile in adults. There is insufficient evidence to recommend against repeat testing of the sample using NAAT after an initial negative result due to a lack of evidence of harm (i.e., financial, length of stay, or delay of treatment) as specified by the Laboratory Medicine Best Practices (LMBP) systematic review method in making such an assessment. Findings from this systematic review provide clarity to diagnostic testing strategies and highlight gaps, such as low numbers of GDH/toxin/PCR studies, in existing evidence on diagnostic performance, which can be used to guide future clinical research studies.

Rapid visual detection of binary toxin producing Clostridium difficile by loop-mediated isothermal amplification

The binary toxin Clostridium difficile transferase (CDT) is frequently observed in C. difficile strains and is associated with an increased severity of C. difficile infection. CDT-producing C. difficile infections cause higher fatality rates than infections with CDT negative isolates. Thus, the rapid and accurate identification of a CDT positive C. difficile infection is critical for effective treatment. The present study demonstrates how loop-mediated isothermal amplification (LAMP) can be used to detect CDT-producing C. difficile based on visual observation. This is a low complexity, rapid molecular method that has the potential to be used within a point of care setting. The specificity and sensitivity of the primers in the LAMP reactions for CDT detection were determined using two different methods, a real-time turbidity monitor and visual detection after the addition of calcein to the reaction tube. The results revealed that target DNA was amplified and visualized by these two detection methods within 60 min at a temperature of 60°C. The sensitivity of the LAMP assay was identified to be 10-fold greater than that of polymerase chain reaction analysis. When 25 alternative bacterial strains lacking CDT were tested, the results of the amplification were negative, confirming the specificity of the primers. In conclusion, the visual LAMP method established in the present study may be a rapid, reliable and cost-effective tool for detecting CDT-producing C. difficile strains at the point of care.

The Use of a Computerized Provider Order Entry Alert to Decrease Rates of Clostridium difficile Testing in Young Pediatric Patients

BACKGROUND Infants and young children are frequently colonized with C. difficile but rarely have symptomatic disease. However, C. difficile testing remains prevalent in this age group. OBJECTIVE To design a computerized provider order entry (CPOE) alert to decrease testing for C. difficile in young children and infants. DESIGN An interventional age-targeted before-after trial with comparison group SETTING Monroe Carell Jr. Children's Hospital at Vanderbilt University, Nashville, Tennessee. PATIENTS All children seen in the inpatient or emergency room settings from July 2012 through July 2013 (pre-CPOE alert) and September 2013 through September 2014 (post-CPOE alert) INTERVENTION In August of 2013, we implemented a CPOE alert advising against testing in infants and young children based on the American Academy of Pediatrics recommendations with an optional override. We further offered healthcare providers educational seminars regarding recommended C. difficile testing. RESULTS The average monthly testing rate significantly decreased after the CPOE alert for children 0-11 months old (11.5 pre-alert vs 0 post-alert per 10,000 patient days; P<.001) and 12-35 months old (61.6 pre-alert vs 30.1 post-alert per 10,000 patients days; P<.001), but not for those children ≥36 months old (50.9 pre-alert vs 46.4 post-alert per 10,000 patient days; P=.3) who were not targeted with a CPOE alert. There were no complications in those children who testing positive for C. difficile. CONCLUSIONS The average monthly testing rate for C. difficile for children <35 months old decreased without complication after the use of a CPOE alert in those who tested positive for C. difficile. Infect Control Hosp Epidemiol 2017;38:542-546.

Fecal Microbiota Transplant

Clostridium difficile infection (CDI) has steadily increased in incidence since the 1990s, with an associated increase in recurrence and severity, which has in turn lead to more intensive care unit (ICU) admissions. The development of recurrent CDI, in particular, has been associated with increasing patient morbidity and mortality as well as an immense financial burden on the health care system. Recently, fecal microbiota transplantation (FMT) has received much publicity as an effective means of treatment for recurrent CDI. The goal of this review is to provide evidence-based recommendations for the diagnosis and management of CDI, with a particular focus on FMT and its utilization in the ICU.

Rapid detection of ermB gene in Clostridium difficile by loop-mediated isothermal amplification

Macrolide-lincosamide-streptogramin B resistance in Clostridium difficile is mostly due to the ermB resistance determinant. Here, we describe a sensitive and rapid molecular method to detect ermB in C. difficile to contribute to the wider epidemiological study. Five sets of loop-mediated isothermal amplification (LAMP) primers were designed and optimized for rapid detection of ermB. The specificity and sensitivity of the primers for ermB were detected, and the ermB LAMP assay was compared to conventional PCR with 80 clinical isolates of C. difficile. Real-time monitoring of turbidity and chromogenic reaction were used to determine negative and positive results. A total of 26 pathogenic bacterial strains of different species were found to be negative for ermB, which indicated the high specificity of the primers. ermB was detected in 78.8 % (63/80) of the clinical isolates by both LAMP and conventional PCR. The detection limit of LAMP was 36.1  pg DNA μl- 1 and its sensitivity was 10-fold greater than that of conventional PCR. This study is the first report regarding the development and application of the LAMP assay for detection of the ermB gene in C. difficile strains. The developed LAMP method is sensitive, specific and provides a user-friendly visual approach for the rapid detection of ermB-bearing C. difficile.

Diagnostic accuracy of loop-mediated isothermal amplification in detection of Clostridium difficile in stool samples: a meta-analysis

INTRODUCTION

Clostridium difficile infection (CDI) remains a diagnostic challenge for clinicians. More recently, loop-mediated isothermal amplification (LAMP) has become readily available for the diagnosis of CDI, and many studies have investigated the usefulness of LAMP for rapid and accurate diagnosis of CDI. However, the overall diagnostic accuracy of LAMP for CDI remains unclear. In this meta-analysis, our aim was to establish the overall diagnostic accuracy of LAMP in detection of Clostridium difficile (CD) in stool samples.

MATERIAL AND METHODS

A search was done in PubMed, MEDLINE, EMBASE and Cochrane Library databases up to February 2014 to identify published studies that evaluated the diagnostic role of LAMP for CD. Methodological quality was assessed according to the quality assessment for studies of diagnostic accuracy (QUADAS) instrument. The sensitivities (SEN), specificities (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR) and diagnostic odds ratio (DOR) were pooled statistically using random effects models. Statistical analysis was performed by employing Meta-Disc 1.4 software. Summary receiver operating characteristic (SROC) curves were used to summarize overall test performance. Funnel plots were used to test the potential publication bias.

RESULT

A total of 9 studies met inclusion criteria for the present meta-analysis. The pooled SEN and SPE for diagnosing CD were 0.93 (95% CI: 0.91-0.95) and 0.98 (95% CI: 0.98-0.99), respectively. The PLR was 47.72 (95% CI: 15.10-150.82), NLR was 0.07 (95% CI: 0.04-0.14) and DOR was 745.19 (95% CI: 229.30-2421.72). The area under the ROC was 0.98. Meta-regression indicated that the total number of samples was a source of heterogeneity for LAMP in detection of CD. The funnel plots suggested no publication bias.

CONCLUSIONS

The LAMP meets the minimum desirable characteristics of a diagnostic test of SEN, SPE and other measures of accuracy in the diagnosis of CD, and it is suitable as a rapid, effective and reliable stand-alone diagnostic test for diagnosis of CDI, potentially decreasing morbidity and nosocomial spread of CD.

Preparation and preliminary application of monoclonal antibodies to the receptor binding region of Clostridium difficile toxin B

A previous nationwide Chinese epidemiological study revealed through isolation of A‑B+ Clostridium difficile strains, which produce toxin B (TcdB), but not toxin A TcdA, that the strains are widespread and more frequent in east Asian countries,. The development of a process capable of detecting TcdB is required in microbiological laboratories in order to facilitate the control of the A‑B+ C. difficile strains, however, no diagnostic reagents have been developed to date. The aim of the present study was to prepare monoclonal antibodies (mAbs) targeting the receptor binding region of TcdB (CDB3), and to establish a double‑antibody sandwich enzyme-linked immunosorbent assay (ds‑ELISA), which can be used for the diagnosis of C. difficile infection. The recombinant protein, glutathione S transferase (GST)‑CDB3 was expressed and purified using an Escherichia coli system. BALB/c mice were immunized with GST‑CDB3 recombinant protein. A hybridoma technique was used for the production of anti‑CDB3 mAb. The hybridoma clones were then screened using indirect ELISA, and anti‑CDB3 mAb was produced in the ascites of the BALB/c mice. Isotyping of anti‑CDB3 mAb was performed using an SBA Clonotyping system/horseradish peroxidase (HRP) ELISA kit. Protein G affinity chromatography was used for purification of anti‑CDB3 mAbs, and the titer and specificity of the anti‑CDB3 mAbs were assessed using indirect ELISA and western blot analysis, respectively. The ds‑ELISA was established using HRP‑labeled anti‑CDB3 mAbd, which were used to detect TcdB clinically in diarrhea stools. A total of five stable hybridoma cell clones (1E7B, 1F8D3, 2F8A6, 3B6F1 and 4A4G2) producing anti‑CDB3 mAb were established. The results of the present study indicated that the immunoglobulin (Ig)G isotype was predominant, as 1E7B2 IgG1 (λ), 2F8A6 IgG2a (κ) and 4A4G2 IgG1 (κ). In addition, the highest titer of anti‑CDB3 mAb (2F8A6 and 4A4G2) was 1:51,200. Western blotting revealed that the 2F8A6 and 4A4G2 mAbs recognized the CDB3 protein specifically. Following anti‑CDB3 mAb (4A4G2) HRP‑labeling, the optimal working concentration was confirmed to be 1:400, and the concentration of coated antibody (2F8A6) was 20 µg/ml. The sensitivity of the ds‑ELISA was 73.33% for the A+B+ toxigenic C. difficile strains, and 86.67% for the A‑B+ toxigenic C. difficile strains, with a specificity of 100% for all. In conclusion, the present study successfully developed novel mAbs specific to CDB3, and developed a ds-ELISA kit with high specificity and sensitivity for the rapid detection of TcdB. This offers a useful tool for the diagnostic assessment of TcdB.

"Paper Machine" for Molecular Diagnostics

Clinical tests based on primer-initiated amplification of specific nucleic acid sequences achieve high levels of sensitivity and specificity. Despite these desirable characteristics, these tests have not reached their full potential because their complexity and expense limit their usefulness to centralized laboratories. This paper describes a device that integrates sample preparation and loop-mediated isothermal amplification (LAMP) with end point detection using a hand-held UV source and camera phone. The prototype device integrates paper microfluidics (to enable fluid handling) and a multilayer structure, or a "paper machine", that allows a central patterned paper strip to slide in and out of fluidic path and thus allows introduction of sample, wash buffers, amplification master mix, and detection reagents with minimal pipetting, in a hand-held, disposable device intended for point-of-care use in resource-limited environments. This device creates a dynamic seal that prevents evaporation during incubation at 65 °C for 1 h. This interval is sufficient to allow a LAMP reaction for the Escherichia coli malB gene to proceed with an analytical sensitivity of 1 double-stranded DNA target copy. Starting with human plasma spiked with whole, live E. coli cells, this paper demonstrates full integration of sample preparation with LAMP amplification and end point detection with a limit of detection of 5 cells. Further, it shows that the method used to prepare sample enables concentration of DNA from sample volumes commonly available from fingerstick blood draw.

Loss of Vancomycin-Resistant Enterococcus Fecal Dominance in an Organ Transplant Patient With Clostridium difficile Colitis After Fecal Microbiota Transplant

We report the use of fecal microbiota transplantation in a single heart-kidney transplant recipient with recurrent Clostridium difficile, vancomycin-resistant Enterococcus (VRE) fecal dominance, and recurrent VRE infections. Fecal microbiota transplantation resulted in the reconstruction of a diverse microbiota with (1) reduced relative abundance of C difficile and VRE and (2) positive clinical outcome.

Multiplex Real-Time PCR Method for Simultaneous Identification and Toxigenic Type Characterization of Clostridium difficile From Stool Samples

Background

The aim of this study was to develop and validate a multiplex real-time PCR assay for simultaneous identification and toxigenic type characterization of Clostridium difficile.

Methods

The multiplex real-time PCR assay targeted and simultaneously detected triose phosphate isomerase (tpi) and binary toxin (cdtA) genes, and toxin A (tcdA) and B (tcdB) genes in the first and sec tubes, respectively. The results of multiplex real-time PCR were compared to those of the BD GeneOhm Cdiff assay, targeting the tcdB gene alone. The toxigenic culture was used as the reference, where toxin genes were detected by multiplex real-time PCR.

Results

A total of 351 stool samples from consecutive patients were included in the study. Fifty-five stool samples (15.6%) were determined to be positive for the presence of C. difficile by using multiplex real-time PCR. Of these, 48 (87.2%) were toxigenic (46 tcdA and tcdB-positive, two positive for only tcdB) and 11 (22.9%) were cdtA-positive. The sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of the multiplex real-time PCR compared with the toxigenic culture were 95.6%, 98.6%, 91.6%, and 99.3%, respectively. The analytical sensitivity of the multiplex real-time PCR assay was determined to be 103colonyforming unit (CFU)/g spiked stool sample and 0.0625 pg genomic DNA from culture. Analytical specificity determined by using 15 enteric and non-clostridial reference strains was 100%.

Conclusions

The multiplex real-time PCR assay accurately detected C. difficile isolates from diarrheal stool samples and characterized its toxin genes in a single PCR run.

Clostridium difficile spores: a major threat to the hospital environment

Clostridium difficile is a Gram-positive, anaerobic spore former and is an important nosocomial and community-acquired pathogenic bacterium. C. difficile infections (CDI) are a leading cause of infections worldwide with elevated rates of morbidity. Despite the fact that two major virulence factors, the enterotoxin TcdA and the cytotoxin TcdB, are essential in the development of CDI, C. difficile spores are the main vehicle of infection, and persistence and transmission of CDI and are thought to play an essential role in episodes of CDI recurrence and horizontal transmission. Recent research has unmasked several properties of C. difficile's unique strategy to form highly transmissible spores and to persist in the colonic environment. Therefore, the aim of this article is to summarize recent advances in the biological properties of C. difficile spores, which might be clinically relevant to improve the management of CDI in hospital environments.

Rapid detection of Streptococcus pneumoniae by real-time fluorescence loop-mediated isothermal amplification

BACKGROUND AND AIM OF STUDY

A significant human pathogenic bacterium, Streptococcus pneumoniae was recognized as a major cause of pneumonia, and is the subject of many humoral immunity studies. Diagnosis is generally made based on clinical suspicion along with a positive culture from a sample from virtually any place in the body. But the testing time is too long. This study is to establish a rapid diagnostic method to identification of Streptococcus pneumoniae.

METHODS

Our laboratory has recently developed a new platform called real-amp, which combines loop-mediated isothermal amplification (LAMP) with a portable tube scanner real-time isothermal instrument for the rapid detection of Streptococcus pneumonia. Two pairs of amplification primers required for this method were derived from a conserved DNA sequence unique to the Streptococcus pneumoniae. The amplification was carried out at 63 degree Celsius using SYBR Green for 60 minutes with the tube scanner set to collect fluorescence signals. Clinical samples of Streptococcus pneumoniae and other bacteria were used to determine the sensitivity and specificity of the primers by comparing with traditional culture method.

RESULTS

The new set of primers consistently detected in laboratory-maintained isolates of Streptococcus pneumoniae from our hospital. The new primers also proved to be more sensitive than the published species-specific primers specifically developed for the LAMP method in detecting Streptococcus pneumoniae.

CONCLUSIONS

This study demonstrates that the Streptococcus pneumoniae LAMP primers developed here have the ability to accurately detect Streptococcus pneumoniae infections by real-time fluorescence LAMP.

Evaluation of the illumigene C. difficile assay for toxigenic Clostridium difficile detection: a prospective study of 302 consecutive clinical fecal samples

Toxigenic Clostridium difficile is a major pathogen causing nosocomial diarrhea. Consequently, rapid detection of toxigenic C. difficile is very important in clinical laboratories. The illumigene C. difficile DNA amplification assay (illumigene; Meridian Bioscience, Inc.) is a rapid method that detects the toxin A gene (tcdA) by loop-mediated isothermal amplification. In the present study, we evaluated the diagnostic performance of the illumigene assay using 302 consecutive stool specimens in comparison with the VIDAS C. difficile A&B enzyme-linked fluorescent immunoassay (VIDAS-CDAB; bioMérieux). Toxigenic culture was used as the reference method. The sensitivity, specificity, positive predictive value, and negative predictive value of the illumigene assay were 88.1%, 96.7%, 86.7%, and 97.1%, respectively, while those of the VIDAS-CDAB assay were 40.4%, 98.8%, 87.5%, and 88.5%, respectively. It is of note that use of a combination of the illumigene and VIDAS-CDAB assays did not improve any of the 4 evaluated parameters (88.1%, 95.5%, 82.5%, and 97.1%, respectively). The illumigene assay showed limits of detection of 250 and 11,467 CFU/mL for ATCC 9688 (tcdA+, tcdB+, cdtB-) and ATCC 43598 (tcdA-, tcdB+, cdtB-) reference strains, respectively, and there was no cross-reactivity with 8 frequently isolated bacterial species. In conclusion, the illumigene assay might be a useful method for rapid detection of toxigenic C. difficile in clinical laboratories. Additionally, the VIDAS-CDAB assay seems unnecessary if the illumigene assay is used.

The Bristol stool scale and its relationship to Clostridium difficile infection

The Bristol stool form scale classifies the relative density of stool samples. In a prospective cohort study, we investigated the associations between stool density, C. difficile assay positivity, hospital-onset C. difficile infection, complications, and severity of C. difficile. We describe associations between the Bristol score, assay positivity, and clinical C. difficile infection.

Advanced techniques for detection and identification of microbial agents of gastroenteritis

Gastroenteritis persists as a worldwide problem, responsible for approximately 2 million deaths annually. Traditional diagnostic methods used in the clinical microbiology laboratory include a myriad of tests, such as culture, microscopy, and immunodiagnostics, which can be labor intensive and suffer from long turnaround times and, in some cases, poor sensitivity. [corrected]. This article reviews recent advances in genomic and proteomic technologies that have been applied to the detection and identification of gastrointestinal pathogens. These methods simplify and speed up the detection of pathogenic microorganisms, and their implementation in the clinical microbiology laboratory has potential to revolutionize the diagnosis of gastroenteritis.

tcdA As a diagnostic target in a loop-mediated amplification assay for detecting toxigenic Clostridium difficile

BACKGROUND

The illumigene® (Meridian Bioscience, Inc., Cincinnati, OH) and GeneOhm® (BD Diagnostics, La Jolla, CA) Clostridium difficile assays target the tcdA gene and tcdB gene, respectively. We assessed the use of tcdA as the molecular target in the illumigene® C. difficile loop-mediated amplification assay in detecting a wide variety of C. difficile strains including those with tcdA deletions.

METHODS

We tested 38 C. difficile strains and 108 patient stool specimens using the illumigene® assay. The GeneOhm® real-time polymerase chain reaction (PCR) assay served as the reference method. Discordant results were resolved by repeat testing, anaerobic culture, and a laboratory-developed real-time PCR targeting tcdA and tcdB.

RESULTS

Both illumigene® and GeneOhm® assays detected all 37 C. difficile toxin B(+) strains representing seven toxinotypes and including four toxin A(-) B(+) isolates. No cross-reactivity with 20 other Clostridium species or toxin-negative C. difficile was observed in either assay. Among patient stool specimens, agreement was 94.4% (102/108). After discordant result resolution, agreement was 96.3% (104/108). Specimens with initially discordant results had target concentrations approaching the limit of detection for the two commercial assays. Discordance appeared unrelated to whether tcdA or tcdB was the amplification target.

CONCLUSION

The tcdA 5' region used by the illumigene® assay is a practical target for toxigenic C. difficile detection.

Clostridium difficile Infection: Epidemiology, Pathogenesis, Risk Factors, and Therapeutic Options

The incidence and mortality rate of Clostridium difficile infection have increased remarkably in both hospital and community settings during the last two decades. The growth of infection may be caused by multiple factors including inappropriate antibiotic usage, poor standards of environmental cleanliness, changes in infection control practices, large outbreaks of C. difficile infection in hospitals, alteration of circulating strains of C. difficile, and spread of hypervirulent strains. Detection of high-risk populations could be helpful for prompt diagnosis and consequent treatment of patients suffering from C. difficile infection. Metronidazole and oral vancomycin are recommended antibiotics for the treatment of initial infection. Current treatments for C. difficile infection consist of supportive care, discontinuing the unnecessary antibiotic, and specific antimicrobial therapy. Moreover, novel approaches include fidaxomicin therapy, monoclonal antibodies, and fecal microbiota transplantation mediated therapy. Fecal microbiota transplantation has shown relevant efficacy to overcome C. difficile infection and reduce its recurrence.

Discrepancies among three laboratory methods for Clostridium difficile detection and a proposal for their optimal use

Clostridium difficile is the major cause of nosocomial diarrhoea. Several detection methods are available for the laboratory diagnosis of C. difficile, but these vary in terms of sensitivity and specificity. In this study, we compared the performance of three following laboratory tests to detect C. difficile: in-house real-time PCR aiming for toxin B gene (tcdB), EIA for detection of toxins A and B (Premier Toxins A & B) and C. difficile culture in selective medium (bioMerieux). Our results were grouped into three categories as follows: (1) C. difficile-associated diarrhoea (CDAD); (2) asymptomatic carriers; and (3) negative results. Among the 113 patients included in the study, 9 (8.0%) were classified as CDAD, 19 (16.8%) were asymptomatic carriers, 76 (67.2%) had negative results and 9 (8.0%) could not be categorized (positive test for C. difficile toxins only). PCR was found to be the most sensitive diagnostic test in our study, with the potential to be used as a screening method for C. difficile colonization/CDAD. Diagnosis of CDAD would be better performed by a combination of PCR and EIA tests.

Detection of Streptococcus pyogenes by use of Illumigene group A Streptococcus assay

The performance of the Illumigene group A Streptococcus assay was evaluated by comparing it to culture using 437 consecutive throat swabs. The Illumigene assay was also directly compared to PCR with 161 samples. This Illumigene assay is rapid and easy to perform. The assay also has high sensitivity (100%) compared to culture or PCR and high specificity (99.2%) compared to PCR. A total of 8.8% of the isolates were erythromycin resistant, and 6.9% were clindamycin resistant.

Effect of nucleic acid amplification testing on population-based incidence rates of Clostridium difficile infection

Nucleic acid amplification testing (NAAT) is increasingly being adopted for diagnosis of Clostridium difficile infection (CDI). Data from 3 states conducting population-based CDI surveillance showed increases ranging from 43% to 67% in CDI incidence attributable to changing from toxin enzyme immunoassays to NAAT. CDI surveillance requires adjustment for testing methods.

Simple system for isothermal DNA amplification coupled to lateral flow detection

Infectious disease diagnosis in point-of-care settings can be greatly improved through integrated, automated nucleic acid testing devices. We have developed an early prototype for a low-cost system which executes isothermal DNA amplification coupled to nucleic acid lateral flow (NALF) detection in a mesofluidic cartridge attached to a portable instrument. Fluid handling inside the cartridge is facilitated through one-way passive valves, flexible pouches, and electrolysis-driven pumps, which promotes a compact and inexpensive instrument design. The closed-system disposable prevents workspace amplicon contamination. The cartridge design is based on standard scalable manufacturing techniques such as injection molding. Nucleic acid amplification occurs in a two-layer pouch that enables efficient heat transfer. We have demonstrated as proof of principle the amplification and detection of Mycobacterium tuberculosis (M.tb) genomic DNA in the cartridge, using either Loop Mediated Amplification (LAMP) or the Exponential Amplification Reaction (EXPAR), both coupled to NALF detection. We envision that a refined version of this cartridge, including upstream sample preparation coupled to amplification and detection, will enable fully-automated sample-in to answer-out infectious disease diagnosis in primary care settings of low-resource countries with high disease burden.

Clostridium difficile Infection

Clostridium difficile is emerging as a common cause of infectious diarrhea. Incidence has increased dramatically since 2000, associated with a new strain that features both increased toxin production and increased resistance to antibiotics. For patients with mild to moderate disease, oral metronidazole is usually the first choice of treatment, and those with severe disease should be treated with vancomycin, with additional intravenous metronidazole in some cases. Fecal microbiota transplantation is a potentially promising therapy for patients with multiple recurrences of C difficile infection. Prevention of nosocomial transmission is crucial to reducing disease outbreaks in health care settings.

Laboratory diagnosis of Clostridium difficile infections: there is light at the end of the colon

Single molecular or multistep assays (glutamate dehydrogenase, toxin A/B, ± molecular) are recommended for the diagnosis of CDI in patients with clinically significant diarrhea. Rapid and accurate tests can improve resource allocations and improve patient care. Enzyme immunoassay (EIA) for toxins A/B is too insensitive for use as a stand-alone assay. This guideline will examine the use of molecular tests and multitest algorithms for the diagnosis of Clostridium difficile infection (CDI). These new tests, alone or in a multistep algorithm consisting of >1 assay, are more expensive than the older EIA assays; however, rapid and accurate testing can save money overall by initiating appropriate treatment and infection control protocols sooner and by possibly reducing length of hospital stay. We recommend testing only unformed stool in patients with clinically significant diarrhea by a molecular method or by a 2- to 3-step algorithm.

Evaluation of the rapid loop-mediated isothermal amplification assay Illumigene for diagnosis of Clostridium difficile in an outbreak situation

An outbreak of Clostridium difficile infection (CDI) at Höglandet Hospital Eksjö in southern Sweden in 2011 was mainly due to a multidrug-resistant PCR ribotype 046 (30% of all samples). Diagnostics used routinely was the Vidas CDAB assay, but to control the outbreak the rapid loop-mediated isothermal amplification (LAMP) assay Illumigene was introduced and both techniques were compared to Toxigenic culture (TC) prospectively. The LAMP assay had a superior sensitivity, that is, 98% compared to 79% for the Vidas CDAB assay. Most importantly, the mean turn-around-time from collecting sample to result was reduced from 59 h to 2 h enabling early isolation of patients and effective hygiene precautions. This may potentially decrease the morbidity and nosocomial transmissions of C. difficile.

Evaluation of an algorithmic approach in comparison with the Illumigene assay for laboratory diagnosis of Clostridium difficile infection

The following three diagnostic algorithms were evaluated in comparison with the Illumigene assay as a stand-alone test for Clostridium difficile detection: glutamate dehydrogenase antigen screen (GDH) followed by toxin A/B antigen testing (Tox A/B) with the cell cytotoxicity assay for discordant specimens (algorithm 1), GDH followed by the Illumigene (algorithm 2), and GDH followed by Tox A/B with the Illumigene for discordant specimens (algorithm 3). A total of 428 stool specimens submitted to three clinical microbiology laboratories in Manitoba, Canada, for C. difficile detection between June 2011 and April 2012 were included in the study. The prevalence of C. difficile in the stool specimens was 14.7% (63/428) based on toxigenic culture (microbiologic reference standard). The sensitivity and specificity of the Illumigene for C. difficile detection were 73.0% and 99.7%, respectively. The corresponding sensitivities and specificities were 65.1% and 100.0% for algorithm 1, 68.3% and 100.0% for algorithm 2, and 69.8% and 100.0% for algorithm 3. Using algorithm 1, a cell cytotoxicity assay was required for toxin detection in 37% of positive tests, prolonging turnaround time. However, the predictive value of a positive test based on a clinical reference standard (all tests positive or cytotoxigenic culture positive and clinical disease on chart review) was slightly higher with algorithm 1 than with the Illumigene assay as a stand-alone test or as part of an algorithm (algorithms 2 and 3). Based on a reduction in turnaround time, simplicity, and acceptable sensitivity and specificity, we recommend algorithm 2 (screening with the GDH antigen test and confirmatory testing with the Illumigene).

Important clinical advances in the understanding of Clostridium difficile infection

PURPOSE OF REVIEW

Clostridium difficile remains an important cause of infectious colitis, particularly in healthcare facilities. This review summarizes recent advances in the epidemiology, diagnosis, and treatment of this endemic pathogen.

RECENT FINDINGS

C. difficile infection (CDI) hospitalizations and mortality rates have increased over the last decade. The BI/NAP1/027 strain has been responsible for epidemics with increased severity and mortality and is now endemic in many settings, particularly North America. Concurrent antibiotics have now been shown to decrease the cure rates for anti-C. difficile therapy and increase the risk of recurrence. Although studies implicate proton pump inhibitors as a risk for CDI, the magnitude of and the biological basis for that risk remain unclear. Molecular diagnostic techniques are rapid and sensitive but highlight the importance of using appropriate clinical testing criteria. Fidaxomicin is a promising new therapy associated with decreased recurrence; infections due to BI strains, however, are associated with inferior outcomes regardless of the treatment agent. Fecal transplantation continues to have impressive success rates for patients with recurrent CDI, and a new colon-sparing surgical procedure presents an intriguing suggested alternative to total colectomy in severe, complicated cases.

SUMMARY

Elucidating CDI risk factors, identifying rapid, accurate diagnostic tools, and validating new treatment approaches remains an urgent priority.

Evaluation of Clostridium difficile fecal load and limit of detection during a prospective comparison of two molecular tests, the illumigene C. difficile and Xpert C. difficile/Epi tests

In a large prospective comparison, the illumigene test detected Clostridium difficile in 98% of toxin-positive and 58% of toxin-negative samples confirmed positive by other methods. The Xpert was uniformly sensitive. Most samples with discrepant results had C. difficile concentrations below the illumigene limit of detection. The significance of low-level C. difficile detection needs investigation.

Performance of Clostridium difficile toxin enzyme immunoassay and nucleic acid amplification tests stratified by patient disease severity

Many clinical laboratories in the United States are transitioning from toxin enzyme immunoassays (EIA) to nucleic acid amplification tests (NAATs) as the primary diagnostic test for Clostridium difficile infection (CDI). While it is known that the analytical sensitivity of the toxin EIA is poor, there are limited clinical data on the performance of these assays for patients with mild or severe CDI. Two hundred ninety-six hospital inpatients with diarrhea and clinical suspicion for CDI were tested prospectively by toxin EIA, by C. difficile NAAT, and with a reference standard toxigenic culture. Following completion of laboratory testing, retrospective chart reviews were performed to stratify patients into mild and severe disease groups based on clinical criteria using a standard point-based system. One hundred forty-three patients with CDI confirmed by toxigenic culture were evaluated in this study. Among the patients with mild CDI, 49% tested positive by toxin EIA and 98% tested positive by NAAT. Among patients with severe CDI, 58% tested positive by toxin EIA and 98% tested positive by NAAT. Increased CDI disease severity was not associated with an increased sensitivity of EIA (P = 0.31). These data demonstrate that toxin EIA performs poorly both for patients with severe CDI and for those with mild CDI and support the routine use of NAAT for the diagnosis of CDI. The presence of stool toxin measured by EIA does not correlate with disease severity.

Molecular techniques for diagnosis of Clostridium difficile infection: systematic review and meta-analysis

OBJECTIVE

To assess the usefulness of 2 rapid molecular diagnostic techniques, polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP), in Clostridium difficile infection (CDI).

METHODS

We conducted a systematic review and meta-analysis to evaluate the accuracy of PCR and LAMP in diagnosis of CDI, including studies that used toxigenic culture or cytotoxicity assay as reference standard.

RESULTS

A search of PubMed and CinAHL medical databases yielded 25 PCR studies, including 11,801 samples that met inclusion criteria and 6 heterogeneous studies that evaluated LAMP. With toxigenic culture as a standard, pooled sensitivity was 0.92 (95% confidence interval [CI], 0.91-0.94); specificity, 0.94 (95% CI, 0.94-0.95); and diagnostic odds ratio, 378 (95% CI, 260-547). With cytotoxicity as a standard, pooled sensitivity was 0.87 (95% CI, 0.84-0.90); specificity, 0.97 (95% CI, 0.97-0.98); and diagnostic odds ratio, 370 (95% CI, 226-606).

CONCLUSION

Polymerase chain reaction is a highly accurate test for identifying CDI. Heterogeneity in LAMP studies did not allow meta-analysis; however, further research into this promising method is warranted.

Clostridium difficile: epidemiology, pathogenesis, management, and prevention of a recalcitrant healthcare-associated pathogen

Clostridium difficile is the leading cause of healthcare-associated infectious diarrhea. Although C difficile is part of normal flora in some healthy individuals, patients with selective risk factors are often vulnerable to the toxigenic potential of this virulent healthcare pathogen. The spectrum of C difficile infection (CDI) is highly variable, ranging from mild to severe illness, presenting with single to multiple disease recurrences. Current approaches to treatment are based on severity of illness, number of recurrences, and clinical presentation. Oral vancomycin and metronidazole have formed the foundation for treatment of CDI, but therapeutic failures are commonly reported, especially involving hypervirulent clones. Alternative therapies, including newer antimicrobials, probiotics, immunotherapy, and fecal transplantation, have all met with varying degrees of efficacy. Although toxigenic culture (TC) testing from anaerobic culture remains the gold standard, newer technologies, including enzyme immunoassay, common antigen (glutamate dehydrogenase) testing, and real-time polymerase chain reaction (PCR) are less time-consuming and rapid. However, TC and PCR have reported high specificity and sensitivity when compared with other laboratory tests. Because of the significant morbidity and mortality associated with CDI, a high index of suspicion is warranted. Prevention and eradication of CDI require a multidisciplinary approach, including early disease recognition through appropriate surveillance, implementation of effective contact isolation strategies, adherence to environmental controls, judicious hand hygiene, evidence-based treatment, and management that includes antibiotic stewardship, continuous education of healthcare workers, and administrative support.