Ribotype 027 Clostridium difficile infections with measurable stool toxin have increased lactoferrin and are associated with a higher mortality

We evaluated clinical and diagnostic indicators of severe C. difficile infection (CDI) and their association with poor clinical outcome. A total of 210 patients positive according to PCR (toxin B: tcdB) were included, with patients having a median age of 62 years and a Charlson co-morbidity index (CI) score of 5. Ninety-one percent (n?=?191) were positive by toxigenic culture and 61 % (n?=?129) had stool toxin. Toxin-positive patients had significantly higher fecal lactoferrin (mean 316 μg/g versus 106 μg/g stool; p?<?0.0001). Forty percent of patients (n?=?85) were infected with ribotype 027 and significantly more of these patients had measurable stool toxin (79 % vs. 50 %; p?<?0.0001). The mean fecal lactoferrin was significantly higher for toxin-positive 027 CDI compared with the 027 toxin-negative group (317 vs 60 μg/g; p?=?0.0014). Ribotype 027 CDI with stool toxin showed a higher all-cause, 100-day mortality compared with non-027 with stool toxin (36 % vs 18 %; p?=?0.017). Logistic regression univariate analysis for odds ratio (OR) and p values revealed that age (OR?=?1.1), intensive care unit treatment (OR?=?2.7), CI (OR?=?1.2), 027 CDI (OR?=?2.1), white blood cell count (OR?=?1.0), albumin level (OR?=?0.1), and stool toxin-positive 027 CDI (OR?=?2.5) were significantly associated with 100-day mortality (p?<?0.05). In conclusion, CDI PCR-positive patients with 027 infection and stool toxin have increased lactoferrin and are at an increased risk of death.     

Fecal calprotectin concentrations in cancer patients with <Emphasis Type="Italic">Clostridium difficile</Emphasis> infection

Fecal calprotectin (fCPT) has been used as a surrogate marker for assessment of intestinal inflammation. We explore the utility of fCPT values as a diagnostic aid in cancer patients with suspected Clostridium difficile infection (CDI). A total of 232 stool specimens submitted for GeneXpert C. difficile PCR testing were included in the study. All specimens were tested for fCPT and toxin/GDH antigens. Clinical severity of CDI cases was determined by the IDSA/SHEA criteria. Significant differences of median fCPT values between CDI (n?=?117, Median 183.6 μg/g) and non-CDI (n?=?115, 145.6 μg/g, p?=?0.006) patients were seen. In CDI patents, significantly lower fCPT values were found in patients with mild to moderate (n?=?95, 182.1 μg/g) than those with severe and severe to complicated (n?=?22, 218.5 μg/g, p?=?0.014) scores, and among those that were toxin positive (n?=?24, 200.2 μg/g) vs. toxin negative (n?=?86, 182.8 μg/g, p?=?0.044). Despite this overall trend, wide variations in fCPT values were found in all categories examined. A logistic regression analysis revealed that the fCPT values correlated independently with the severity of clinical manifestations (OR?=?2.021, 95%CI?=?1.132–3.608); however, it did not correlate with other clinical outcomes. Our study findings show that high fecal calprotectin levels correlate with toxin-positive and clinically severe CDI; however, wide variations in individual measurements preclude establishment of reliable cut-offs for routine diagnostic use in cancer patients.     

Binary toxin and its clinical importance in <Emphasis Type="Italic">Clostridium difficile</Emphasis> infection,Belgium

Binary toxin-producing Clostridium difficile strains such as ribotypes 027 and 078 have been associated with increased Clostridium difficile infection (CDI) severity. Our objective was to investigate the association between presence of the binary toxin gene and CDI severity and recurrence. We performed a laboratory-based retrospective study including patients between January 2013 and March 2015 whose fecal samples were analyzed by polymerase chain reaction (PCR) for the presence of the genes for toxin B and binary toxin and a deletion in the tcdC gene, specific for ribotype 027. Clinical and epidemiological characteristics were compared between 33 binary toxin-positive CDI patients and 33 binary toxin-negative CDI patients. Subsequently, the characteristics of 66 CDI patients were compared to those of 66 diarrhea patients who were carriers of non-toxigenic C. difficile strains. Fifty-nine of 1034 (5.7 %) fecal samples analyzed by PCR were binary toxin-positive, belonging to 33 different patients. No samples were positive for ribotype 027. Binary toxin-positive CDI patients did not differ from binary toxin-negative CDI patients in terms of disease recurrence, morbidity, or mortality, except for a higher peripheral leukocytosis in the binary toxin-positive group (16.30?×?10⁹/L vs. 11.65?×?10⁹/L; p?=?0.02). The second part of our study showed that CDI patients had more severe disease, but not a higher 30-day mortality rate than diarrhea patients with a non-toxicogenic C. difficile strain. In our setting with a low prevalence of ribotype 027, the presence of the binary toxin gene is not associated with poor outcome.     

Impact of ribotype 027 on Clostridium difficile infection in a geriatric department

The purposes of this study were to describe the epidemiology (2001–2009) of Clostridium difficile infections (CDI) in a geriatric department and to compare the clinical data of patients infected with a 027 or non-027 strain. We retrospectively identified all geriatric patients with CDI and analysed the clinical and microbiological data of 133 patients for whom a ribotype was available between March 2003 and December 2009. The incidence of CDI in our geriatric department increased from 0.2 per 100 admissions in 2001 to 8.1 in 2004 and decreased to 1.3 in 2008 before a new rise to 2.1 in 2009. The percentage of ribotype 027 decreased from 2007 but it remained the most prevalent ribotype during the years 2007–2009, with a greater dispersion of ribotypes. The mean age of the patients was 84 years and the median Charlson index was 6.0. Previous use of fluoroquinolones was a significant risk factor for developing a CDI with an 027 strain (p?=?0.001). Cure was significantly lower in the 027 group (p?=?0.003). The total attributable mortality was 24.1 %. A multiparametric model showed that attributable mortality was influenced by the ribotype 027 (p?=?0.037), the severity of clinical symptoms (p?=?0.001) and the type of treatment (p?=?0.002). Oral vancomycin had a protective effect against mortality. Attention should be paid to elderly patients developing a CDI, especially after the administration of fluoroquinolones. Oral vancomycin could be recommended as the first-line agent not only to protect against recurrence or severe CDI, but to diminish the attributable mortality risk.     

Faecal lactoferrin and calprotectin in patients with <Emphasis Type="Italic">Clostridium difficile</Emphasis> infection: a case–control study

Calprotectin and lactoferrin are released by the gastrointestinal tract in response to infection and mucosal inflammation. Our objective was to assess the usefulness of quantifying faecal lactoferrin and calprotectin concentrations in Clostridium difficile infection (CDI) patients with or without free toxins in the stools. We conducted a single-centre 22-month case–control study. Patients with a positive CDI diagnosis were compared to two control groups: group 1 = diarrhoeic patients negative for C. difficile and matched (1:1) to CDI cases on the ward location and age, and group 2 = diarrhoeic patients colonised with a non-toxigenic strain of C. difficile. Faecal lactoferrin and calprotectin concentrations in faeces were determined for patients with CDI and controls. Of 135 patients with CDI, 87 (64.4%) had a positive stool cytotoxicity assay (free toxin) and 48 (35.6%) had a positive toxigenic culture without detectable toxins in the stools. The median lactoferrin values were 26.8 μg/g, 8.0 μg/g and 15.8 μg/g in CDI patients and groups 1 and 2, respectively. The median calprotectin values were 218.0 μg/g, 111.5 μg/g and 111.3 μg/g, respectively. Among patients with CDI, faecal lactoferrin and calprotectin levels were higher in those with free toxins in their stools (39.2 vs. 10.2 μg/g, p = 0.003 and 274.0 vs. 166.0 μg/g, p = 0.051, respectively). Both faecal calprotectin and lactoferrin were higher in patients with CDI, especially in those with detectable toxin in faeces, suggesting a correlation between intestinal inflammation and toxins in stools.     

Clostridium difficile as a cause of healthcare-associated diarrhoea among children in Auckland,New Zealand: clinical and molecular epidemiology

We aimed to determine the incidence of Clostridium difficile infection (CDI), the molecular epidemiology of circulating C. difficile strains and risk factors for CDI among hospitalised children in the Auckland region. A cross-sectional study was undertaken of hospitalised children <15 years of age in two hospitals investigated for healthcare-associated diarrhoea between November 2011 and June 2012. Stool specimens were analysed for the presence of C. difficile using a two-step testing algorithm including polymerase chain reaction (PCR). C. difficile was cultured and PCR ribotyping performed. Demographic data, illness characteristics and risk factors were compared between children with and without CDI. Non-duplicate stool specimens were collected from 320 children with a median age of 1.2 years (range 3 days to 15 years). Forty-six patients (14 %) tested met the definition for CDI. The overall incidence of CDI was 2.0 per 10,000 bed days. The percentage of positive tests among neonates was only 2.6 %. PCR ribotyping showed a range of strains, with ribotype 014 being the most common. Significant risk factors for CDI were treatment with proton pump inhibitors [risk ratio (RR) 1.74, 95 % confidence interval (CI) 1.09–5.59; p?=?0.002], presence of underlying malignancy (RR 2.71, 95 % CI 1.65–4.62; p?=?0.001), receiving chemotherapy (RR 2.70, 95 % CI 1.41–4.83; p?=?0.003) and exposure to antibiotics (RR 1.17, 95 % CI 0.99–1.17; p?=?0.03). C. difficile is an important cause of healthcare-associated diarrhoea in this paediatric population. The notion that neonatal populations will always have high rates of colonisation with C. difficile may not be correct. Several risk factors associated with CDI among adults were also found to be significant.     

Risk factors for recurrence in patients with Clostridium difficile infection due to 027 and non-027 ribotypes

Objectives

Our objective was to evaluate factors associated with recurrence in patients with 027+ and 027– Clostridium difficile infection (CDI).

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.     

Community-onset Clostridium difficile infection at a tertiary medical center in southern Taiwan, 2007–2015

Background

Clostridium difficile infection (CDI) is well-known as the major cause of infectious diarrhea in hospitalized patients. Community-onset CDI (CO-CDI) is an emerging threat. However, clinical information of CO-CDI in Taiwan remains scarce.

Asymptomatic Clostridium difficile carriage rate post-fecal microbiota transplant is low: a prospective clinical and stool assessment

ObjectivesWe aimed to assess the asymptomatic Clostridium difficile carriage rates following fecal microbiota transplantation (FMT).MethodsAll patients who underwent FMT for recurrent Clostridium difficile infection (CDI) via colonoscopy or sigmoidoscopy between June 2013 and April 2015 and had a minimum of 8-week follow-up post FMT at two tertiary care referral centres were included in the study. Patients were prospectively followed both clinically and with stool assessments for 8 weeks post FMT. Assessments occurred at 1 week and 4 weeks post FMT to assess for failure. Failure was defined as presence of diarrhoeal symptoms and a positive CDI stool test by polymerase chain reaction for toxin gene (PCR) at any time point during the 8-week follow-up period. CDI stool testing using PCR was performed at weeks 1 and 4 post FMT in asymptomatic patients as well.Results167 patients were included. Twenty-eight patients (16.7% (28/167)) were FMT failures throughout the 8-week period. At week 1, seven patients had already failed the FMT. Of the remaining 160 patients, 144 were asymptomatic, and among these, 141 were negative for C. difficile toxin gene by PCR. This resulted in an asymptomatic carriage rate of 2.1% (3/144). At week 4, 143 patients had not yet failed FMT. Of these patients 129 patients were asymptomatic and among those, 125 were negative by PCR, resulting in an asymptomatic carriage rate of 3% (3/129).ConclusionsAsymptomatic carriage after FMT is rare. This suggests that testing for cure after FMT in asymptomatic patients is not necessary.     

Is there a relationship between the presence of the binary toxin genes in <Emphasis Type="Italic">Clostridium difficile</Emphasis> strains and the severity of <Emphasis Type="Italic">C. difficile</Emphasis> infection (CDI)?

Some strains of Clostridium difficile produce a binary toxin, in addition to the main C. difficile virulence factors (toxins A and B). There have been conflicting reports regarding the role of binary toxin and its relationship to the severity of C. difficile infection (CDI). Samples, isolates and clinical data were collected as part of a prospective multicentre diagnostic study. Clostridium difficile isolates (n = 1259) were tested by polymerase chain reaction (PCR) assay to detect binary toxin genes cdtA and cdtB. The PCR binary toxin gene results were compared with clinical severity and outcome data, including 30-day all-cause mortality. The 1259 isolates corresponded to 1083 different patients (October 2010 to September 2011). The prevalence of binary toxin positive strains was significantly higher in faecal samples with detectable toxin A/B than in those without toxin but that were positive by cytotoxigenic culture (26.3% vs. 10.3%, p < 0.001). The presence of binary toxin correlated moderately with markers of CDI severity (white cell count, serum albumin concentration and serum creatinine concentration). However, the risk ratio for all-cause mortality was 1.68 for binary toxin positive patients and patients were significantly less likely to survive if they had CDI caused by a binary toxin gene positive strain, even after adjusting for age (p < 0.001). The presence of binary toxin genes does not predict the clinical severity of CDI, but it is significantly associated with the risk of all-cause mortality.     

Clostridium difficile infection in children hospitalized due to diarrhea

The frequency of Clostridium difficile infection (CDI)-related hospitalizations is increasing. The aim of this study was to determine the extent of CDI among children hospitalized with diarrhea, risk factors or predictors for severe CDI, the prevalence of NAP1, and to compare the course of CDI depending on bacteria toxicity profile. A retrospective analysis of case records of 64 children (age range 3 months–16 years, median age 2.12 years) with CDI as defined by diarrheal disease and positive polymerase chain reaction (PCR) test (Xpert C. difficile) was conducted. Modified national adult guidelines were used to assess the severity of CDI. CDIs represented 2.7 % of patients with diarrhea (13.5 cases per 1,000 admissions). Thirty-three CDIs (52 %) were community-associated. Antibacterial use preceded CDI in 61 patients (95 %). Seventeen cases (27 %) were binary toxin-positive (CDT+), 13 of which were NAP1 (20.5 %). Over 75 % of CDIs with NAP1 was hospital-acquired, and more often proceeded with generalized infection (p?<?0.05). Risk factors for severe CDI (34 %) included NAP1 [odds ratio (OR), 4.85; 95 % confidence interval (Cl), 1.23, 21.86) and co-morbidities (OR, 4.25; 95 % Cl, 1.34, 14.38). Diarrhea ≥10 stools daily was associated with severe CDI (p?=?0.01). Recurrence occurred in three patients (4.5 %). There was no mortality. C. difficile is an important factor of antibiotic-associated diarrhea in children. Co-morbidities and NAP1 predispose to severe CDI.     

Expression of CXCL2 in the Serum and Cerebrospinal Fluid of Patients with HIV and Syphilis or Neurosyphilis

The potential mechanisms for blood–brain barrier damage and the diagnosis of neurosyphilis in HIV patients co-infected with syphilis (HIV-S) are unclear. The aim of the study was to determine the expression of CXCL2 in the serum and cerebrospinal fluid (CSF) of HIV-S patients. A total of 34 HIV patients and 7 controls were enrolled in a HIV clinical cohort for diagnosis of neurosyphilis in Taiwan. Serum and CSF concentrations of CXCL2 were determined by ELISA. Neurosyphilis was defined as a CSF white blood cell count of ≧20 cells/μl or a reactive CSF Venereal Disease Research Laboratory (VDRL). Demographics and medical histories were collected. All the patients with HIV-S were males. Most (80 %) had sex with men (MSM) and serum rapid plasma reagin (RPR) titers of ≧1:32. The medium age was 37 (range 21–68)?years. The medium CD4 T cell counts at the time of the diagnosis of syphilis were 299 (range 92–434)?cells/μl. Eight patients (24 %) had neurosyphilis based on a reactive CSF VDRL test (n?=?5) or increased CSF white blood cell counts of ≧20 cells/μl (n?=?3). The concentrations of CSF CXCL2 were significantly higher in patients with HIV and neurosyphilis as compared to HIV with syphilis, HIV, and controls (p?=?0.012). There were no significant differences in serum concentrations between the four groups. There was a correlation between CSF CXCL2 concentrations with neurosyphilis (p?=?0.017), CSF white blood cell count (p?=?0.001), and CSF protein levels (p?=?0.005). The CSF level of CXCL2 can be used to distinguish those with or without neurosyphilis in HIV infected patients.     

Oral teicoplanin versus oral vancomycin for the treatment of severe <Emphasis Type="Italic">Clostridium difficile</Emphasis> infection: a prospective observational study

The aim of this study was to compare clinical cure rate, recurrence rate and time to resolution of diarrhea in patients with severe and severe-complicated Clostridium difficile infection (CDI) treated with teicoplanin or vancomycin. This two-year prospective observational study included patients with first episode or first recurrence of CDI who had severe or severe-complicated CDI and were treated with teicoplanin or vancomycin. Primary outcomes of interest were clinical cure rate at discharge and recurrence rate after eight weeks follow up, and secondary outcomes were all-cause mortality and time to resolution of diarrhea. Among 287 study patients, 107 were treated with teicoplanin and 180 with vancomycin. The mean age of patients was 73.5?±?10.6 years. One hundred eighty six patients (64.8%) had prior CDI episode. Severe complicated disease was detected in 23/107 (21.5%) and 42/180 (23.3%) patients treated with teicoplanin and vancomycin, respectively. There was no statistically significant difference in time to resolution of diarrhea between two treatment arms (6.0?±?3.4 vs 6.2?±?3.1 days, p?=?0.672). Treatment with teicoplanin resulted in significantly higher clinical cure rate compared to vancomycin [90.7% vs 79.4%, p?=?0.013, odds ratio (OR) (95% confidence interval (CI)) 2.51 (1.19–5.28)]. Recurrence rates were significantly lower in patients treated with teicoplanin [9/97 (9.3%) vs 49/143 (34.3%), p?<?0.001, OR (95%CI) 0.20 (0.09–0.42)]. There was no statistically significant difference in overall mortality rate. Teicoplanin might be a good treatment option for patients with severe CDI. Patients treated with teicoplanin experienced remarkably lower recurrence rates compared to vancomycin-treated patients.     

Clinical features of Clostridium difficile infection and molecular characterization of the isolated strains in a cohort of Danish hospitalized patients

The purpose of this study was to compare clinical features of Clostridium difficile infection (CDI) to toxin gene profiles of the strains isolated from Danish hospitalized patients. C. difficile isolates were characterized by PCR based molecular typing methods including toxin gene profiling and analysis of deletions and truncating mutations in the toxin regulating gene tcdC. Clinical features were obtained by questionnaire. Thirty percent of the CDI cases were classified as community-acquired. Infection by C. difficile with genes encoding both toxin A, toxin B and the binary toxin was significantly associated with hospital-acquired/healthcare-associated CDI compared to community-acquired CDI. Significantly higher leukocyte counts and more severe clinical manifestations were observed in patients infected by C. difficile containing genes also encoding the binary toxin together with toxin A and B compared to patients infected by C. difficile harbouring only toxin A and B. In conclusion, infection by C. difficile harbouring genes encoding both toxin A, toxin B and the binary toxin were associated with hospital acquisition, higher leukocyte counts and severe clinical disease.     

High pneumococcal DNA load,procalcitonin and suPAR levels correlate to severe disease development in patients with pneumococcal pneumonia

Community-acquired pneumonia (CAP) is mostly caused by Streptococcus pneumoniae. Identification of the pathogen causing CAP can be achieved by conventional culture techniques of sputum and/or blood, antigen detection from urine or molecular analysis. However, it remains difficult to determine patients who are at risk of severe disease development (intensive care unit [ICU] admittance and/or death). In this retrospective study, 121 patients admitted to the emergency department with pneumonia symptoms were included. Several markers of infection (pneumococcal DNA load in blood (real-time LytA PCR), white blood cell (WBC) count, C-reactive protein (CRP), procalcitonin (PCT) and soluble urokinase plasminogen activator receptor (suPAR) levels) were assessed for their ability to predict severe disease development. Of 121 patients, 6 were excluded from the study because of an alternative diagnosis, whereas 8 were excluded from biomarker analysis because of the presence of co-morbidities. Of the 115 patients analysed by the LytA PCR, 23 were positive. PCR detected S. pneumoniae DNA in 82% of patients with positive blood culture for S. pneumoniae. PCR missed three samples from patients in which S. pneumoniae was recovered by blood cultures. However, eight additional LytA PCR-positive samples were detected from patients whose blood cultures remained negative. Pneumococcal DNA load was also monitored in time for 31 patients, of whom 11 had positive PCR results. For 10 out of 11 (91%) positive PCR patients, a clear increase in Ct-values was observed, indicating a lower pneumococcal DNA load in the blood as a result of antibiotic therapy. Biomarker analysis was performed in 107 patients, of whom 29 showed severe disease development. Pneumococcal DNA load (p = 0.026), PCT (p = 0.046) and suPAR (p = 0.001) levels most reliably predicted severe disease development. In conclusion, in patients with CAP, higher pneumococcal DNA load, PCT and suPAR values are associated with severe disease development (ICU admission and/or death). These biomarkers may be useful tools for triage of patients suspected of having CAP in the emergency department.     

Increased age and proton pump inhibitors are associated with severe Clostridium difficile infections in children

BackgroundClostridium difficile infection (CDI) is increasing in children. We aimed to compare the clinical characteristics between CDI and colonization and to identify the risk factors for severe diseases of CDI in children.MethodWe retrospectively reviewed 124 children (1–18 years old) from 2011 to 2018. CDI was defined as diarrhea (≥3 loose stool in the past 24 h) with confirmed toxigenic strain. Colonization was defined as presence of C. difficile without clinical symptoms. Severe diseases included ileus, acute kidney injury, gastrointestinal bleeding or mortality. Patients younger than 1 year old and coinfections with other enteric pathogens were excluded.ResultsAmong 124 patients with C. difficile identified, 49 of them fulfilled CDI definition and 75 had C. difficile colonization. Children with CDI were more likely to present with watery (74% vs. 1%, p < 0.01) and mucoid stool (25% vs. 7%, p < 0.01) and occult blood in stool (67% vs. 33%, p < 0.01) than children with colonization. In CDI cases, elevated age-adjusted creatinine (18% vs. 0%, p = 0.03) and hyponatremia (134 mEq/L vs. 137 mEq/L, p = 0.04) were found. Also, they had more complicated diseases (27% vs. 0%, p < 0.01). On multivariate analysis, age older than 4 years (adjusted odds ratio: 5.83; 95% confidence interval: 1.05–32.27) and proton pump inhibitor use (PPI) (adjusted odds ratio: 7.25; 95% confidence interval: 1.07–49.07) were the independent factors for severe diseases.ConclusionsWatery diarrhea, mucoid stool and occult blood in stool could differentiate CDI from colonization. Patients with increased age and previous PPI use were the independent risk factors for severe diseases in children.     

An outbreak of <Emphasis Type="Italic">Clostridium difficile</Emphasis> PCR ribotype 027 in Spain: risk factors for recurrence and a novel treatment strategy

An outbreak of Clostridium difficile infection (CDI) caused by ribotype 027 (B1/NAP1) began in our hospital in November 2014, and produced 141 episodes in the following months. The aim of this study is to describe this outbreak, assess risk factors for recurrence of CDI-027 and to analyze the implementation of a novel treatment strategy. This is a prospective study of all patients with CDI-027, from November 2014 to November 2015. The epidemiological data were collected daily for each patient. We compared clinical characteristics and treatment between patients with and without recurrence of CDI-027. Interestingly, liver cirrhosis was present in 22% of the patients, and most of them received prophylaxis for hepatic encephalopathy with rifaximin. Patients were also taking antimicrobial drugs (93.6%) and proton pump inhibitors (80.1%). Overall, 27 (23.5%) patients had a first recurrence of CDI-027. Liver cirrhosis increased the risk of recurrence (44.4% vs 14.8%). Patients treated with a prolonged oral vancomycin regimen vs the conventional regimen (oral metronidazole or 10 days of vancomycin) had fewer recurrences (8.6 versus 44.7% [p ≤ 0.01]; OR, 0.91; 95% CI, 0.028–0.294) and less attributable mortality (0% versus 7.1%; p = 0.058). We report an outbreak of CDI-027, mainly in patients with liver cirrhosis. Recurrence of CDI-027 was more common in those patients. A novel approach involving high-dose prolonged vancomycin taper as a first-line treatment, together with a bundle of outbreak measures, seemed to reduce the number of cases of CDI-027, recurrences, and attributable mortality. Nevertheless, this approach warrants further investigation.     

Clinical heterogeneity of patients with stool samples testing PCR+/Tox− from a two-step <Emphasis Type="Italic">Clostridium difficile</Emphasis> 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.     

Development and Validation of Digital Enzyme-Linked Immunosorbent Assays for Ultrasensitive Detection and Quantification of Clostridium difficile Toxins in Stool

The currently available diagnostics for Clostridium difficile infection (CDI) have major limitations. Despite mounting evidence that toxin detection is paramount for diagnosis, conventional toxin immunoassays are insufficiently sensitive and cytotoxicity assays too complex; assays that detect toxigenic organisms (toxigenic culture [TC] and nucleic acid amplification testing [NAAT]) are confounded by asymptomatic colonization by toxigenic C. difficile. We developed ultrasensitive digital enzyme-linked immunosorbent assays (ELISAs) for toxins A and B using single-molecule array technology and validated the assays using (i) culture filtrates from a panel of clinical C. difficile isolates and (ii) 149 adult stool specimens already tested routinely by NAAT. The digital ELISAs detected toxins A and B in stool with limits of detection of 0.45 and 1.5 pg/ml, respectively, quantified toxins across a 4-log range, and detected toxins from all clinical strains studied. Using specimens that were negative by cytotoxicity assay/TC/NAAT, clinical cutoffs were set at 29.4 pg/ml (toxin A) and 23.3 pg/ml (toxin B); the resulting clinical specificities were 96% and 98%, respectively. The toxin B digital ELISA was 100% sensitive versus cytotoxicity assay. Twenty-five percent and 22% of the samples positive by NAAT and TC, respectively, were negative by the toxin B digital ELISA, consistent with the presence of organism but minimal or no toxin. The mean toxin levels by digital ELISA were 1.5- to 1.7-fold higher in five patients with CDI-attributable severe outcomes, versus 68 patients without, but this difference was not statistically significant. Ultrasensitive digital ELISAs for the detection and quantification of toxins A and B in stool can provide a rapid and simple tool for the diagnosis of CDI with both high analytical sensitivity and high clinical specificity.