Quantitative Fecal Lactoferrin in Toxin-Positive and Toxin-Negative Clostridium difficile Specimens

Abstract

Quantitative fecal lactoferrin was measured in 112 patients tested for toxigenic Clostridium difficile using glutamate dehydrogenase (GDH) and toxin immunoassays combined with tcdB PCR. Lactoferrin levels were higher in the GDH-positive/toxin-positive group (79 g/ml) than in the GDH-positive/toxin-negative/PCR-positive (21 g/ml) and the GDH-negative groups (13 g/ ml). Differences in fecal lactoferrin levels suggest variable presence or severity of C. difficile infection among toxin-positive and toxin-negative patients. Diagnostic testing for Clostridium difficile infection (CDI) may be accomplished through (i) organism detection by anaerobic culture or glutamate dehydrogenase (GDH) immunoassay with subsequent confirmation of toxigenicity, (ii) toxin detection by cell cytotoxicity neutralization assay (CCNA) or enzyme immunoassay (EIA), and (iii) nucleic acid amplification tests (NAAT) for tcdA, tcdB, and/or other C. difficile genes. Given that the rate of positivity of NAAT assays and GDH immunoassays approaches that of toxigenic culture (1, 2), while those of CCNA and EIA are significantly lower (3), universal testing by NAAT or by multistep GDH screening algorithms is endorsed by IDSA/ SHEA consensus (4). Because toxin production is necessary for organism pathogenesis, however, debate persists as to whether direct toxin measurements may offer a theoretical advantage with respect to clinical specificity (5, 6). If toxin positivity were a better indicator of CDI than NAAT positivity, it would follow that levels of fecal lactoferrin (a measure of colonic inflammation) should be higher in toxin-positive patients than in NAAT-positive/toxinnegative patients. The aim of this study, therefore, was to assess fecal lactoferrin values among toxin-positive, NAAT-positive/ toxin-negative, and NAAT-negative/toxin-negative patients.Based upon results from a single academic medical center of a routine, two-step C. difficile diagnostic algorithm (7), which incorporates GDH and toxin A/B lateral flow EIA (C. Diff Quick Check Complete; TechLab, Blacksburg, VA) with tcdB PCR (Gene Xpert; Cepheid, Sunnyvale, CA), 112 previously frozen, unique patient stool samples were selected for study inclusion. Fecal lactoferrin levels were determined for all samples using quantitative enzyme-linked immunosorbent assay (ELISA) (IBD Scan; TechLab, Blacksburg, VA) as per the manufacturer's instruction with a modification (to improve assay precision) that initial specimen aliquots were weighed to the nearest 0.001 g and diluted 1:10 (wt/vol) in kit diluent. A final dilution of 1:500 was used for all samples. Patient electronic medical records were queried to determine history of immunosuppression, inflammatory bowel disease (IBD) and/or prior bowel surgery, results of other stool studies, and peripheral white blood cell (WBC) count within 48 h of C. difficile testing. Data were analyzed using a statistical software program (Minitab 16), and Mann-Whitney U test and Fisher's exact test were used to study group differences in lactoferrin levels.Coe...

Elevated fecal calprotectin associates with adverse outcomes from Clostridium difficile infection in older adults

“…It has been previously demonstrated that fecal lactoferrin levels are higher in patients with detectable stool Clostridial toxin(s) [31], and that there is a high concordance between lactoferrin and calprotectin levels [10]. This suggests that there is an association between the degree of toxin production and clinical severity that also influences lactoferrin/calprotectin levels, but prior studies regarding this have reached contradictory conclusions [32–36].…”

Diagnosis of Clostridium difficile Infection: an Ongoing Conundrum for Clinicians and for Clinical Laboratories

“…Since then, others have reported on the utility of fecal lactoferrin testing for assessing severity of C. difficile infection (162), as a marker for infection associated with moxifloxacinresistant strains (163), and in testing algorithms as a first step in deciding which patients with diarrhea should be tested for C. difficile (159). It has also been used to determine the clinical significance of results using multistep algorithms that involve GDH screening and PCR confirmation (164). In the latter scenarios, lactoferrin levels were higher in patients who were GDH positive/ toxin positive than in GDH-positive/toxin-negative/PCR-positive or GDH-negative patients (164).…”

“…It has also been used to determine the clinical significance of results using multistep algorithms that involve GDH screening and PCR confirmation (164). In the latter scenarios, lactoferrin levels were higher in patients who were GDH positive/ toxin positive than in GDH-positive/toxin-negative/PCR-positive or GDH-negative patients (164). In a study by van Langenberg et al, the authors reported a negative predictive value of 92% when the manufacturer's cutoff was lowered from 7.25 g/ml to 1.25 g/ml (159).…”

Calprotectin and Lactoferrin Faecal Levels in Patients with Clostridium difficile Infection (CDI): A Prospective Cohort Study

“…Others have shown a significant association when comparing FC levels in toxin positive and GDH positive plus tcdA/tcdB PCR confirmed patients when compared to diarrhoea controls [24]. Similarly, FL has also been shown to be elevated in CDI patients [20], [25]–[27], with more recent studies suggesting a positive correlation with disease severity [28]–[30] and fluoroquinolone resistance [31]. There are however limitations with the published studies: these include their retrospective nature, limited phenotype data, lack of matched controls, use of non-quantitative tests, and variations in the assessment of CDI outcome measures.…”