The potential value of faecal lactoferrin as a screening test in hospitalized patients with diarrhoea

Host response to Clostridium difficile infection: Diagnostics and detection

Clostridium difficile infection (CDI) is a significant healthcare concern worldwide, and C. difficile is recognised as the most frequent aetiological agent of infectious healthcare-associated diarrhoea in hospitalised adult patients. The clinical manifestation of CDI varies from self-limited diarrhoea to life-threatening colitis. Such a broad disease spectrum can be explained by the impact of host factors. Currently, a complex CDI aetiology is widely accepted, acknowledging the interaction between bacteria and the host. C. difficile strains producing clostridial toxins A and B are considered toxigenic and can cause disease; those not producing the toxins are non-pathogenic. A person colonised with a toxigenic strain will not necessarily develop CDI. It is imperative to recognise patients with active disease from those only colonised with this pathogen and to implement appropriate treatment. This can be achieved by diagnostics that rely on host factors specific to CDI. This review will focus on major aspects of CDI pathogenesis and molecular mechanisms, describing host factors in disease progression and assessment of the host response in order to facilitate the development of CDI-specific diagnostics.

Calprotectin and lactoferrin faecal levels in patients with Clostridium difficile infection (CDI): a prospective cohort study

Measurement of both calprotectin and lactoferrin in faeces has successfully been used to discriminate between functional and inflammatory bowel conditions, but evidence is limited for Clostridium difficile infection (CDI). We prospectively recruited a cohort of 164 CDI cases and 52 controls with antibiotic-associated diarrhoea (AAD). Information on disease severity, duration of symptoms, 30-day mortality and 90-day recurrence as markers of complicated CDI were recorded. Specimens were subject to microbiological culture and PCR-ribotyping. Levels of faecal calprotectin (FC) and lactoferrin (FL) were measured by ELISA. Statistical analysis was conducted using percentile categorisation. ROC curve analysis was employed to determine optimal cut-off values. Both markers were highly correlated with each other (r² = 0.74) and elevated in cases compared to controls (p<0.0001; ROC>0.85), although we observed a large amount of variability across both groups. The optimal case-control cut-off point was 148 mg/kg for FC and 8.1 ng/µl for FL. Median values for FL in CDI cases were significantly greater in patients suffering from severe disease compared to non-severe disease (104.6 vs. 40.1 ng/µl, p = 0.02), but were not significant for FC (969.3 vs. 512.7 mg/kg, p = 0.09). Neither marker was associated with 90-day recurrence, prolonged CDI symptoms, positive culture results and colonisation by ribotype 027. Both FC and FL distinguished between CDI cases and AAD controls. Although FL was associated with disease severity in CDI patients, this showed high inter-individual variability and was an isolated finding. Thus, FC and FL are unlikely to be useful as biomarkers of complicated CDI disease.

Diagnosis of Clostridium difficile infection: an ongoing conundrum for clinicians and for clinical laboratories

Clostridium difficile is a formidable nosocomial and community-acquired pathogen, causing clinical presentations ranging from asymptomatic colonization to self-limiting diarrhea to toxic megacolon and fulminant colitis. Since the early 2000s, the incidence of C. difficile disease has increased dramatically, and this is thought to be due to the emergence of new strain types. For many years, the mainstay of C. difficile disease diagnosis was enzyme immunoassays for detection of the C. difficile toxin(s), although it is now generally accepted that these assays lack sensitivity. A number of molecular assays are commercially available for the detection of C. difficile. This review covers the history and biology of C. difficile and provides an in-depth discussion of the laboratory methods used for the diagnosis of C. difficile infection (CDI). In addition, strain typing methods for C. difficile and the evolving epidemiology of colonization and infection with this organism are discussed. Finally, considerations for diagnosing C. difficile disease in special patient populations, such as children, oncology patients, transplant patients, and patients with inflammatory bowel disease, are described. As detection of C. difficile in clinical specimens does not always equate with disease, the diagnosis of C. difficile infection continues to be a challenge for both laboratories and clinicians.

Discriminatory potential of C-reactive protein, cytokines, and fecal markers in infectious gastroenteritis in adults

This study evaluates potential markers in blood and stools for their ability to distinguish bacterial from viral gastroenteritis. A total of 108 patients were prospectively recruited, of which 27 showed bacterial, 30 viral, and 51 no detectable pathogen, respectively. Cytokines, C-reactive protein (CRP), and white blood cells as well as the 2 fecal markers lactoferrin and calprotectin were determined. Statistics comprised Kruskal-Wallis test and U test in addition to an assessment of receiver operating characteristic. Interferon γ (IFNγ) levels were significantly increased in the viral group compared to the bacterial and nonspecific group. For the bacterial group, both fecal markers lactoferrin and calprotectin as well as CRP were significantly higher in comparison to the other 2 groups. To differentiate between bacterial and viral gastroenteritis, CRP, serum IFNγ, and the fecal proteins lactoferrin and calprotectin may be useful. A corresponding algorithm should be evaluated prospectively.

Lewis score correlates more closely with fecal calprotectin than Capsule Endoscopy Crohn's Disease Activity Index

BACKGROUND

Small-bowel capsule endoscopy (SBCE) is an invaluable imaging method for the small bowel. The Lewis score (LS) and the Capsule Endoscopy Crohn's Disease Activity Index (CECDAI) have been developed to standardize the reporting of small-bowel inflammation. Fecal calprotectin (FC) represents a highly reliable biomarker of intestinal inflammation.

AIM

To assess the performance of the two SBCE inflammation scoring systems by correlating them with FC. Furthermore, to define threshold levels for CECDAI.

METHODS

Retrospective study; patients who underwent SBCE and had FC measurement shortly before or after SBCE. LS and CECDAI were calculated by a single reviewer and correlated [Spearman's (r ( s ))] with the FC results. Linear regression analysis was used to identify threshold levels for CECDAI.

RESULTS

Forty-nine patients; three subgroups A, B and C (based on FC levels <100, 100-200, and ≥200 μg/g, respectively). LS appears to correlate with FC (r ( s ) = 0.448, p = 0.0014), unlike CECDAI, which does not demonstrate significant correlation (r ( s ) = 0.245, p = 0.089). Strongly positive correlation between FC and LS was observed in subgroup A (r ( s ) = 0.68, p = 0.0047), while in subgroups B and C, neither LS nor CECDAI showed correlation with FC. Significant correlation between LS and CECDAI was demonstrated (r ( s ) = 0. 6324, p < 0.0001). Linear regression analysis demonstrates that LS thresholds of 135 and 790 correspond with CECDAI levels of 3.8 and 5.8, respectively.

CONCLUSIONS

LS performs better than CECDAI in describing small-bowel inflammation, especially at FC levels of <100 μg/g. Furthermore, CECDAI levels of 3.8 and 5.8 seem to correspond to LS thresholds of 135 and 790, respectively.

The patient presenting with acute dysentery--a systematic review

OBJECTIVES

The etiologies, clinical presentations and diagnosis of acute pathogen-specific dysentery in children and adults in industrialized and developing regions is described to help develop recommendations for therapy.

METHODS

We conducted a systematic review of literature published between January 2000 and June 2011 to determine the frequency of occurrence of pathogen-specific dysentery.

RESULTS

Shigella, Salmonella, and Campylobacter remain the most frequent bacterial causes of dysentery worldwide. Shiga toxin-producing Escherichia coli (STEC) is potentially important in industrialized countries. Entamoeba histolytica must be considered in the developing world, particularly in rural or periurban areas. Clinicians should use epidemiological clues and knowledge of endemicity to suspect Vibrio spp., Aeromonas spp., Plesiomonas spp., Yersinia enterocolitica, Clostridium difficile, Cytomegalovirus or Schistosoma mansoni in cases presenting with dysentery. A single fecal sample studied for etiologic agents is the customary way to make an etiologic diagnosis.

CONCLUSIONS

While a majority of dysenteric cases will not have an identifiable agent causing the illness, when an etiologic organism is identified, other than STEC, each has a specific recommended form of therapy, which is provided in this review.