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A rapid test for infectious and inflammatory enteritis
J R Miller1, L J Barrett, K Kotloff
1Department of Medicine, University of Virginia School of Medicine, Charlottesville.
Background:
Inflammatory illnesses are an indication for specific diagnostic studies and possible antimicrobial therapy. The presence of fecal leukocytes has been used as a marker of inflammatory diarrhea; however, microscopic examination of the fecal smear is unreliable if the specimen is transported, refrigerated, frozen, or collected by swab.
Objective:
To evaluate a rapid, sensitive, semiquantitative test for detection of fecal leukocytes using antilactoferrin latex bead agglutination (LFLA), a test that remains sensitive even after specimens are refrigerated, frozen, or stored on swabs.
Methods:
LFLA titers were determined in stool specimens from previously healthy volunteers before and after experimental infection with different enteric pathogens and from patients with nosocomial diarrhea caused by Clostridium difficile.
Results:
Healthy controls and subjects with noninflammatory diarrhea caused by Vibrio cholerae consistently demonstrated LFLA titers less than 1:50. In contrast, subjects with inflammatory diarrhea caused by Shigella species and C difficile had markedly elevated titers. Titers for subjects with experimental shigellosis ranged from 1:50 to 1:3200, with seven (78%) of nine at 1:400 or greater. Titers for patients with C difficile enteritis ranged as high as 1:1200, with six (50%) of 12 at 1:400 or greater. Subjects with experimental enteropathogenic Escherichia coli infection also had elevated titers, ranging from 1:100 to 1:1600, with three (43%) of seven at 1:400 or greater. Titers for subjects with experimental enterotoxigenic E coli infection were moderately elevated, with nine (53%) of 17 ranging from 1:50 to 1:200 (only one [6%] of 17 was > or = 1:400), suggesting a mild inflammatory process.
Conclusions:
The fecal LFLA assay distinguishes inflammatory from noninflammatory diarrhea, may provide new information on mildly inflammatory processes, and may be a useful, rapid test in a diagnostic algorithm for acute, infectious diarrheal illnesses.
Insights
A new fecal lactoferrin latex bead agglutination (LFLA) test accurately detects inflammatory diarrhea, even with stored samples. This rapid assay aids in diagnosing infectious diarrheal illnesses.
Area of Science:
- Gastroenterology
- Infectious Diseases
- Clinical Diagnostics
Background:
- Fecal leukocytes are markers for inflammatory diarrhea, but traditional microscopic examination is unreliable with processed specimens.
- Current diagnostic methods for infectious diarrhea lack sensitivity and speed, especially for preserved samples.
Purpose of the Study:
- To evaluate the rapid, sensitive, and semiquantitative antilactoferrin latex bead agglutination (LFLA) assay for detecting fecal leukocytes.
- To determine if LFLA remains sensitive with refrigerated, frozen, or swab-collected stool specimens.
Main Methods:
- LFLA titers were measured in stool samples from healthy volunteers experimentally infected with enteric pathogens.
- LFLA titers were also analyzed in patients with nosocomial diarrhea caused by Clostridium difficile.
Main Results:
- Non-inflammatory diarrhea (e.g., Vibrio cholerae) showed low LFLA titers (<1:50).
- Inflammatory diarrhea (Shigella, C. difficile, enteropathogenic E. coli) demonstrated significantly elevated LFLA titers (≥1:400 in 43-78% of cases).
- Enterotoxigenic E. coli infection showed moderately elevated titers, indicating milder inflammation.
Conclusions:
- The fecal LFLA assay effectively differentiates inflammatory from non-inflammatory diarrhea.
- LFLA provides valuable insights into mildly inflammatory diarrheal processes.
- This rapid test can be a useful tool in the diagnostic workup of acute infectious diarrhea.