Open AccessEvaluation of Four Different Diagnostic Tests To Detect Clostridium difficile in Piglets
Author(s) -
E. C. Keessen,
ke E.M. Hopman,
L.A.M.G. van Leengoed,
Alphons J.A.M. van Asten,
C. Hermanus,
Ed J. Kuijper,
L.J.A. Lipman
Publication year - 2011
Publication title -
journal of clinical microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.349
H-Index - 255
eISSN - 1070-633X
pISSN - 0095-1137
DOI - 10.1128/jcm.00242-11
Subject(s) - clostridium difficile , feces , gold standard (test) , diarrhea , microbiology and biotechnology , predictive value , enterotoxin , biology , clostridium , enteritis , clostridium difficile toxin b , diagnostic test , pathogen , medicine , veterinary medicine , virology , clostridium difficile toxin a , antibiotics , bacteria , escherichia coli , biochemistry , genetics , gene
Clostridium difficile is emerging as pathogen in both humans and animals. In 2000 it was described as one of the causes of neonatal enteritis in piglets, and it is now the most common cause of neonatal diarrhea in the United States. In Europe,C. difficile infection (CDI) in both neonatal piglets and adult sows has also been reported. Diagnosis of this infection is based on detection of the bacteriumC. difficile or its toxins A and B. Most detection methods, however, are only validated for diagnosing human infections. In this study three commercially available enzyme immunoassays (EIAs) and a commercial real-time-PCR (Becton, Dickinson, and Company) were evaluated by testing 172 pig fecal specimens (139 diarrheic and 33 nondiarrheic piglets). The results of each test were compared to those of cytotoxicity assays (CTAs) and toxigenic culture as the “gold standards.” Compared to CTAs, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were, respectively, as follows: for real-time PCR, 91.6, 37.1, 57.6, and 82.5%; for Premier Toxins A&B (Meridian), 83.1, 31.5, 53.1, and 66.7%; for ImmunoCard Toxins A&B kit (ICTAB; Meridian), 86.6, 56.8, 66.9, and 80.7%; and for VIDAS (bioMérieux), 54.8, 92.6, 85.0, and 72.8%. Compared to toxigenic culture, the sensitivity, specificity, PPV, and NPV were, respectively, as follows: for real-time PCR, 93.0, 34.7, 50.0, and 87.5%; for Premier Toxins A&B, 80.3, 27.7, 43.8, and 66.7%; and for ICTAB, 80.0, 46.2, 52.8, and 75.4%; and for VIDAS, 56.4, 89.8, 77.5, and 76.7%. We conclude that all tests had an unacceptably low performance as a single test for the detection ofC. difficile in pig herds and that a two-step algorithm is necessary, similar to that in cases of human CDI. Of all of the assays, the real-time PCR had the highest NPV compared to both reference methods and is therefore the most appropriate test to screen for the absence ofC. difficile in pigs as a first step in the algorithm. The second step would be a confirmation of the positive results by toxigenic culture.