Sandwich ELISA detection of Clostridium perfringens cells and alpha-toxin from field cases of necrotic enteritis of poultry.
ABSTRACT Sandwich ELISAs (sELISAs) for the detection of Clostridium perfringens cells and alpha-toxin were developed and used to screen intestinal samples from normal broiler chickens and from clinical cases of necrotic enteritis. The assays clearly distinguished between the two sets of samples. The sELISA absorbance values from samples obtained from the majority of healthy birds were low and those from the majority of necrotic enteritis cases were high. Together, the assays provide a suitable test for the rapid screening for the diagnosis of necrotic enteritis in poultry.
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ABSTRACT: While previous studies have demonstrated an association between equine grass sickness (EGS) and the presence of Clostridium botulinum within ileal contents and faeces, no such associations with other intestinal-derived anaerobic bacteria have been extensively investigated. The prevalence of C. perfringens in the ileal contents and faeces of EGS horses is greater than control horses; the detection of C. perfringens in faeces by ELISA could be diagnostically beneficial in a clinical setting. The prevalence of C. perfringens in faeces from EGS horses and healthy grazing control horses was determined by both selective culture and ELISA to permit both validation of the ELISA and inter-group comparisons. Additionally, the prevalence of C. perfringens (ELISA) in ileal contents from EGS horses was compared with that for control horses with nongastrointestinal disease. Finally, the prevalence of C. perfringens (ELISA) in faeces from EGS cases was compared with that from both horses with which they shared pasture at the time of disease onset and non-EGS colic horses. When compared with culture, the ELISA had a sensitivity and specificity of 86 and 98%, respectively. The prevalence of C. perfringens in faeces as determined by both culture and ELISA was significantly higher (P<0.001) for EGS horses (7/9 and 15/37, respectively) than for healthy grazing controls (0/60 and 1/74, respectively). The prevalence of C. perfringens in ileal contents from EGS horses (5/10) was greater than that for horses with nongastrointestinal disease (1/12) at a level that approached significance (P = 0.056). EGS cases had a significantly greater prevalence of C. perfringens in faeces (15/37) than co-grazing horses (1/18) and colic (1/16) horses. The specificity (93%) and PPV (94%) of the detection of C. perfringens by ELISA on faecal samples in relation to disease status (EGS compared with colic horses) was good. Sensitivity (41%) and NPV (39%) were poor. The use of a commercial ELISA to detect faecal C. perfringens may be diagnostically beneficial when differentiating EGS cases from colic cases, although further work is required to fully evaluate its potential.Equine Veterinary Journal 09/2010; 42(6):494-9. · 2.29 Impact Factor
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ABSTRACT: Clostridium perfringens is a major enteric pathogen that is responsible for causing necrotic enteritis of poultry. The ability to adhere to the host's intestinal epithelium and to extracellular matrix molecules (ECMM) in the gut, are strategies used by numerous bacterial enteropathogens, however, C. perfringens has received comparatively little attention in this respect. The present study investigated sixteen type A C. perfringens isolates from chickens, with varying disease producing ability with respect to necrotic enteritis in chickens, for their ability to adhere to nine different extracellular matrix molecules (ECMM) and to the intestinal epithelial cell line Caco-2. C. perfringens strains were able to bind to ECMMs and there was strain variation. Strains of C. perfringens that produced severe disease, were capable of binding to collagen type III, IV and V, fibrinogen, laminin and vitronectin at higher levels than less severe disease producing strains, suggesting that the ability to adhere to ECMMs might enhance virulence with respect to induction of necrotic enteritis. In addition, severe disease producing strains also bound better to collagen type III and IV and fibrinogen, than non-disease producing strains. The present study also showed that some strains of C. perfringens possessed the ability to adhere to Caco-2 cells; however no relationship was found between the ability to adhere to Caco-2 cells and disease producing ability.Anaerobe 10/2010; 16(5):533-9. · 2.02 Impact Factor
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ABSTRACT: 1. The effect of three different levels of dietary trypsin inhibitor activity (achieved by varying the amount of non-toasted full fat soya bean in replacement for toasted full fat soya bean) on the incidence of spontaneously-occurring sub-clinical necrotic enteritis (NE) in broiler chickens was compared. A fourth dietary treatment compared the effect of a diet that used potato protein concentrate as the major protein source. The determined trypsin inhibitor activity increased with the increasing content of non-toasted soya bean: 1·90, 6·21, 8·46 and 3·72 mg/g for the three soya bean diets (0, 100 and 200 g of non-toasted soya bean/kg) and the potato protein diet respectively. 2. Although increasing amounts of the non-toasted full-fat soya bean increased the feed intakes of the birds, there was a marked reduction in protein digestibility, weight gain and feed conversion efficiency. 3. There was a linear increase in sub-clinical NE lesions in the duodenum, jejunum, mid small intestine and ileum with increasing non-toasted soya bean. Caecal Clostridium perfringens counts increased with the increasing dietary content of non-toasted soya bean. Serum α-toxin antibodies were higher in the birds fed the 200 g non-toasted soya bean/kg diet compared with the other diets. 4. The results demonstrated that variation in the amount of non-toasted dietary soya bean not only affects growth performance of broilers but also affects the incidence of sub-clinical necrotic enteritis in the flock. Ensuring the lowest possible trypsin-inhibitor activity in soya bean samples is a valuable tool to improve the health and welfare of birds and in reducing the financial losses from this disease.British Poultry Science 06/2011; 52(3):359-67. · 1.15 Impact Factor