Affiliation:
1. Applied Microbiology, Center for Chemistry and Chemical Engineering, Lund Institute of Technology, Lund University, SE-221 00 Lund,1 and
2. Swedish Meats R&D, SE-222 40 Kävlinge,2 Sweden
Abstract
ABSTRACT
A specific and sensitive combined selection and enrichment PCR procedure was developed for the detection of
Clostridium botulinum
types B, E, and F in fecal samples from slaughtered pigs. Two enrichment PCR assays, using the DNA polymerase
rTth,
were constructed. One assay was specific for the type B neurotoxin gene, and the other assay was specific for the type E and F neurotoxin genes. Based on examination of 29 strains of
C. botulinum
, 16 strains of other
Clostridium
spp., and 48 non-
Clostridium
strains, it was concluded that the two PCR assays detect
C. botulinum
types B, E, and F specifically. Sample preparation prior to the PCR was based on heat treatment of feces homogenate at 70°C for 10 min, enrichment in tryptone-peptone-glucose-yeast extract broth at 30°C for 18 h, and DNA extraction. The detection limits after sample preparation were established as being 10 spores per g of fecal sample for nonproteolytic type B, and 3.0 × 10
3
spores per g of fecal sample for type E and nonproteolytic type F with a detection probability of 95%. Seventy-eight pig fecal samples collected from slaughter houses were analyzed according to the combined selection and enrichment PCR procedure, and 62% were found to be PCR positive with respect to the type B neurotoxin gene. No samples were positive regarding the type E and F neurotoxin genes, indicating a prevalence of less than 1.3%. Thirty-four (71%) of the positive fecal samples had a spore load of less than 4 spores per g. Statistical analysis showed that both rearing conditions (outdoors and indoors) and seasonal variation (summer and winter) had significant effects on the prevalence of
C. botulinum
type B, whereas the effects of geographical location (southern and central Sweden) were less significant.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
68 articles.
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