title: Prevalence of cpb2, encoding beta2 toxin, in Clostridium perfringens field isolates: correlation of genotype with phenotype.
abstract: Beta2 toxin, encoded by the cpb2 gene, has been implicated in the pathogenesis of porcine, equine and bovine enteritis by type A Clostridium perfringens. By incorporating primers to cpb2 into a multiplex genotyping PCR, we screened 3270 field isolates of C. perfringens. Of these, 37.2% were PCR positive for the cpb2 gene. The majority of isolates from cases of porcine enteritis were positive for cpb2 (>85%), and this was even more true for C. perfringens isolated from cases of porcine neonatal enteritis (91.8%). In contrast, isolates from normal pigs only contained cpb2 in 11.1% of cases. The correlation between enteritis in other animal species and the presence of cpb2 was not so strong. cpb2 was found in 21.4% of C. perfringens isolates from cattle with enteritis, and in 47.3% of isolates from calves with enteritis or abomastitis. The prevalence of cpb2 varied with genotype, with type A isolates being positive for this gene in 35.1% of cases. Furthermore, enterotoxigenic type D or type E strains almost always carried cpb2. We cloned a 6xHIS-tagged beta2 (HIS-beta2) and used this protein to raise antiserum against beta2. Culture supernatants from 68 cpb2-positive and 13 cpb2-negative strains were tested for the presence of beta2 by Western blotting. In cpb2-positive isolates of porcine origin, beta2 was almost always detected (96.9%). However, in cpb2-positive isolates from other animal species, only 50.0% expressed beta2 protein. The high rate of cpb2-positivity among strains from neonatal pigs with enteritis and the high correlation of genotype with phenotype, supports the contention that beta2 toxin plays a role in the pathogenesis of these infections. However, it may be important to consider the use of an additional method for the detection of beta2 toxin in non-porcine cpb2-positive isolates when making claims about the role of beta2 in enteritis in non-porcine species.
authors.affiliation: Department of Veterinary Science and Microbiology, The University of Arizona, 1117 East Lowell Street, Tucson, AZ 85721, USA.
authors.forename: Dawn M
authors.initials: DM
authors.lastname: Bueschel
authors.forename: B Helen
authors.initials: BH
authors.lastname: Jost
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Billington
authors.forename: Hien T
authors.initials: HT
authors.lastname: Trinh
authors.forename: J Glenn
authors.initials: JG
authors.lastname: Songer
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001427:Bacterial Toxins / Q000096:biosynthesis / Q000235:genetics*; D001717:Birds; D002161:Camelids, New World; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000382:microbiology*; D003001:Cloning, Molecular; D003015:Clostridium Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D003016:Clostridium perfringens / Q000235:genetics* / Q000472:pathogenicity; D003670:Deer; D004285:Dogs; D004751:Enteritis / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D005516:Food Microbiology; D015964:Gene Expression Regulation, Bacterial; D005838:Genotype; D006041:Goats; D006736:Horses; D006801:Humans; D008297:Male; D010641:Phenotype; D016133:Polymerase Chain Reaction / Q000662:veterinary; D015995:Prevalence; D012756:Sheep; D012988:Soil Microbiology; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology / Q000382:microbiology*
chemical_list: D001427:Bacterial Toxins; C109896:cpb2 protein, Clostridium perfringens