Clostridium perfringens Type E Animal Enteritis Isolates with Highly Conserved, Silent Enterotoxin Gene Sequences |
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| Authors: | Stephen J Billington Eva U Wieckowski Mahfuzur R Sarker Dawn Bueschel J Glenn Songer and Bruce A McClane |
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| Institution: | Department of Veterinary Science and Microbiology, University of Arizona, Tucson, Arizona 85721,1. and Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 152612. |
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| Abstract: | Several Clostridium perfringens genotype E isolates, all associated with hemorrhagic enteritis of neonatal calves, were identified by multiplex PCR. These genotype E isolates were demonstrated to express α and ι toxins, but, despite carrying sequences for the gene (cpe) encoding C. perfringens enterotoxin (CPE), were unable to express CPE. These silent cpe sequences were shown to be highly conserved among type E isolates. However, relative to the functional cpe gene of type A isolates, these silent type E cpe sequences were found to contain nine nonsense and two frameshift mutations and to lack the initiation codon, promoters, and ribosome binding site. The type E animal enteritis isolates carrying these silent cpe sequences do not appear to be clonally related, and their silent type E cpe sequences are always located, near the ι toxin genes, on episomal DNA. These findings suggest that the highly conserved, silent cpe sequences present in most or all type E isolates may have resulted from the recent horizontal transfer of an episome, which also carries ι toxin genes, to several different type A C. perfringens isolates. |
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