Heat resistance differences are common between both vegetative cells and spores of Clostridium perfringens type F isolates carrying a chromosomal vs plasmid-borne enterotoxin gene

type F isolates utilize enterotoxin (CPE) to cause food poisoning (FP) and nonfoodborne gastrointestinal diseases. The enterotoxin gene ( ) can be located on either the chromosome or plasmids, but most FP isolates carry a chromosomal (c ) gene. Our 2000 article in (66:3234-3240, 2000, https://doi.org/10.1128/aem.66.8.3234-3240.2000https://doi.org/10.1128/AEM.66.8.3234-3240.2000) determined that vegetative cells and spores of c- isolates are more heat resistant than those of plasmid (p- ) isolates, which is favorable for their survival in improperly cooked or held food. However, that 2000 article was recently retracted (90:e00249-24, 2024, https://doi.org/10.1128/aem.00249-24). To our knowledge, the 2000 article remains the only study reporting that heat resistance differences are common between both vegetative cells and spores of type F c- isolates vs type F p- isolates. To confirm and preserve this information in the literature, the heat resistance portion of the 2000 study has been repeated. The 2024 results reproduced the 2000 results by indicating that, relative to the surveyed type F p- isolates, the vegetative cells of surveyed type F c- isolates are ~2-fold more heat resistant and the spores of most surveyed c- isolates are ~30-fold more heat resistant. However, consistent with several reports since our 2000 paper, one surveyed type F c- isolate (which did not appreciably sporulate in 2000 but sporulated in 2024) produced spores with intermediate heat sensitivity, confirming that spores of some type F c- isolates lack exceptional heat resistance.IMPORTANCE type F food poisoning (FP), which is the second most common bacterial cause of FP, involves the production of enterotoxin. While the enterotoxin gene ( ) can be located on either the chromosome or plasmids in type F isolates, most FP cases are caused by chromosomal isolates. The current results support the conclusion that the vegetative cells and spores of type F chromosomal isolates are often more heat resistant than vegetative cells and spores of type F plasmid isolates. Greater heat resistance should favor the survival of the spores and vegetative cells of those chromosomal isolates in temperature-abused food, which may help explain the strong association of type F chromosomal strains with FP.