Further Comparison of Temperature Effects on Growth and Survival of <i>Clostridium perfringens</i> Type A Isolates Carrying a Chromosomal or Plasmid-Borne Enterotoxin Gene

<jats:title>ABSTRACT</jats:title> <jats:p> <jats:italic>Clostridium perfringens</jats:italic> type A isolates can carry the enterotoxin gene ( <jats:italic>cpe</jats:italic> ) on either their chromosome or a plasmid, but food poisoning isolates usually have a chromosomal <jats:italic>cpe</jats:italic> gene. This linkage between chromosomal <jats:italic>cpe</jats:italic> isolates and food poisoning has previously been attributed, at least in part, to better high-temperature survival of chromosomal <jats:italic>cpe</jats:italic> isolates than of plasmid <jats:italic>cpe</jats:italic> isolates. In the current study we assessed whether vegetative cells and spores of chromosomal <jats:italic>cpe</jats:italic> isolates also survive better than vegetative cells and spores of plasmid <jats:italic>cpe</jats:italic> isolates survive when the vegetative cells and spores are subjected to low temperatures. Vegetative cells of chromosomal <jats:italic>cpe</jats:italic> isolates exhibited about eightfold-higher decimal reduction values (D values) at 4°C and threefold-higher D values at −20°C than vegetative cells of plasmid <jats:italic>cpe</jats:italic> isolates exhibited. After 6 months of incubation at 4°C and −20°C, the average log reductions in viability for spores of plasmid <jats:italic>cpe</jats:italic> isolates were about fourfold and about threefold greater, respectively, than the average log reductions in viability for spores from chromosomal <jats:italic>cpe</jats:italic> isolates. <jats:italic>C. perfringens</jats:italic> type A isolates carrying a chromosomal <jats:italic>cpe</jats:italic> gene also grew significantly faster than plasmid <jats:italic>cpe</jats:italic> isolates grew at 25°C, 37°C, or 43°C. In addition, chromosomal <jats:italic>cpe</jats:italic> isolates grew at higher maximum and lower minimum temperatures than plasmid <jats:italic>cpe</jats:italic> isolates grew. Collectively, these results suggest that chromosomal <jats:italic>cpe</jats:italic> isolates are commonly involved in food poisoning because of their greater resistance to low (as well as high) temperatures for both survival and growth. They also indicate the importance of proper low-temperature storage conditions, as well as heating, for prevention of <jats:italic>C. perfringens</jats:italic> type A food poisoning. </jats:p>