The vegetative growth of tetanus bacilli was examined in mice challenged intramuscularly with spores suspended in 4% CaCI solution. The viable count of organisms in material derived by grinding up the injection site was low at 6 hours and thereafter increased to counts of the order of 2×10 colony-forming units of in the ground-up lesion about 24 hours after inoculation. At that time the lesion volume was only about 1 ml.

In mice challenged with 1200 to 120,000 spores or in those given 2 MLD of toxin, the time taken for the resulting ascending tetanus to progress from its first appearance to become severe enough to prove fatal was similar-about 17 hours. For the infected mice and those challenged with toxin, however, the time of onset of the first signs of tetanus differed: it was 13 hours after inoculation of toxin, but 20 hours after injection of spores. It is suggested that the difference represents the time taken for the injected spores to form 2 MLD of toxin in the mouse, i.e., about 7 hours after challenge. At this time the numbers of viable organisms at the site of infection had not detectably increased, but rapid growth was about to begin.

These observations suggest that a lethal dose of tetanus toxin may be produced rapidly in an infected tissue by a very small number of viable organisms. Within 24 hours of challenge, a heavy growth of may be present in a lesion only about 1 ml in volume.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error