Clostridium tetani bacteraemia in the plague area in France: Two cases.

Clostridium tetani (C. tetani) bacteraemia is a rare situation, with only four case reports in the literature. Fourteen teeth from the 1590 plague site in Fédons, France, were surface decontaminated before the pulp was cultured under strict anaerobiosis with negative controls. Colonies were identified by mass spectrometry and whole genome sequencing, and C. tetani-specific PCR was performed using DNA extracted from dental pulps, calculus and sediments. C. tetani cultured in two dental pulp specimens from two individuals was firmly identified by MALDI-TOF mass spectrometry, and whole genome sequencing confirmed toxigenic C. tetani. In the remaining twelve individuals, no such C. tetani was recovered and further detection by PCR and palaeoculturomics of dental calculus and sediments surrounding the teeth in these two individuals remained negative. Toxigenic C. tetani which did not result from mere environmental contamination, caused bacteraemia in two individuals from a modern time plague site in France.