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

Background: Paleoculturomics aims to culture ancient pathogens from human remains such as dental pulp, which traps a drop of blood at the time of the death, to diagnose bacteraemia. Clostridium tetani (C. tetani) bacteraemia is a rare situation, with only four case reports in the literature. Methods: Fourteen teeth collected from 14 individuals buried at the site of the 1590 plague in Fedons, 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. Results: 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. Conclusion: Toxigenic C. tetani which did not result from mere environmental contamination, caused bacteraemia in two individuals from a modern time plague site in France. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was supported by the French Government under Investments for the Future, program managed by the Agence Nationale de la Recherche (ANR, National Agency for Research) (reference: Mediterranee Infection 10-IAHU-03). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present work are contained in the manuscript