How to optimise the yield of forensic and clinical post-mortem microbiology with an adequate sampling: a proposal for standardisation.

Post-mortem microbiology (PMM) is an important tool in forensic pathology, helping to determine the cause and manner of death, especially in difficult scenarios such as sudden unexpected death (SD). Currently, there is a lack of standardization of PMM sampling throughout Europe. We present recommendations elaborated by a panel of European experts aimed to standardize microbiological sampling in the most frequent forensic and clinical post-mortem situations. A network of forensic microbiologists, pathologists and physicians from Spain, England, Belgium, Italy and Turkey shaped a flexible protocol providing minimal requirements for PMM sampling at four practical scenarios: SD, bioterrorism, tissue and cell transplantation (TCT) and paleomicrobiology. Biosafety recommendations were also included. SD was categorized into four subgroups according to the age of the deceased and circumstances at autopsy: (1) included SD in infancy and childhood (0-16 years); (2) corresponded to SD in the young (17-35 years); (3) comprised SD at any age with clinical symptoms; and (4) included traumatic/iatrogenic SD. For each subgroup, a minimum set of samples and general recommendations for microbiological analyses were established. Sampling recommendations for main bioterrorism scenarios were provided. In the TCT setting, the Belgian sampling protocol was presented as an example. Finally, regarding paleomicrobiology, the sampling selection for different types of human remains was reviewed. This proposal for standardization in the sampling constitutes the first step towards a consensus in PMM procedures. In addition, the protocol flexibility to adapt the sampling to the clinical scenario and specific forensic findings adds a cost-benefit value.