Micologia forense: uma revisão sistemática e uma nova proposta de metodologia de isolamento e identificação de fungos associados à estimativa do intervalo post-mortem (IPM)

Abstract

Fungi are mostly decomposers, being present throughout the putrefaction process, and have aerovagant spores, which allow these organisms access to the most diverse and extreme environments. In addition, fungal colonies grow radially and centrifugally, allowing us to assume the time required for their development, which can be used to estimate the post-mortem interval (IPM). In this sense, forensic mycology, with all its methodological potential, emerges as a possible tool for the forensic area. However, due to a great lack of knowledge regarding fungal biology in a forensic environment, the factors that can accelerate or delay fungal development and their possible applications to assist in legal resolutions, even though they are commonly found at crime scenes, are often discarded as possible evidence, since forensic professionals do not know how to take advantage of them. Therefore, based on the above, this work was divided into 2 parts. The first led to the proposal to systematize the scientific evidence related to the use of mycology in the criminal context. To this end, a systematic review was carried out, searching the PUBMED, EMBASE, Web of Science, LILACs and OpenGrey databases, using MeSH and free terms based on the PICO strategy (P: population; I: intervention; C: comparison; and O: outcome), for articles published until February 2024 on the forensic application of fungi found in human cadavers. The results in the databases retrieved 106 articles, of which, through the Rayyan QCRI manager, 13 articles were selected. After reading in full and assessing the methodological quality using the Joanna Briggs Institute (JBI) protocol, 6 articles were included in the review. The results indicate that mycology is an auxiliary tool that can be used in forensic studies as long as professionals have a minimum knowledge of fungal biology and the microbiological techniques that should be applied. The second part of the study was to evaluate fungal growth on different substrates in order to develop a protocol for the production of culture media that is more suitable for forensic science. Since this is a recent field, it is necessary to optimize and standardize mycobiota analysis methods and determine factors that may influence the results. To this end, ubiquitous fungi were inoculated into media already established in medical mycology and into media designed to mimic cadaveric substrates from chicken liver. Fungal growth was analyzed by means of visual readings, caliper measurements, and ImageJ analysis, carried out for 14 days after inoculation of these fungi. Initially, it was observed that there were differences in the speed of fungal growth, with faster sporulation in media containing plant extract than in those containing animal protein, suggesting that the culture medium is an interfering factor that needs to be considered in the IPM analysis.