PCR-based identification of drowning: four case reports

Abstract

Proper diagnosis in drowning victims is often difficult due to the lack of signs specific to drowning. The diatom test is a widely used procedure for the diagnosis. Some types of water contain only minimal amounts of diatom cells which may provide false-negative results, while a negative diatom test result does not exclude drowning. In proving drowning, we used a polymerase chain reaction (PCR)-based biological method in addition to the conventional methods. DNA was extracted from postmortem spleen tissues and water of the drowning site. Samples were tested with algae (diatoms and small green algae)- and cyanobacteria (blue-green algae)-specific primers. We present here multiple drowning cases in which diatom tests of the postmortem tissue samples and the water were negative. In each case, the presence of phytoplanktonic DNA strengthened the autopsy diagnosis of drowning even in the absence of visible diatoms. In the future, the PCR method may be of consideration as a possible supplement of the diatom test in the examination of presumed drowning cases.

Research advances in forensic diatom testing

“…Rácz et al [ 17 ] applied a polymerase chain reaction (PCR)-based method to identify phytoplankton (cyanobacteria, green algae, etc.) DNA from spleen tissues during autopsy and drowning water samples.…”

Massively parallel sequencing is unlocking the potential of environmental trace evidence

“…For DNA metabarcoding a two-step PCR approach is unfavourable as the relative abundance of taxa can be biased towards the more abundant taxa [103,104]. While diatom DNA approaches have focussed on determination of drowning [78,105], the use of diatom DNA to link a suspect to a waterbody or identify geographical provenance is unexplored. Further, diatom DNA transfer and recovery, crucial elements for demonstrating the feasibility of this approach for forensic science, are also unexplored.…”

Microbial forensics: new breakthroughs and future prospects

“…In the previous decade, attention has expanded to the use of other microorganismsbacteria and cyanobacteria (Kakizaki et al 2010;Lucci et al 2008) and phytoplankton, including microalgae (Díaz-Palma et al 2009)using different approaches such as classical culture-dependent methods (Huys et al 2012;Kakizaki et al 2009;Lucci et al 2008), light (Sitthiwong et al 2014) or electron microscopy (Lunetta et al 1998) or PCR-based techniques (He et al 2008;Huys et al 2012;Rácz et al 2016;Tie et al 2010). These other microorganisms are much more abundant and present smaller sizes (ranging between 0.2 and 2 μm) than diatoms and, therefore, at least theoretically, would provide more informative results.…”