Identifying background microbiomes in an evidence recovery laboratory: A preliminary study

Area of Science:

• Forensic microbiology
• Microbial ecology
• Human DNA analysis

Background:

• 16S rRNA profiling shows potential for forensic identification.
• Forensic laboratories may utilize microbial profiling alongside human DNA analysis.
• Understanding background microbial signatures in forensic environments is crucial for accurate interpretation.

Purpose of the Study:

• To establish the background microbiome of an Evidence Recovery Laboratory (ERL).
• To assess microbial transfer from participants to ERL surfaces.
• To correlate microbial profiles with human DNA presence in a forensic setting.

Main Methods:

• Sampling of ERL surfaces at three timepoints: pre-cleaning, post-cleaning, and post-use.
• 16S rRNA gene sequencing for microbial profiling of ERL surfaces and human participants.
• Standard forensic STR profiling for human nuclear DNA analysis.

Main Results:

• No consistent microbial signature was found across sampled ERL items over time.
• Major bacterial phyla in ERL samples were consistent with human skin microbiomes.
• Clustering observed between participant microbiomes and ERL surfaces post-use, indicating microbial deposition.
• Human DNA was detected in ERL samples, but showed no correlation with microbial profiles.

Conclusions:

• Microbial communities may be inadvertently transferred into forensic settings over time.
• The background microbiome of a forensic laboratory can be influenced by human presence.
• Further research is needed to understand the implications of microbial transfer for forensic investigations.