Forensic Identification using skin bacterial communities
1.
2. Human skin harbors large numbers of
bacteria
Studies have shown skin-associated bacterial
communities are diverse
So diverse that only 13% of bacterial
phylotypes are shared between any given
person.
3. Bacteria communities are actually fairly stable
as well
Communities return to normal within hours
of hand washing.
Individuals have personally unique, temporary
stable, and transferable skin-associated
bacterial colonies.
4. The authors hypothesize that they could use
the residual skin bacteria left on objects for
forensic identification, matching the bacteria
on the object to the skin-associated bacteria
of the individual who touched the object.
5. Three criteria had to be met
◦ The bacteria collected had to allow for adequate
characterization
◦ Skin bacteria had to persist for days to week
◦ Surfaces touched had to be linked to individuals by
a degree of similarity.
6. For the keyboard study, three individuals and
their keyboards were swabbed.
For the mouse study they used nine
individuals.
For the “storage” study they swabbed 2
healthy adults in the right axillary.
7. Target gene 16s rRNA
Used MO BIO PowerSoil DNA Isolation kits.
0.1% Agarose gels were used
DNA staining was done using SYBR sage DNA
gel stain in 0.5xTBE
Pyrosequencing was carried out using454 Life
Sciences genome Sequencer FLX instrument.
8. This image has been created during "DensityDesign
Integrated Course Final Synthesis Studio" at Polytechnic
University of Milan, organized by DensityDesign Research
Lab. Image is released under CC-BY-SA licence.
Attribution goes to "Jacopo Pompilii, DensityDesign
Research Lab"
14. Criteria one and three met.
Bacteria communities resembled that of the
owners hands.
Similarity between the colonies was shown.
Bacteria can be recovered from relatively
small surfaces.
15. Two individuals bacterial communities stayed
relatively similar.
Standard indoor conditions showed the
bacterial community owner could still be
reasonably identified
16. Showed bacterial communities still remained
unique to their owners
They remained unique after time had passed.
Was compared to 270 stored bacterial
community genomes.
17. More studies like this are needed
Forensics is a science that needs to be sure
and certain of results.
Further testing would allow for more accuracy
18. Fierer, Noah, et al. "Forensic identification
using skin bacteria communities."
Proceedings of the National Academy of
Sciences of the United States of America
107.14 (2010): 6477-6481. Web.
Lawley, Rochard. A Revolution in the
Microbiology Labratory. 7 October 2009.
web site. 22 February 2015.
<http://www.foodsafetywatch.org/features
/a-revolution-in-the-microbiology-
laboratory/>.
