You’re Leaving a Bacterial Fingerprint on Your Keyboard

The bacterial communities that live on human skin may form a bacterial fingerprint on the items that you touch, reports Wired.com.

In a new study led by microbiologists Rob Knight and Noah Fierer of the University of Colorado, Boulder, researchers swabbed three different keyboards and nine mice for bacteria, then compared the genomic variation between the communities to deduce whose hands had been touching what. The people were clearly identifiable from the bacterial communities they’d transferred to their computer input devices.

“The results demonstrate that bacterial DNA can be recovered from relatively small surfaces, that the composition of the keyboard-associated communities are distinct across the three keyboards, and that individuals leave unique bacterial ‘fingerprints’ on their keyboards,” wrote Knight and his colleagues at the University of Colorado, Boulder in a new paper in the Proceedings of the National Academy of Sciences.

Despite the excitement, we’re just beginning to understand the bacterial community variations within a single body and between individuals. The new study adds a helpful plank of knowledge in pointing out that human skin microbiomes are diverse enough to allow researchers to distinguish between people.

While the most obvious implication of the work might seem to be that the skin microbiome technique could be used in forensic settings, this technique is not coming to a courtroom near you, said Jacques Ravel, a microbiologist at the University of Maryland who works on both the human microbiome and more general forensic science.

“It’s a nice piece of work but the forensic aspect as far as I’m concerned is the weakest,” Ravel concluded.

The researchers will need a lot more evidence that human microbiomes don’t change rapidly in time — and that bacterial communities transferred to keyboards endure with few changes.