Time.com:

Researchers analyzed 780 swab samples — 390 from mobile phones and 390 from the hands that used them — in 12 U.K. cities. They found that 16% of both hands and phones were contaminated with E. coli, potentially illness-causing bacteria that is fecal in origin. The likely reason: because people don’t wash their hands after using the toilet.

The researchers discovered that 82 percent of phones had some form of bacterial contamination. Their conclusion is that people either aren’t washing their hands sufficiently or are lying about it when asked.

Gives new meaning to the expression “butt dialing,” that’s for sure.