ATLANTA (AP) — An outbreak of infected tattoos has led to an unlikely source: the ink.

With the growing popularity of tattoos, health officials say they are seeing more cases of a nasty skin infection caused by a common bacteria traced to the ink. In the largest outbreak, 19 people in Rochester, N.Y., ended up with bubbly rashes on their new tattoos, researchers reported Wednesday.

Infections from tattooing are nothing new. Hepatitis, staph infections and even the superbug known as MRSA have been tied to tattoos. Dirty needles and unsanitary conditions are often to blame.