DES MOINES, Iowa (AP) – A Des Moines hospital is alerting about 2,600 people who had open-heart surgery there from 2012 to 2015 that they might have been exposed to a bacterial infection. The Des Moines Register reports that two of the former Mercy Medical Center patients have been diagnosed with an infection with the germs, called non-tuberculous mycobacteria.

Iowa Department of Public Health medical director Patricia Quinlisk described the germ as “a cousin to tuberculosis, but it’s much less potent and much more slow-growing.” She says University of Iowa Hospitals and Clinics issued a similar warning earlier this year. Quinlisk says people who undergo the heart procedures tend to have weak immune systems.

Mercy Medical Center says the bacteria could have spread from a heart-lung bypass machine used in heart surgery.