The antibiotic-resistant drug can cause death in half of seriously ill patients, according to the CDC, and is difficult to treat.

The University of California Los Angeles warned Wednesday that 179 patients had been exposed to a potentially deadly “superbug” via contaminated medical instruments and could be responsible for two deaths.

The patients at Ronald Reagan UCLA Medical Center were exposed to Enterobacteriaceae (CRE), an antibiotic-resistant and carbapenem-resistant bug, between the months of October and January, the university acknowledged in a statement as reported by Fox News.

The patients will receive home-testing kits, which are to be returned to UCLA for analysis.

CRE is difficult to treat because antibiotics don’t generally work on it. A seriously infected patient has a roughly 50 percent change of dying, according to the Centers for Disease Control and Prevention.

CRE causes infections in the bladder or lungs and usually results in coughing, chills, or fever. It’s not the first time there has been a CRE outbreak, as it has been reported in every state except for Maine, Alaska, and Idaho.

The culprit in the UCLA case are the specialized endoscopes used for diagnosing and treating problems in the pancreas and bile duct. Authorities believe these instruments were contaminated and were then inserted into the throats of patient. They discovered the problem during tests of a patient.

Two different endoscopes are believed to have been contaminated even though they were sterilized according to the correct procedure, the report states.

Authorities at UCLA has since removed the devices and decontamination procedures were implemented to clamp down on the situation.

A recent major outbreak was in 2013 in Illinois, when dozens of patients were exposed, and some of the cases were also linked to a tainted endoscope, prompting the hospital to change sterilization procedures.