PORTLAND (AP) — A Portland teen who died after routine oral surgery in February was killed by flesh-eating bacteria.

The chief medical examiner’s report said that 18- year-old Benjamin LaMontagne died of necrotizing fasciitis — an infection that caused his neck and jaw to swell.

The Portland Press Herald reports that the bacteria can be transferred through surgical procedures, getting blood drawn, small cuts and bruises.

After the Chevrus High School student had four wisdom teeth removed in February, the swelling in his left jaw grew worse and he struggled to swallow and eat.

The report says that on the night of his death three days later, his mother found him in the bathroom where he was breathing but not responding verbally. He was pronounced dead at home shortly after.