Last month’s salmonella outbreak got over 1,500 people sick. And one reason salmonella may be such a heavy hitter is that it actually hijacks our immune response for its own benefit. That’s according to a study in the journal Nature.

Bacteria in our gut gobble up things like sugars and fatty acids, which they can break down either through respiration or fermentation. Respiration provides a bigger energy kick. But it requires oxygen, which is sparse in the gut. So most bacteria go the fermentation route.

Except salmonella. Because it’s adapted to use the respiration route. Not with oxygen, but via a sulfur compound—something most bacteria can’t do.

The insidious thing is that the sulfur compound the salmonella feast on is a by-product of the attack our white blood cells launch against the invaders. So by protecting ourselves, we’re also ensuring that salmonella stay well-fed. Because a more inflamed gut allows salmonella bacteria to outcompete good bacteria, and explode in numbers. And the little buggers also use our attempts to expel them with vomiting and diarrhea. Those are both excellent ways for the bugs to get to their next victims.