'One of the strategies to limit bacteria growth is to stop absorbing and transporting iron from the intestines - during an active infection, available iron drops dramatically (as do zinc and manganese). That’s a really effective broad-spectrum defense - as far as I know, the only human bacterial pathogen that doesn’t actually seem to need iron is the Lyme disease spirochete Borellia burgdorferi, and it makes up for that by requiring manganese instead.'

https://www.science.org/content/blog-post/war-iron