Your article on microbial-efflux-pump research immediately caused me to relate the phenomenon to immune system response. Have the researchers considered the possibility of such a response triggering the formation of efflux pumps, either specific to the triggering “foreign” body or to a group of bodies similar to the cow pox-small pox link?

Robert E. Hubbard
Winter Haven, Fla.

The subject is a good one for future research, says Paul M.