Antibiotics normally act in concert with an organism’s immune system to eliminate an infection. However, the drugs can have broad side effects, including eliminating “good” bacteria in the course of fighting off a pathogen. A new study led by researchers from the Broad Institute of MIT and Harvard, MIT, and the Wyss Institute for Biologically Inspired Engineering has shown that antibiotics can also reduce the ability of mouse immune cells to kill bacteria, and that changes to the biochemical environment directly elicited by treatment can protect the bacterial pathogen. The work was published today in Cell Host & Microbe.