As antibacterial resistance continues to render obsolete the use of some antibiotics, some have turned to bacteria-killing viruses--bacteriophages, or phages, for short--to treat acute infections as well as some chronic illnesses. Graham Hatfull, the Eberly Family Professor of Biotechnology in the Dietrich School, has just discovered how a specific mutation in a bacterium results in phage resistance. The results were published February 23, in the journal Nature Microbiology.