In an age of increasingly antibiotic-resistant bacteria, Bdellovibrio is a possible ray of hope. It is a parasitic gram-negative bacterium that feeds off other gram-negative bacteria, such as Legionella and Salmonella. This cannibalistic tendency makes it an exciting potential alternative to antibiotics when fighting infections caused by gram-negative bacteria. Research shows that it preys effectively on such bacteria and does so without harming surrounding human cells. Hopes are now focusing on its potential role in indirectly fighting infections caused by gram-positive bacteria, such as Staphylococcus aureus.