In the March 23 issue of PLoS Pathogens, Rockefeller’s Vincent A. Fischetti and colleagues at St. Jude show that middle ear infections in mice can be prevented by giving the mice a lysin ?a protein derived from a virus that infects bacteria. The new technology may prevent children with the flu from developing secondary ear infections and would be an attractive alternative to traditional antibiotics, to which bacteria are rapidly becoming resistant.
The bacteria that cause middle ear infections, Streptococcus pneumoniae, aren’t transmitted at school. They already reside on the mucosal membranes in the nose, waiting for their chance to strike. When a child catches the flu, or another virus that causes an upper respiratory infection, the bacteria seize the opportunity and migrate to the middle ear, causing a secondary infection. The new treatment would kill the bacteria before it had a chance to move.
"These bacteria take advantage of a viral infection by striking when our resistance is lowered," says Fischetti, head of Rockefeller’s Laboratory of Bacterial Pathogenesis and Immunology. "You should start taking an antibiotic the moment you come down with the viral infection to prevent the secondary infection, but physicians are reluctant to do this for fear of increasing resistance to antibiotics. So we’re really in a catch-22 situation."
Fischetti’s lab has done extensive research on lysins, which are proteins derived from viruses that normally infect bacteria. After a virus has infected the bacteria and replicated, it uses lysins to punch holes in the bacteria’s cell wall, killing the bacteria, in order to escape. Fischetti’s lab has studied many different lysins and found