For parents, eight million cases of acute middle-ear infections every year adds up to a lot of sleepless nights and trips to the pediatrician.
But new research from a collaboration between Rockefeller University and St. Jude Children's Research Hospital could change all that. Research in mice suggests that a lysin - a protein derived from viruses that infect bacteria - may prevent children from developing secondary ear infections. The new technology would be an attractive alternative to traditional antibiotics, to which the 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 Vincent Fischetti, head of the Laboratory of Bacterial Pathogenesis and Immunology. "You should start taking an antibiotic the moment you come down with the virus 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 a lot of research on lysins, which are proteins derived from the 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 that they work even from outside the bacterial cell as well as from the inside. In addition, unlike antibiotics, which kill many of the body's beneficial bacteria along with the disease-causing ones they target, lysins are highly specific. Each lysin will only kill a specific type of bacteria, leaving the body's normal flora untouched.