Before the advent of antibiotics, pneumonia claimed so many lives - and was so feared - that it was called the "captain of the ship of death."
Now, at a time when the new antibiotics have proved futile against resistant strains of bacteria, researchers at Rockefeller University are using a different tactic to keep this ship at bay. Instead of using synthetic weapons, they are using nature's: an enzyme that has proved so effective at killing Streptococcus pneumoniae that it has been put on the front lines in the battle against infectious disease.
"The past decade has seen S. pneumoniae evolve new resistance mechanisms much more quickly than scientists have been able to develop antibiotics to combat them," says Vincent A. Fischetti, head of the Laboratory of Bacterial Pathogenesis and Immunology. "This enzyme represents one of the most promising therapeutic options to stop this arms race between S. pneumoniae and humans with a final blow."
According to some estimates, 5 to 10 percent of healthy adults and 15 to 40 percent of healthy children are carriers of S. pneumoniae, which normally resides in the nose. If the immune system doesn't keep these bacteria in check or an upper respiratory infection occurs, they can start to multiply and travel to different organs such as the lungs (causing pneumonia), brain (meningitis) or ears (otitis media), with sometimes fatal consequences. The prognosis is particularly bad in children and the elderly: In 2004 alone, 40 percent of children and older adults who developed pneumonia due to S. pneumoniae died of the disease.
The new research, which appears in the February issue of Critical Care Medicine, reveals that the enzyme Cpl-1, which is produced by bacteria-infecting viruses called bacteriophages, can successfully reach lung tissue in mice and reverse the symptoms of severe pneumococcal pneumonia. "Administering drugs through the blood is an effective way of treating disease, but not all drugs can remain active in that environment," says Fischetti. His team not only shows that Cpl-1 can make the trek but that it is also highly effective when it reaches its destination.