Until now, there has been no strategy to remove the reservoir of S. pneumoniae from the noses and throats of humans. Yet, this "home base" provides an excellent target for controlling infections.
"This enzyme will kill pneumococci on mucous membranes within seconds," says Jutta Loeffler, M.D., first author of the paper and a postdoctoral fellow at Rockefeller. "By treating individuals carrying this bacterium with the enzyme, you could significantly reduce the reservoir of these bugs in the population and consequently reduce infection rates."
Such a decline in the number of worldwide infections would lessen the need for traditional antibiotics and subsequently ease the mounting drug-resistance problem.
Bacteriophage, or phage, can be found just about anywhere: in sewage and soil and any other locations where bacteria are found. As part of their normal lifecycle, these tiny viruses infect, replicate, then burst out of bacteria before infecting their next host.
Special phage enzymes, which punch holes in the bacterial cell wall, ensure the phage a rapid exit; without this outer layer of protection the bacteria essentially cannot hold themselves together, and, they explode.
Fischetti discovered that the phage enzymes also work when applied to the outside of the bacterial cells: by adding a few drops of phage enzyme to a test tube of millions of bacteria, he found that he could kill nearly all of them within a few seconds.
Because phage enzymes are specific for the species or strain of bacterium from which they were produced, cultivating a tailor-made killer for any bacterium of interest may be possible. Last February, for example, Fischetti and colleagues reported the isolation of a phage enzyme specific for Group A streptococci, an infectious pathogen that causes strep throat and flesh-eating disease. Human clinical trials testing the
Contact: Whitney Clavin