Bacterial viruses, or bacteriophage, worm their way into bacterial cells, copy themselves and then, as an exit strategy, produce enzymes that quickly destroy the bacterial cell wall, killing the bacteria and releasing the viral offspring.

"These are highly evolved enzymes that work efficiently and rapidly to kill specific bacteria. The best use of these enzymes is to decolonize humans from carrying pathogenic bacteria in certain settings, such as hospitals, nursing homes and day care centers," says Vincent Fischetti, who is presenting data today at the American Society for Microbiology's Conference on the New Phage Biology.

Bacteria such as group A streptococci, Streptococcus pneumoniae and Staphylococcus aureus are common causes of infections, ranging from minor skin infections and ear infections in day care centers to deadly pneumonia in nursing homes and hospitals. In most instances human beings are the only reservoir of these bacteria, often carrying them unknowingly in their nose or throat. Enzymes targeting these bacteria could be delivered orally or nasally to reduce or eliminate colonization.

"If you greatly reduce the number of bacteria that are carried by individuals in these settings, the chance of infection will be minimized or even eliminated," says Fischetti.

In animal model experiments, Fischetti and his colleagues colonized mice with streptococcal or pneumococcal bacteria, either orally or nasally. They were able to remove the colonization completely using phage enzymes delivered in a single dose.

Because these enzymes are derived from viruses that infect and kill specific bacteria, they are like smart bombs that target and kill only the species or strain of bacteria for whic
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Contact: Jim Sliwa
jsliwa@asmusa.org
202-942-9297
American Society for Microbiology
5-Aug-2004