Rapid killing of Streptococcus pneumoniae with a bacteriophage cell wall hydrolase

Nasopharyngeal carriage is the major reservoir for Streptococcus pneumoniae in the community. Although eliminating this reservoir would greatly reduce disease occurrence, no suitable intervention has been available for this purpose. We show here that seconds after contact, a purified pneumococcal bacteriophage lytic enzyme (Pal) is able to kill 15 common serotypes of pneumococci, including highly penicillin-resistant strains. In vivo, previously colonized mice revealed undetectable pneumococcal titers 5 hours after a single enzyme treatment. Pal enzyme had little or no effect on microorganisms normally found in the human oropharynx, and Pal-resistant pneumococci could not be detected after extensive exposure to the enzyme.