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Published on: January 17, 2014
Prevention and elimination of upper respiratory colonization of mice by group A streptococci by using a bacteriophage
D Nelson1, L Loomis, V A Fischetti
1The Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA. nelsond@rockefeller.edu
Abstract:
Bacteriophage lytic enzymes quickly destroy the cell wall of the host bacterium to release progeny phage. Because such lytic enzymes specifically kill the species in which they were produced, they may represent an effective way to control pathogenic bacteria without disturbing normal microflora. In this report, we studied a murein hydrolase from the streptococcal bacteriophage C(1) termed lysin. This enzyme is specific for groups A, C, and E streptococci, with little or no activity toward several oral streptococci or other commensal organisms tested. Using purified lysin in vitro, we show that 1,000 units (10 ng) of enzyme is sufficient to sterilize a culture of approximately 10(7) group A streptococci within 5 seconds. When a single dose of lysin (250 units) is first added to the oral cavity of mice, followed by 10(7) live group A streptococci, it provides protection from colonization (28.5% infected, n = 21) compared with controls without lysin (70.5% infected, n = 17) (P < 0.03). Furthermore, when lysin (500 units) was given orally to 9 heavily colonized mice, no detectable streptococci were observed 2 h after lysin treatment. In all, these studies show that lysin represents a unique murein hydrolase that has a rapid lethal effect both in vitro and in vivo on group A streptococci, without affecting other indigenous microorganisms analyzed. This general approach may be used to either eliminate or reduce streptococci from the upper respiratory mucosal epithelium of either carriers or infected individuals, thus reducing associated disease.
Insights
Bacteriophage lysin rapidly kills Group A Streptococcus bacteria, offering a targeted approach to control pathogens without harming beneficial microflora. This enzyme shows promise for reducing streptococcal colonization in vivo.
Area of Science:
- Microbiology
- Enzymology
- Bacteriology
Background:
- Bacteriophage lytic enzymes offer species-specific pathogen control.
- Lysins degrade bacterial cell walls, leading to host cell lysis.
- Targeting pathogenic bacteria without disrupting normal microflora is a key challenge in infectious disease control.
Purpose of the Study:
- To investigate the properties and efficacy of a specific murein hydrolase, lysin, from streptococcal bacteriophage C(1).
- To evaluate lysin's activity against Group A streptococci in vitro and in vivo.
- To assess lysin's specificity and potential as a therapeutic agent for streptococcal infections.
Main Methods:
- Purification and characterization of lysin.
- In vitro assays to determine lysin's bactericidal activity against Group A streptococci.
- In vivo studies in mice to assess lysin's protective effect against colonization and its efficacy in reducing existing colonization.
Main Results:
- Lysin demonstrated rapid and potent bactericidal activity against Group A streptococci in vitro, sterilizing cultures within seconds.
- In vivo, lysin significantly reduced Group A streptococcal colonization in the oral cavities of mice.
- Lysin showed high specificity, with minimal activity against other tested streptococci and commensal organisms.
Conclusions:
- Lysin is a highly effective murein hydrolase with rapid lethal activity against Group A streptococci.
- Lysin's specificity suggests its potential as a targeted therapeutic agent for controlling streptococcal infections.
- This approach may reduce or eliminate streptococci from mucosal surfaces, thereby decreasing disease transmission.
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