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Lysis of staphylococcal mastitis pathogens by bacteriophage phi11 endolysin
David M Donovan1, Michelle Lardeo, Juli Foster-Frey
1Biotechnology and Germplasm Laboratory, ANRI/Agricultural Research Service, US Department of Agriculture, 10300 Baltimore Avenue, Beltsville, MD 20705, USA. ddonovan@anri.barc.usda.gov
FEMS Microbiology Letters
|October 24, 2006
Summary
Staphylococcus aureus bacteriophage phi11 endolysin effectively lyses mastitis pathogens, including Staphylococcus aureus and coagulase-negative staphylococci. This protein antimicrobial retains activity in milk conditions and shows potential for treating staphylococcal infections.
Area of Science:
- Microbiology
- Biochemistry
- Antimicrobial Research
Background:
- Staphylococcus aureus is a major cause of mastitis in dairy animals.
- Bacteriophage endolysins are enzymes with potential as protein antimicrobials.
- phi11 endolysin from Staphylococcus aureus bacteriophage possesses multiple functional domains.
Purpose of the Study:
- To evaluate the lytic activity of phi11 endolysin against staphylococcal mastitis pathogens.
- To determine the optimal conditions for endolysin activity, particularly in a milk environment.
- To investigate the role of specific domains in the lytic function of phi11 endolysin.
Main Methods:
- Purification of Staphylococcus aureus bacteriophage phi11 endolysin.
- Turbidity reduction assays to measure lytic activity.
- Testing activity across various pH and calcium concentrations relevant to milk.
Main Results:
- Purified phi11 endolysin demonstrated potent lytic activity against Staphylococcus aureus and coagulase-negative staphylococci.
- The lytic activity was sustained at pH 6.7 and 3 mM free calcium, mimicking milk conditions.
- Endolysin variants lacking the SH3b cell wall-binding domain but retaining the endopeptidase domain also exhibited staphylolytic activity.
Conclusions:
- phi11 endolysin is a promising candidate protein antimicrobial for treating staphylococcal mastitis.
- Its activity in milk conditions suggests potential for direct application in dairy herds.
- The endopeptidase domain alone is sufficient for significant staphylococcal lysis, offering avenues for engineered antimicrobial development.
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