Nisin F in the treatment of respiratory tract infections caused by Staphylococcus aureus

To determine the antimicrobial activity of nisin F against Staphylococcus aureus in the respiratory tract. The respiratory tract of nonimmunosuppressed and immunosuppressed Wistar rats were colonized with 4 x 10(5) viable cells of S. aureus K and then treated by administering 8192 arbitrary units (AU) nisin F intranasal. Symptoms of pneumonia were detected in the trachea and lungs of immunosuppressed rats that had not been treated with nisin F. The trachea and lungs of immunosuppressed rats treated with nisin F were healthy. No significant differences were recorded in blood cell indices. The antimicrobial activity of low concentrations nisin F (80-320 AU ml(-1)) was slightly stimulated by lysozyme and lactoferrin. Nisin F inhibited the growth of S. aureus K in the respiratory tract of immunocompromised rats. Treatment with nisin F at 8192 AU proofed safe, as the trachea, lungs, bronchi and haematology of the rats appeared normal. Nisin F is nontoxic and may be used to control respiratory tract infections caused by S. aureus. This is, however, a preliminary study with an animal model and need to be confirmed with studies on humans.