Influence of Mucin on the Activity of the Antiseptic Lavasept® against Staphylococcus aureus

Background: Lavasept ® , containing the polymeric biguanide polyhexanide, may be effective against Staphylococcus aureus colonizing the nasal mucosa. To obtain basic data on its suitability for that purpose, its antimicrobial activity was examined in the presence of mucin. Methods: A disk diffusion test was applied using Mueller-Hinton agar, and disks soaked with a therapeutic and a 10-fold higher concentration of Lavasept. Commercially available mucin preparations from porcine stomach were added to the test system. Reference strains and 20 clinically isolates of S. aureus, and reference strains of Escherichia coli, Pseudomonas aeruginosa, Enterococcusfaecalis, and Candida albicans were tested. Results: Supplementation of the test medium with 1% mucin completely abolished the activity of disks loaded with the therapeutically used concentration of the antiseptic. The neutralizing effect of mucin occurred with all test strains. Conclusions: The inactivation of Lavasept by mucin may hamper a reliable clearance of nasal S. aureus carriage.