The ability of nisin F to control Staphylococcus aureus infection in the peritoneal cavity, as studied in mice

Aims: To determine the ability of nisin F to control systematic infection caused by Staphylococcus aureus, using C57BL/6 mice as a model. Methods and Results: Twelve mice were intraperitoneally injected with 1 x 108 viable cells of Staph. aureus Xen 36 containing the modified Photorhabdus luminescence luxABCDE operon on plasmid pAUL-A Tn4001. After 4 h, six mice were intraperitoneally injected with 640 arbitrary units (AU) nisin F, and six were injected with sterile saline. Six mice, not infected with Staph. aureus, were treated with nisin F, and six not infected were left untreated. The viability of Staph. aureus Xen 36 was monitored over 48 h by recording photon emission levels. Nisin F suppressed Staph. aureus for 15 min in vivo. No abnormalities were recorded in blood analyses and internal organs of mice treated with nisin F. Conclusions: Nisin F suppressed the growth of Staph. aureus in the peritoneal cavity for at least 15 min. Re-emergence of Staph. aureus bioluminescence over the next 44 h suggests that nisin F was inactivated, most probably by proteolytic enzymes. Significance and Impact of the Study: A single dosage of nisin F administered in the peritoneal cavity controlled the growth of Staph. aureus for at least 15 min in vivo.