Mersacidin eradicates methicillin-resistant Staphylococcus aureus (MRSA) in a mouse rhinitis model.
OBJECTIVE
Methicillin-resistant Staphylococcus aureus (MRSA) often colonize the anterior nares, and nasal carriage remains the main source of bacterial dissemination. The aim of this study was to assess the in vivo activity of the lantibiotic mersacidin against MRSA colonizing nasal epithelia.


METHODS
The efficiency of mersacidin in the eradication of MRSA was tested employing mice pre-treated with hydrocortisone and inoculated intranasally either three or six times with a bacterial suspension.


RESULTS
In mersacidin-treated animals, pre-colonized with MRSA, bacteria could not be detected in blood, lungs, liver, kidney, spleen or nasal scrapings and there were no lesions manifested after intraperitoneal drug application. Blood samples from infected mice obtained 2 h after mersacidin therapy revealed anti-MRSA activity in a serum bactericidal test. Moreover, elevated interleukin-1beta and tumour necrosis factor-alpha titres were noticed in the pre-infected but not in cured animals. In contrast, mersacidin did not induce differences in the cytokine profiles of treated uninfected control mice.


CONCLUSIONS
In the mouse rhinitis model, mersacidin was able to eradicate MRSA colonization. The site of action (epithelium versus blood) of mersacidin needs to be further explored.
Department of Medical Microbiology, Dermatology and Infection, Lund University, Sölvegatan 23, SE-223 62 Lund, Sweden. Danuta.Kruszewska@telia.com
Danuta
D
Kruszewska
Hans-Georg
HG
Sahl
Gabriele
G
Bierbaum
Ulrike
U
Pag
Sean O
SO
Hynes
Asa
A
Ljungh
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001430:Bacteriocins; D005260:Female; D006854:Hydrocortisone; D007375:Interleukin-1 / Q000096:biosynthesis; D008233:Lymphotoxin-alpha / Q000096:biosynthesis; D016106:Methicillin Resistance; D051379:Mice; D008807:Mice, Inbred BALB C; D008826:Microbial Sensitivity Tests; D009297:Nasal Mucosa / Q000382:microbiology; D010455:Peptides / Q000494:pharmacology / Q000627:therapeutic use*; D015203:Reproducibility of Results; D012220:Rhinitis / Q000188:drug therapy* / Q000382:microbiology; D015610:Serum Bactericidal Test; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects
D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D007375:Interleukin-1; D008233:Lymphotoxin-alpha; D010455:Peptides; C069959:mersacidin; D006854:Hydrocortisone