Nisin, alone and combined with peptidoglycan-modulating antibiotics: activity against methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci.
OBJECTIVE
We have sought ways to circumvent resistance, by combining nisin with other antibiotics known to target bacterial cell wall biosynthesis.


METHODS
Twenty strains each of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) were tested in vitro by standardized methods against nisin alone and combined with bacitracin, ramoplanin and chloramphenicol.


RESULTS
Ramoplanin was the most potent compound, and bacitracin had the least activity. Two-way synergy was observed with nisin and ramoplanin. However, chloramphenicol was clearly antagonistic to the activity of nisin.


CONCLUSIONS
Observations of synergy between nisin and ramoplanin against MRSA and VRE offer a promising approach to the concept of combining nisin with inhibitors of cell wall peptidoglycan. Further investigations are needed in order to develop this approach as a clinical possibility.
Brumfitt
W
W
Department of Medical Microbiology, Royal Free and University College Medical School, London NW3 2PF, UK.
Salton
M R J
MR
Hamilton-Miller
J M T
JM
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D004359:Drug Therapy, Combination / Q000494:pharmacology*; D016983:Enterococcus / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D016106:Methicillin Resistance / Q000502:physiology; D008826:Microbial Sensitivity Tests / Q000706:statistics & numerical data; D009561:Nisin / Q000494:pharmacology*; D010457:Peptidoglycan / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification; D020713:Vancomycin Resistance / Q000502:physiology
D000900:Anti-Bacterial Agents; D010457:Peptidoglycan; D009561:Nisin