Studies with bioengineered Nisin peptides highlight the broad‐spectrum potency of Nisin V

Nisin A is the most thoroughly investigated member of the lantibiotic family of antimicrobial peptides. In addition to a long history of safe use as a food antimicrobial, its activity against multi‐drug resistant pathogens has resulted in a renewed interest in applying nisin as a chemotherapeutic to treat bacterial infections. The wealth of Nisin‐related information that has been generated has also led to the development of the biotechnological capacity to engineer novel Nisin variants with a view to improving the function and physicochemical properties of this already potent peptide. However, the identification of bioengineered Nisin derivatives with enhanced antimicrobial activity against Gram‐positive targets is a recent event. In this study, we created stable producers of the most promising derivatives of Nisin A generated to date [M21V (hereafter Nisin V) and K22T (hereafter Nisin T)] and assessed their potency against a range of drug‐resistant clinical, veterinary and food pathogens. Nisin T exhibited increased activity against all veterinary isolates, including streptococci and staphylococci, and against a number of multi‐drug resistant clinical isolates including MRSA, but not vancomycin‐resistant enterococci. In contrast, Nisin V displayed increased potency against all targets tested including hVISA strains and the hyper‐virulent Clostridium difficile ribotype 027 and against important food pathogens such as Listeria monocytogenes and Bacillus cereus. Significantly, this enhanced activity was validated in a model food system against L. monocytogenes. We conclude that Nisin V possesses significant potential as a novel preservative or chemotherapeutic compound.