Table 2. Deferred antagonism assays of L. lactis NZ9800 strains producing nisin A (wild type control) and the nisin derivative I4V against representative strains of S. pseudintermedius and S. intermedius.

Strain	Nisin A	Nisin I4V	P-value
	mm	mm
S. pseudintermedius DK729	16.90 ± 0.48	17.96 ± 0.50	0.009
S. pseudintermedius DSM21284	16.88 ± 0.29	18.06 ± 0.14	0.008
S. intermedius DSM 20373	16.84 ± 0.27	18.27 ± 0.07	0.039

Values are the mean of triplicate deferred antagonism assays and represent zone of inhibition (diameter of zone). All values in bold reached statistical significance compared to nisin control (Student’s t-test: P < 0.05).