Extended Data Figure 8 |. BPSCSK’s lantibiotic has a narrower spectrum of activity against Gram-positive commensal strains.
a, VRE was inoculated in media conditioned with BPSCSK, Lactococcus lactis, or BPcontrol culture protein precipitate (n = 4 biologically independent samples/4 independent experiments) and growth was monitored 24 hours post-inoculation. b,c, Culture broth was conditioned with proteins precipitated from BPSCSK, BPcontrol, or commercial nisin-A and serially diluted. The minimal inhibitory concentration (MIC) was determined for common nosocomial pathogens (b) or 158 strains from a commensal biobank (n = 2 biologically independent samples/2 independent experiments) (c) by calculating the highest dilution factor that inhibited growth. The resistance index is a ratio between MIC of BPcontrol-conditioned media over the MIC of BPSCSK or nisin-A-conditioned media (b). The lantibiotic sensitivity ratio was calculated as the MIC of nisin-A over the MIC of BPSCSK’s lantibiotic for each strain (c). All statistical analyses were performed using the Mann-Whitney rank sum test (two-tailed) comparing experimental conditions to a negative control (a) or between two experimental conditions (b,c). *p-value < 0.05 (= 0.0286), **** p-value < 0.0001. Center values (median) center values (median), error bars (1.5 * interquartile range).