Purpose: The objective was to assess the antimicrobial activity of 8-TriA1 and a partially purified preparation of the native peptide.
Methods: The spectrum of activity was determined with 8-TriA1 against the following organisms: Bacillus spp. (2 strains), Carnobacterium maltaromatcium, Clostridium botulinum (3 strains), Enterococcus faecalis (2 strains), enterohemorrhagic E. coli (11 strains), Lactobacillus casei, Lb. curvatus, Lb. sakei, Listeria monocytogenes (4 strains), S. enterica Enterica (5 strains), Staphylococcus aureus (3 strains) and Weissella confusa. The MIC of 1 mM 8-TriA1 was determined against C. botulinum, L. monocytogenes, S. aureus AT-1, and W. confusa. The supernatant of a 48 h culture of P. terrae NRRL B-30644 was passed through an Amberlite XAD16N column and an antimicrobial preparation (AMP) was eluted with 80% isopropanol containing 0.1% trifluoroacetic acid. After concentration, antimicrobial activity was confirmed using S. enterica and E. coli as indicators.
Results: The activity of the 8-TriA1 was greatest among Gram-negative indicators, including species of E. coli and Salmonella Enterica, with less activity against Bacillus spp., Carnobacterium, C. botulinum, L. monocytogenes and S. aureus. Regardless of concentration, no activity was observed against Enterococcus, Lactobacillus, and Weissella. The MIC ranged from 23.8 - 380.0 mg/l, depending on the target organism. The AMP had activity against S. enterica and E. coli.
Significance: Evidence of antimicrobial activity was observed with 8-TriA1. Partial purification of TriA1 provided a crude antimicrobial preparation that was active against Gram-negative pathogens and could be used to control pathogens in meat.