Bactericidal effect of multi-drug resistance bacteria using lactic acid bacteria and evaluation of protease-stable bacteriocins
2016
Ishikawa, J. ((Miyagi University, Sendai, Miyagi (Japan). Graduate School of Food, Agricultural and Environmental Sciences), (Industrial Technology Institute, Miyagi Prefectural Government, Sendai, Miyagi (Japan))) | Kinoshita, H. | Komoda, T. | Suda, Y. | Ishida, M.
Recently, improper use of antibiotics in human and animals is to a large degree involved in the emergence of multidrug resistance bacteria. Lactic acid bacteria (LAB) are known as useful microorganisms, and the bacteriocins produced by LAB kill closely related bacteria. In this study, we examined whether bacteriocins can suppress drug resistance bacteria, and the selected bacteriocins were characterized. The 27 strains were selected from the 908 of LAB strains by antibacterial assay against Lactobacillus delbrueckii subsp. bulgaricus JCM1002sup(T) and Bacillus sp. C107. Total 11 strains of drug resistance bacteria were isolated from foods and porcine feces. The culture supernatants from the selected LAB showed antibacterial activities against drug resistance bacteria. The antibacterial activities of the culture supernatants from the selected LAB were tested against JCM1002sup(T) after pH adjustment at 6.2, protease treatment at 37degC for 18 h, and heat treatment at 121degC for 15 min, and a heat-map dendrogram was constructed. Their antimicrobial activities were grouped according to their pH-dependency and heatresistance. Especially, the culture supernatant of Lactococcus lactis MBR916 showed high protease stability. The antimicrobial spectrum suggests that MBR916 produces a nisin-like bacteriocin. The molecular weight of MBR916 bacteriocin, however, was estimated to be about 4200 by SDS-PAGE and in situ antibacterial assay that was different from that of nisin A. Moreover, protease stability of bacteriocin was higher than nisin A. These suggest that the bacteriocin of MBR916 may be novel.
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