Partial characterization of bacteriocins produced by human Lactococcus lactis and Pediococccus acidilactici isolates.
OBJECTIVE
The aim of this study was to isolate bacteriocin-producing lactic acid bacteria (LAB) from human intestine.


RESULTS
A total of 111 LAB were isolated from human adult stool and screened for their bacteriocin production. Neutralized cell-free supernatants from Lactococcus lactis subsp. lactis MM19 and Pediococcus acidilactici MM33 showed antimicrobial activity. The antimicrobials in the supernatant from a culture of L. lactis inhibited Enterococcus faecium, various species of Lactobacillus and Staphylococcus aureus; while those in the supernatant from a culture of P. acidilactici inhibited Enterococcus spp., some lactobacilli and various serotypes of Listeria monocytogenes. The antimicrobial metabolites were heat-stable and were active over a pH range of 2-10. The antimicrobial activities of the supernatants of both bacteria were inhibited by many proteases but not by catalase. The plate overlay assay allowed an approximation of size between 3.5 and 6 kDa for both antimicrobial substances.


CONCLUSIONS
As the antagonistic factor(s) produced by L. lactis MM19 and P. acidilactici MM33 were sensitive to proteolytic enzymes, it could be hypothesized that bacteriocins were involved in the inhibitory activities. Inhibition spectrum and biochemical analysis showed that these bacteria produced two distinct bacteriocins.


CONCLUSIONS
We are the first to isolate bacteriocin-producing strains of Pediococcus and Lactococcus from human intestine. These strains might be useful for control of enteric pathogens.
Millette
M
M
INRS-Institut Armand-Frappier, Research Laboratories in Sciences Applied to Food, Canadian Irradiation Centre, 531, Boulevard des Prairies, Laval, Québec, Canada, H7V 1B7.
Dupont
C
C
Archambault
D
D
Lacroix
M
M
D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000032:analysis; D001430:Bacteriocins / Q000378:metabolism / Q000494:pharmacology*; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D016983:Enterococcus / Q000187:drug effects; D005243:Feces / Q000382:microbiology; D005720:Gamma Rays; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007422:Intestines / Q000382:microbiology; D007778:Lactobacillus / Q000187:drug effects; D013294:Lactococcus lactis / Q000302:isolation & purification / Q000378:metabolism* / Q000528:radiation effects; D008089:Listeria monocytogenes / Q000187:drug effects; D010376:Pediococcus / Q000302:isolation & purification / Q000378:metabolism* / Q000528:radiation effects; D013211:Staphylococcus aureus / Q000187:drug effects; D013997:Time Factors
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001430:Bacteriocins; D003470:Culture Media