Purification and identification of the pediocin produced by Pediococcus acidilactici MM33, a new human intestinal strain.
OBJECTIVE
The aim of this study was to purify and identify the bacteriocin produced by Pediococcus acidilactici MM33, a strain previously isolated from human gut.


RESULTS
Purification of the bacteriocin was performed by cationic exchange chromatography followed by a reverse phase step. Biochemical and mass spectrometry analysis showed homology with pediocin PA-1. To verify if P. acidilactici MM33 carried the pediocin PA-1 gene, total DNA was used to amplify the pediocin gene. The PCR product obtained was then sequenced and the nucleotide sequence revealed to be identical to that of pediocin PA-1. Treatment of P. acidilactici MM33 with novobiocin resulted in a plasmid-cured strain without bacteriocin-producing capacity. Antimicrobial assay and molecular analysis demonstrated that this strain was ped(-) suggesting that the ped cluster is plasmid encoded. Antimicrobial assay revealed that pediocin was bactericidal against Listeria monocytogenes, showing a minimal inhibitory concentration (MIC) of 200 AU ml(-1).


CONCLUSIONS
A two-step purification procedure was elaborated in this study. The bacteriocin secreted by the human strain P. acidilactici MM33 is carried on a plasmid and the amino acid sequence is identical to pediocin PA-1.


CONCLUSIONS
Pediococcus acidilactici MM33 is the first human pediocin-producing strain reported and could be used as probiotic to prevent enteric pathogen colonization.
Millette
M
M
INRS-Institut Armand-Frappier, Research Laboratories in Sciences Applied to Food, Canadian Irradiation Centre, Laval, QC, Canada.
Dupont
C
C
Shareck
F
F
Ruiz
M T
MT
Archambault
D
D
Lacroix
M
M
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000302:isolation & purification*; D000898:Antibiosis; D001430:Bacteriocins / Q000235:genetics*; D001483:Base Sequence; D002852:Chromatography, Ion Exchange; D052978:Disk Diffusion Antimicrobial Tests; D006801:Humans; D007422:Intestines / Q000382:microbiology*; D008089:Listeria monocytogenes / Q000502:physiology; D008969:Molecular Sequence Data; D000070017:Pediocins; D010376:Pediococcus / Q000378:metabolism*; D010957:Plasmids; D016133:Polymerase Chain Reaction / Q000379:methods
D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D000070017:Pediocins; C074288:pediocin PA-1