Efeito da co-cultura de Lactococcus lactis subsp. lactis (R7) em Listeria monocytogenes

Abstract

Listeria monocytogenesis a pathogenic microorganism which causes a disease called listeriosis that occurs with thein gestion of contaminated food. For the control of contamination by this microorganism there is evidence that growth in co-culture with lactic acid bacteriamay affect its growth. The mechanism by which this phenomeno noccursis the quorum sensing, a signaling process between the bacterial cells which allows collective control of gene expression tooccur, being carried out by production, secretion and detection of auto inducers. Thus, the present study aims to investigate the inhibitory action of L. Lactissubsp. lactis (R7) from L. monocytogenes ATCC 7644 and from isolate L. monocytogenes L9 by means of the quorum sensing process. For this, the study evaluated the multiplication in mono-culture and co-culture, transcription of the luxS gene and investigation of the effect of L. monocytogenes mediated by the luxS gene by quorum sensing in L. lactis subsp. lactis (R7). With that, it was possibleto observe the reduction of the multiplication curve of the two strains of L.monocytogenes when in co-culture with L. Lactis R7 and also the pH changes coinciding with the reduction of the curves of both L.monocytogenes, which suggests the use some mechanism of inhibition of L. lactis R7 in the multiplication of the pathogen.