ANTIBIOFILM EFFICACY OF BACTERIOCINS AGAINST THE EMERGENT PATHOGEN Listeria monocytogenes

CONSTANZA MELIAN; EMILSE V. BENTENCOURT; LUCÍA M. MENDOZA; PATRICIA CASTELLANO; GRACIELA VIGNOLO

San Miguel de Tucumán

Congreso; XII CONGRESO ARGENTINO DE MICROBIOLOGIA GENERAL; 2017

Listeria monocytogenes is a foodbornepathogen able to survive in a wide range of environments even at refrigeratedconditions. Moreover, some strains of L.monocytogenes can form biofilm facilitating their persistence in the foodprocessing environments. Recently, major advances have been made in theprevention and control of pathogens biofilm by lactic acid bacteria (LAB) ortheir bacteriocins. The aim of this work was to investigate the ability ofbacteriocins produced by Lactobacilluscurvatus CRL705 and L. curvatusCRL1532 to compete with L. monocytogenesFBUNT during biofilm formation on polystyrene microplate. Biofilm formation ofListeria strains (L. monocytogenesFBUNT, CECT 4031T, Scott A) with and without bacteriocins usingcrystal violet method after 6 days of incubation at 10 °C was determined. Thestrain L. monocytogenes FBUNT wasselected due to its high biofilm-forming capacity in the control samples. Both bacteriocinsinhibited biofilm development of pathogen microorganism being the bacteriocinproduced by L. curvatus CRL705 the mosteffective. In addition, the presence and expression of genes related to L. monocytogenes biofilm formation werestudied by PCR and real time-PCR, respectively. L. monocytogenes FBUNT showed to harbor luxS and pfs genes encodingenzymes that catalyze S-ribosyl homocysteine and genes of agrBDCA system. During sessile growth, the expression levels of agrB and luxS genes were 2-fold higher than under planktonic growth. Inpresence of both bacteriocins a higher expression of agrD gene was observed. Expression levels of agrB and luxS genes decreasedat higher concentrations of bacteriocins assayed which could indicate that bacteriocinaddition affected expression of key genes involved in biofilm formation. Theseresults evidence the potential use of the bacteriocins produced by L. curvatus CRL705 and CRL1532 asinhibitors of L. monocytogenes biofilmformation in refrigerating conditions.