Bioinformatic Analysis of virulence regulator PrfA and Antimicrobial Resistance of Listeria monocytogenes isolated from artisan cheeses in Cundinamarca Angélica Garzón Boada 1 , Cristian Baquero Duarte 2 , Juan David Sánchez Calderón 3 , Nathalie López 4 , Maria Mercedes Zambrano 5* y María Consuelo Vanegas López 6* . 1,2,3, Laboratorio de Ecología Microbiana y de Alimentos – LEMA, Departamento de Ciencias Biológicas, Universidad de los Andes. Bogotá, Colombia. Teléfono: 3394949 Ext. 3339. Dirección: Carrera 1 No. 18A – 10 Oficina A 216. 4, Estudiante de Microbiología, Universidad de los Andes. Bogotá, Colombia. . 5, Directora Científica Corpogen. Bogotá, Colombia. Correo electrónico: Teléfono: 8050106. Dirección: Carrera 5 No. 66A – 34. 6 Directora Laboratorio de Ecología Microbiana y de Alimentos – LEMA mzambran@uniandes.edu.co. mvanegas@uniandes.edu.co. ABSTRACT Several studies have demonstrated the presence of L. monocytogenes in non industrialized cheeses in Colombia. In Cundinamarca one of the main products is artisan cheese, which is highly consumed by tourist and native population. Previously, molecular serotyping was consider as a determinant test to establish L. monocytogenes virulence, however today it is consider that this test is not sufficient and efforts have been made in the characterization, molecular study and function of PrfA regulator in the expression of the virulence of this microorganism.The aim of this study was to find the frequency of Listeria monocytogenes in artisan cheeses from the main producer area in Cundinamarca, carry out a bioinformatic analysis of PrfA regulator and determine the antimicrobial resistance of circulant strains. From 50 samples, 33 presuntive strains of L. monocytogenes were isolated; 14 (42.3%) of them were identified as L. monocytogenes by PCR. prfA regulator sequencing was performed to the 14 strains. Multiple alignment by t-coffee found a great identity (>80%) between the nucleotide and amino acid sequences isolated in this study and Listeria monocytogenes serotype 4b str. F2365 reported as virulent in NCBI. All strains were resistant to more than 2 antibiotics and two strains showed resistance to more than 8, including streptomycin and penicillin, which are some of the first choice antibiotics in Colombia to treat L. monocytogenes infections. The results of this study evidence that in Colombia are circulating multiresistant strains of Listeria monocytogenes in food, which may be important in epidemiology and become a vehicle of transmission of resistance genes to other pathogenic and nonpathogenic bacteria, also causing problems in clinical treatment. This is the first report of the prfA 9RO  1R   5HYLVWD $OLPHQWRV +R\  