Microbiologist and Clinical Chemist since 1988, Associate Professor of the School of Microbiology of the University of Costa Rica (UCR) since 1987, and is also Professor 2of the School of Biological Sciences in the Baccalaureate in biology, concentration in Biotechnology, National University. He is the author of educational brochures for the degree course in microbiology Biosafety in medical bacteriology (2002), Quality assurance in medical bacteriology (2005) and Diagnostic bacteriology (2012). He is the author and co-author of more than twenty-four publications in national and international journals. The most recent are: Rodríguez S, Ramírez T, Montero M, Chavarría D, Valle G, Rojas N. 2016. Antibacterial Efficacy of a Dispersion of Silver Nanoparticles in Citrate Medium for the Treatment of E. faecalis: an In Vitro Study. Odovtos-Int. J. Dent. Sc. 18:99-107. Suárez-Esquivel, M., Ruiz-Villalobos, N., Jiménez-Rojas, C., Barquero-Calvo, E., Chacón-Díaz, C., Víquez-Ruiz, E., Rojas-Campos N, Baker KS, Oviedo-Sánchez G, Amuy E, Chaves-Olarte E, Thomson NR, Moreno E, Guzmán-Verri, C. 2017. Brucella neotomae Infection in Humans, Costa Rica. Emerging Infectious Diseases, 23, 997–1000. Artavia-León A, Romero-Guerrero A, Sancho-Blanco C, Rojas N, Umaña-Castro R. 2017. Diversity of Aerobic Bacteria Isolated from Oral and Cloacal Cavities from Free-Living Snakes Species in Costa Rica Rainforest. Int Sch Res Notices. 20; 8934285. Rojas I, Barquero-Calvo E, van Balen JC, Rojas N, Muñoz-Vargas L, Hoet AE. 2017. High Prevalence of Multidrug-Resistant Community-Acquired Methicillin-Resistant Staphylococcus aureus at the Largest Veterinary Teaching Hospital in Costa Rica. Vector Borne Zoonotic Dis. Sep;17(9):645-653. Hernández-Mora G, Ruiz-Villalobos N, Bonilla-Montoya R, Romero-Zúñiga JJ, Jiménez-Arias J, González-Barrientos R, Barquero-Calvo E, Chacón-Díaz C, Rojas N, Chaves-Olarte E, Guzmán-Verri C, Moreno E. 2017 Epidemiology of bovine brucellosis in Costa Rica: Lessons learned from failures in the control of the disease. PLoS One. Aug 10;12(8):e0182380. Villalobos-Vindas JM, Amuy E, Barquero-Calvo E, Rojas N, Chacón-Díaz C, Chaves-Olarte E, Guzman-Verri C, Moreno E. 2017. Brucellosis caused by the wood rat pathogen Brucella neotomae: two case reports. J Med Case Rep. 19;11: 1496-8