1309 A R T Í C U L O D E I N V E S T I G A C I Ó N Rev Méd Chile 2009; 137: 1309-1314 Resistencia a metronidazol y claritromicina en aislamientos de Helicobacter pylori de pacientes dispépticos en Colombia Adalucy Álvarez 1a , José Ignacio Moncayo 1b , Jorge Javier Santacruz 1b , Luisa Fernanda Corredor 1c , Elizabeth Reinosa 1d , José W illiam M artínez 2 , Leonardo Beltrán 3e . Antimicrobial susceptibility of Helicobacter pylori strains isolated in Colombia Background: Helicobacter pylori antimicrobial resistance rates differ among countries and even between different areas of a country. In Colombia, the most commonly used antimicrobials for the treatment of H pylori infection are amoxicillin, clarithromycin and metronidazole. Aim: To determine antimicrobial susceptibility of H pylori strains isolated in Colombia. Materials and methods: Eighty eight strains of H pylori were isolated and identified by microbiological methods and confirmed with polymerase chain reaction (PCR). The detection of antimicrobial resistance to amoxicillin, clarithromycin, metronidazole and tetraclycline, was conducted by the Etest method. Mutations in the 23S rDNA, involved in resistance to clarithromycin, were detected using PCR and restriction fragment lenght polymorphism. Results: Eighty eight and 2.2% of the strains were resistant to metronidazole and clarithromycin, respectively. No isolate was simultaneously resistant to amoxicillin or tetracycline. The two clarithromycin resistant strains were homozygous for the A2143G mutation. No mutations were found in the remaining 86 susceptible strains. Conclusions: The high rate of metronidazole resistance in our population precludes the use of this drug for the empirical treatment of H pylori infection (Rev Méd Chile 2009; 137: 1309-14). ( Key words: Antibacterial agents; Helicobacter pylori; Metronidazole) Recibido el 29 de enero, 2009. Aceptado el 8 de septiembre, 2009. Trabajo financiado por la Vicerrectoría de Investigaciones, Innovación y Extensión de la Universidad Tecnológica de Pereira, Colombia. 1 Laboratorio de Microbiología y Parasitología, Centro de Biología Molecular y Biotecnología, De- partamento de Ciencias Básicas, Facultad de Ciencias de la Salud, Universidad Tecnológica de Pereira, Pereira, Colombia. 2 Departamento de Medicina Comunitaria y 3 Laboratorio de Genética Médica, Facultad de Ciencias de la Salud, Universidad Tecnológica de Pereira, Pereira, Colombia. a Bacterióloga, MSc en Biología Molecular y Biotecnología b Licenciado en Biología, MSc en Microbiología c Licenciada en Biología y Química, MSc en Biología Molecular y Biotecnología d Estudiante X semestre de Medicina e Químico Industrial Correspondencia a: Adalucy Álvarez Aldana. Universidad Tec- nológica de Pereira, Facultad de Medicina, Laboratorio de Microbiología y Parasitología. Vereda La Julita. Pereira, Colom- bia. E mail: adalucy@yahoo.es /adalucyalvarez@utp.edu.co