RESUMEN Introduccion . Los estudios de Staphylococcus aureus en personal de salud permiten reducir su diseminacion en las infecciones intrahospitalarias y mejorar la calidad de vida de los pacientes. La colonizacion por S. aureus en personal de salud de un hospital de tercer nivel, se evaluo caracterizandolo fenotipica y molecularmente. Metodos: Una poblacion de 62 trabajadores y 216 estudiantes de medicina, mediante analisis del antibiograma y polimorfismo del gen agr . Resultados: S. aureus colonizo el 30,1% del personal; 17,5% trabajadores, 33,8% estudiantes. El 10,8% fueron meticilino-resistentes, 9 aislados presentaron el gen mecA , ocho resistentes a oxacilina y cefoxitina (88,9% de sensibilidad). La variante II considerada de origen hospitalario, se presento en el 7,7% de aislados, el agr tipo III de origen comunitario en el 27,6% de aislados meticilino-sensibles. Conclusion. El personal hospitalario presento colonizacion por S. aureus de origen hospitalario y comunitario. Es necesario adoptar medidas profilacticas e higienicas para evitar diseminacion y prevenir infecciones. Palabras Clave . Staphylococcus aureus , antibioticos, portadores asintomaticos, personal de salud, SARM. ABSTRACT CHARACTERIZATION OF STAPHYLOCOCCUS AUREUS PRESENT IN HEALTH PERSONNEL OF A MID-COMPLEXITY HOSPITAL OF THE CITY OF CALI, 2012 Introduction . Studies of Staphylococcus aureus in health personnel reduce its spread in nosocomial infections and improve the quality of life of patients. The colonization state by S. aureus in health personnel of a tertiary hospital was performed by phenotypic and molecular characterization. Methods : A population of 62 health workers and 216 medical students were evaluated by analysis of antibiotic susceptibility and polymorphism of agr gene. Results : S. aureus colonized 30.1% of staff individuals, 17.5% of workers, 33.8 % of students. 10.8% were methicillin- resistant, 9 isolated harbored mec A gene, and eight were resistant to oxacillin and cefoxitin (88.9 % sensitivity). The agr II associated with hospital source was in 7.7 % of the isolates and agr type III -associated with a community source- was found in 27.6 % of meticillin-sensitive isolates. Conclusion. Hospital health staff showed colonization by S. aureus of both community and hospital sources. To prevent their spread and infections, prophylactic and hygienic measures are necessary. Keywords. Staphylococcus aureus , Antibiotics, Asymptomatic carriers, health personnel, MRSA.