Introduction: Methicillin-resistant Staphylococcus aureus is a frequent pathogen at critical care services. Its presence leads to increased hospital stays and mortality risk in patients with bacteremia. However, the etiology of this resistance marker has not been fully studied. Objective: To identify risk factors associated with the emergence of methicillin-resistant S. aureus bacteremia in critically ill patients treated at intensive care units in BogotĂĄ, Colombia.
Materials and methods:We conducted a retrospective paired case-control study, nested in a cohort of patients diagnosed with S. aureus bacteremia and treated at intensive care units between 2006 and 2008 in BogotĂĄ. Cases were patients with positive blood culture to methicillin resistance, matched in a 1:1 ratio with methicillin-sensitive controls isolated from the same institution and hospitalization year. We used conditional logistic regression to analyze the risk factors associated with the presence of resistance, with emphasis on prior antibiotic therapy. Results: We included 372 patients with S. aureus bacteremia. Factors such as the use of pre-hospital devices: vascular (OR=1.986, 95% CI 1.038 to 3.801) and urinary (OR=2.559, 95% CI: 1.170 to 5.596), along with the number of previously used antibiotics, were associated with the emergence of resistance. The number of antibiotics used previously was determined to have a gradient effect, particularly carbapenems.
Conclusions:The rational use of antibiotics and surveillance of exposure to surgical procedures or use of invasive devices are interventions that could diminish the emergence of methicillin-resistant S. aureus bacteremia causes. IntroducciĂłn. Staphylococcus aureus resistente a la meticilina es uno de los agentes patĂłgenos mĂĄs frecuentes en las unidades de cuidados intensivos. Su presencia prolonga las hospitalizaciones y aumenta el riesgo de mortalidad en los pacientes con bacteriemia. Sin embargo, la etiologĂa de este marcador de resistencia no ha sido completamente estudiada. Objetivo. Determinar los factores asociados con la apariciĂłn de S. aureus resistente a la meticilina causante de bacteriemia en pacientes atendidos en unidades de cuidados intensivos en BogotĂĄ. Materiales y mĂŠtodos. Se hizo un estudio retrospectivo de casos y controles emparejados, anidado en una cohorte de pacientes con diagnĂłstico de bacteriemia por S. aureus atendidos en unidades de cuidados intensivos de BogotĂĄ entre 2006 y 2008. Los casos fueron pacientes con hemocultivo positivo para resistencia a la meticilina, emparejados 1 a 1 con controles con hemocultivos sensibles 613 Conclusiones. El uso racional de antibiĂłticos y la vigilancia de la exposiciĂłn a procedimientos quirĂşrgicos o al uso de dispositivos invasivos, son intervenciones que podrĂan disminuir la apariciĂłn de S. aureus resistente a meticilina causante de bacteriemia.Palabras clave: Staphylococcus aureus resistente a meticilina; factores de riesgo; farmacorresistencia microbiana; unidades de cuidados intensivos; estudios de casos y controles.