[Clinical significance of Staphylococcus aureus in urine]. / Significado clínico del aislamiento de Staphylococcus aureus en muestras de orina.

INTRODUCTION: To evaluate the clinical significance of the isolation of Staphylococcus aureus in urine samples. METHODS: A retrospective study was performed on adult patients identified from a microbiology database in a 200-bed general hospital between the years 2000 and 2009. The demographic data, comorbidities, and risk factors, were reviewed, particularly those associated with the concomitant isolation of S.aureus in blood cultures. RESULTS: The frequency of S.aureus found in urine samples was 0.63%. A total of 43 patients (mean age 68.7 years [SD±16], and 58.1% males) were identified in the database. A Charlson comorbidity index >3 was observed in 20.9%. Concurrent bacteremia was seen in 48.8%. Two groups of patients were distinguished: with concomitant bacteremia (n=21) or without (n=22). Intervention in the urinary tract significantly predicted (P=.00004) bacteriuria without bacteremia (81.8%), compared to bacteremia cases (19%). The attributable mortality was 47.6% in patients with bacteremia compared to non-bacteremia (no deaths), even though the appropriate antibiotic treatment was more frequent among patients with bacteremia (92% and 60%, respectively). CONCLUSION: The presence of S.aureus in urine was accompanied by bacteremia in half of the cases, but in patients without previous urinary tract intervention such a possibility increased to 81%. Concomitant bacteremia predicts a worse prognosis even with appropriate treatment.

Significado clínico del aislamiento de Staphylococcus aureus en muestras de orina / Clinical significance of Staphylococcus aureus in urine

Introducción Evaluación del significado clínico del aislamiento de Staphylococcus aureus en muestras de orina. Métodos Se realizó un estudio retrospectivo en pacientes adultos identificados, entre los años 2000 y 2009, de la base de datos de microbiología en un hospital general de 200 camas. Se revisaron variables demográficas, comorbilidad y factores de riesgo, especialmente los vinculados con el aislamiento concomitante de S. aureus en sangre. Resultados La frecuencia de S. aureus en muestras de orina positivas fue del 0,63%. Cuarenta y tres pacientes fueron identificados, con una edad promedio de 68,7 años (DE ± 16), de los cuales el 58,1% fueron varones. Un índice de comorbilidad de Charlson > 3 se observó en el 20,9%. La presencia de bacteriemia simultánea se observó en el 48,8%. Se distinguieron 2 grupos de pacientes según tuvieran bacteriemia concomitante (n = 21) o no (n = 22). La instrumentación de la vía urinaria predijo significativamente (p = 0,00004) la bacteriuria sin bacteriemia (81,8%) comparada con casos bacteriémicos (19%). La mortalidad atribuible fue del 47,6% en los casos con bacteriemia comparada con los no bacteriémicos (sin muertes), aun cuando el tratamiento antibiótico adecuado fue más frecuente entre los pacientes con bacteriemia (92 y 60%, respectivamente). Conclusiones La presencia de S. aureus en orina se acompaña de bacteriemia en la mitad de los casos, y la ausencia de instrumentación previa aumenta esa posibilidad al 81%. La bacteriemia concomitante alerta sobre un peor pronóstico aun con tratamiento adecuado(AU)

Introduction To evaluate the clinical significance of the isolation of Staphylococcus aureus in urine samples. Methods A retrospective study was performed on adult patients identified from a microbiology database in a 200-bed general hospital between the years 2000 and 2009. The demographic data, comorbidities, and risk factors, were reviewed, particularly those associated with the concomitant isolation of S. aureus in blood cultures. Results The frequency of S. aureus found in urine samples was 0.63%. A total of 43 patients (mean age 68.7 years [SD ± 16], and 58.1% males) were identified in the database. A Charlson comorbidity index > 3 was observed in 20.9%. Concurrent bacteremia was seen in 48.8%. Two groups of patients were distinguished: with concomitant bacteremia (n = 21) or without (n = 22). Intervention in the urinary tract significantly predicted (P = .00004) bacteriuria without bacteremia (81.8%), compared to bacteremia cases (19%). The attributable mortality was 47.6% in patients with bacteremia compared to non-bacteremia (no deaths), even though the appropriate antibiotic treatment was more frequent among patients with bacteremia (92% and 60%, respectively). Conclusion The presence of S. aureus in urine was accompanied by bacteremia in half of the cases, but in patients without previous urinary tract intervention such a possibility increased to 81%. Concomitant bacteremia predicts a worse prognosis even with appropriate treatment(AU)