Risk factors for mortality caused by Staphylococcus aureus bacteremia in cancer patients

Introduction Staphylococcus aureus is the cause of 11–33% of nosocomial bloodstream infections and has a complication rate close to 50%. S. aureus accounts for 31% of isolates in the Instituto Nacional de Cancerología (INC), in Bogotá, Colombia, and is the main etiological agent of bacteremia. This study describes the risk factors for mortality caused by S. aureus bacteremia in cancer patients. Methods This is a retrospective, analytical, observational cohort study of 267 cases of bacteremia caused by S. aureus. Data from all bacteremic patients with proven cancer were extracted, and variables were introduced in a multivariate analysis using a Cox proportional hazards model. Results A total of 354 bacteremic patients were identified between 2001 and 2005, and 267 patients met the specified inclusion and exclusion criteria. Among these, death was considered secondary to S. aureus infection in 31%. Independent predictors of mortality related to S. aureus bacteremia in the multivariate analysis were: severity of sepsis at onset of bacteremia (HR 6.5, 95% CI 3.1–13.6), age (HR 1.03, 95% CI 1.01–1.04), non-eradicable source of infection (HR 36.3, 95% CI 5.2–254.1), heart failure (HR 10.6; 95% CI 1.8–63.7), and primary bacteremia (HR 6.3, 95% CI 1.3–31.0).Conclusion Severity of sepsis at the time bacteremia was detected, a non-eradicable source of infection (including primary bacteremia), and comorbid conditions were risk factors for mortality caused by S. aureus bacteremia in cancer patients. These risk factors do not differ considerably from those of patients who do not have cancer (AU)

Introducción Staphylococcus aureus es responsible por el 11 al 33% de las bacteriemias nosocomiales y tiene una tasa de complicaciones cercana al 50%; S. aureus es responsible de 31% de los aislamientos en el Instituto Nacional de Cancerología (INC) en Bogotá, Colombia, y es el agente etiológico más importante de las bacteriemias. Este estudio tenía como objetivo describir los factores de riesgo de mortalidad ocasionada por la bacteriemia por S. aureus en pacientes con cáncer. Métodos Este es un estudio de cohorte retrospectiva, analítico, observacion de 267 casos de bacteriemia ocasionada por S. aureus. Los datos clínicos de los pacientes con cáncer fueron obtenidos y las variables introducidas en un análisis multivariado utilizando un modelo de riesgos proporcionales de Cox.Resultados354 pacientes bacteriemicos fueron detectados entre 2001 y 2005; 267 pacientes cumplieron con los criterios de inclusión y no fueron excluidos. 31% de los pacientes tuvieron como desenlace mortalidad secundaria a la infección por S. aureus. Los factores de riesgo de mortalidad independientes en el análisis multivariado fueron: estado de sepsis al inicio de la bacteriemia (razón de riesgos RR 6.5), edad (RR 1.03), fuente no erradicable de infección (RR 36.3), falla cardíaca (RR 10.6) y bacteriemia primaria (RR 6.3). Conclusión Los factores de riesgo para mortalidad ocasionada por bacteriemia por S. aureus fueron el estado de la sepsis al momento de la detección de la bacteriemia, una fuente no erradicable de infección (incluyendo bacteriemia primaria) y las patologías comórbidas. Estos factores de riesgo no varían considerablemente con respecto a pacientes sin cáncer (AU)

Risk factors for mortality caused by Staphylococcus aureus bacteremia in cancer patients.

INTRODUCTION: Staphylococcus aureus is the cause of 11-33% of nosocomial bloodstream infections and has a complication rate close to 50%. S. aureus accounts for 31% of isolates in the Instituto Nacional de Cancerología (INC), in Bogotá, Colombia, and is the main etiological agent of bacteremia. This study describes the risk factors for mortality caused by S. aureus bacteremia in cancer patients. METHODS: This is a retrospective, analytical, observational cohort study of 267 cases of bacteremia caused by S. aureus. Data from all bacteremic patients with proven cancer were extracted, and variables were introduced in a multivariate analysis using a Cox proportional hazards model. RESULTS: A total of 354 bacteremic patients were identified between 2001 and 2005, and 267 patients met the specified inclusion and exclusion criteria. Among these, death was considered secondary to S. aureus infection in 31%. Independent predictors of mortality related to S. aureus bacteremia in the multivariate analysis were: severity of sepsis at onset of bacteremia (HR 6.5, 95% CI 3.1-13.6), age (HR 1.03, 95% CI 1.01-1.04), non-eradicable source of infection (HR 36.3, 95% CI 5.2-254.1), heart failure (HR 10.6; 95% CI 1.8-63.7), and primary bacteremia (HR 6.3, 95% CI 1.3-31.0). CONCLUSION: Severity of sepsis at the time bacteremia was detected, a non-eradicable source of infection (including primary bacteremia), and comorbid conditions were risk factors for mortality caused by S. aureus bacteremia in cancer patients. These risk factors do not differ considerably from those of patients who do not have cancer.

[Therapeutic approach to Staphylococcus aureus bacteremia]. / Enfoque terapéutico de la bacteriemia por Staphylococcus aureus.

Staphylococcus aureus is an important human pathogen, responsible for 11-33% of the bacteremias acquired in the hospital setting and nearly 50% of those acquired in the community at large. The epidemiology of S. aureus bacteremia is discussed, with an special emphasis on the situation in Colombia and the resistance mechanisms against the major drug groups used for the treatment. The clinical keys and laboratory support for the appropriate clinical approaches are presented together with the therapeutic strategies for the treatment of patients with S. aureus bacteremia.

Enfoque terapéutico de la bacteriemia por Staphylococcus aureus / Therapeutic approach to Staphylococcus aureus bacteremia

Staphylococcus aureus es un patógeno importante que causa cerca de 11 por ciento a 33 por ciento de las bacteriemias hospitalarias y un porcentaje importante de las adquiridas en la comunidad, con una tasa de complicaciones cercana a 50 por ciento. En la siguiente revisión se destaca la epidemiología de la bacteriemia por S. aureus, con especial referencia a la situación de este patógeno en Colombia, la frecuencia y los mecanismos de resistencia a los medicamentos más frecuentemente usados en este contexto, y se discuten los elementos semiológicos, clínicos y de laboratorio que influyen en el enfoque diagnóstico y terapéutico de los pacientes con bacteriemia por este microorganismo.

Staphylococcus aureus is an important human pathogen, responsible for 11-33% of the bacteremias acquired in the hospital setting and nearly 50% of those acquired in the community at large. The epidemiology of S. aureus bacteremia is discussed, with an special emphasis on the situation in Colombia and the resistance mechanisms against the major drug groups used for the treatment. The clinical keys and laboratory support for the appropriate clinical approaches are presented together with the therapeutic strategies for the treatment of patients with S. aureus bacteremia.