Epidemiology of bloodstream infections at a Cancer Center

CONTEXT: Cancer patients are at unusually high risk for developing bloodstream infections (BSI), which are a major cause of in-hospital morbidity and mortality. OBJECTIVE: To describe the epidemiological characteristics and the etiology of BSI in cancer patients. DESIGN: Descriptive study. SETTING: Terciary Oncology Care Center. PARTICIPANTS: During a 24-month period all hospitalized patients with clinically significant BSI were evaluated in relation to several clinical and demographic factors. RESULTS: The study enrolled 435 episodes of BSI (349 patients). The majority of the episodes occurred among non-neutropenic patients (58.6 percent) and in those younger than 40 years (58.2 percent). There was a higher occurrence of unimicrobial infections (74.9 percent), nosocomial episodes (68.3 percent) and of those of undetermined origin (52.8 percent). Central venous catheters (CVC) were present in 63.2 percent of the episodes. Overall, the commonest isolates from blood in patients with hematology diseases and solid tumors were staphylococci (32 percent and 34.7 percent, respectively). There were 70 episodes of fungemia with a predominance of Candida albicans organisms (50.6 percent). Fungi were identified in 52.5 percent of persistent BSI and in 91.4 percent of patients with CVC. Gram-negative bacilli prompted the CVC removal in 45.5 percent of the episodes. Oxacillin resistance was detected in 26.3 percent of Staphylococcus aureus isolates and in 61.8 percent of coagulase-negative Staphylococcus. Vancomycin-resistant enterococci were not observed. Initial empirical antimicrobial therapy was considered appropriate in 60.5 percent of the cases. CONCLUSION: The identification of the microbiology profile of BSI and the recognition of possible risk factors in high-risk cancer patients may help in planning and conducting more effective infection control and preventive measures, and may also allow further analytical studies for reducing severe infectious complications in such groups of patients

Estudio comparativo de dos sistemas de hemocultivos en micosis sistemicas asociadas al S.I.D.A. / Comparative study between two hemoculture systems in systematic mycosis related to AIDS

Se realizo un estudio comparativo de dos metodos de hemocultivos para hongos en pacientes VIH positivos que presentaban fiebre prolongada o una micosis sistemica confirmada. La tecnica convencional consistio en sembrar 5-10 ml de sangre venosa en frascos con caldo tripteina-soya y polianetol sulfonato de sodio como anticoagulante. A los 7 y 14 dias de incubacion a 37 grados C se realizaron repiques en medios de agar-miel de Sabouraud y agar-infusion de cerebro y corazon. El metodo de centrifugacion-lisis se llevo a cabo con 5 a 10 ml de sangre venosa heparinizada, se separo el plasma por centrifugacion, el sedimento fue tratado con una solucion de saponina al 0,5 por ciento despues de obtenida la lisis, la muestra fue nuevamente centrifugada y el material restante se sembro en agar-miel de Sabouraud y agar-infusion de cerebro y corazon, la incubacion se realizo a 28 y 37 grados C. Fueron estudiadas 288 muestras, que se procesaron simultaneamente por los dos sistemas. La tecnica convencional permitio el aislamiento de Cryptococcus neoformans en el 7,9 por ciento de los materiales, en tanto que el Histoplasma capsulatum, fue aislado en el 1 por ciento . El sistema de centrifugacion-lisis recupero el C. neoformans en el 7,3 por ciento de los hemocultivos y el H. capsulatum en el 3,8 por ciento . El lapso medio para el aislamiento e identificacion de ambos hongos fue 7 dias mas corto con el metodo de centrifugacion-lisis. Esta ultima tecnica resulto ser mas simple, mas rapida y mas sensible que el procedimiento convencional. Se comprobaron funguemias en el 86,2 por ciento de los casos de criptococosis y en el 70,5 por ciento de las histoplasmosis asociadas al S.I.D.A.