Mario Calvo A

Utilidad clínica de los hemocultivos en pacientes hospitalizados por neumonía adquirida en la comunidad

Background: The clinical role of blood cultures (BC) in the management of hospitalized patients with community-acquired pneumonia (CAP) is controversial. Aim: To evaluate the clinical usefulness of blood cultures in CAP. Material and methods: We prospectively studied 244 immunocompetent adults with two or more BC obtained at admission. The diagnostic yield of BC and its impact on antibiotic therapy were assessed. Results: Mean age (x±sd) of patients was 67±20 years, 80% had underlying diseases and 29% received antibiotics prior to admission. Hospital length of stay was 10.4±10 days and global mortality was 7%. The diagnostic yield of BC was only 8.2% (20 patients). Mortality was significantly higher in patients with positive BC (20%) than in those with negative BC (5.8%). In only one of the 20 patients with positive BC (0.4% of total study population), attending physicians changed empiric antimicrobial therapy based on these results. Conclusions: This study confirms that the diagnostic yield of BC in CAP hospitalized patients is low, that mortality in bacteremic patients is high and suggests that clinical usefulness of BC to guide changes on empiric antimicrobial therapy is limited, in part because attending physicians seldom use such information (Rev Med Chile 2002; 130: 993-1000).

Etiología de la neumonía en pacientes chilenos infectados por el virus de la inmunodeficiencia humana

Objetivos: Establecer la etiologia de la neumonia y comparar el rendimiento de diferentes tecnicas para el diagnostico de las infecciones por Pneumocystis jiroveci y Mycobacterium tuberculosis en pacientes con infeccion por virus de inmunodeficiencia humana (VIH). Material y Metodos: De cada paciente se obtuvo esputo inducido y se efectuo LBA. A las muestras obtenidas se les realizo tinciones de Gram, Ziehl-Neelsen, plata e inmunofluores-cencia (IF) para P. jiroveci y M. tuberculosis; reaccion de polimerasa en cadena (RPC) para ambos microorganismos; cultivos aerobicos, fungicos, para micobacterias, virus respiratorios y citomegalovirus. Tambien se realizo determinacion de IgM de Mycoplasma pneumoniae y Chlamydophyla pneumoniae y antigeno urinario de Legionella pneumophila. Resultados: Se incluyeron 60 pacientes, lograndose diagnostico etiologico en 97% de los casos. Pneumocystis jiroveci fue la etiologia mas frecuente (58%), seguida por Streptococcus pneumoniae (12%) y Mycobacterium avium complex (MAC) (12%). Mycobacterium tuberculosis fue encontrado en 5%. Conclusiones: La comparacion de los metodos diagnosticos para P. jiroveci mostro una mayor sensibilidad de la IF y tincion de plata en LBA que en esputo; sin embargo, la RPC fue igualmente sensible en ambos tipos de muestras. Con esta estrategia se logro establecer etiologia en la gran mayoria de los pacientes. La etiologia mas comun fue P. jiroveci. IF en LBA sigue siendo el estandar para el diagnostico de la neumonia por P. jiroveci.

Estudio de la cinética de citoquinas en sepsis grave y su relación con mortalidad y score de disfunción orgánica

BACKGROUND The Infectious Systemic Inflammatory Response syndrome and multiple organic dysfunction have common physiopathological mechanisms. Multiple organic dysfunction can be assessed using severity scores. AIM To relate cytokine kinetics with a multiple organic dysfunction score during sepsis. MATERIAL AND METHODS Tumor necrosis factor alpha (TNF alpha) and interleukin 6 (IL6) kinetics were studied in 25 patients with severe sepsis with less than 48 h of evolution and interleukin 1 beta (IL beta) kinetics was studied in 13 patients. Measurements were made at 0, 12, 24 and 48 hours after admission to the study, using an ELISA technique. These parameters were correlated with the Marshall multiple organic dysfunction score and survival. RESULTS Mean age of study subjects was 70 years, the APACHE II score was 16.9 +/- 6 and the Marshall score was 6.8 +/- 3.6. Sepsis was of pulmonary origin in 56% of patients and intra abdominal in 32%. Mortality was 36%. TNF alpha increased during the study period (24.1 pg/ml initially and 37.8 pg/ml at 24 hours, with a slight posterior reduction, p < 0.02). These levels had no association with mortality or organic dysfunction. IL6 remained elevated during the first hours and had a tendency to decrease thereafter. Decreased patients had higher values than survivors (306 pg/ml and 55.4 pg/ml respectively, p = 0.011). Its values were tightly correlated with Marshall score, with the number of failing organs, with the presence of shock and with probability of dying during hospitalization. IL1 beta remained low and was not associated with clinical parameters. CONCLUSIONS There is a tight correlation between the elevation of IL6 and the severity of the Systemic Inflammatory Response and mortality in these patients with sepsis.

Inmunogenicidad de una vacuna recombinante anti hepatitis B en personal de salud

El virus de hepatitis B (HB) es capaz de persistir en un porcentaje de los infectados produciendo enfermedad hepatica cronica a largo plazo. El personal de salud es un grupo especialmente expuesto a contraer esta infeccion. Actualmente se dispone de vacunas anti HB inmunogenicas, eficaces y seguras. Aunque la mayoria de las personas responde en forma adecuada, un porcentaje bajo son no respondedores. Con el objeto de evaluar la respuesta inmune a una vacuna recombinante e identificar potenciales factores de riesgo de una respuesta inadecuada, se realizo un estudio prospectivo en funcionarios de la salud. A los 6 meses de recibir 3 dosis de vacuna contra HB (0-1-6 meses) se les midio titulo de anticuerpos contra antigeno de superficie de hepatitis B (anti HBs). Se estudiaron 485 sujetos con una relacion mujer: hombre de 2,6:1 y una edad promedio de 35,8 anos. De los 485, 409 (84,3%) funcionarios presentaron niveles mayores de 100 mUI/ml, 55 (11,3%) mostraron niveles entre 10 y 100 mUI/ml y 21 (4,3%) bajo 10 mUI/ml (4,3%). Un analisis multivariado de estos 3 grupos mostro que a mayor edad, los niveles de anti HBs eran menores (p 10 mUI/ml.)

Tratamiento de la neumonía asociada a ventilación mecánica

Ventilator-associated pneumonia is a life-threatening disease causing an increased morbidity, mortality, cost and length of stay in the intensive care unit. Inappropriate treatment is frequent and it is associated with worse prognosis. This document is an evidence based consensus which discusses treatment aspects of this complication. Empiric treatment should be based on local epidemiology and data collected through the national nosocomial infection surveillance and reliable microbiology. Antibiotic treatment on specific microorganisms is also recommended

Tratamiento de las infecciones asociadas a catéteres venosos centrales

El tratamiento de las infecciones del torrentesanguineo (ITS) asociadas a cateteres venososcentrales (CVC) esta basado en su mayor parteen series clinicas, recomendaciones de expertos,guias clinicas y un reducido numero de estudioscaso-control. No se dispone lamentablemente deensayos clinicos randomizados que permitan efec-tuar recomendaciones solidas para el manejo deestas complicaciones. Por ello, la calidad de laevidencia corresponde mayoritariamente a unade tipo III.La metodologia utilizada para analizar este temaconsistio en el analisis de las principales pregun-tas que enfrentan los clinicos cuando sospechano confirman una ITS asociada a CVC. Lasinterrogantes que el grupo estimo necesario res-ponder se presentan en la Tabla 1.