Francisco Alvarez Lerma

Infecciones nosocomiales por Staphylococcus aureus en pacientes críticos en unidades de cuidados intensivos

Fundamento y objetivo: Investigar la frecuencia de infecciones nosocomiales por Staphylococcus aureus en pacientes criticos ingresados en unidades de cuidados intensivos (UCI) de Espana y describir las caracteristicas y la evolucion de aquellos en quienes se han aislado. Pacientes y metodo: Se ha realizado un estudio prospectivo, observacional y multicentrico, en el que se ha incluido a los pacientes ingresados en las UCI de los hospitales participantes en el Estudio Nacional de Vigilancia de Infeccion Nosocomial (ENVIN) durante 1 o 2 meses desde el ano 1997 hasta 2003. Los pacientes se clasificaron como infectados por S. aureus, infectados por otros microorganismos y sin infecciones nosocomiales. Resultados: De 34.914 pacientes controlados 3.450 (9,9%) adquirieron 5.599 infecciones nosocomiales durante su estancia en la UCI (16,0 infecciones por cada 100 pacientes). En 682 (19,8%) de los pacientes con infecciones se identificaron 775 infecciones en las que uno de los microorganismos responsables era S. aureus (incidencia acumulada: 2,2 episodios de infeccion por S. aureus por 100 pacientes). Se observo un predominio de S. aureus en las neumonias relacionadas con ventilacion mecanica (21,4%) y en las bacteriemias relacionadas con cateteres (13,0%). Las variables que se asociaron de forma individual con la aparicion de infeccion por S. aureus fueron el sexo masculino (odds ratio [OR] = 1,25; intervalo de confianza [IC] del 95%, 1,03-1,52) y los procesos de base traumatica (OR = 1,72; IC del 95%, 1,26-2,35), mientras que la mayor edad fue un factor protector (OR = 0,90; IC del 95%, 0,84-0,96). La mortalidad de los pacientes con infeccion por S. aureus fue significativamente superior a la de los pacientes con infecciones por otros microorganismos y, a su vez, la de ambas fue superior a la de los pacientes sin infecciones (el 34,5, el 30,3 y el 10,7%, respectivamente). En 208 (30,5%) pacientes las infecciones fueron debidas a S. aureus resistentes a meticilina, las cuales aumentaron de forma significativa a lo largo de los anos analizados (p = 0,001). La mortalidad de los pacientes con infecciones producidas por S. aureus resistente a meticilina fue del 35,1%, y la de las producidas por S. aureus sensibles a meticilina del 34,2% (p = NS). Conclusiones: S. aureus esta presente en el 19,8% de los pacientes con infecciones adquiridas en las UCI, principalmente en neumonias relacionadas con ventilacion mecanica. La mortalidad de los pacientes con infecciones por S. aureus ha sido superior a la de los pacientes con infecciones por otros microorganismos y a la de pacientes sin infecciones. Por el contrario, no se han identificado diferencias en la evolucion de los pacientes con infecciones por S. aureus sensibles o resistentes a meticilina.

Combatting resistance in intensive care: the multimodal approach of the Spanish ICU “Zero Resistance” program

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2015 and co-published as a series in Critical Care. Other articles in the series can be found online at http://ccforum.com/series/annualupdate2015. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

Pharmacokinetics and Pharmacodynamics of Levofloxacin in Intensive Care Patients

AbstractObjective: A prospective pharmacokinetic study was performed in Caucasian patients from an intensive care unit with respiratory support to evaluate the influence of this circumstance on the pharmacokinetic behaviour of levofloxacin. Patients and methods: A standard dosage regimen of 500 mg/day was administered to nine Caucasian patients included in the study, irrespective of their demographic characteristics. The experimental data on plasma concentrations were analysed by independent-modelling techniques to estimate the following pharmacokinetic parameters: area under the plasma concentration-time curve (AUC), volume of distribution at steady state (Vss), plasma clearance (CL), maximum plasma concentration at steady state (Cmax,ss) and elimination half-life (t½β). Multiple regression analysis was applied to establish the type of correlation between the pharmacokinetic parameters and patient characteristics; the Monte Carlo simulation technique was implemented for the pharmacokinetic/pharmacodynamic analysis based on the probability distribution of the values of AUC/ minimum inhibitory concentration (MIC) and Cmax,ss/MIC observed in this group of patients. Results and conclusion: The results show that for AUC the simplest linear model with creatinine clearance as the only independent variable fits the data at a 99% confidence level, explaining more than 85% of the observed variability in this parameter. The volume of distribution, however, showed a statistical correlation with the severity of the illness (Simplified Acute Physiology Score II), although total bodyweight also explains a high percentage of variability of these parameters. Since the group of patients included in the study was small and also included obese individuals, it is difficult to estimate with precision the contribution of each circumstance (overweight or illness severity) to the pharmacokinetic behaviour of levofloxacin.

Infección por enterococo en pacientes críticos ingresados en la UCI

BACKGROUND AND OBJECTIVE: To determine the frequency of infections caused by Enterococcus spp. in critically ill patients admitted to ICUs in Spain and to describe the clinical features and outcome of those patients in whom this pathogen was isolated. PATIENTS AND METHOD: Prospective, observational, multicenter study. Patients admitted to the ICUs who participated in the National Surveillance Study of Nosocomial Infections (ENVIN) from 1997 to 2001 were included. Patients were classified as infected by Enterococcus spp., infected by other pathogens, and without nosocomial infection (non-infected). RESULTS: Of 21,972 patients, 2,177 (9.9%) had acquired 3,490 nosocomial infections during their stay in the ICU. In 223 patients (10.2%), 239 episodes of infections in which one of the causative pathogen was Enterococcus spp. were identified (cumulative incidence 1.1 episodes of Enterococcus spp. infection per 100 patients). Enterococcus spp. accounted for urinary infection in 14.3% of cases and secondary bacteremia in 12.2% especially those related with abdominal infection (20%) and soft tissue infection (21.4%). Predominant species was E. faecalis in 197 isolates (82.4%). After multivariate analysis, variables significantly associated with infection caused by Enterococcus spp. included: age (odds ratio [OR]=1.13; 95% confidence interval [CI], 1.01-1.25); APACHE II score (OR=1.19; CI 95%, 1.07-1.32); and length of ICU stay (OR=1.02; CI 95%, 1.01-1.03). There were no differences in the overall ICU mortality rate between patients with Enterococcus spp. infection (31.8%) and those with infection caused by other pathogens (31.8%), although in both cases the mortality rate was significantly higher than in non-infected patients (11.1%). CONCLUSIONS: Enterococcus spp. was present in 10.2% patients with ICU-acquired infection. Infection by Enterococcus spp. mainly occurred in the form of urinary tract infection and secondary bacteremia, mainly related to abdominal and soft tissue infections. E. faecalis predominated in all foci. There were no differences in mortality between patients with Enterococcus spp. infection and patients with infection caused by other pathogens.