Ramón Pérez-Cano

Epidemiology and Clinical Features of Infections Caused by Extended-Spectrum Beta-Lactamase-Producing Escherichia coli in Nonhospitalized Patients

ABSTRACT Infections due to extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (ESBLEC) in nonhospitalized patients seem to be emerging in different countries. Their incidence, epidemiology, and clinical impact in the community have not been studied. We describe the epidemiology and clinical features of infections caused by ESBLEC in nonhospitalized patients in Spain and the results of a case-control study performed to investigate the risk factors associated with the acquisition of these organisms. The clonal relatedness of the organisms was assessed by repetitive extragenic palindromic sequence PCR. The ESBLs and the genes encoding the ESBLs were initially characterized by isoelectric focusing and PCR, respectively. Forty-nine patients (76% with urinary tract infections, 22% with asymptomatic bacteriuria, and 2% with acute cholangitis) were included. Six patients were bacteremic. Diabetes mellitus (odds ratio, 5.5; 95% confidence interval, 1.6 to 18.7), previous fluoroquinolone use (odds ratio, 7.6; 95% confidence interval, 1.9 to 30.1), recurrent urinary tract infections (odds ratio, 4.5; 95% confidence interval, 1.3 to 15.1), a previous hospital admission (odds ratio, 18.2; 95% confidence interval, 5.3 to 61.1), and older age in male patients (odds ratio per year, 1.03; 95% confidence interval, 1.03 to 1.05) were identified as risk factors by multivariate analysis. The ESBLEC isolates were not clonally related. The ESBLs were characterized as members of the CTX-M-9 group, the SHV group, and the TEM group in 64, 18, and 18% of the isolates, respectively. ESBLEC is an emergent cause of urinary tract infections in nonhospitalized patients. There was no evidence of horizontal transmission of ESBLEC strains. Avoidance of fluoroquinolone use in high-risk patients should be considered whenever possible in order to avoid the selection of these organisms.

Clinical and Molecular Epidemiology of Extended-Spectrum β -Lactamase—Producing Escherichia coli as a Cause of Nosocomial Infection or Colonization: Implications for Control

BACKGROUND Extended-spectrum beta-lactamase (ESBL)-producing members of the Enterobacteriaceae family are important nosocomial pathogens. Escherichia coli producing a specific family of ESBL (the CTX-M enzymes) are emerging worldwide. The epidemiology of these organisms as causes of nosocomial infection is poorly understood. The aims of this study were to investigate the clinical and molecular epidemiology of nosocomial infection or colonization due to ESBL-producing E. coli in hospitalized patients, consider the specific types of ESBLs produced, and identify the risk factors for infection and colonization with these organisms. METHODS All patients with nosocomial colonization and/or infection due to ESBL-producing E. coli in 2 centers (a tertiary care hospital and a geriatric care center) identified between January 2001 and May 2002 were included. A double case-control study was performed. The clonal relatedness of the isolates was studied by repetitive extragenic palindromic-polymerase chain reaction and pulsed-field gel electrophoresis. ESBLs were characterized by isoelectric focusing, polymerase chain reaction, and sequencing. RESULTS Forty-seven case patients were included. CTX-M-producing E. coli were clonally unrelated and more frequently susceptible to nonoxyimino-beta-lactams. Alternately, isolates producing SHV- and TEM-type ESBL were epidemic and multidrug resistant. Urinary catheterization was a risk factor for both CTX-M-producing and SHV-TEM-producing isolates. Previous oxyimino-beta-lactam use, diabetes, and ultimately fatal or nonfatal underlying diseases were independent risk factors for infection or colonization with CTX-M-producing isolates, whereas previous fluoroquinolone use was associated with infection or colonization with SHV-TEM-producing isolates. CONCLUSIONS The epidemiology of ESBL-producing E. coli as a cause of nosocomial infection is complex. Sporadic CTX-M-producing isolates coexisted with epidemic multidrug-resistant SHV-TEM-producing isolates. These data should be taken into account for the design of control measures.

Características epidemiológicas, clínicas y pronósticas de la infección por Stenotrophomonas maltophilia

Introduccion Stenotrophomonas maltophilia es un patogeno multirresistente que se esta aislando con frecuencia creciente de pacientes predispuestos. Hay pocos estudios que hayan evaluado su epidemiologia y relevancia clinica en pacientes de un hospital general. Metodos Estudio prospectivo de la cohorte de casos de infeccion por S. maltophilia entre enero de 1998 y enero de 2001 en el Hospital Universitario Virgen Macarena de Sevilla. Se recogieron variables demograficas, enfermedades de base, gravedad al ingreso (indice APACHE II), procedimientos invasivos, uso previo de antimicrobianos, repercusion sistemica, tratamiento y mortalidad. Resultados S. maltophilia se aislo en muestras clinicas de 87 pacientes, de los cuales se incluyeron los 45 casos (52%) en los que se considero que estaba causando infeccion. El 40% estaba en unidad de cuidados intensivos (UCI) y el 13% eran ambulatorios. La infeccion se considero asociada a la atencion sanitaria en el 91%. El 82% habian recibido antibioticos. El tipo de infeccion mas frecuente fue la neumonia seguida de otras infecciones respiratorias, urinarias y de piel y tejidos blandos. Presentaron sepsis grave o shock septico el 12%. El tratamiento antimicrobiano mas utilizado fue trimetoprima-sulfametoxazol (60%). La mortalidad bruta fue del 44%; el unico factor asociado a la mortalidad bruta fue el indice APACHE II. La mortalidad atribuible a la infeccion fue del 13%, y solo ocurrio en pacientes con neumonia. Conclusion S. maltophilia causa un amplio espectro de infecciones asociadas a la atencion sanitaria en pacientes predispuestos, aunque la mitad de los pacientes en que se aislo se consideraron solo colonizados. La mortalidad bruta se asocia con la gravedad basal. La neumonia se asocia con elevada mortalidad.

Bacteriemias por Acinetobacter baumannii: características clínicas y pronósticas

Objetivo Analisis de la incidencia, caracteristicas clinicas y pronostico de las bacteriemias por Acinetobacter baumannii Metodos Estudio prospectivo de la cohorte de bacteriemias por A. baumannii detectadas entre enero de 1995 y diciembre de 1998. A. baumannii se identifico segun las recomendaciones mas recientes Resultados Se incluyeron 133 bacteriemias, todas de adquisicion nosocomial. La densidad de incidencia fue de 2,02 episodios/10.000 pacientes-dia y descendio a 0,40 episodios/10.000 pacientes-dia con la aplicacion del programa de control. El 70% de los pacientes estaba o habia estado en la unidad de cuidados intensivos. El 85% padecia enfermedades cronicas concomitantes y el 62% un indice de gravedad de Hilf superior a 4. El 78% de las cepas eran multirresistentes y el 28% resistentes a imipenem. La mortalidad atribuible fue del 25,6%. El analisis multivariado mostro que el tratamiento antibiotico inapropiado, el shock septico y un mayor indice de gravedad de Hilf fueron factores independientes de mal pronostico Conclusion La bacteriemia por A. baumannii afecta fundamentalmente a pacientes graves sometidos a multiples procedimientos invasivos, en los que la morbimortalidad puede ser elevada. El tratamiento antimicrobiano inadecuado se asocio, entre otros factores, a un peor pronostico