Asunto(s)
Antibacterianos/uso terapéutico , Cefalosporinas/uso terapéutico , Farmacorresistencia Bacteriana Múltiple/genética , Infecciones por Haemophilus/tratamiento farmacológico , Haemophilus parainfluenzae/genética , Proteínas de Unión a las Penicilinas/genética , Infecciones Comunitarias Adquiridas/tratamiento farmacológico , Infecciones Comunitarias Adquiridas/microbiología , Genoma Bacteriano/genética , Infecciones por Haemophilus/microbiología , Haemophilus parainfluenzae/efectos de los fármacos , Haemophilus parainfluenzae/aislamiento & purificación , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Proteínas de Unión a las Penicilinas/metabolismoAsunto(s)
Farmacorresistencia Bacteriana Múltiple , Infecciones por Escherichia coli/microbiología , Escherichia coli/enzimología , Escherichia coli/aislamiento & purificación , beta-Lactamasas/biosíntesis , Anciano , Antibacterianos/farmacología , Técnicas de Tipificación Bacteriana , Escherichia coli/clasificación , Escherichia coli/efectos de los fármacos , Genotipo , Humanos , Pruebas de Sensibilidad Microbiana , Tipificación MolecularRESUMEN
Bloodstream infection (BSI) due to Proteus mirabilis strains is a relatively uncommon clinical entity, and its significance has received little attention. This study was initiated to evaluate risk factors and treatment outcome of BSI episodes due to P. mirabilis producing extended-spectrum beta-lactamases (ESBLs). Twenty-five BSI episodes caused by P. mirabilis occurred at our hospital (Ospedale di Circolo e Fondazione Macchi, Varese, Italy) over a 7.5-year period. Phenotypic and molecular methods were used to assess ESBL production. Clinical records of BSI patients were examined retrospectively. Demographic data, underlying diseases (according to McCabe and Jackson classification and Charlson weighted index), risk factors, and treatment outcome were investigated by comparing cases due to ESBL-positive strains to cases due to ESBL-negative strains. Eleven isolates were found to express ESBLs (TEM-52 or TEM-92). The remaining 14 isolates were ESBL negative and were uniformly susceptible to extended-spectrum cephalosporins and monobactams. Comparison of the two groups showed that previous hospitalization in a nursing home (P = 0.04) and use of bladder catheter (P = 0.01) were significant risk factors for infections due to ESBL-positive strains. In addition, cases due to ESBL-positive strains showed a significantly higher mortality attributable to BSI (P = 0.04). BSI cases due to ESBL-negative isolates uniformly responded to therapy, whereas 5/11 cases due to ESBL-positive isolates failed to respond (P < 0.01). Use of carbapenems was associated with complete response independently of ESBL production. Therapeutic failure and mortality may occur in BSI episodes caused by ESBL-positive P. mirabilis isolates. Thus, recognition of ESBL-positive strains appears to be critical for the clinical management of patients with systemic P. mirabilis infections.
Asunto(s)
Antibacterianos/uso terapéutico , Bacteriemia , Infecciones por Proteus , Proteus mirabilis/efectos de los fármacos , beta-Lactamasas/metabolismo , Anciano , Anciano de 80 o más Años , Antibacterianos/farmacología , Bacteriemia/tratamiento farmacológico , Bacteriemia/epidemiología , Bacteriemia/microbiología , Bacteriemia/mortalidad , Farmacorresistencia Bacteriana , Femenino , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Infecciones por Proteus/tratamiento farmacológico , Infecciones por Proteus/epidemiología , Infecciones por Proteus/microbiología , Infecciones por Proteus/mortalidad , Proteus mirabilis/enzimología , Proteus mirabilis/patogenicidad , Factores de Riesgo , Resultado del Tratamiento , beta-Lactamasas/genéticaRESUMEN
The treatment outcome of 35 cases of bacteremia due to Klebsiella pneumoniae isolates producing TEM-52 extended-spectrum beta-lactamase was studied. Twenty-eight cases, classified as "nonfatal disease" using the McCabe and Jackson classification, were investigated with regard to ciprofloxacin and imipenem response. Because ciprofloxacin was active in vitro against 21 of 28 isolates, only the treatment outcome of the ciprofloxacin-susceptible subgroup was evaluated. Eight of 10 cases occurred in patients who experienced a complete response to imipenem; 2 of 10 failed to respond. In contrast, only 2 of 7 cases had a partial response to ciprofloxacin, and, in 5 of 7 cases, the treatment failed. Statistical analysis revealed a significant difference in the treatment outcome of the 2 groups (P=.03). Because the isolates had minimum inhibitory concentrations of ciprofloxacin close to the susceptibility breakpoint, treatment failure could be ascribed to the inability of the drug to reach therapeutic concentrations at infected sites.