Objective. To assess the risks factors for urinary tract infections (UTIs) caused by Extended-Spectrum Beta-Lactamases (ESBLs)-producing E. coli and the molecular characterization of ESBLs. Materials and methods. A case-control study was performed to identify risk factors in consecutively recruited patients with UTIs caused by ESBLs or non-ESBLs-producing E. coli in a tertiary hospital in Mexico. Results. ESBLs-producing E. coli were isolated from 22/70 (31%) patients with E. coli UTIs over a three month period. All isolates were resistant to cephalosporins and quinolones but susceptible to carbapenems, amikacin and nitrofurantoin. Prior antibiotic treatment with more than two antibiotic families (OR=6.86; 95%CI 1.06-157.70; p=0.028), recurrent symptomatic UTIs (OR=5.60; 95%CI 1.88-17.87; p=0.001) and previous hospitalization (OR=5.06; 95%CI 1.64-17.69; p=0.002) were significant risk factors. Sixteen isolates harbored the beta-lactamase (bla)CTX-M-15 gene and five the blaTEM-1 gene. Conclusions. One of every three patients presented UTIs with ESBLs-producing beta-lactams and fluoroquinolone resistant E. coli. Risk factors and resistance patterns must be taken into account for developing antibiotic use policies in these settings.

Objetivo. Evaluar los factores de riesgo en infecciones de vías urinarias (IVUs) causadas por E. coli productora de Beta-Lactamasas de espectro extendido (BLEEs) y caracterizar las BLEEs. Material y métodos. Estudio de casos y controles en pacientes consecutivos con IVUs causadas por E. coli productoras o no de BLEEs en un hospital de referencia. Resultados. E. coli productora de BLEEs se aisló en 22/70 (31%) pacientes con IVUs por E. coli durante un periodo de tres meses. Todos los aislamientos fueron resistentes a cefalosporinas y quinolonas, pero susceptibles a carbapenemes, amikacina y nitrofurantoina. Factores de riesgo significativos incluyeron tratamiento previo con más de dos familias de antibióticos (OR=6.86; IC95% 1.06-157.70; p=0.028), IVUs sintomáticas recurrentes (OR=5.60; IC95% 1.88-17.87; p=0.001) y hospitalizaciones previas (OR=5.06; IC95% 1.64-17.69; p=0.002). Dieciséis aislamientos presentaron el gen betalactamasas (bla)CTX-M-15 y cinco el gen blaTEM-1. Conclusiones. Uno de cada tres pacientes presentó IVU con E. coli resistente a beta-lactámicos, fluoroquinolonas y productora de BLEEs. En estos casos, los factores de riesgo y patrones de resistencia deberían tomarse en cuenta para recomendar tratamiento.

Objective. To assess the risks factors for urinary tract infections (UTIs) caused by Extended-Spectrum Beta-Lactamases (ESBLs)-producing E. coli and the molecular characterization of ESBLs. Materials and methods. A case-control study was performed to identify risk factors in consecutively recruited patients with UTIs caused by ESBLs or non-ESBLs-producing E. coli in a tertiary hospital in Mexico. Results. ESBLs-producing E. coli were isolated from 22/70 (31%) patients with E. coli UTIs over a three month period. All isolates were resistant to cephalosporins and quinolones but susceptible to carbapenems, amikacin and nitrofurantoin. Prior antibiotic treatment with more than two antibiotic families (OR=6.86; 95%CI 1.06-157.70; p=0.028), recurrent symptomatic UTIs (OR=5.60; 95%CI 1.88-17.87; p=0.001) and previous hospitalization (OR=5.06; 95%CI 1.64-17.69; p=0.002) were significant risk factors. Sixteen isolates harbored the beta-lactamase (bla)CTX-M-15 gene and five the blaTEM-1 gene. Conclusions. One of every three patients presented UTIs with ESBLs-producing beta-lactams and fluoroquinolone resistant E. coli. Risk factors and resistance patterns must be taken into account for developing antibiotic use policies in these settings.

Objetivo. Evaluar los factores de riesgo en infecciones de vías urinarias (IVUs) causadas por E. coli productora de Beta-Lactamasas de espectro extendido (BLEEs) y caracterizar las BLEEs. Material y métodos. Estudio de casos y controles en pacientes consecutivos con IVUs causadas por E. coli productoras o no de BLEEs en un hospital de referencia. Resultados. E. coli productora de BLEEs se aisló en 22/70 (31%) pacientes con IVUs por E. coli durante un periodo de tres meses. Todos los aislamientos fueron resistentes a cefalosporinas y quinolonas, pero susceptibles a carbapenemes, amikacina y nitrofurantoina. Factores de riesgo significativos incluyeron tratamiento previo con más de dos familias de antibióticos (OR=6.86; IC95% 1.06-157.70; p=0.028), IVUs sintomáticas recurrentes (OR=5.60; IC95% 1.88-17.87; p=0.001) y hospitalizaciones previas (OR=5.06; IC95% 1.64-17.69; p=0.002). Dieciséis aislamientos presentaron el gen betalactamasas (bla)CTX-M-15 y cinco el gen blaTEM-1. Conclusiones. Uno de cada tres pacientes presentó IVU con E. coli resistente a beta-lactámicos, fluoroquinolonas y productora de BLEEs. En estos casos, los factores de riesgo y patrones de resistencia deberían tomarse en cuenta para recomendar tratamiento.