title: Impact of the MIC of piperacillin/tazobactam on the outcome for patients with bacteraemia due to Enterobacteriaceae: the Bacteraemia-MIC project.
abstract: OBJECTIVE
  Our objective was to evaluate the impact of low versus borderline MIC of piperacillin/tazobactam on the clinical outcomes of patients with bacteraemia caused by Enterobacteriaceae who were treated with that antimicrobial.
  
  
  METHODS
  A prospective observational multicentre cohort study was conducted in 13 Spanish university hospitals. Patients >17 years old with bacteraemia due to Enterobacteriaceae who received empirical piperacillin/tazobactam treatment for at least 48 h were included. Outcome variables were clinical response at day 21, clinical response at end of treatment with piperacillin/tazobactam and all-cause 30 day mortality. Univariate and multivariate logistic regression analyses were performed.
  
  
  RESULTS
  Overall, 275 patients were included in the analysis; 248 (90.2%) in the low MIC group (≤ 4 mg/L) and 27 (9.8%) in the borderline MIC group (8-16 mg/L). The biliary tract was the most common source of infection (48.4%) and Escherichia coli was the most frequent pathogen (63.3%). Crude 30 day mortality rates were 10.5% and 11.1% for the low MIC group and the borderline MIC group, respectively (relative risk = 1.06, 95% CI = 0.34-3.27, P = 1). Multivariate analysis of failure at day 21 and at end of treatment with piperacillin/tazobactam and 30 day mortality showed no trend towards increased clinical failure or mortality with borderline MICs (OR = 0.96, 95% CI = 0.18-4.88, P = 0.96; OR = 0.47, 95% CI = 0.10-2.26, P = 0.35; OR = 1.48, 95% CI = 0.33-6.68, P = 0.6).
  
  
  CONCLUSIONS
  We did not find that higher piperacillin/tazobactam MIC within the susceptible or intermediate susceptibility range had a significant influence on the outcome for patients with bacteraemia due to Enterobacteriaceae.
authors.affiliation: Unidad Clínica Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospitales Universitarios Virgen Macarena y Virgen del Rocío, Seville, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Delgado-Valverde
authors.affiliation: Unidad Clínica Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospitales Universitarios Virgen Macarena y Virgen del Rocío, Seville, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Torres
authors.affiliation: Unidad Clínica Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospitales Universitarios Virgen Macarena y Virgen del Rocío, Seville, Spain.
authors.forename: Adoración
authors.initials: A
authors.lastname: Valiente-Mendez
authors.affiliation: Departamento de Enfermedades Infecciosas, Hospital Universitari Valld'Hebron, Barcelona, Spain.
authors.forename: Benito
authors.initials: B
authors.lastname: Almirante
authors.affiliation: Servicio de Enfermedades Infecciosas, Hospital Universitari de Bellvitge-IDIBELL, Barcelona, Spain.
authors.forename: Silvia
authors.initials: S
authors.lastname: Gómez-Zorrilla
authors.affiliation: Servicio de Microbiología, Hospital Son Espases, Palma de Mallorca, Spain.
authors.forename: Núria
authors.initials: N
authors.lastname: Borrell
authors.affiliation: Unidad Clínica de Enfermedades Infecciosas y Microbiología, Hospital Universitario de Valme, Sevilla, Spain.
authors.forename: Juan E
authors.initials: JE
authors.lastname: Corzo
authors.affiliation: Servicio de Enfermedades Infecciosas, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain Facultad de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Gurgui
authors.affiliation: Servicio de Microbiología, Hospital Clínic, Barcelona, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Almela
authors.affiliation: Servicio de Enfermedades Infecciosas, Hospital San Pedro-CIBIR, Logroño, Spain.
authors.forename: Lara
authors.initials: L
authors.lastname: García-Álvarez
authors.affiliation: Servicio de Microbiología, Complejo Hospitalario Universitario A Coruña, A Coruña, Spain.
authors.forename: María Cruz
authors.initials: MC
authors.lastname: Fontecoba-Sánchez
authors.affiliation: Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla-IDIVAL, Santander, Spain Departamento de Biología Molecular, Universidad de Cantabria, Santander, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Martínez-Martínez
authors.affiliation: Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Cantón
authors.affiliation: Unidad Clínica Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospitales Universitarios Virgen Macarena y Virgen del Rocío, Seville, Spain Instituto de Biomedicina de Sevilla (IBIS), Seville, Spain.
authors.forename: Julia
authors.initials: J
authors.lastname: Praena
authors.affiliation: Unidad Clínica de Enfermedades Infecciosas, Hospital Universitario Reina Sofía, Córdoba, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Causse
authors.affiliation: Unidad Clínica Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospitales Universitarios Virgen Macarena y Virgen del Rocío, Seville, Spain.
authors.forename: Belén
authors.initials: B
authors.lastname: Gutiérrez-Gutiérrez
authors.affiliation: Burns Trauma and Critical Care Research Centre, University of Queensland, Brisbane, Australia.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Roberts
authors.affiliation: Department of Pharmacy, Vassar Brothers Medical Center, Poughkeepsie, NY, USA Optimum Dosing Strategies, Bloomingdale, NJ, USA.
authors.forename: Andras
authors.initials: A
authors.lastname: Farkas
authors.affiliation: Unidad Clínica Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospitales Universitarios Virgen Macarena y Virgen del Rocío, Seville, Spain Departamento de Microbiología, Universidad de Sevilla, Seville, Spain.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Pascual
authors.affiliation: Unidad Clínica Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospitales Universitarios Virgen Macarena y Virgen del Rocío, Seville, Spain Departamento de Medicina, Universidad de Sevilla, Seville, Spain jesusrb@us.es.
authors.forename: Jesús
authors.initials: J
authors.lastname: Rodríguez-Baño
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000188:drug therapy* / Q000382:microbiology / Q000401:mortality; D004755:Enterobacteriaceae / Q000187:drug effects*; D004756:Enterobacteriaceae Infections / Q000188:drug therapy* / Q000382:microbiology / Q000401:mortality; D005260:Female; D006785:Hospitals, University; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D010397:Penicillanic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D010878:Piperacillin / Q000494:pharmacology / Q000627:therapeutic use; D000077725:Piperacillin, Tazobactam Drug Combination; D011446:Prospective Studies; D013030:Spain; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000077725:Piperacillin, Tazobactam Drug Combination; D010397:Penicillanic Acid; D010878:Piperacillin