title: Colistin Dosage without Loading Dose Is Efficacious when Treating Carbapenem-Resistant Acinetobacter baumannii Ventilator-Associated Pneumonia Caused by Strains with High Susceptibility to Colistin.
abstract: OBJECTIVE
  This study aims to analyze the mortality and the length of ICU stay (LOS) of A. baumannii VAP compared to respiratory colonization in patients with mechanical ventilation (MV).
  
  
  METHODS
  A prospective cohort study was performed in an ICU of adult patients (February 2010-June 2011). One hundred patients on MV with A. baumannii in lower respiratory airways were recruited, and classified as VAP or airways colonization according to CPIS criteria, with a punctuation ≥6. LOS, 30-days mortality, A. baumannii bacteremia, and clinical features including antibiotic therapy were recorded. Multivariate analysis (linear and Cox regression) and survival analysis (Kaplan-Meier curves) were performed.
  
  
  RESULTS
  Fifty-seven VAP and 43 colonized A. baumannii patients were analyzed. Among the A. baumannii strains, 99% were non-susceptible to carbapenems and the MIC90 of colistin was 0.12 mg/l. Therapy was appropriate in 94.6% of VAP patients, most of them with colistin 6 MIU/day, although in 13 (23.6%) cases colistin was started 48 hours after the onset of VAP. Mortality was similar in both groups (VAP 24.6% vs. colonized 27.9%, p = 0.7). Bacteremia and acute kidney insufficiency were associated with decreased survival (p = 0.02 and p = 0.04, respectively) in VAP patients. LOS was 21.5 (11.5-42.75) vs. 9 (6-22) days for VAP and colonized patients (p = 0.004). VAP (p = 0.003) and age (p = 0.01) were independently related to a longer LOS.
  
  
  CONCLUSIONS
  Multidrug-resistant A. baumannii VAP treated with colistin does not have a different mortality compared to lower airways colonization, among patients on mechanical-ventilation, in a setting of high susceptibility to colistin of A. baumannii.
authors.affiliation: Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine Infectious Diseases Research Group Institute of Biomedicine of Seville (IBiS) University of Seville/CSIC/University Hospitals Virgen del Rocio and Virgen Macarena, Seville, Spain.
authors.forename: Rocío
authors.identifier: http://orcid.org/0000-0002-7101-2514
authors.initials: R
authors.lastname: Álvarez-Marín
authors.affiliation: Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine Infectious Diseases Research Group Institute of Biomedicine of Seville (IBiS) University of Seville/CSIC/University Hospitals Virgen del Rocio and Virgen Macarena, Seville, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: López-Rojas
authors.affiliation: Clinical Unit of Critical Care and Emergencies, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain.
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Márquez
authors.affiliation: Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine Infectious Diseases Research Group Institute of Biomedicine of Seville (IBiS) University of Seville/CSIC/University Hospitals Virgen del Rocio and Virgen Macarena, Seville, Spain.
authors.forename: María José
authors.initials: MJ
authors.lastname: Gómez
authors.affiliation: Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine Infectious Diseases Research Group Institute of Biomedicine of Seville (IBiS) University of Seville/CSIC/University Hospitals Virgen del Rocio and Virgen Macarena, Seville, Spain.
authors.forename: José
authors.initials: J
authors.lastname: Molina
authors.affiliation: Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine Infectious Diseases Research Group Institute of Biomedicine of Seville (IBiS) University of Seville/CSIC/University Hospitals Virgen del Rocio and Virgen Macarena, Seville, Spain.
authors.forename: José Miguel
authors.initials: JM
authors.lastname: Cisneros
authors.affiliation: Clinical Unit of Critical Care and Emergencies, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Ortiz-Leyba
authors.affiliation: Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine Infectious Diseases Research Group Institute of Biomedicine of Seville (IBiS) University of Seville/CSIC/University Hospitals Virgen del Rocio and Virgen Macarena, Seville, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Aznar
authors.affiliation: Clinical Unit of Critical Care, University Hospital Virgen Macarena, Seville, Spain.
authors.forename: José
authors.initials: J
authors.lastname: Garnacho-Montero
authors.affiliation: Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine Infectious Diseases Research Group Institute of Biomedicine of Seville (IBiS) University of Seville/CSIC/University Hospitals Virgen del Rocio and Virgen Macarena, Seville, Spain.
authors.forename: Jerónimo
authors.initials: J
authors.lastname: Pachón
mesh_terms: D040981:Acinetobacter baumannii / Q000378:metabolism*; D000328:Adult; D016470:Bacteremia / Q000188:drug therapy / Q000382:microbiology / Q000401:mortality; D015780:Carbapenems; D003091:Colistin / Q000008:administration & dosage*; D018572:Disease-Free Survival; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D053717:Pneumonia, Ventilator-Associated / Q000188:drug therapy / Q000382:microbiology / Q000401:mortality; D011446:Prospective Studies; D015996:Survival Rate
chemical_list: D015780:Carbapenems; D003091:Colistin