Colistin Dosage without Loading Dose Is Efficacious when Treating Carbapenem-Resistant Acinetobacter baumannii Ventilator-Associated Pneumonia Caused by Strains with High Susceptibility to Colistin

• Published in: PLoS ONE 2016, Vol.11 (12), p.e0168468
• Main Authors: Álvarez-Marín, Rocío, López-Rojas, Rafael, Márquez, Juan Antonio, Gómez, María José, Molina, José, Cisneros, José Miguel, Ortiz-Leyba, Carlos, Aznar, Javier, Garnacho-Montero, José, Pachón, Jerónimo
• Format: Report
• Language: English
• Subjects: Acinetobacter infections; Care and treatment; Colistin; Dose-response relationship; Health aspects; Ventilator-associated pneumonia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0168468

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). 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 [greater than or equal to]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. Fifty-seven VAP and 43 colonized A. baumannii patients were analyzed. Among the A. baumannii strains, 99% were non-susceptible to carbapenems and the MIC.sub.90 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. 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.