Open Access Research article

Adjunctive aerosolized colistin for multi-drug resistant gram-negative pneumonia in the critically ill: a retrospective study

Neha M Doshi1, Charles H Cook2, Kari L Mount3, Stanislaw P Stawicki2, Erin N Frazee4, Heather A Personett4, Garrett E Schramm4, Heather M Arnold5 and Claire V Murphy3*

Author Affiliations

1 Department of Pharmacy, St. Luke's University Health Network, Bethlehem, PA, USA

2 Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA

3 Department of Pharmacy, The Ohio State University Wexner Medical Center, Columbus, OH, USA

4 Pharmacy Services, Mayo Clinic, Rochester, MN, USA

5 Department of Pharmacy, Barnes-Jewish Hospital, St. Louis, MO, USA

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BMC Anesthesiology 2013, 13:45  doi:10.1186/1471-2253-13-45

Published: 25 November 2013

Abstract

Background

The incidence of multi-drug resistant (MDR) gram-negative (GN) organisms including Pseudomonas and Acinetobacter spp has increased in the last decade, prompting re-evaluation of colistin for the management of these infections. Aerosolized colistin as an adjunct to intravenous therapy is a current option for the management of MDR-GN pneumonia, although data supporting this practice is limited. This study evaluates the efficacy of adjunctive aerosolized colistin in combination with intravenous colistin in critically ill patients with MDR-GN pneumonia.

Methods

A retrospective multi-center cohort analysis comparing critically ill patients with MDR-GN pneumonia who received intravenous colistin (IV) alone or in combination with adjunctive aerosolized colistin (IV/AER) with a primary endpoint of clinical cure at the end of colistin therapy. Secondary endpoints included microbiologic cure, duration of mechanical ventilation, length of stay, and hospital mortality. A post-hoc subgroup analysis was performed for patients with high quality cultures used for diagnosis of MDR-GN pneumonia. Dichotomous data were compared using Fisher’s exact test while the student’s t-test or Mann–Whitney U test were used for continuous variables.

Results

Ninety-five patients met criteria for evaluation with 51 patients receiving IV and 44 receiving IV/AER. Baseline characteristics were similar between the two groups. Twenty patients (39.2%) receiving IV and 24 (54.5%) receiving IV/AER achieved clinical cure (p = 0.135). There was no difference in microbiologic cure rates between the IV and IV/AER colistin groups (40.7vs. 44.4%, p = 0.805). The IV group demonstrated a trend towards higher pneumonia attributable mortality (70.4 vs. 40%, p = 0.055). In the subgroup analysis of patients with high quality respiratory cultures, there was a significantly lower clinical cure rate for those in the IV group as compared to the IV/AER group (31.3 vs. 57.1%, p = 0.033).

Conclusions

Addition of aerosolized colistin to IV colistin may improve clinical cure and mortality for patients with MDR-GN pneumonia. Larger, prospective trials are warranted to confirm the benefit of adjunctive aerosolized colistin in critically ill patients with MDR-GN pneumonia.

Keywords:
Colistin; Multiple drug resistance; Pneumonia; Critical illness; Pseudomonas; Acinetobacter; Aerosolized