Colistin alone or combined with sulbactam or carbapenem against A. baumannii in ventilator-associated pneumonia.

Introduction: Colistin use has increased over the last ten years because of multidrug-resistant microorganisms. The aim of this study was to compare the clinical and microbiological efficacy of colistin alone or in combination with sulbactam or carbapenem in the treatment of ventilator-associated pneumonia (VAP) due to multidrug-resistant (MDR) and extremely drug-resistant (XDR) A. baumannii.

Methodology: Cases treated for VAP because of MDR and XDR A. baumannii between January 2011 and January 2013 were included in the study. The primary and secondary outcome for colistin alone, colistin with sulbactam, and colistin with carbapenems were evaluated. The primary outcomes were clinical efficacy and microbiological efficacy; the secondary outcomes were nephrotoxicity, length of hospitalization, and mortality.

Results: A total of 70 VAP patients were evaluated. A total of 17 patients (24.3%) were administered colistin alone, 20 patients (28.6%) were administered colistin and sulbactam, and 33 patients (47.1%) were administered colistin and carbapenem. Clinical and microbiological response rates were higher in the carbapenem combination group (63.6% and 63.6% in both) than in the sulbactam combination group, which registered 55.0% and 60.0%, respectively. However, this did not represent a significant difference statistically (p > 0.05). There was also no significant difference between colistin alone and the combination groups regarding clinical and microbiological efficacy and mortality.

Conclusions: Neither the administration of colistin alone nor colistin combined with either sulbactam or carbapenem had any noticeable advantage in the treatment of VAP in terms of clinical response, microbiological response, nephrotoxicity, length of hospitalization, and mortality.