Use of colistin in treating multi-resistant Gram-negative organisms in a specialised burns unit

Patients with burns are at an increased risk of infection which can affect their outcome-duration of hospital stay, intensive care requirements, organ support, inotrope requirements, renal replacement therapy, ventilatory requirements and overall mortality. Our study aimed to evaluate the use of colistin in our burns intensive care unit (ICU) in treating multi-resistant Gram-negative infections. This was a retrospective study carried out in a regional referral centre for burns and plastics, Chelmsford, UK. We looked at data from patients admitted to our intensive care over a two-year period from November 2003 to November 2005. All patients who received colistin were included in the study. Admission data included demographic data and burn data, other relevant medical history, and blood results. We also recorded: length of ICU stay, ultimate outcome, total dose of colistin, repeated doses, and mode of drug delivery, organ support, organisms grown and their resistance. Response to colistin was judged by improvement in clinical status, decrease in white blood cell count (WCC) and inflammatory markers and no growth on cultures. The data were subjected to non-parametric Wilcoxon Signed Rank Test using SPSS version 14. Twenty-nine patients were included in the study all of whom received colistin in one form or the other. The average total dose of colistin was 69 million units (range 1-268). Of these, 17 patients survived (58.6%) and 12 died (41.4%). Twenty patients improved (69%) and 9 did not improve (31%) after administration of colistin. We also compared creatinine levels on admission and post colistin. We used non-parametric Wilcoxon Signed Rank test which showed no difference in the two groups (p=0.38). We found colistin to be safe and effective in treating multi-resistant Gram-negative infections in burns patients and we did not see any statistically significant impairment of renal function.