Opportunities to enhance antibiotic stewardship: colistin use and outcomes in a low-resource setting

BACKGROUND: Colistin use is increasing with the rise in MDR Gram-negative infections globally. Effective antibiotic stewardship is essential to preserve this antibiotic of last resort. OBJECTIVES: This study investigated stewardship and safety errors related to colistin use to identify opportunities for improvement. PATIENTS AND METHODS: A prospective descriptive study involving all patients 13 years and older treated with colistin at a tertiary hospital in Cape Town, South Africa, between August 2018 and June 2019. We collected clinical, laboratory and outcome data and assessed provided treatment for stewardship and safety errors. RESULTS: We included 44 patients. Treatment errors were identified for 34 (77%) patients (median = 1), most commonly inadequate monitoring of renal function (N = 16, 32%). We also identified no rational indication for colistin (N = 9, 20%), loading dose error (N = 12, 27%); maintenance dose error (N = 10, 23%); no prior culture (N = 11, 25%); and failure to de-escalate (2 of 9) or adjust dose to changes in renal function (6 of 15). All cause in-hospital mortality was 47%. Amongst survivors, median ICU stay was 6 days and hospital stay more than 30 days. Eight (18%) patients developed renal injury or failure during treatment. Three (7%) patients in this study were found to have colistin-resistant organisms including two prior to colistin exposure. CONCLUSIONS: This study has identified opportunities to enhance colistin stewardship and improve efficacy and safety of prescription. The appearance of colistin-resistant organisms reinforces the urgent need to ensure effective and appropriate use of colistin.