Investigation of the effect of colistin monotherapy and colistin-meropenem combine therapy on mortality in patients with colistin-resistant a.baumannii bacteriama in Ankara City Hospital intensive care unit

Objective: In our study, we aimed to investigate the effect of colistin monotherapy and colistin-meropenem combined therapy on mortality in patients with carbapenem-resistant A.baumannii bacteremia. Materials and methods: In Ankara City Hospital Intensive Care Unit, 62 patients with carbapenem-resistant A.baumannii (KRAB) bacteremia, who met the inclusion criteria, who received colistin monotherapy, and 98 patients who received colistin combined therapy with meropenem were identified. These patients were formed into 2 groups according to the treatments they received. The groups were recorded at the time of hospitalization, bacteremia and treatment response, and the effects on mortality and clinical response were examined by comparing vital signs, laboratory findings and scoring. Results: Those who received monotherapy and combination therapy were not superior to each other on the primary outcome, 28-day mortality. No superiority was found between treatments on 14-day mortality, clinical response, and microbiological response, which were determined as secondary outcomes. Those with a mortality expectation above 25% were reanalyzed according to the treatment groups, and no superiority of the treatments was found. Conclusions: Combination therapy of meropenem and colistin did not provide superiority over monotherapy in patients with KRAB bacteremia, and there is a possibility that combination therapy may increase resistance rates and side effects rates. However, attention should be paid to the development of colistin resistance. Keywords: carbapenem resistant A.baumannii (KRAB), bacteremia, colistin monotherapy, meropenem and colistin combined therapy