Colistin Resistance in Carbapenem-Resistant Klebsiella pneumoniae: De Novo or Drug Exposure?

To The Editor—It is with interest that we read the study by Rojas et al on colistin resistance in carbapenem-resistant Klebsiella pneumoniae (CRKp), which occurred in 13% (n = 31) of their isolates [1]. The authors found that colistin exposure was uncommon in the cohort as a whole and occurred in only 6/27 (22%) patients with colistin-resistant isolates, for whom treatment data was available beyond 14 days prior to infection. This finding is surprising given that colistin exposure has been associated with colistin resistance in multiple studies, mainly from outbreak settings in southern Europe [2–6]. One important question that arises from these findings is how far back clinical records were available and the length of time for colistin administration. In order to effectively prioritize future interventions, we must accurately understand the relative importance of de novo resistance to polymyxins vs resistance due to previous drug exposure.

http://ift.tt/2uUQOlD