The threat of colistin resistance among carbapenem-resistant Klebsiella pneumoniae isolates in Iran

Colistin belongs to polymyxin family of antibiotics which are polypeptide bactericidal agents acting mainly by disruption of outer-membrane in Gram-negative bacteria (GNB). This antibiotic group (including polymyxin B and colistin) was approved for clinical use in the late 1950s but fell out of favour soon because of the reported high incidence of nephrotoxicity. With increasing the emergence of extensively-drug resistant (XDR)-GNB and paucity of new marketed antibiotics, polymyxins have recently regained significant clinical interest. They are currently considered as the last-line defense against problematic XDR-GNB notably carbapenem-resistant Enterobacteriaceae (CRE) and Acinetobacter baumannii.