Emergent of Colistin Resistant Enterobacteriaceae carrying the mcr-1 gene among clinical isolates from patients in an Argentine hospital: Clinical and microbiological aspects

The recent emergence of multidrug-resistant (MDR) or extremely drug-resistant (XDR) Gram-negative bacteria has renewed interest in colistin (Polymyxins, a family of cationic polypeptide antibiotics) as a last-resort in the treatment of severe bacterial infections [1,2], despite being a drug with potential serious adverse events (mainly high risk of nephrotoxicity) [3,4]. Acquired resistance to polymyxins is generally associated with chromosomal mutations [5,6].