Pentamidine: a drug to consider re-purposing in the targeted treatment of multi-drug resistant bacterial infections?

The recent emergence of plasmid-mediated colistin resistance (1) highlights a new problem in the development of bacterial antimicrobial resistance. Colistin, while an old antibiotic, is increasingly turned to as a “drug of last resort” for many recalcitrant Gram-negative infections. With the efficacy of this drug now compromised, the spread of pan-resistant organisms is a very real threat. To meet this challenge clinicians are seeking new treatment options, however with a drug development pipeline that is virtually dry, an urgent rethinking of how we employ our existing arsenal of antibiotics is required to deal with this problem. Un-orthodox combinations of existing antimicrobial drugs are increasingly being used, often with little rationale on how such combinations are selected beyond the thinking that ‘more is likely to be better’ (2). There is a clear need for a precision medicine approach that combines robust laboratory testing methods with effective dosing strategies for individual patients.