Multidrug-resistant Gram-negative infections: the use of colistin.

The emergence of nosocomial infections due to multidrug-resistant Gram-negative bacteria led to the revival of 'forgotten' antibiotics, such as polymyxins. Colistin, mainly colistimethate sodium (polymyxin E), has been predominantly used. Recent studies suggest that colistin administered as monotherapy or combination therapy is an effective and safe antimicrobial agent for multidrug-resistant Gram-negative bacteria infections. The reported colistin nephrotoxicity is 20% or lower. Although colistin is commonly administered intravenously, it can also be administered via inhalation for pneumonia/ventilator-associated pneumonia treatment or by the intraventricular/intrathecal route for meningitis/ventriculitis treatment. Randomized controlled trials are needed to answer clinical questions such as the appropriate colistin dose, to compare colistin monotherapy with combination therapy, and to determine the exact therapeutic role of aerosolized or intrathecal/intraventricular administration of colistin.