Using the antibiotic colistin—a tool of last resort

Colistin is mainly used for gram-negative rods like Pseudomonas, Klebsiella, Acinetobacter, and E. coli. It's an antibiotic of last resort—used for critically ill patients, intensive care units, oncology, and organ transplant patients. In this video, from our Antimicrobial Stewardship Essentials course, you'll learn all about this amphipathic antibiotic, including mechanism of action, side effects, and why this should only be used under specialist supervision.

Each day, patients die of bacterial infections for which no active agents are available. This course will familiarize you with the wide variety of antimicrobial agents available, as well as their mechanisms of action, spectrum of activity, and toxicity profiles, so you can be more selective in choosing an agent when one is required and do your part to delay antimicrobial resistance.

[00:00:00] Colistin is an amphipathic antibiotic, both hydrophobic or nonpolar, and hydrophilic, polar. It disrupts the outer membrane of gram-negative organisms like a detergent, making them osmotically unstable, killing them. Primary use is for multidrug-resistant Gram-negative rods such as Pseudomonas aeruginosa, Klebsiella, Acinetobacter, and E. coli.

[00:00:30] Colistin is one of the antibiotics of last resort. Increasing bacterial resistance to antibiotics has resulted in decreasing treatment options for patients with community-acquired and hospital-acquired infections. The need to treat multidrug-resistant Gram-negative bacteria in human beings has caused a reintroduction of colistin use primarily in critically ill patients in intensive care units and patients with decreased

[00:01:00] immunity due to cancer chemotherapy or organ transplantation. There is an approximately 30% to 60% risk of nephrotoxicity associated with the use of colistin and its similar cousin polymyxin B. Use of colistin is also associated with a dose-related reversible neurotoxicity which is manifested as peripheral neuropathy and neuromuscular blockade and can result in muscle weakness and even apnea.

[00:01:30] Colistin should be used under the direction of an intensivist or infectious disease consultant. Legislation controlling the use of colistin for veterinary and human use has been considered in South Africa. Furthermore, it has been suggested that colistin not be used in food-producing animals at all in order to prevent further development of drug resistance.