An international panel of infectious disease and antimicrobial researchers have published new practice guidelines for the clinical use of polymyxin antibiotics.

Polymyxins are a class of antibiotics that have "… assumed an important role as salvage therapy for otherwise untreatable gram‐negative infections, most notably multidrug‐resistant (MDR) and extensively drug‐resistant (XDR) strains of Pseudomonas aeruginosa, Acinetobacter baumannii, and Enterobacteriaceae," according to the guidelines, which were published in Pharmacotherapy.

The guidelines specifically concern the polymyxin antibiotics colistin (polymyxin E) and polymyxin B. They became available in the 1950s, but their use fell out of favor because of toxicity concerns, according to a news release. However, in the effort to combat superbugs, their clinical use has resurged. 

Unfortunately, as the researchers note in the guidelines, "Since their reintroduction into the clinic, significant confusion remains due to the existence of several different conventions used to describe doses of the polymyxins, differences in their formulations, outdated product information and uncertainties about susceptibility testing that has led to lack of clarity on how to optimally utilize and dose colistin and polymyxin B."

The guidelines establish new standards for polymyxins in areas including maximum dosage, treatment strategies and best practice for use in combination with other antibiotics.

"These guidelines represent consensus recommendations from expert clinicians and scientists around the globe to guide polymyxin therapy in gram-negative infections where no treatments appear to exist," said Brian Tsuji, who co-led the panel and is professor of pharmacy practice in the University of Buffalo School of Pharmacy and Pharmaceutical Sciences, in the release.

The guidelines have received endorsements from the American College of Clinical Pharmacy, European Society of Clinical Microbiology and Infectious Diseases, Infectious Diseases Society of America, International Society for Anti-infective Pharmacology, Society of Critical Care Medicine and Society of Infectious Diseases Pharmacists.