New guidelines for last-line defence against superbugs

Doctors can now more confidently administer a drug that protects against bacterial superbugs thanks to the development of scientifically-based dosing guidelines for the antibiotic colistin.

Colistin treats serious infections in critically ill patients, including those with kidney failure who are receiving dialysis. The guidelines, developed by Monash University researchers as part of an international team, will allow for more effective use of the drug and reduce the likelihood of bacteria developing resistance to it.

The team’s research paper, along with the new guidelines, has been published in the July issue of the international journal Antimicrobial Agents and Chemotherapy.

Professor Roger L. Nation and Associate Professor Jian Li, from the Monash Institute of Pharmaceutical Sciences, played a key role in initiating the international research effort that led to the current study.

They said colistin was increasingly the last option available to treat seriously ill patients who have infections caused by an important class of antibiotic-resistant bacteria, known as Gram-negative ‘superbugs’.

“The rise of antibiotic-resistant bacteria, combined with very few new antibiotics in development, has meant colistin is often the only treatment that hospital physicians can use in critically ill patients who are most at risk from a superbug infection,” Professor Nation said.

“Unfortunately, colistin was developed more than 50 years ago when manufacturers were not required to provide accurate dosing guidelines. This has meant doctors are often shooting in the dark with respect to how much colistin should be administered to individual patients.”

Professor Nation said insufficient dosage could leave patients vulnerable to infection and enable bacteria to become resistant, which could lead to more powerful superbugs in the future.

The international research team was able to develop a dosing formula for colistin based on their results from 105 critically ill patients administered the antibiotic.

All of the patients were already receiving colistin for either a bloodstream infection or pneumonia due to multi-drug resistant bacteria. The patients were located at hospitals in Thailand or the USA.

Associate Professor Li, who has worked with Professor Nation on colistin for more than 12 years, said the new guidelines would improve patient care.

“These scientifically-based guidelines will allow doctors to better use this very important last-line antibiotic and minimise the emergence of resistance,” Associate Professor Li said.

(Source: Monash University: Antimicrobial Agents and Chemotherapy)