One Health Antibiotic Stewardship: Lessons from Colistin

As the number of effective antibiotics drops due to rising numbers of multidrug-resistant bacteria, clinicians increasingly rely on antibiotics of last resort to treat people who are infected with these bacteria.

This has led experts to focus on how to appropriately manage and regulate shared-use antibiotics in human and animal health.

In an article published in The Lancet Infectious Diseases, Marc Mendelson, PhD, from Groote Schuur Hospital, University of Cape Town, Cape Town, South Africa, and colleagues discuss the approach that South Africa has taken to promote stewardship of the last-resort antibiotic colistin.

“National One Health stewardship of colistin is pertinent to all shared-use antibiotics across the One Health platform,” the authors write.

Colistin has been used in veterinary medicine for decades, in particular, to treat Gram-negative gastrointestinal infections in poultry and pigs. In contrast, the antibiotic is a last-resort option for treating people in part because it is toxic to the kidneys.

However, the rising challenge of treating multidrug-resistant Gram-negative bacterial infections in people has led to the resurrection of antibiotics such as the polymyxin colistin.

Yet, the efficacy of colistin has now also been under threat since 2016, when the first transferable gene for colistin resistance was identified in China, and later in many other countries.

In response to increasing use of antibiotics and rising numbers of multidrug-resistant bacterial infections, South Africa created a program to advance national stewardship of colistin across the One Health platform of human, animal, and environmental health.

According to the authors, identification of the mobile colistin-resistance gene MCR-1 in Escherichia coli in South African poultry, and identification of MCR-1-induced colistin resistance in South African patients triggered the response.

This led to the formation of South Africa’s Colistin Working Group in 2016, assembled by the South African Medicines Control Council.

The Group analyzed data on colistin consumption, as well as data on resistance to colistin in people and animals in South Africa. They also evaluated a report by the European Medicines Agency which shared updated evidence and advice on colistin products for the European Union.

Based on all the available data, the Colistin Working Group provided detailed recommendations about what action the South African Government and stakeholders could take to alleviate colistin resistance.

These recommendations included: short-term interventions such as preventing compounding of medicines containing antibiotics and colistin for food-producing animals; medium-term interventions such as increasing surveillance of colistin residues in food; and long-term interventions such as phasing out the use of all antibiotics for growth promotion in food-producing animals.

Indeed, in 2016, the South African Veterinary Council also issued a letter to all members of the veterinary profession, effectively banning colistin use in food-producing animals. “It is recommended that colistin not be used in food-producing animals at all,” the letter stated, “unless the veterinarian can justify its use at the hand of a sensitivity test and as a very last resort to treat an animal. Any conduct to the contrary would be regarded by Council as unprofessional conduct.”

The Colistin Working Group found that information was lacking, however, about colistin resistance in the environment in South Africa. Studies did show sustained levels of antimicrobials (although colistin was not included in the analysis), agrochemicals, and personal care products in the effluent from 3 drinking water production facilities. The results also identified antibiotic-resistant bacteria in the same water from these 3 facilities.

Combined with the data on colistin resistance in people and animals, the findings from these environmental studies highlighted the need to establish an antimicrobial monitoring and evaluation program (to include colistin). This will be further developed in conjunction with the Ministerial Advisory Committee on Antimicrobial Resistance, the authors say, in collaboration with South Africa’s Water and Research Commission.

“We believe that our approach of convening intersectoral stakeholders across the One Health platform to develop a national strategy for the stewardship of antibiotics provides valuable lessons for future work in South Africa, and that such a method could be useful in other countries,” concluded Dr. Mendelson and colleagues.

Dr. Parry graduated from the University of Liverpool, England in 1997 and is a board-certified veterinary pathologist. After 13 years working in academia, she founded Midwest Veterinary Pathology, LLC where she now works as a private consultant. She is passionate about veterinary education and serves on the Indiana Veterinary Medical Association’s Continuing Education Committee. She regularly writes continuing education articles for veterinary organizations and journals and has also served on the American College of Veterinary Pathologists’ Examination Committee and Education Committee.