September 20, 2019

Antimicrobial resistance rising rapidly in low, middle-income countries: study

A team of researchers led by Thomas Van Boeckel, SNF Assistant Professor of Health Geography and Policy at ETH Zurich, published on September 20 a map of antimicrobial resistance (AMR) in animals in low- and middle-income countries in the journal Science. The study is titled, "Global Trends in Antimicrobial Resistance in Animals in Low- and Middle-Income Countries".

Low- and middle income countries have limited surveillance capacities to track antimicrobial use and resistance on farms. Antimicrobial use is usually less regulated and documented there than in wealthy industrialised countries with established surveillance systems.

The team built a large literature database and examined where, and in which animals species resistance occurred for the common foodborne bacteria Salmonella, E. coli, Campylobacter and Staphylococcus.

The study identified north-eastern India, north-eastern China, northern Pakistan, Iran, eastern Turkey, south coast of Brazil, Nile delta, Red river delta in Vietnam and the areas surrounding Mexico City and Johannesburg as AMR hotspots. The trend was also seen in Kenya, Morocco, Uruguay, Brazil, Iran, Chile, besides central India and southern China.

An important finding of the study is that thus far, few resistance hotspots have emerged in Africa with the exception of Nigeria and the surroundings of Johannesburg.

The highest resistance rates were associated with the antimicrobials most frequently used in animals: tetracyclines, sulphonamides, penicillins and quinolones.

The researchers introduced a new index to track the evolution of resistance to multiple drugs: the proportion of drugs tested in each region with resistance rates greater than 50%. Globally, this index has almost tripled for chicken and swine over the last two decades. Currently, one third of drugs fail 50% of the time in chicken and one quarter of drugs fail in 50% of the time in swine.

"This alarming trend shows that the drugs used in animal farming are rapidly losing their efficacy," Van Boeckel says.

"Antimicrobial resistance is a global problem. There is little point in making considerable efforts to reduce it on one side of the world if it is increasing dramatically on the other side," he adds.

For their current study, the team of researchers from ETH, Princeton University and the Free University of Brussels gathered thousands of publications as well as unpublished veterinary reports from around the world. The researchers used this database to produce the AMR maps.

However, the maps do not cover the entire research area; there are large gaps in particular in South America, which researchers attribute to a lack of publicly available data. "There are hardly any official figures or data from large parts of South America," says co-author and ETH postdoctoral fellow Joao Pires. He said this surprised him, as much more data is available from some African countries, despite resources for conducting surveys being more limited than in South America. Scientists warn that missing AMR data in Uruguay, Paraguay, Argentina and Brazil is a global concern as these are large meat exporters.

The team has created an open-access web platform (LINK) to share their findings and gather additional data on resistance in animals. For example, veterinarians and state-authorities can upload data on resistance in their region to the platform and share it with other people who are interested.

Van Boeckel hopes that scientists from countries with more limited resources for whom publishing cost in academic journal can be a barrier will be able to share their findings and get recognition for their work on the platform. "In this way, we can ensure that the data is not just stuffed away in a drawer" he says, "because there are many relevant findings lying dormant, especially in Africa or India, that would complete the global picture of resistance that we try to draw in this first assessment. The platform could also help donors to identify the regions most affected by resistance in order to be able to finance specific interventions."

"The rich countries of the Global North, where antimicrobials have been used since the 1950s, should help make the transition a success," opines Van Boeckel.

Specifically for India, in 2017, the country put together a National Action Plan to tackle antibiotic resistance bringing together various sectors like healthcare and animal husbandry together. The programme aims to establish a surveillance network, generate quality data on AMR, strengthen infection control guidelines and practices, promote rational use of antibiotics, and generate awareness.

Most recently, the Indian government banned the use of one last-line antimicrobial drug, colistin, for use in animals (/contents/07-23-2019/576eed6a-fe23-4f94-827f-db809a6dc6eb-0604.html). "Colistin ban is a good step; there is absolutely no reason it should be used in animals, and usually for growth promotion," says Ramanan Laxminarayan, study co-author and director of Center for Disease Dynamics, Economics & Policy, Washington DC, United States.