The moose that amble through Alaska’s largest city are leaving more in their wake than piles of nugget-shaped feces.
Within that scat, researchers from the University of Alaska Anchorage have discovered, is something troubling: microbes that are resistant to several varieties of antibiotics.
Antibiotic-resistant Escherichia coli, a pathogen commonly abbreviated as E. coli, and other antibiotic-resistant microbes have been found in moose scat collected from locations throughout Anchorage and in some areas beyond – by waterways, in parks, in backyard in residential neighborhoods, in parking lots near medical facilities and elsewhere. Possibly most concerning is the discovery of antibiotic resistance in moose scat collected from wooded areas used for camping by homeless people, said Grace Leu-Burke, the assistant UAA College of Health professor leading the research project. That is what has struck her students, Leu-Burke said. “They’re really worried about the homeless people. Because the first thing is they don’t have access to clean water. And it’s right there,” she said.
Among the hot spots for moose scat collection is a wooded pathway just south of the UAA Health Sciences Building, where her office and lab are located. There, by a bridge that crosses a small creek on a sunny March morning, was a small pile of food containers and other trash left, evidence of a makeshift campsite.
“When I see this, I just worry,” Leu-Burke said, indicating the debris. She and her students have even found drug-injecting needles in some scat-collection sites, she said.
More than 1,000 moose live in or walk through Anchorage, it is estimated. There is no sign that the presence of antibiotic-resistant microbes is causing any health problems for them, Leu-Burke said.
But the pathogens could make their way to people, and the most likely transmitters would be dogs, she said.
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Pharmaceutical antibiotics have been in use for about a century. In 1928, penicillin derived from mold was found to kill many bacteria that historically led to illness and death. Over time, their use expanded beyond human health to agricultural purposes, including mass-scale dosing of livestock. While antibiotics are valuable for human and animal health, their widespread use has an unfortunate side effect: evolution of resistant bacteria that do not respond to various types of antibiotics. That has led medical and agricultural policymakers around the world to develop more careful protocols for antibiotic use. There are now national and international programs working on ways to combat the spread of antibiotic resistance.
Antibiotic resistance has caused health problems for people in Anchorage, as has been the case elsewhere. Six Alaska hospital patients have been identified since the start of 2022 with serious infections of antibiotic-resistant pathogens, according to a recent bulletin from the state Division of Public Health’s epidemiology section. A decade ago, antibiotic-resistant infections were linked to deaths of some Alaska hospital patients.
Leu-Burke, who iss program director of medical laboratory science at UAA’s School of Allied Health, started her UAA moose-surveillance work in 2018. For consistency, samples are collected at the same time of the year, in the spring, when snow is softening. Samples are frozen for a year before being cultured. As of this spring semester, there will have been over 300 scat samples cultured, she said.
Results from samples collected from 2018 to 2020, which Leu-Burke presented on February 28 at a One Health conference hosted by the University of Alaska Fairbanks, show about 40% of the collected scat had E. coli that survived the year of freeze. Among those, there was resistance to all types of antibiotics tested.
Those findings may be disheartening, but they are not surprising, said Christina Ahlstrom, a geneticist with the U.S. Geological Survey’s Alaska Science Center who has been studying antibiotic resistance in Alaska birds.
“It’s not good. But I think this is just the world that we are living in at the moment,” said Ahlstrom, who has been working with USGS colleagues to track gulls at various Alaska locations.
What they have found in their studies of gulls is consistent with other studies: Where there is more human presence, such as in cities with big, open, bird-attracting landfills, there is more likelihood that that gulls will carry antibiotic-resistant microbes. Gulls can also carry those microbes over long distances as they migrate, the USGS scientists have found.
Even Arctic terns, which fly between the Arctic and Antarctic and are the world’s longest-distance migratory birds, can carry antibiotic-resistant microbes, other research has found.
While Ahlstrom said she does not know of any studies of antibiotic resistance in Alaska mammals other than Leu-Burke’s work, there have been studies of mammals in somewhat similar environments.
A 2021 study detailed “widespread” presence of antibiotic-resistant microbes in harbor seals and harbor porpoises in Washington state’s Salish Sea, for example. A 2021 Swedish study of wild bears that analyzed both modern animals and museum specimens dating back as far as 180 years found a pattern reflecting human use of antibiotics. There was some good news in the study: It found that antibiotic resistance levels in bears decreased in recent years, suggesting that recent controls on antibiotic use and management have had a positive effect.
Ahlstrom pointed out that there is some natural antibiotic resistance in the environment, but it is usually associated with bacteria that does not carry diseases that infect people or animals. When the resistance shows up in bacteria like E. coli, it has probably been introduced by humans in some way, she said.
“It really shouldn’t be there, and we really don’t know what the consequences are for the ecosystem,” she said.
Tracking the precise pathways of human-introduced antibiotic resistance is difficult.
For Anchorage moose, likely deliverers are birds like those being monitored by the USGS scientists, Leu-Burke said. “That’s the most common, and that’s really a strong indicator,” she said.
That is logical, she said: Birds fly around source sites like local wastewater streams and, if they have migrated from the south, big agricultural operations, and they share space in Anchorage with moose. Evidence of the link is in the discoveries made by her team of overlap in the type of antibiotic-resistant microbes carried by moose and birds, especially along waterways.
But her group has also found some differences in the bacterial types, indicating non-bird sources. Leu-Burke said it makes her wonder if there are possible effects to bark-eating moose from pesticides being sprayed on trees to protect them from beetle infestations.
On the positive side, the work has become effective hands-on education for enthusiastic student researchers, who are able to do lab work that goes beyond an academic exercise and has real-life significance, Leu-Burke said. Her students carry fecal-collection kits in their backpacks, even during spring break, a prime collection period, and she is also busy during that time of the year. “That’s why I’m never off on spring break,” she said.
Though moose in highly traveled Anchorage remains the main focus, some students have branched out to other locations and to other mammals.
Caribou scat samples collected by one student from the Tok and Chicken areas, for example, produced results that were inconclusive but raised enough questions to warrant further investigation. Bear scat collected by another student by Eklutna Lake tested positive for some antibiotic resistance microbes.
As the surveillance work continues, important lessons are emerging, she said. One is to consider environmental factors as well as risks of prescription-medicine overuse.
“What I try to impress upon the medical community is that we have to stop thinking that all our antimicrobial resistance is coming from misuse of antibiotics,” she said.
Another lesson is that Anchorage-area residents should handle moose scat in the same way they handle any potential infectious agent, she said. That means the Alaska tradition of using moose nuggets as garden fertilizer might no longer be a good idea, she said.
“I don’t think it’s a safe use for compost at this time, at least in the Anchorage Bowl area,” she said. “I’m all one for doing natural stuff, but it’s got more things in it than I suspected.”
That goes for another once-accepted use of moose nuggets – the crafting of them into gift items like necklaces and cocktail swizzle sticks.
“There is no zero-risk anymore, is what I’m saying. We can no longer make jewelry out of moose scat,” she said.
Alaska Beacon is part of States Newsroom, a network of news bureaus supported by grants and a coalition of donors as a 501c(3) public charity. Alaska Beacon maintains editorial independence. Contact Editor Andrew Kitchenman for questions: info@alaskabeacon.com. Follow Alaska Beacon on Facebook and Twitter.
