Antibiotic resistance occurs when microorganisms such as bacteria and fungi acquire the capacity to resist the treatments meant to destroy them. Because these hazardous microorganisms continue to multiply, diseases caused by antibiotic-resistant pathogens are becoming more difficult, if not impossible, to cure. To make matters worse, antibiotic-resistant bacteria were recently detected in the digestive tracts of lemurs – specifically those considered pets.
Researchers at Duke University uncovered indications of antibiotic resistance in the digestive tracts of lemurs living near people. The closer the interaction, the greater the amount of antibiotic resistance discovered, according to the findings.
Professor of Evolutionary Anthropology Christine Drea and graduate student Sally Bornbusch conducted a study in which they collected ring-tailed lemur feces to sequence the DNA of each bacterial species in order to check for genetic indicators of antibiotic resistance. A total of ten populations of lemurs were examined in the research including one from Madagascar’s Lemur Rescue Center, one from the Duke Lemur Center in North Carolina, one from the pet lemur population in Madagascar, and seven from Madagascar’s wild.
In the gut microflora of wild lemurs, the average percentage of resistance genes is essentially zero. However, in captive lemurs, this percentage is 25 times higher. This percentage seems to increase even further to about 35 times in pet lemurs compared to wild lemurs.
Researchers say competent veterinary care is to blame. Lemurs at research institutions are given medications, such as antibiotics, for illnesses. Not surprisingly, they have more direct exposure to these drugs than their natural relatives, and therefore, developed antibiotic-resistant gut microbes.
On the other hand, pet lemurs, who had not had veterinary treatment, were shown to have the greatest concentration of antibiotic resistance genes. Because it is prohibited in Madagascar to own a lemur as a pet, individuals who do so are reluctant to take them to a vet and risk incurring legal penalties. Therefore, this indicates that these antibiotic-resistant microorganisms are being passed on to their companion pet lemurs by sharing their habitat with them.
The lemurs’ physical and social environments seem to be a significant factor in their resistance to antibiotics, according to Bornbusch. Because they are generalists by nature, ring-tailed lemurs feed on anything from feces to dirt. However, within the confines of a home setting, they are most likely fed human or pet food and being nestled in the laps of their owners.
“Microbes are like an overlaying blanket on everything. They’re not only in our guts, but also on our skin, our furniture, and in our food and water,” Bornbusch adds. “They’re everywhere, all the time, and they are easily transmitted between environments.” Because of this, Bornbusch and experts warn that domesticating these animals is dangerous to lemurs as well as humans.
Wild lemurs have different levels of resistance to antibiotics based on how many people lived near them, based on the results. Lemurs that live in areas where livestock graze, crops are farmed, or visitors travel have more antibiotic-resistant organisms than those that live in virtually untouched areas. However, they still have significantly fewer antibiotic resistance bacteria than lemurs that live near humans. “Antibiotic treatment is clearly not the only mechanism leading to a higher abundance of resistance genes in these animals,” says Bornbusch.
Interestingly, a comparable amount of antibiotic resistance genes are found in lemurs kept in research institutions that have not previously been treated for illness. The types of resistance genes obtained appeared to be influenced by the lemur’s proximity to people. Ring-tailed lemurs from Madagascar have gut microbes resistant to medicines used to fight plagues that cause outbreaks. Conversely, American lemurs have gut microbes resistant to antibiotics commonly administered in the U.S.
These antibiotic-resistance genes have been around for a long time – changing and developing in microorganisms as part of a defense mechanism against antibiotics found in nature.This function is seldom an issue in a naturalistic environment. That is, until people exploited the potency of natural antibiotics and made them widely available. “Humans came along, developed antibiotics, spread them all around us, and propagated these resistance genes into natural environments and into the microbiomes of wildlife,” says Bornbusch.
This research has the potential to improve conservation and animal treatment methods. “Even if these results are slightly scary, they help us use microbiome science to hone veterinary practices and conservation activities,” adds Bornbusch.
More study is required in order to truly comprehend the effects of these resistant genes on animals. “Right now, we know that these resistance genes are out there, but we don’t know whether they are truly harmful to lemurs,” says Bornbusch. “These results give us a stepping-stone for research on the impact of these resistant microbes on wildlife and their environment.”
This study is published in Frontiers in Ecology and Evolution.