"There's a Bacteria For That"
Kira Peikoff was the editor-in-chief of Leaps.org from 2017 to 2021. As a journalist, her work has appeared in The New York Times, Newsweek, Nautilus, Popular Mechanics, The New York Academy of Sciences, and other outlets. She is also the author of four suspense novels that explore controversial issues arising from scientific innovation: Living Proof, No Time to Die, Die Again Tomorrow, and Mother Knows Best. Peikoff holds a B.A. in Journalism from New York University and an M.S. in Bioethics from Columbia University. She lives in New Jersey with her husband and two young sons. Follow her on Twitter @KiraPeikoff.

Bacteria Lactobacillus, gram-positive rod-shaped lactic acid bacteria which are part of normal flora of human intestine are used as probiotics and in yogurt production, close-up view. (Image copyright: Fotolia)
"There's an app for that." Get ready for a cutting-edge twist on this common phrase. In the life sciences, researchers in the field of synthetic biology are engineering microbes to execute specific tasks, like diagnosing gut inflammation, purifying dirty water, and cleaning up oil spills. Here are five academic and commercial projects underway now that will make you want to add the term "designer bacteria" to your vocab.
1) Bacteria that can sense, diagnose and treat disorders of the gut.
Dr. Pamela Silver at Harvard Medical School has engineered non-pathenogenic strains of E. Coli bacteria, which she calls "living diagnostics and therapeutics," to accurately sense whether an animal has been exposed to antibiotics and whether inflammation is present in its intestines.
Imagine a "living FitBit" that could report on your gut health in real time.
So how does it work? "The bacteria have a genetic switch like a light switch," she explains, "and when they are exposed to an antibiotic or an inflammatory response, the light switch flips to on and the bacteria turn color." In a study that Silver and her colleagues published earlier this year, the bacteria in mouse guts turned blue when exposed to the chemical tetrathionate, which is produced during inflammation. Then, when the animal excreted waste, its feces were also blue. For safety reasons, the excreted bacteria can additionally be programmed to self-destruct so as not to contaminate the environment.
The implications for human health go way beyond a non-invasive alternative to colonoscopies. Imagine "a living FitBit," Silver says with a laugh – a probiotic your doctor could prescribe that could colonize your gut to report on your intestinal health and your diet—and even treat pathogens at the same time. Another potential application is to deploy this new tool in the skin as a living sensor. "Your skin has a defined population of bacteria and those could be engineered to sense a lot," she says, such as pathological changes and toxic environmental exposures.
But one big social question in this emerging research remains how open the public and regulators will be to genetically modified organisms as drugs. Silver says that acceptance will require "patient advocacy, education, and showing these actually work. We have shown in an animal that it can work. So far, in humans, it's unclear."
"Live biotherapeutic products" is a whole new category of drug.
2) Bacteria that can treat a rare metabolic disease.
The startup company Synlogic, based in Cambridge, Mass., has designed an experimental pill containing a strain of E. Coli bacteria that can soak up excess ammonia in a person's stomach, treating those who suffer from toxic elevated blood ammonia levels. This condition, called hyperammonemia, can occur in those with chronic liver disease or genetic urea cycle disorders. The pill is genetically engineered to convert ammonia into a beneficial amino acid instead.
Just a few weeks ago, the company announced positive data from its Phase 1 trial, in which the pill was tested on a group of 52 healthy volunteers for the first time. The study was randomized, double-blind and placebo-controlled, which means that neither the researchers nor the subjects knew who was getting the active pill vs. a sham one. This design is the gold standard in clinical research because it overcomes bias and produces objective results. So far, the pill appears to be safe and well-tolerated, and the company plans to continue the next phase of testing in 2018. Synlogic's treatment stands to be the first of this category of therapy—called "live biotherapeutic products"—that will be scrutinized by the FDA when the time comes for possible market approval.
3) Bacteria that can be sprayed on land to clean up an oil spill.
"This is science fiction, but it's become a lot less science fiction in the last couple of years," says Floyd E. Romesberg, a professor of chemistry whose lab at the Scripps Research Institute in California is on the forefront of synthetic biology.
"We have literally increased the biology that cells can write stories with."
His lab has added two new letters to the code of life. At the most fundamental level, all life on Earth, including human, animal, and bacteria, relies on the four "letters" or chemical building blocks of A, T, C, and G to store biological information inside a cell and then retrieve it in the form of proteins that perform essential tasks. For the first time in history, Romesberg and his team have now developed an unnatural base pair—an X and a Y—capable of storing increased information.
"We have literally increased the biology that cells can write stories with," he says. "With new letters, you can write new words, new sentences, and you can tell new stories, as opposed to taking the limited vocabulary you have and trying to rearrange it."
The implications of his research are immense; applications range from developing therapeutic proteins as drugs, to bestowing cells with new properties, such as oxidizing oil after a spill. He imagines a future scenario in which, for example, specially engineered bacteria are sprayed on a beach, eat the oil for three generations of their life—less than a day—and then die off, since they will be unable to replicate their own DNA. Afterwards, the beach is clean.
"What we are struggling with now is the first steps toward doing that – the cell relying on unnatural information to survive, rather than doing something new yet," he says, "but that's where we are headed."
4) Bacteria that can deliver cancer-killing drugs inside tumors.
Researcher Jeff Hasty at UCSD has engineered a strain of Salmonella bacteria to penetrate cancer tumors and deliver drugs that stop their growth. His approach is especially clever because it solves a major problem in cancer drug delivery: chemotherapy relies on blood vessels for transit, but blood vessels don't exist deep inside tumors. Using this fact to his advantage, Hasty and his team designed bacteria that can sneak drugs all the way into a tumor and then self-destruct, taking the tumor down in the process.
So far, the treatment in mice has been successful; their tumors stopped growing after they were given the bacteria, and along with the use of chemotherapy, their life expectancy increased by half.
Many questions remain in terms of applicability to tumors in human beings, but the notion of a bacterial therapy remains a promising clinical approach for treating cancer in the future.
Craft beer experts couldn't tell the difference between beer brewed with regular vs. recycled water.
5) Bacteria that can convert wastewater into drinkable water.
Boston-based company Cambrian Innovation has a patented product called the EcoVolt MINI that uses microbes to generate energy through contact with electrodes. The company has collaborated with breweries across the country, taking their waste water and converting it to clean water and clean energy. Through the company's bioelectrochemical system, microbes eat the contaminants in the wastewater, and as a byproduct they produce methane, which can be converted to heat and power; in some cases, the process generates enough energy to send some back to the brewery.
"The main goal of the system is to produce cleaner water; the energy is an added product," explains Claire Aviles, Cambrian's marketing and communications manager.
The wastewater treatment is so effective that the water can be made suitable for reuse. One brewery client, for example, recently experimented with using the recycled water to brew a beer at a festival in California. They used the same recipe for two beers—one with typical city water and one with recycled water from Cambrian's system—and offered a side-by-side taste test to consumers and craft beer experts alike.
"Most people couldn't tell which was which," Aviles says.
In fact, most of the tasters preferred the beer brewed with the recycled water.
Turns out bacteria aren't always dirty after all.
Kira Peikoff was the editor-in-chief of Leaps.org from 2017 to 2021. As a journalist, her work has appeared in The New York Times, Newsweek, Nautilus, Popular Mechanics, The New York Academy of Sciences, and other outlets. She is also the author of four suspense novels that explore controversial issues arising from scientific innovation: Living Proof, No Time to Die, Die Again Tomorrow, and Mother Knows Best. Peikoff holds a B.A. in Journalism from New York University and an M.S. in Bioethics from Columbia University. She lives in New Jersey with her husband and two young sons. Follow her on Twitter @KiraPeikoff.
Why we don’t have more COVID-19 vaccines for animals
COVID-19 vaccines for humans number 30, while only three vaccines are available for animals, even though many species have been infected.
Responding to COVID-19 outbreaks at more than 200 mink farms, the Danish government, in November 2020, culled its entire mink population. The Danish armed forces helped farmers slaughter each of their 17 million minks, which are normally farmed for their valuable fur.
The SARS-CoV-2 virus, said officials, spread from human handlers to the small, ferret-like animals, mutated, and then spread back to several hundred humans. Although the mass extermination faced much criticism, Denmark’s prime minister defended the decision last month, stating that the step was “necessary” and that the Danish government had “a responsibility for the health of the entire world.”
Over the past two and half years, COVID-19 infections have been reported in numerous animal species around the world. In addition to the Danish minks, there is other evidence that the virus can mutate as it’s transmitted back and forth between humans and animals, which increases the risk to public health. According to the World Health Organisation (WHO), COVID-19 vaccines for animals may protect the infected species and prevent the transmission of viral mutations. However, the development of such vaccines has been slow. Scientists attribute the deficiency to a lack of data.
“Several animal species have been predicted and found to be susceptible to SARS-CoV-2,” says Suresh V. Kuchipudi, interim director of the Animal Diagnostic Laboratory at the Huck Institutes of Life Sciences. But the risk remains unknown for many animals in several parts of the world, he says. “Therefore, there is an urgent need to monitor the SARS-CoV-2 exposure of high-risk animals in different parts of the world.”
In June, India introduced Ancovax, its first COVID-19 vaccine for animals. The development came a year after the nation reported that the virus had infected eight Asiatic lions, with two of them dying. While 30 COVID-19 vaccines for humans have been approved for general or emergency use across the world, Ancovax is only the third such vaccine for animals. The first, named Carnivac-Cov, was registered by Russia in March last year, followed by another vaccine four months later, developed by Zoetis, a U.S. pharmaceutical company.
Christina Lood, a Zoetis spokesperson, says the company has donated over 26,000 doses of its animal vaccine to over 200 zoos – in addition to 20 conservatories, sanctuaries and other animal organizations located in over a dozen countries, including Canada, Chile and the U.S. The vaccine, she adds, has been administered to more than 300 mammalian species so far.
“At least 75 percent of emerging infectious diseases have an animal origin, including COVID-19,” says Lood. “Now more than ever before, we can all see the important connection between animal health and human health."
The Dangers of COVID-19 Infections among Animals
Cases of the virus in animals have been reported in several countries across the world. As of March this year, 29 kinds of animals have been infected. These include pet animals like dogs, cats, ferrets and hamsters; farmed animals like minks; wild animals like the white-tailed deer, mule deer and black-tailed marmoset; and animals in zoos and sanctuaries, including hyenas, hippopotamuses and manatees. Despite the widespread infection, the U.S. Centres for Diseases Control and Prevention (CDC) has noted that “we don’t yet know all of the animals that can get infected,” adding that more studies and surveillance are needed to understand how the virus is spread between humans and animals.
Leyi Wang, a veterinary virologist at the Veterinary Diagnostic Laboratory, University of Illinois, says that captive and pet animals most often get infected by humans. It goes both ways, he says, citing a recent study in Hong Kong that found the virus spread from pet hamsters to people.
Wang’s bigger concern is the possibility that humans or domestic animals could transmit the virus back to wildlife, creating an uncontrollable reservoir of the disease, especially given the difficulty of vaccinating non-captive wild animals. Such spillbacks have happened previously with diseases such as plague, yellow-fever, and rabies.
It’s challenging and expensive to develop and implement animal vaccines, and demand has been lacking as the broader health risk for animals isn’t well known among the public. People tend to think only about their house pets.
In the past, other human respiratory viruses have proven fatal for endangered great apes like chimpanzees and gorillas. Fearing that COVID-19 could have the same effect, primatologists have been working to protect primates throughout the pandemic. Meanwhile, virus reservoirs have already been created among other animals, Wang says. “Deer of over 20 U.S. states were tested SARS-CoV-2 positive,” says Wang, pointing to a study that confirmed human-to-deer transmission as well as deer-to-deer transmission. It remains unclear how many wildlife species may be susceptible to the disease due to interaction with infected deer, says Wang.
In April, the CDC expressed concerns over new coronavirus variants mutating in wildlife, urging health authorities to monitor the spread of the contagion in animals as threats to humans. The WHO has made similar recommendations.
Challenges to Vaccine Development
Zoetis initiated development activities for its COVID-19 vaccine in February 2020 when the first known infection of a dog occurred in Hong Kong. The pharmaceutical giant completed the initial development work and studies on dogs and cats, and shared their findings at the World One Health Congress in the fall of 2020. A few months later, after a troop of eight gorillas contracted the virus at the San Diego Zoo Safari Park, Zoetis donated its experimental vaccine for emergency use in the great ape population.
Zoetis has uniquely formulated its COVID-19 vaccine for animals. It uses the same antigen as human vaccines, but it includes a different type of carrier protein for inducing a strong immune response. “The unique combination of antigen and carrier ensures safety and efficacy for the species in which a vaccine is used,” says Lood.
But it’s challenging and expensive to develop and implement animal vaccines, and demand has been lacking as the broader health risk for animals isn’t well known among the public. People tend to think only about their house pets. “As it became apparent that risk of severe disease for household pets such as cats and dogs was low, demand for those vaccines decreased before they became commercially available,” says William Karesh, executive vice-president for health and policy at EcoHealth Alliance. He adds that in affected commercial mink farms, the utility of a vaccine could justify the cost in some cases.
Although scientists have made tremendous advances in making vaccines for animals, Kuchipudi thinks that the need for COVID-19 vaccines for animals “must be evaluated based on many factors, including the susceptibility of the particular animal species, health implications, and cost.”.
Not every scientist feels the need for animal vaccines. Joel Baines, a professor of virology at Cornell University’s Baker Institute for Animal Health, says that while domestic cats are the most susceptible to COVID-19, they usually suffer mild infections. Big cats in zoos are vulnerable, but they can be isolated or distanced from humans. He says that mink farms are a relatively small industry and, by ensuring that human handlers are COVID negative, such outbreaks can be curtailed.
Baines also suggests that human vaccines could probably work in animals, as they were tested in animals during early clinical trials and induced immune responses. “However, these vaccines should be used in humans as a priority and it would be unethical to use a vaccine meant for humans to vaccinate an animal if vaccine doses are at all limiting,” he says.
William Karesh, president of the World Animal Health Organization Working Group on Wildlife Diseases, says the best way to protect animals is to reduce their exposure to infected people.
William Karesh
In the absence of enough vaccines, Karesh says that the best way to protect animals is the same as protecting unvaccinated humans - reduce their exposure to infected people by isolating them when necessary. “People working with or spending time with wild animals should follow available guidelines, which includes testing themselves and wearing PPE to avoid accidentally infecting wildlife,” he says.
The Link between Animal and Human Health
Although there is a need for animal vaccines in response to virus outbreaks, the best approach is to try to prevent the outbreaks in the first place, explains K. Srinath Reddy, president of the Public Health Foundation of India. He says that the incidence of zoonotic diseases has increased in the past six decades because human actions like increased deforestation, wildlife trade and animal meat consumption have opened an ecological window for disease transmission between humans and animals. Such actions chip away at the natural barriers between humans and forest-dwelling viruses, while building conveyor belts for the transmission of zoonotic diseases like COVID-19.
Many studies suggest that the source of COVID-19 was infected live animals sold at a wet market in China’s Wuhan. The market sold live dogs, rats, porcupines, badgers, hares, foxes, hedgehogs, marmots and Chinese muntjac (small deer) and, according to a study published in July, the virus was found on the market’s stalls, animal cages, carts and water drains.
This research strongly suggests that COVID-19 is a zoonotic disease, one that jumps from animals to humans due to our close relationship with them in agriculture, as companions and in the natural environment. Half of the infectious diseases that affect people come from animals, but the study of zoonotic diseases has been historically underfunded, even as they can reduce the likelihood and cost of future pandemics.
“We need to invest in vaccines,” says Reddy, “but that cannot be a substitute for an ecologically sensible approach to curtailing zoonotic diseases.”
Podcast: The Friday Five weekly roundup in health research
Researchers are making progress on a vaccine for Lyme disease, sex differences in cancer, new research on reducing your risk of dementia with leisure activities, and more in this week's Friday Five
The Friday Five covers five stories in health research that you may have missed this week. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on scientific creativity and progress to give you a therapeutic dose of inspiration headed into the weekend.
Covered in this week's Friday Five:
- Sex differences in cancer
- Promising research on a vaccine for Lyme disease
- Using a super material for brain-like devices
- Measuring your immunity to Covid
- Reducing risk of dementia with leisure activities
Matt Fuchs is the editor-in-chief of Leaps.org. He is also a contributing reporter to the Washington Post and has written for the New York Times, Time Magazine, WIRED and the Washington Post Magazine, among other outlets. Follow him on Twitter @fuchswriter.