In this episode of Tiny Show and Tell Us, we consider if bacteriophages could become our biggest allies in the fight against antibiotic resistance. Then we cover the historical role of "night soil men" and how some sewage treatment systems today are setting the standard for sustainable management of human excrement while also making sure we don't get sick.听
Transcript of this Episode
Sam: Welcome to Tiny Show and Tell Us, the bonus series where you write in with your favorite science news or factoid, and we read your email aloud and then dive deeper. I'm Sam Jones and I'm here with my co-host, Deboki Chakravarti.
Deboki: Hi, Sam. I'm really excited to hear what you are sharing on behalf of someone else. These episodes are a lot of fun, but before we kick off today, we need to give a big thank you to science journalist Ariana Remmel, who did the research for this episode, and also just a reminder that we can make these episodes because people have written in to make them possible. So if you'd like to contribute, send an email to tinymatters@acs.org or fill out the form linked in the episode description with your tiny show and tell us.
Okay, I will get started first.
Sam: Great.
Deboki: Sam, I have a story from listener Erica who says, "I work for a company developing bacteriophages as an alternative to antibiotics. More and more bacteria are becoming resistant to nearly all available antibiotics, and antibiotics can have serious side effects. Bacteriophages are a fascinating, effective and important alternative to antibiotics that can save lives with minimal side effects."
Sam: I'm interested and yeah, I want to hear about this.
Deboki: Yeah, yeah. So I mean, antibiotics are wonderful drugs. They've made a huge difference in medicine, but they have also come with their share of consequences, and so one of the major ones that we have to get started with is antibiotic resistance.
So antibiotics are molecules that are able to interfere with bacteria in some way. They might break up the cell wall. They make it harder for bacteria to kind of go about and do their thing, and so that obviously super helpful for infections. We want to disrupt whatever bacteria is causing the infection, throw an antibiotic at it, and hopefully that will take care of business.
Unfortunately, bacteria are also very, very, very good at adapting to things, and they've been able to evolve and adapt to these antibiotics, and that has led to the rise of antibiotic resistant infections, including some infections that have developed a superbug status. So that's a very questionable honor to us. They obviously love it. Well, they can't love it. They're a bacteria, but if they could love it and be honored, they would. These are things like C. difficile, MRSA, MDR, TB, they're that have gotten really good at resisting the antibiotics that have become otherwise pretty standard care in medicine. And according to the CDC, there are more than 2.8 million antimicrobial resistant infections in the US each year.
Sam: Yeah, that's a huge number.
Deboki: I never realized it was that many. I know antibiotic resistance is a huge issue. I just hadn't thought of it in those terms, and they've led to more than 35,000 deaths. And a really sad part about this is that they often end up being contracted while patients are staying in the hospital. And so in general, deaths from antimicrobial resistant infections were going down until 2020, which is of course the year that COVID hit. And during that time, infections that started in the hospitals actually started going up and they have stayed up at least for 2021 and 2022. I haven't seen the more recent numbers, but that's just really, I mean, there's so many unfortunate consequences of the pandemic, and this is another one of those.
And also, Erica mentioned in her question, even setting aside antibiotic resistance, antibiotics come with some pretty serious side effects. They can cause diarrhea, nausea, vomiting, dizziness, and also sometimes people are allergic to antibiotics, and so that's a big challenge as well. So there's a lot of good reasons for people to want to find an alternative to antibiotics, and this is where bacteriophages, which are sometimes also called phages, this is where they come in.
And so bacteriophages are basically just viruses that can infect bacteria. They were first discovered in the 1910s, and they were actually the thing that people were trying to use to treat bacterial diseases before antibiotics were discovered. So I just think that's really cool. It makes sense. We discover that these things infect bacteria, and so that's-
Sam: It's very logical. It's like if this thing can infect bacteria, then we should use it to kill them so that we're cured.
Deboki: Yeah, exactly. I'm not sure why we ended up with antibiotics. Maybe it's just we made it happen and we figured out how to make them. I assume it's something like that. But yeah, now we're coming back kind of full circle. And so there are viruses. What they do is they infect a host cell and they use that cell to replicate. Bacteriophages have different types of life cycles, and so if they're in what's called the lytic cycle, they can actually burst and kill the host cell. So people have been working on trying to figure out whether bacteriophages can replace antibiotics. So we found a recent paper from 2022 in the Journal of Biomedical Science titled "Bacteriophages and Antibiotic Interactions in Clinical Practice: What we have learned so far," and the authors bring up a few points in this paper. One of them is that phages work differently from antibiotics. Again, they're killing and bursting the host cell. So there isn't apparently the same kind of risk for developing resistance to phages that there is in antibiotics, but there's also the possibility that we could combine them. There's no reason to think, "Oh, we just have to use phage therapy or we just have to use antibiotics." They might actually be more effective if we use them in combination.
Sam: Right.
Deboki: At the same time though, the authors warned that there are cases where phages might hinder the performance of antibiotics. So there's just a lot that needs to be done.
Sam: Maybe because the phages are already interfering with the bacteria, so the antibiotics that typically would target a cell wall or this or that aren't going to be able to do what they need to do.
Deboki: Yeah, yeah. I wonder if the phages themselves are making molecules maybe for some aspect of their survival is adaptive to make sure that certain aspects of the bacteria are working. I'm really curious because I am sure it's really complicated deciding what phages you can use in what context, what kind of life cycle they're in, and how they're going to trigger that lytic cycle to happen.
Sam: I feel like, sorry to cut you off. I was just going to say this is such a thing too, where sometimes in biology you think these approaches could be additive, and then you have to really think about actually how could they be conflicting with each other? Because I think, logically, if we can take this bacteria from two sides, it's toast, but it actually could be worse and you should stick with just one. Which ... yeah, yeah.
Deboki: It's not this magical thing where you can just combine all of the therapies and they will make the magic therapy. Biology is so many different series of interactions that are so complex, and we're never really going to be able to process them all. So we're kind of just throwing things out there and hoping we get to something good that we can comprehend.
So phage therapy is a routine medical practice in some countries like Georgia, Poland and Russia. But in the US, phage therapy is not an FDA approved treatment, but according to the American 中国365bet中文官网 for Microbiology, there are some people who, if they've exhausted all the other approved treatments and they still have this infection persisting, they might qualify for expanded access. There's also a center at UC San Diego called the Center for Innovative Phage Applications and Therapeutics that's working towards making phage therapies a possibility in the US. So yeah, it's definitely something that people are working towards, including our listener, Erica. So I think obviously when it comes to bacterial infections, the more that we can diversify the way that we approach it, the more that seems like something we're going to really need to be able to do because bacteria are so adaptable. They've been around for so long.
Sam: I know. They're like, "You guys just showed up."
Deboki: Yeah, we're just tiny little babies to bacteria.
Sam: Exactly. Well, that's really interesting. All right. Well, I'm going to take ... you know what? I would say that if you want to go out on a limb, maybe this, what I'm going to share with you is somewhat related, literally just because it's about poop and we know there's a lot of bacteria in there. So that's it. That's the connection.
So I have a Tiny Show and Tell Us from listener Eliana who wrote in saying, "Hi. I recently listened to the Tiny Matters episode about sewage and the Seine, and it reminded me of this Twitter thread that I had read before about composting toilets, a small scale, modern take on essentially the night soil system mentioned in the episode using sawdust to control the smell. I recall the thread previously also having a link to a proposal for a large scale composting toilet system, which seems to have now been deleted. But the Marsh system used in Arcata ..."--I think it's Arcata, California. A-R-C-A-T-A, so I'm going to say Arcata. I'm sorry to people from Arcata if it's not pronounced Arcata--"... California is seriously impressive. The fact that carbon storing an ecosystem helping systems like this could also open up clean swimmable waterways is a nice bonus as well. Keep up the good work on the podcast." Thanks, Eliana.
Okay, so let's talk about this. First, unfortunately, that thread is no longer, but it's okay because there's still a lot to talk about.
Deboki: That's the problem with the internet. Everything is deleted, but also so hard to find again.
Sam: Right? It's like it lasts forever, yet sometimes you would have to spend hours and hours and hours tracking it down, so apologies to whoever started that thread. It sounds like it was very informative talking about composting toilets, et cetera, but we've still got a lot to talk about here.
So first, Eliana mentions that we mentioned the night soil system in our episode about sewage in the sun, which was Episode 64 from July of last year, but we did only talk about it briefly. I think it was like two sentences maybe. So what is night soil? It's a euphemism for human excrement and for millennia, people around the world have collected night soil from outhouses, latrines, other household bathroom facilities, and then have used it as agricultural fertilizers. So this practice though pretty much stopped in the West during the Industrial Revolution of the early 19th century.
So early 1800s, cities were growing. It became more difficult to collect and dispose of night soil, both because of the number of people who would need to get that service, and then also the distance between populated city centers and dump sites. If a city is growing, you really got to take it further and further outside that area. Otherwise things are going to get gross, which if you listen to Episode 64, you'll learn they often got very gross all the time for many centuries.
So back to the night soil, workers who were responsible for carting away night soil were called night soil men, and they were primarily required to do this work at night because it smells, it was kind of gross. In New York City, it was apparently pretty common to dump night soil directly into the Hudson River, and as we know from the episode that we did, dumping human excrement directly into rivers was just kind of what people did a lot of the time.
Deboki: I feel like this is nature's sewage system.
Sam: Really pleasant, and we're still trying to make up for it, although, obviously, that is not a good practice for the health of the river or the people who may be trying to get water from it or eat fish out of it or swim in it. Night soil as well as animal manure actually have a lot of nutrients that basically just go to waste with our current sanitation system, which also uses a ton of water. And so then that brings us to the marsh system in Arcata, California that Eliana mentioned.
So the Arcata Marsh and Wildlife Sanctuary in Northern California is an example of an industrial wastewater treatment facility that both sanitizes sewage and returns nutrients to the land, which is very cool. So most modern wastewater treatment plants, the Arcata facility first separates solid materials from soluble waste. The raw sewage that enters the plant is gravity filtered through a screen just to remove large debris, so that could be like gravel sticks, other stuff, that are carted off to a landfill. And then the solids are later collected as a sludge, which I know we talked about sludge, that is heated, stirred, and decomposed by anaerobic bacteria, another bacteria for the win. Bacteria do a lot of things, great things, bad things. They do it all.
Then that sludge is dried, mixed with wood chips and plant waste, and it's composted for use in the city's natural areas and parks, because at that point it has been broken down, it's been heated, it's gone through all of these sterilization processes. So it's cool. I mean, you could say like, "Oh, that's kind of gross that it's in the national areas and parks," but it's-
Deboki: I mean, that's happening anyways. That's the way that nature works in our parks. It's just other animal poo, basically.
Sam: Totally. Yeah. So I think there's something that some people think, but humans are so much grosser and we are pretty gross. However, this is a pretty cool way to do things in a way that's not going to make anybody sick, so I'm very pro.
Okay, so then the water purification part, once the solids have been removed, the liquid waste is pumped to oxidation ponds where aerobic bacteria and other microorganisms will naturally break down soluble organics in the water. And then after enough time has passed, the water will be pumped into a treatment marsh thick with floating and submerged plants. Very cool. Then these conditions will support different types of bacteria and microorganisms while the oxy ponds continue to break down remaining waste compounds. And so, the water is then disinfected, passed through a second wetland treatment phase to sort of polish it off, and then returned to Humboldt Bay, which is not far from San Francisco as clean water.
Deboki: That's really cool. And that's really impressive engineering too. I think it's cool how many different levels of thoughts seem to have gone into using as much as possible. I'm curious how well it works, how much it is able to actually conserve, or not conserve, but how much it's actually able to make use of our waste. Because I think if it works really well, that would be really cool to be able to see used more widely and just have our waste used more effectively so it's not actually waste. Because again, if we talk about nature. In nature, actually, waste isn't really a thing, I think. It's just a part of a bigger ecosystem, and that's sort of what they're reconstituting here, it feels like.
Sam: Right. They're trying to get back to a more natural nutrient cycling that our septic systems have really thrown off.
Deboki: And it's hard because we need those systems to help with our health, and so it's not like, oh, we got to return to just throwing poop in the water. That's not what we're trying to do. It's like, how do we kind of keep the thing that helps us and has made such a difference to human health, but also in a way that helps still keep things connected and doesn't actually treat waste as something that has nothing to offer.
Sam: Yeah. The tricky thing is that there are so many of us humans, we have now spread and harbor so many different diseases. It's not as simple as it once was.
Deboki: Back in the good old days of poo.
Sam: The good old days of poo, approximately 200,000 years ago. But yeah, so it's interesting like merging, I don't want to say the old and the new because it's not old. This is just how the ecosystems work, but bringing in, yeah, the natural element and then making sure that we also are ensuring that people are still protected and healthy.
I can't remember off the top of my head how much waste the Arcata facility brings in because I think that's one of the things too, right? Can we scale this up? Could this be something that exists just outside of, say, Washington DC as well, like that. It's really interesting.
Deboki: Yeah. Well, thank you. That was really neat.
Thanks to Eliana and Erica for sending in a Tiny Show and Tell Us a bonus episode from Tiny Matters created by the American Chemical 中国365bet中文官网 and produced by Multitude. And a big thank you again to science journalist, Ariana Remmel, who did the research for this episode.
Sam: Send us an email to be featured in a future Tiny Show and Tell Us episode at tinymatters@acs.org, or you can fill out the form that's linked in the episode description. We'll see you next time.
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