E15 - wasterwater surveillance & ID
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[00:00:07] Nav: Hello and welcome back to communicable the podcast brought to you by CMI Communications ESCMID's open access journal covering infectious diseases and clinical microbiology. My name is Navaneeth Narayanan. I'm an infectious disease pharmacist and clinical associate professor at Rutgers University in the United States and an editor at CMI Communications.

[00:00:26] Nav: I'm joined by my co host Emily McDonald. A subspecialty physician in general internal medicine and a scientist at the Research Institute of , McGill University Health Center in Montreal, Canada, and a fellow editor at CMI communications.

[00:00:41] Emily: Hi, everyone.

[00:00:42] Nav: Today's episode is really going to dive into a powerful epidemiological tool that I think most of us, have heard about, but want to know more about, which is wastewater surveillance and we're lucky to have 2 expert guests with us. The 1st is Dr. Nasreen Hassoun-Kheir. Dr. Hassoun-Kheir received her, medical degree from Technician, Israel Institute of technology in 2010 completed her internal medicine specialization in 2017 and infectious disease training in 2021 at Rambam healthcare campus. Since then, she has joined the unit of infection, prevention and control at Geneva University hospitals and WHO collaborating centers.

[00:01:20] Nav: On an AMR research fellowship, Dr. Hassoun-Kheir has been pursuing a master's in science and epidemiology at the London School of hygiene and tropical medicine. since 2022 Her main research interests include the burden of. cross transmission of multi drug resistant organisms, hospital acquired infections and aquatic ecosystems as reservoirs for resistant pathogens.

[00:01:42] Nav: She is currently working on a JPI AMR funded reservoir project focusing on hospital wastewaters for sentinel surveillance of AMR.

[00:01:51] Nasreen: Hi, everyone. Thank you for having me here.

[00:01:53] Emily: Our second guest is professor David Graham. Professor David Graham has led numerous environmental and health surveillance projects around the world for almost 40 years.

[00:02:02] Emily: He was co lead author of the 2023 UNEP report Bracing for Superbugs, Strengthening Environmental Action in the One Health Response to Antimicrobial Resistance, and is chair of the integration team preparing the new UN Quadripartite Guide for One Health Integrated Surveillance of Antimicrobial Use and Resistance.

[00:02:20] Emily: Graham co initiated the Pan American Network for Environmental Epidemiology, co authored the 2021 World Economic Forum report on the economics of waterborne AMR, and was a UK expert advisory group who helped operationalize the COVID 19 wastewater surveillance network during the pandemic. Graham is also a chartered professional and civil engineer.

[00:02:40] Emily: With further expertise in microbial genetics and genomics and environmental chemistry. Among his current interests is employing AI and machine learning to identify gaps in global health research. He's emeritus professor of engineering at Newcastle University in the UK and a research professor at Durham University and also a visiting professor at the Chinese Academy of Sciences.

[00:03:00] Emily: David, welcome to Communicable.

[00:03:01] David: Thank you for having me.

As our listeners know, we usually start these episodes off with an icebreaker or a get to know you question for our guests, also for our hosts. So my question today is, what was the first time you remember being excited about science or sparked to go into the field or your current career now?

I'll start first. I was first inspired in grade 10 chemistry class. I thought that my teacher was really cool and I loved the way that he taught chemistry. So I went on to do a bachelor in chemistry in university and one of my professors there I also found really inspiring.

[00:03:40] Emily: So the reason I'm telling you this story is because I had these two chemistry professors who I found really funny, inspiring. They really, of sparked me to go into science. And then a couple of years later, after I graduated, I learned that they were actually best friends from elementary school.

[00:03:56] Emily: So, that's how I got into science in the first place. how about you, Nev?

[00:04:01] Nav: So, that's almost as the fact that my answer was going to be my high school chemistry teacher as well, who was absolutely engaging and funny. I mean, the science was quite interesting, but he was just so funny in the stories he told us about all the things that he did.

[00:04:17] Nav: at this point, I wouldn't be surprised if he was related to one of your chemistry teachers now to make the story even better. But, We'll never know. that along with honestly, just, when I was even younger watching this, a us based show called, Bill Nye, the science guy, and just how fun those experiments were, but then it really came to fruition when I had chemistry in high school.

I promise we didn't talk about that beforehand.

[00:04:38] Emily: Unplanned.

[00:04:39] Nav: David, what about you?

[00:04:41] David: Well, my story is completely different. when I was a high school student, I wanted to be a professional baseball player, and I signed a contract outta baseball, and I didn't even think about science. I, I was pretty good as a student, but my baseball with my priority and, as it turned out, when I signed the contract, I simply wasn't good enough.

[00:04:59] David: And so I didn't really know what to do. And my brother happened to be in engineering university. And because I was pretty good at mathematics, I decided I'd do that with not really any goal in mind. However, what I'd always loved was water. I loved everything to do with water. And so I migrated into the water engineering program and did my bachelor's and master's. And still not knowing what I was going to do, I went to the Dominican Republic to work in a hospital as an intern. I thought after doing that, I was going to come back and do a medical degree.

[00:05:31] David: But through a series of unexpected events, I ended up not doing that and working in industry for a while, ultimately going back and doing my PhD somewhat later. So the inspirational moment for me was. when I started my PhD, because I was going to do it in hydrogeology and my professor, my advisor said, if you want to do anything for me, whether it's physics or chemistry or biology, you've got to take a biochemistry class in a medical school.

[00:06:00] David: And I'd never taken a biology class before. And so I took this class in the medical school I just absolutely loved it. my background is kind of strange is that I'm a practicing civil engineer with degrees in biochemistry and genetics with a very medical and health oriented bias.

[00:06:18] David: wasn't really 1 inspiration, but it was a series I followed that ended up in what I do, which is sort of medicine at mass scales through water and environmental protection.

[00:06:29] Emily: Very cool. last but not least, Nasreen.

[00:06:33] Nasreen: Well, for me, I went back to, a cartoon show that I used to watch as a kid called Once Upon a Time Life. I don't know, it was broadcasted all around the world and translated to many different languages and it just pictured the human body from the inside. So you had, like, snapshots of a kid going in the park and then, you know.

[00:06:52] Nasreen: Microbes are getting inside the body and the, superheroes of the white blood cells turning on and starting to fight and, it was fascinating for me as a kid to see how do our body look from the inside and how it acts like a whole system, a whole universe and all these actors. it really was very inspiring to me.

[00:07:13] Nasreen: I don't know how much it seeded the way for me to become an infectious disease physician or a medical doctor, but I was always interested in that. along the way, as David say, you learn new things, you are exposed to many different elements and you. Zoom in to, your passion in science and your excitement about the world around.

[00:07:34] Nasreen: And I guess an infectious diseases field of work, it's one of the, fields in medicine that you always take into account. Also another universe that's happening around. you, that's not the case in other, medical fields and all the interactions around the human body and human populations are fascinating.

[00:07:56] Emily: I just have to say that reminds me of a TV show that aired in Canada called The Magic School Bus starring Miss Frizzle. I think it was a very similar type of television show, a cartoon that would go inside the body and I also found that inspirational.

[00:08:10] Nav: Yeah, it did that's exactly what I thought about as soon as she said, you know, visualizing the inside of the human body. I'm pretty sure that came on, like, before after Bill and I, the science guy. So, .

[00:08:20] Nav: Thank you. Thank you guys for sharing that. It's actually always really fascinating to hear sort of the winding story. And I think It shows people, especially people aspiring to the field that there isn't 1 clear path to steam places like, our guests are. So now we'll go on to topic for today, which is wastewater surveillance.

I feel over the last 5, 10 years, especially, , in response to the covid pandemic, there's been a spike in publications and a lot of discussion about this. for me, it initially felt like a new tool in terms of epidemiological surveillance. But really, it actually seems like it's not.

There's a recent talk at my institution by this really phenomenal microbiologist I work with Tom Kern and one of his slides. I remember him showing that there was a paper published in 1942, and it was called Periodic Examination of Sewage in For the virus of polio myelitis, right in the abstract, it said, quote, it is likely that the periodic sampling of sewage for pathogenic viruses or bacteria may be a method of epidemiological value.

[00:09:21] Nav: Clearly, this has been around for decades, but really is sort of getting a shine over the last last few years. And so I'm really glad to have have you both with us today. And so, David, maybe we can really just start off with some basic context for our listeners. when we say or hear wastewater surveillance, what does that actually entail?

[00:09:40] Nav: and how do we use this as a tool for epidemiological surveillance?

[00:09:44] David: that's a great question. I'm going to start off by going back, and talking about what wastewater really is. wastewater is the product of all the things we do in our life. It's related to our health, what goes down the toilet, what goes down the sink, the [00:10:00] chemicals we use, it's sort of a mirror of the nature of our life.

[00:10:04] David: and in fact, if you think about that from that perspective, When you want to know something about a society, whether it's health or other factors, you can measure wastewater as that paper you quoted in 1942 was saying. when you think about wastewater or waste, one of the things that archaeologists look for are called midden pits.

[00:10:24] David: Or midden pits. Septic points and so these midden pits are the holy grail for trying to understand the society a midden pit is basically their solid waste dump for a community from It might be some primordial time or in medieval times. And in fact, I was working on a project about 6 years ago.

[00:10:43] David: Where, we were doing genetic investigation for cholera in a area that was a midden pit, a wasted dump for a medieval town from the 14th century. we were looking for cholera cysts using genetic methods. So the thing is, this isn't something that's new, as you said. We've been using this in my world of water engineering for, ever since I've been doing.

[00:11:04] David: Water engineering. The difference is that we now have much greater level of engagement with people from the medical side. And, that's where the key is. Now we're at the sort of cusp of really making a difference. So within that context, what we do is we just collect wastewater. The wastewater can come from any place.

[00:11:23] David: It could come from a community. It could come from a present. It could come from a school. bearing in mind what you're getting in that wastewater is a mirror of all the things that are going on the place from which you're collecting the wastewater. So when it comes to wastewater, when we collect it, we can measure things.

[00:11:39] David: And it's really more what, what you can imagine that controls what you can measure. We can measure thousands of chemicals, thousands of genes, innumerable bacteria. viable and not viable.

[00:11:52] David: Sometimes we're making those measurements because we're trying to protect the environment downstream due to pollution. But what's become more important, and this is what we're talking about now relative to wastewater surveillance, is what we're measuring in wastewater to tell us what's happening upstream.

[00:12:07] David: Whether there's disease, whether there is COVID 19, whether there's polio, whether there's increasing levels of particular types of drug resistance related to antibiotics being used in a hospital, for example. So, there's a lot of technical details involved in it, but that's really what it is in a simple sense.

When it comes to wastewater surveillance, what we want to do is, be able to measure things and then tell people like Nazarene what we found, and then tie that to what's actually happening in a behavioral level, whether it's in a hospital or other, setting. that's the principle.

Thank you David. And so Nareen, actually, I just wanted to, tie that into, the work that you do. So when we think about wastewater surveillance, how does that fit? Into what we think about as infection surveillance. Is this something you look at alone? Does it fit into a paradigm of other surveillance systems?

[00:12:57] Nav: Or where does this work in terms of infection prevention, infection control?

[00:13:01] Nasreen: Thank you, Nav, for this question. what David touched upon is very important in terms of the connection between the water world that has been going in parallel to the medical world. And now with the COVID, everyone is all of a sudden interested in working with each other and understanding what Each world could contribute to the other, and it's actually very fascinating to explore the water ecology and water systems in the medical perspective, and as clinicians also, you understand that our way of looking at things is a little bit different.

this highlights the importance of connecting and working together to make sure that clinicians or health systems or health policy makers could do the best out of the output that water society is actually presenting. so if we go to surveillance by itself, by the definition of surveillance, it's actually the continuous, systematic collection of data, analysis and interpretation of this data, dissemination of results to inform health policymaking or improve public health, et cetera, et cetera.

[00:14:12] Nasreen: We need the surveillance to be representative. We need it to be. timely to enable us to do things with this information and to produce actionable data that we could use. And wastewater surveillance is actually, a tool that could help in this aspect, but it's by no means standalone tool. So, in healthcare systems, we look at, different types of surveillance.

[00:14:37] Nasreen: We have syndromic surveillance, looking at specific cases, hospital acquired infections, bloodstream infections, surgical site infections, or, influenza like illnesses in GP clinics. Or we have pathogen specific Surveillance, which is more lab based and which also relates better to wastewater surveillance.

[00:14:57] Nasreen: And then we look for specific viruses. We look for highly multi drug resistant organisms. it's a huge amount of work in hospitals to track patients with colonization, with infection, and to screen the correct patients. So there's some risk stratification done, there's lots of resources invested in this, and many of the carrier patients, most probably not the infected patients, but carrier colonized patients with resistant bacteria will go undetected, unscreened, or if they are screened, they're not screened while they are colonized.

[00:15:28] Nasreen: So we try, you know, to hit to the target, but it doesn't really work all the time. So there's lots of detection gaps. And this is where wastewater surveillance could actually complement. It could just. bridge these gaps and show us exactly a broader picture of what's going on in the facility level, in the population level, and it could give us more timely, let's say, hand on the pulse to understand what's actually going on, and maybe serve as early warning system, detect some new variants, some changes that are of immense importance.

[00:16:00] Nasreen: And maybe when we discover that clinically, it might be a little bit more Too late or an outbreak context. So it is really, helpful tool, but it's not a standalone tool by no means. And it's important to say that today, surveillance in general has also evolved in parallel. So we have lots of, artificial intelligence prediction models, machine learning methods that are being applied in order also to make the traditional surveillance more automated and more accurate.

[00:16:31] Nasreen: So I think combining this with the safety net, let's say, of wastewater surveillance is amazing because it just increases the potential and the, the preparedness and the ability to understand the overall picture rather than the small tiny piece that we're looking at in our specific methods.

[00:16:50] Emily: Very interesting. So we could think about wastewater surveillance as an early warning system. David, why is it that wastewater surveillance was or is crucial for pandemic preparedness?

[00:17:06] David: if you think about wastewater surveillance, what it really is, is it's a diagnostic tool to tell you something about the health of the community or the city or the country it's so it's, it's a mirror of mass health.

And, if you think about the word pandemic preparedness, this is related to mass consequences of things that are happening related to health care. And so. I think it's almost central to preparedness because once one of the problems we had when we were using wastewater surveillance during the pandemic, and in some countries, it was more successful than others.

[00:17:40] David: But I think broadly speaking, it wasn't as successful as it should have been in terms of the monitoring of wastewater relative to cope The, problem was that people had not been monitoring enough prior to the pandemic to know what normal looked like. So we were doing all this massive monitoring and yet we didn't really have any control because we were only dealing with the pandemic.

[00:18:04] David: And this is the reason why it's become so important now. We now know what we should have done before the last pandemic. And so part of this ability of looking at the mass scale health. of a community is looking at what's in the waste. Now I'm going to say one devil's advocate comment and that is that it wasn't completely successful during the pandemic and most most countries have discarded as an approach and part of the reason for that was that We were measuring things in the environment and people in the health care side were trying to manage the health problem, which was the pandemic.

[00:18:40] David: And one of the problems is people on the environmental side. We're generating information that wasn't directly useful for the people who are actually dealing with the health care of the individual. this is something that we're working intensely on right now because we realized that was the problem.

[00:18:55] David: And so one of the things that we're doing relative to these UN guides that we're preparing is trying to come up with ways of making sure that when we have a pandemic, We have the appropriate knowledge from wastewater beforehand, and we have the needed knowledge from the healthcare system beforehand.

[00:19:14] David: And then we've got to have a way of communicating that information between disciplines. And that's one of the big problems right now. And in terms of having this not be as successful as it could be, it's that communication between the disciplines. , there are many things that.

[00:19:29] David: Wastewater can provide in a preparedness sense that you can't get through testing within a hospital. It can tell you things, especially at community level health, that simply you're just not going to get from hospital monitoring. And that's one of the things that we're working on right now is trying to come up with measures of different things of community scale importance.

[00:19:51] David: It's like therapeutic drugs related to Problems we can tell you areas in a city that's mildly depressed or part of the city that's having a good [00:20:00] time and it's through things that we can learn through wastewater monitoring.

[00:20:04] David: So it's a long answer to a short question. I think it's almost essential. Now. I was going to say 1, last thing is that people have been pitching. This is an early warning system. And the magic word there is what does early mean? And this was another mistake that was made during the pandemic.

[00:20:21] David: Early we're thinking, well, we were going to tell you he had a case tomorrow in an individual and it doesn't work that way. Wastewater it's telling you the mass scale movement. It's looking at the new appearance of a variant, but it's still essential information that you're not going to capture within the hospital or the community health setting.

so I think wastewater surveillance is best for things like, preparedness of mass scale health, because it's the thing where it's going to be the most exact and most useful. So, it's a long, circuitous answer, but, I think it's essential. And I hopefully I could a couple of reasons why

[00:20:58] Emily: First of all, just in terms of puns today, it's certainly a system that we will try not to flush and we won't waste it. if I could ask a follow up question, is, is it just for scientists? Can this be used by the public? Was there interest during the past pandemic?

be future interest by members of the public to use this for their own health and safety?

[00:21:19] David: I suppose my question for you is what do you mean by used by the public? I mean, we've done this type of work in very low income countries where we have people out with test kits beside a sewer, an open sewer, and they're monitoring in their sewers.

[00:21:34] David: And it's got some crude estimation of what's in the waste there related to potential health threats.

, I can give you an example. in Quebec, the public health system was releasing publicly the wastewater data during the pandemic so that people could go online and see within their neighborhood what the rates were and people were opting or not to change their behavior based on local rates that were made public about wastewater surveillance.

one of the things that you want is an educated population what you're describing of the Quebec was done in other places we in the UK didn't make it as public at the time because there was some concern over sensationalizing What we were measuring, .

[00:22:20] David: I mean, we knew in Newcastle, where I live, where Omicron was going to appear 2 weeks before it appeared. Then, in other words, there was no Omicron cases during the pandemic and 2 weeks beforehand, 1 particular area of Newcastle, we found it in the wastewater.

[00:22:34] David: So we knew. In about one to two weeks, it was going to show up and then cases started to appear. We didn't use it in a predictive sense, but it just told us the type of things we could learn and the public, was somewhat involved in that process. It was sort of an early warning to tell the public you've got to start being careful because this , new variant is going to be coming soon.

[00:22:55] Emily: Understood thanks for commenting on that.

[00:22:58] Nav: And I think that's helpful. rooting in terms of what we mean by an early warning surveillance system, because I think everything has a different definition when you think about weather forecasting and, hurricane warnings. Right? Even a matter of 15 minutes can make a difference for evacuating, you know, a community.

[00:23:15] Nav: And so, It might not be as tight as that, but even for pandemic preparedness, I think, getting the word out early and engaging communities. I think it's quite important. So thank you, David, for that. nice perspective. along those lines, we're talking about maybe community use Nasreen.

[00:23:30] Nav: Can you Give us an example, particularly in the health care setting where wastewater surveillance has become, or maybe will in the very near future sort of become a core tool and how that's used. We've had examples already just in passing of coveted and other sort of surveillance, but.

[00:23:47] Nav: what example do you think we need to talk about or bring, to the forefront for this in the healthcare setting?

[00:23:52] Nasreen: , just to comment on this early warning and , The clinician or medical society having expectations from, , wastewater surveillance or other, reservoir explorations, there is a wide variability or difference between what we know for surveillance, for for benchmarking, for quantification, for trends.

[00:24:12] Nasreen: And even though we use mostly standardized methods to measure the same thing over time and benchmark ourselves to the previous season or to the previous, settings or different words, we find it hard to benchmark or to say, this is a threshold that we should. It's an early warning, there's something going on, this increase or problem or change is challenging even with traditional standardized surveillance.

[00:24:39] Nasreen: So it's even more when we're trying to explore a new world of, surveillance that we don't really understand. fully understand yet. we should be very cautious, but still it could work. we have, for example, countries changing their vaccination strategies to polio, myelitis according to appearance of the, virus, in the wastewaters.

[00:24:59] Nasreen: prior to clinical cases. It can be a few weeks. I don't imagine that it will help us to make, prompt decisions based on very timely data, but still it could draw some margins. If I go to your question on healthcare settings. So I guess there's lots of interest in healthcare settings in terms of AMR, multidrug resistant organisms and, Lots of the evidence that comes on health in general comes from hospitals and healthcare settings and less from community, which is a big problem and which Westwater surveillance could actually do us a great favor of being able also to portray things that we cannot really measure.

[00:25:36] Nasreen: But in hospitals, we know, That hospital wastewater is very rich in antimicrobial resistance resistant bacteria and in resistance genes. we actually looked in that, previously in a systematic review and we found the discrepancy between hospital and community wastewater.

for me as a clinician, what was striking, finding was the lack of standardization of methods. and the whole new world that you get a lot of data, but you don't really know how to measure it and how to digest it. So now in the hospital I work in, we're trying to implement wastewater surveillance.

[00:26:14] Nasreen: When trying to tackle this from a clinician perspective, you ask different questions. So if I want to check if I'm in a low intimacy setting and I want to check whether I have a problem, the sole detection of a resistant strain, that's, going on, like, there's an outbreak in neighboring country and I detect it in my hospital sewage is an alert that I should maybe change my practice or start responding in screening patients or looking for a problem.

[00:26:44] Nasreen: While if I'm checking whether I'm doing well, I would like to see the trends over time and benchmark myself or I'm implementing a huge change. Project and I want to see an effect. Hopefully, I might need more quantification and more understanding of how much resistance do I see in the sewer system of the hospital?

[00:27:06] Nasreen: so the question that we ask actually dictates how are we going to deal with wastewater? surveillance in the hospital? it's Important to keep in mind that there are inherent challenges in wastewater surveillance. not only hospitalized patients contribute to, wastewater of the hospital.

[00:27:24] Nasreen: We have also the laundry, we have the cafeteria, we have the visitors, we have the staff. There is the problem of rainfall and there's dilution effects. So it's also, sensitive to external, factors that might, Cause problems interpreting the data, and there is also. other chemicals that are distributed and discharged into the wastewater, including antibiotics and metabolites of antibiotics from the patients.

[00:27:50] Nasreen: all of this together, makes the wastewater a bit hard to understand. We don't know how much resistance we find in the wastewater because of resistance strains that are coming directly from the patient or resistance strains that are persisting in the biofilms, in the hospital plumbing or in the hospital sewer.

[00:28:10] Nasreen: And it's very hard to, to explore that. And we need this evidence in order to understand as clinicians, how much can we rely on these figures that we're getting from the wastewater to, feed back our practices. So there is a lot to be explored in that, but I think in terms of AMR, there is a huge potential to use this, in healthcare settings.

[00:28:35] Emily: That's a really good overview of some of the uses, but also some of the challenges. David, I don't know if you want to add on from your perspective, additional challenges that we face in using wastewater surveillance.

[00:28:47] David: I agree with almost everything that has been said, but there are some technical challenges that we're working with right now is that what we're to do is is correctly bound.

[00:28:59] David: The type of information that we can reliably provide to people on the health care side for wastewater monitoring. there's a couple of things that we can't provide. And there are very important things for example, if you're dealing with an infectious disease physician, they, they care about a viable pathogen that's causing disease.

[00:29:19] David: Whereas the genetic methods that we can use most economically to screen samples are not able to detect a viable organism that's causing disease. Many people in the world are trying to come up with methods to do it. But that means that there's a limitation and we have to fall back on traditional microbiology, which we do a lot of to monitoring wastewater.

when you're coming to specific questions that are happening, say, around a health care facility or within a community details matter. And there are some things that wastewater can do, and there are certain things that wastewater can't do. I think that's something that we've found, since we've gone through the pandemic, and now we're [00:30:00] looking at AMR, particularly on mass and local scales, getting together as a group.

[00:30:05] David: Yeah. A bunch of people like me and a bunch of people on the medical or the veterinary or the crop or health protection side relative to food supply. We've learned so much from each other. And this is the process we're going through now is we're trying to cross pollinate in reality. And also sort of reality check each other's expectations.

In other words, what can we provide? What do you need? We had a meeting with the director of health for Newcastle near the end of the pandemic and said, okay, let's think about what other things we can do and we were very biased towards saying, well, what can we do for hospitals and what sort of things can we measure that could feedback knowledge for hospitals?

[00:30:45] David: And to the health director wasn't really interested in that. He was interested in chemicals in the, community scale. I mentioned this before, related to mental health. They don't have any way of measuring.

[00:30:56] David: And this is something that they could measure through wastewater. The second thing that they were interested in was something that I'd never even heard of before. And I'm only providing these examples because there were things that I was ignorant of when I was monitoring wastewater for the country.

[00:31:10] David: And one was ghost patients. They have to do their epidemiological assessments based on the number of people that they think is in a place. The problem is, if you're in a university town, where say 60 percent of the population are students, who may or may not be there. You have no way of knowing how many people are there.

[00:31:29] David: But I can tell you based on the genetic information that we can detect from a wastewater sample. So they want us to give them a better estimate of the number of people that are there. This is not on an individual basis, but we can actually do that sort of thing with a high level of precision.

[00:31:45] David: Whereas you can't do that any other way, unless you go door to door and knock on doors. And the way we do it's dead easy. So, there were things that, we didn't even think were of importance, which were of their primary importance, and it was through this sort of communication and cross educational process that we actually became better, , but we're sort of stepping over these various different obstacles to come to some sort of harmonized way of doing this.

But if you, pick up an organism, are you able to tell, for example, whether it comes from a human or an animal, or does it depend on the organism?

[00:32:17] David: The answer is probably not. what we've seen now is there's so many, say, for example, drug resistance genes or drug resistance gene cassettes.

[00:32:28] David: There's so many out in nature. And they're so cross pollinated across nature, you can't say with absolute certainty as to whether a particular organism or gene, say a resistance gene or pathogen, has come from this organism or that organism. On the other hand, we can use genetic source tracking within carefully designed sampling programs to tell you where the genes are or the organisms are circulating in the direction of flow of organisms. So if you just look at the organism, you can't tell. But if you look at the organism within the context of all the different other things that you can measure in a particular place, you can then link cause and effects and pathways of spread through that this is the whole thing behind the push at the UN towards one health or integrated health, the environment and people and domestic animals and the crops is the fact that we're trying now to think about health from this one health perspective, the organism is invisible, it's just what it is, but it could come from a cow or it could come from a person or it could be sitting on a leaf.

[00:33:32] David: but once you've contextualized it within a monitoring program, you can then say where it's from and then work on cause and effects and prevention.

[00:33:42] Emily: another question I had, and maybe anybody can answer this is, are there organisms we know that it doesn't work for? So if people asked for things where you can say right away, we've looked into that and that's just technically not possible.

[00:33:53] David: to be honest, I don't think we've ever found something we couldn't measure.

[00:33:58] David: The question we have, and it's really probably one of the bigger questions is we can't measure what we don't know about. And this is one of the things that Nazarene mentioned, AI, we're starting to work on trying to predict the most probable next drug resistant organisms based on gene cassettes and that sort of thing that are circulating around the environment.

[00:34:19] David: So the answer is, if we know about it. We can detect it. Now, we can't necessarily contextualize a risk or anything like that immediately without working with Nazarene and the world of epidemiologists. But, what we can't do is we can't tell you what the next mutant's going to be or the next variant's going to be, though we're starting to develop methods that are going to try and do that.

[00:34:43] David: Say, okay, what the most likely variants for a particular virus or a particular pathogen or a particular mobile element that transports a virulence factor. We're, working on that now we're trying to use intelligent systems to predict the most likely organisms of concern for the future.

[00:35:02] David: And actually, I'm pretty optimistic that we're going to be able to do that. So the answer is, there probably isn't anything that we know about, that we couldn't potentially measure. But, whether we can provide useful information, Nazrin, or not, I'm not sure.

[00:35:18] Nasreen: If I may add on that, there is a lot of, tracking in the wastewater, a lot of tracking and screening and surveillance in health, but the overlap is still a big question mark.

[00:35:32] Nasreen: There are studies looking at concordance, there are studies trying to track, specific strain types or to look if we find this in the sewer, we find it in the patient, but the composite of all the factors that are going inside this. melting pot over time and correlation of this human source isolates to, wastewater isolates is still not fully So there is still some work to understand what the capabilities of the water world are and how can they feed into the medical world. For example, in this project that we're starting now, we wanted to check AMR. We're looking for, four different hospitals in the world. We're looking at, ESBL, and carbapenemals producing enterobacterialis, carriage in patients, in sinks and toilets, in wastewater.

[00:36:28] Nasreen: And we face the problem of how do we measure? We know how to measure, these MDROs in our patients. But what is the right approach to it in our sinks, in our toilets, in our wastewater? We want some quantification. Should we use culture based or culture independent? If I find a gene, what does it mean that there's a resistance gene, in the wastewater.

[00:36:48] Nasreen: Should I look for the same bacteria, for the same host bacteria? Should I track the plasmid that I'm trying to do? and our interests in microbiology and in species in general are different. So we're looking at enterobacterialis, we're looking at non fermenters, and they're looking at aeromonas, and they're looking at environmental bacteria.

[00:37:06] Nasreen: And actually, both of these talk to each other in the sewer, but we are looking with different eyes, with different perspectives. So there is still some way to go.

[00:37:16] Nav: This is fascinating. I mean, just in this conversation it sounds like the number of applications it can have is so vast and wide.

[00:37:24] Nav: But comes down to also having the Right people and different perspectives in the same room to help interpret it in a way that you understand what's going on technically. And then you can translate that to something actionable from a public health standpoint, because even just in the conversation that we're having, we're talking about pandemic preparedness for COVID or things that are vaccine preventable.

[00:37:45] Nav: And so then that informs a different vaccine strategy, but for AMR it might. Inform a different infection control strategy or looking a bit closer into the patients coming into your health care facility. And so even the action plans have quite a bit of heterogeneity in a good way, meaning that they seem adaptable to the information that's there, but that root or what I'm taking away from what you guys are telling us is that the root of understanding or interpreting that information is Is the core of it all because if you off in a little bit of a wrong direction of how you interpret that data, then that sets you up in a wrong way.

[00:38:19] Nav: And so, I mean, I really like what you said, David, about having all these people. In the same room, right? The public health folks and epidemiologists, the clinicians, the engineers, the veterinary folks, , the food science folks. And these are people I think a lot of us don't think about routinely.

[00:38:34] Nav: And so I think it's really just helpful to acknowledge.

[00:38:37] David: I just would make one additional reminder, and in some respects, I'm re saying something I said before.

Is that. of the things that monitoring wastewater and water and soil in the environment for things of prospectively medical and veterinary importance is it tells you what's circulating around nature. And in fact, we live in nature and what we discard, outside of our wastewater. Just discharge from a treatment plant.

[00:39:07] David: Those are things that are now going to be mirroring what's part of that society. And, this is where I'm most excited about surveillance I've just completed a study with colleagues in China, where we looked at wastewater treatment plants across the whole country, and it wasn't in an assessment of the treatment plants.

[00:39:26] David: The treatment plants are working fine, but it was what was going into the treatment plants. Because what was going into the treatment plants told us things about the regional health status of all parts of China. And we found very consequential differences in different parts of China. you've got a country where there's a lot of centralized medicine, and yet the regions are very different.

[00:39:48] David: in reality, the biggest factor that affects what we find, in this case related to AMR, is in regions that have higher levels of large animal agriculture and higher levels of antibiotic [00:40:00] use. Surprise, surprise, there's higher levels of resistance in those parts of the country. this provides a potential exposure, potential recirculation back into the human populations.

I personally think this type of information could change the way we make decisions. about prioritization of how we use antibiotics, how we handle animal waste that might feed into the water supply. These are all these greater things that you can get from environmental surveillance, including wastewater, that you really can't get any other way.

[00:40:32] David: And the thing is we can do it relatively inexpensively and we can do it quite precisely. because we've been doing this for 30 years and it's just now applying it for a different purpose of what we've always done.

We find wastewater monitoring, environmental monitoring really helpful in developing countries or low to middle income countries.

[00:40:51] David: Because they don't have as developed a health care system, they don't have as much health care related surveillance, we were working in one country in South America, and providing wastewater data to help their health department. This was during the pandemic related to COVID, but other things.

[00:41:07] David: And we were the only way they could determine what was happening across the country, because they didn't have the infrastructure that, Switzerland or the UK or the United States or Canada has. And so the wastewater was their mirror. It was the way of saying what's happening across the community.

[00:41:25] David: And there was no other way of doing it now, as we said, is how do you sample all these different sources? Well, to be honest, we're doing it more and more, and we're standardizing methods, and eventually in the not too distant future, we'll have a very unified way of doing this, and a harmonized way of interpreting the data.

[00:41:43] David: I'm quite optimistic, actually.

If I may add on that is on the specific area of, AMR, also in high income countries, the frequency of AMR determines in the community is a big knowledge gap. We don't really know. We try as much as we can. we try to look at community acquired infections based on the time of presentation to the hospital to try and infer about what's going on in the community, but doing clinical research in the community in terms of AMR.

[00:42:15] Nasreen: is very, very challenging. So there is a huge detection bias that we have. in this behalf, wastewater surveillance would just uncover a large amount of information that could help us understand the dynamics, the circulation, the pathogen distribution, the resistant distribution in different areas, among the different pathogens, just thinking about, urinary tract infections in the community, resistance, bacteria, just, it's a great tool that could also help us more understand the clinical work we do.

[00:42:50] Nasreen: So we're just looking forward for David's, more, standardized and interpretable, information that we could use, in our, research, projects as well.

[00:43:00] Emily: as a final question for you both, we've heard about so many potential uses today. If you had to pick your top most exciting, use of wastewater surveillance to study, you know, over the next five to 10 years, what would you pick? Maybe I'll start with you Nasreen.

[00:43:17] Nasreen: Oh, that's a hard one, but I think it would be the integration of, wastewater surveillance.

[00:43:25] Nasreen: In infection prevention and control, both in healthcare and community settings. How do I see this, information or this data fit into the whole, portfolio and the whole decision making that I do as a infection prevention practitioner or as a policymaker in the community level? And how can I, make sure that it, Might help, my practice or my work to be more effective. I think it's fascinating, and, after validating and understanding and then using and showing, an impact at the end of the way. I think it's a great, thing to, aspire for.

[00:44:04] Emily: And how about yourself, David?

[00:44:05] David: in some respects, I think I've, already said what I think the most useful is. And that is, in, mass scale strategic decision making relative to healthcare. Now, I see all different uses. a very specific level within a community or near a hospital or near a prison or a healthcare facility of some sort.

when it comes to the use, we've talked about that. I think there's two things we have to work on . First is what I said earlier is that right now, There's a tendency amongst people who work in the environment to measure things that aren't of any use to.

[00:44:41] David: people who are in the healthcare side. There are certain things that they can measure. We can measure metagenomes. We can do genomes. We can do all this fancy genetics. But in fact, that genetics currently cannot tell you that you've got a viable pathogen. It's just going to tell you all about the potential for something being there rather than the problem.

[00:45:01] David: So that question of us on a scientific level, and this is pure science, of answering the question of how do we determine viability. Based on genetic data, and we can't do that. So it's not really talking about use, but that's something that's really important. But I think the most important for us to operationalize this and make it useful rather than use is that we just have to increase the level of education between people in the different sectors.

[00:45:29] David: It's about what each sector needs. I'm actually critical of everybody. Thank you. Cause everybody works in silos and, you know, the medical people don't know anything about the environment. The environmental people don't know anything about medical stuff, but these are all experts. And one of the problems with experts, expert thinks they're right all the time.

And what I've discovered after many years of working is I'm not an expert at everything. And the way I learn about things is by sitting down and talking with physicians, or if I need to have something about animal rearing, I sit down and talk with vets. And I would say I'm probably rather unusual in the sense of water engineers, and most of them don't.

[00:46:12] David: tool of all these different fancy methods they can do with data analysis and so forth. And they do it, but they don't talk to the physician. So they don't talk to the veterinarians. And I think that's where the question of use becomes important. And maybe use isn't the right word. It's how do we operationalize this and make it useful?

[00:46:32] David: it's getting people on the same page and having people be more open minded about that. their own specialization and recognizing that the questions that an ICU physician needs to know aren't the things you're going to measure in the environment. You're going to have to change what you do based on what other people need.

the opposite is true between the two disciplines. So I know I didn't really answer your question, but the thing is, this is what I think is important is once we've got through that, what you can use it for is, as large as your imagination.

[00:47:03] Nav: I actually think in certain ways, , , you did answer the question in terms of future, it seems like the cross pollination across fields needs to become better, more efficient and more seamless.

[00:47:15] Nav: And, you know, part of the inspiration for initial question is that, you know, what was the. It's such a spark for you at a young age to make you curious about science. And I think we shouldn't forget that we still need that curiosity and spark and humility now, even as maybe experts in our field, having humility of information that's not within our field directly, but contributes and we cross collaborate with.

[00:47:39] Nav: And so I do like that message, David. I think that's quite important for, for us. Anyone to really to hear within their own respective fields. And so, as we're coming to a close now, I think, clinicians really can benefit from this understanding of wastewater surveillance, what data and knowledge it offers and how it can be used and maybe can inspire a little bit of action, even at the more local level in the health care field.

[00:48:04] Nav: I remember actually reading the other day that there was a survey of infectious diseases physicians in the U. S. and only about, I think, 22 percent said that they looked at wastewater surveillance data regularly. and so, you know, there might be a gap in equipping frontline folks that work at the bedside with information that could be useful.

[00:48:23] Nav: But as we've talked about, there's still a ways of, translating that information to becoming. the most useful for, clinicians. And so there's, there's a lot of things that I think we need to work on. with that, I just want to close with, you, David and Nasreen.

[00:48:37] Nav: If you had one key message that you want to leave our listeners with, what would that be Nasreen, maybe we can start with you and then David, we can give you the final word.

[00:48:45] Nasreen: I understand the hesitancy. I understand that it's not, Straightforward To digest the information of wastewater surveillance in the, current, landscape that we're working in.

[00:48:57] Nasreen: but my key message would be to dare to explore, to check. it's, like, you know, I received these periodic reports of influenza variants going in the community lately. And I want to know what's going on when it started, what is the type that's, more prevalent this year.

[00:49:16] Nasreen: It's the same way, whether it's coming from clinical surveillance or wastewater surveillance, it shouldn't really. Make much difference for me in terms of it's a way for me connect with the outer world and be aware of what's going on around my area or around my, practice. the other key message is dare to ask questions.

[00:49:40] Nasreen: to connect with other experts within One Health projects I worked with David in a previous project as well, and I had the chance to be a clinician in a group with computational biologists, engineers, environmentalists, mathematicians, and you see that Everyone is asking about the same things, but they're talking in different languages, So it's [00:50:00] very important to bring our clinical expertise to fine tune what can be done in this world. And now there are lots of interest in wastewater surveillance, also among clinicians with some investigator initiated studies, looking at their own hospital.

[00:50:18] Nasreen: And there's a lot of questions, a lot of, time points where input from people that have expertise in water science and environment, etc. become very, very, critical. And by these conversations, you might Do a larger impact you'll do good for your own project by doing maybe things better But also you bridge the gap between the different worlds to make profit of what could be Done with wastewater surveillance.

[00:50:51] David: my comment is Somewhat similar but I'll say in a slightly different way we've been doing this type of surveillance specifically for health. So about 20 years and, one of the problems I've had is convincing people in the medical community that the type of thing that I'm doing is useful to them.

[00:51:09] David: Part of the reason why they haven't been receptive is that they don't really have enough background education relative to the things outside of their own specific discipline and volunteered to teach a class for free in the medical school at the University of Newcastle and they said on using environmental surveillance and environmental health and infectious disease prevention.

[00:51:33] David: they would love to do it, but they don't have time. the medical students don't have enough time for that because they've got to take all these courses because of getting registered and so forth. As it turned out, they weren't really taking a specific course in infectious disease anymore.

it's because a place like the UK, well, infectious disease isn't something you're trained for. But on the other hand, if you're in Bangladesh, it's the center of health. Infectious disease issues. so I was trying to say, okay, I want to go out there and prophesize not the importance of the environment, but just awareness of what's out there.

[00:52:06] David: What could be of use to you as an individual physician? So there's problems to do with parochial thinking a little bit. I think that's it. particularly in the medical world, but lesser extent in the veterinary world. I think the thing is, we've got to cross educate.

[00:52:21] David: I'm very encouraging to hear from Nazarene that, that their physicians are asking those questions. for example, I don't do a project anymore. Unless I've got a physician. I won't do I'm not realizing. I'm not going to serve anybody's best purpose. If we're in an environment where it's agricultural, I won't do it unless I've got a vet.

[00:52:40] David: I want to have a vet. I want to have an epidemiologist. Actually, I want to have an anthropologist or social scientist because behavior becomes critically important relative to health prevention, especially in emerging countries and developing countries where I do most of my work. So, my final message is really that we've got to become a little bit open minded within our disciplines and then be aware of what educational opportunities we can provide each other and become a little bit smarter as a larger group.

[00:53:07] Nav: Thank you both. it's funny because you're saying the same message in 2 different ways, which is exactly what we're talking about. But I think we're hearing each other very, very well. And so I, really appreciate that. take to those messages. , thank you so much to our guests, Go ahead.

[00:53:20] Emily: Sorry. Before you read the closing credits. I just wasn't that happy with my pun before. So I prepared another one. Just if you'll indulge me. okay. Get ready. Okay. Here it is. Scientists say there's an increased rate of sewage in the wastewater of lawyers.

[00:53:39] Nav: Oh, Emily.

[00:53:41] Emily: Better?

[00:53:42] Nav: that was fantastic. Dr. McDonald. I really appreciate you for the, for the closing remarks. You got to raise the bar of this conversation and yes, raise the bar.

[00:53:51] Nav: Not too high, especially if we're talking about lawyers. , but seriously, thank you guys so much. Thank you to our guests, Nasreen Hassoun-kheir and Professor David Graham. thank you for listening to Communicable, the CMI's podcast. this episode was hosted by Navaneeth Narayanan and Emily McDonald, editors at CMI.

[00:54:09] Nav: com, ESCMID's open access journal. It was edited and produced by Katie Hostettler-Oi and peer reviewed by Dr. James Donnelly. of the Royal College of Surgeons in Ireland, Dublin, Ireland. Theme music was composed and conducted by Joseph McDade. This episode will be citable with a written summary referenced by a DOI in the next eight weeks, and any literature we've discussed today will be found in the show's notes.

[00:54:32] Nav: You can subscribe to Communicable on Spotify, Apple, wherever you get your podcasts, or you can find it on ESMED's website. for the CMI comms journal. Thank you for listening and helping CMI comms and ESCMID move the conversation in ID and clinical microbiology further along.