By Christian Railsback and Dr. Kimothy Smith
The podcast currently has 10 episodes available.
Water, like everything else on Earth, including you, is full of bacteria. But not all bacteria are created equal, with many being more harmful than others. Yes, Escherichia coli (E. coli) pollutes our ground and surface water through fecal contamination, but the bacteria is also simply found and widely distributed in nature.
As one of our hosts, Christian, bid adieu to us, his last pathogen of choice is E. coli. Listen in as the bacteria-loving buds discuss strains and characteristics, causes, effects, and environments of this curious bug.
More about E. coli:
CDC’s summary of E. coli
What is E. coli O157:H7?
Coliform Bacteria in Drinking Water Supplies
Stay tuned for more episodes, posting on the first Thursday of each month. Subscribe to our show wherever you get your podcasts and find more info at weebeastiespodcast.com
The Wee Beasties podcast is a production of Nephros, Inc., a company committed to improving the human relationship with water through leading, accessible technology
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SHOW TRANSCRIPT:
Christian: Kimothy…
Kimothy: Christian…
Christian: Happy New Year. What a year it has been, eh?
Kimothy: Happy New Year, Christian. Yeah, what a great year. And a big year ahead – lots of changes. Including for you – this is your last podcast today, right?
Christian: Yeah, that’s correct. Really sad to have to move on – I think this is such an important forum to have these conversations, and I will miss the opportunity to share microbiology with our audience.
Kimothy: Well, what do you think our Swan Song should be for your last episode?
Christian: I thought E. coli might be a good one to end on. A well-known, and often misunderstood, waterborne pathogen.
Kimothy: Yeah, no doubt, Christian.
Christian: So, when I think of E. coli, I immediately go to headlines about spinach recalls and announcements about contaminated meat at restaurants. But E. coli bacteria can just as easily contaminate a municipal water supply, right? And E. coli is a gut bacterium, so when something is contaminated, are we just saying that it has gut bacteria or, really, just poop in the water? Help me understand this, is water contaminated with E. coli, just water that has fecal matter in it?
Kimothy: [laughs] Well, yes, essentially. But, let’s back up for a moment and outline a few things. So, E. coli is a bacterium that lives in the intestines of warm-blooded animals, and most strains of E. coli bacteria are not harmful and are an essential part of the gut flora for healthy digestion. That said, there are several pathogenic strains, the most common one in the U.S. being a Shiga toxin-producing E. coli called, O157:H7. Now, all E. coli is part of a group I mentioned during our last episode, called coliforms. Coliforms are a kind of rod-shaped bacteria that are found in soil, plants, and intestinal tracts of animals – in this group you have total coliforms and fecal coliforms. The most prevalent fecal coliform species is E. coli. And the most dangerous fecal coliform is E. coli O157:H7, so to get back to your question. Yes, it’s poopy water.
Christian: Ahh, I knew it. So that’s the scoop on poop?
Kimothy: Well, the gut microbiome has a lot more to it than that, but that’s the scoop on E. coli in water.
Christian: Okay, okay…so, a couple of things at which I’d like to take a closer look. I got that if water has E. coli in it, it is because the water has been contaminated with fecal matter, but you mentioned Shiga toxin E. coli and coliforms. What is Shiga toxin and why do we care about coliforms? I mean, I don’t want coliforms in my drinking water, but you’ve mentioned coliforms in two episodes now, so I just wanted to pause and ask a little more. What’s the importance here?
Kimothy: Sure, Christian. So, coliforms, as I mentioned encompasses a group of rod-shaped bacteria, and the reason they’re important is, first, they always exist in the digestive tracts of animals and their waste; and second, they are a great ‘indicator’ organism. That is, you can test for coliforms as a diagnostic tool that can give you a read on the probability of other pathogenic organisms being present in your sample. If you conduct a coliform test and it’s positive, you know on a list of probable outcomes, that there is some risk of contracting a waterborne illness or disease.
Okay, now for the Shiga toxin: The E. coli that produce Shiga toxin are called Shiga toxin-producing E. coli or STEC for short. The most common type of STEC is O157:H7 and has emerged as one of the most serious causes of severe human gastrointestinal disease. Now, the pathogenesis involves the E. coli bacterium releasing the Shiga toxin in the gut of a human which attacks and destroys the lining of the intestinal tract, resulting in bloody diarrhea. According to the CDC, there are about 70,000 cases of hospitalization from O157:H7 every year in the US.
Christian: Rowdy, so E. coli contamination in municipal or building water is a result of some source of coliforms that isn’t being addressed either through secondary disinfection or filters.
Kimothy: Yeah, that’s correct.
Christian: Okay, so aside from bloody diarrhea, which sounds less than ideal, are there any other symptoms one can expect from E. coli O157:H7?
Kimothy: Well, yes, unfortunately. Abdominal cramping, headache, and watery diarrhea may persist for seven to ten days and in severe cases, the disease may result in kidney failure. A condition known as hemolytic uremic syndrome (HUS) can eventually occur that results in massive retention of fluid because the kidneys stop working, and then it becomes a life-threatening event at that point. The most susceptible populations here are the very young and the very old due to weakened immunity, but the best approach to prevention is having a multi-barrier solution for your water supply – disinfection AND filters, and make sure you’re routinely testing the water to ensure it’s pathogen-free.
Christian: Alright, well that was a great snapshot on E. coli, a microorganism I think is talked about a lot with authority, but often doesn’t get the detailed attention it needs. Thanks for having one last chat with me, Kimothy!
Kimothy: You bet, Christian.
“Mary has died of Typhoid Fever”. Ah, yes. If you are of a certain generation, you remember being met with these abrupt notifications while playing Oregon Trail. While this game taught generations of young people about Western migration in 19th-century America, it also familiarized them with various diseases…and, how to avoid getting run over by wagon wheels.
This month, our hosts are exploring the root of the cause – diving into species and subspecies of Salmonella.
More about Salmonella:
CDC’s summary of Salmonella
Salmonella Nomenclature
Mary Mallon (1869-1938) and the history of typhoid fever
Stay tuned for more episodes, posting on the first Thursday of each month. Subscribe to our show wherever you get your podcasts and find more info at weebeastiespodcast.com
The Wee Beasties podcast is a production of Nephros, Inc., a company committed to improving the human relationship with water through leading, accessible technology.
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SHOW TRANSCRIPT:
Christian: I am back with Dr. Kimothy Smith. Kimothy, welcome back!
Kimothy: Thanks, Christian. What’s new?
Christian: Well, I’ve been combing through the annals of gastroenterology in search of the origin of “Typhoid Mary” and learned a few things I’d like to share.
Kimothy: By all means. What ya got?
Christian: Alright, so check it out, in case you’re not current on your NYC history or your only reference for Typhoid fever was that Oregon Trail game back in the late ’80s…and this is literally from the Annals of Gastroenterology…I’ll throw a link in the show notes – Typhoid Mary was the name eventually given to a woman named, Mary Mallon who lived in NYC in the early 1900s and became notorious as a healthy carrier of Salmonella thypi – the bacterium that causes Typhoid fever. She was an immigrant, not necessarily well off, and was employed as a cook for wealthy families. Now, this was before a vaccine was available and before antibiotics. An investigation had started because there were many people getting sick with a fever, and the investigator trying to track down the source noticed there were pockets of families employing the same cook. Mary was leaving after the infection had occurred to move on to a new family to cook for them. In the end, there were 122 people infected, 5 dead. And that year over 3,000 people in NYC had become infected in 1907 – she was apparently the source.
What’s interesting is that there was no tracking mechanism in place, so investigations had to be done just by a small group or single man. There was an assumption that a microorganism was suspected of being responsible, but nobody knew why. The investigation really corroborated that hypothesis which eventually came from a team of veterinary scientists. So, in 1880, this guy Daniel Elmer Salmon ended up naming Salmonella typhi as a consequence of this investigation.
Kimothy: Sticking with your history bend for a minute, this is not so long after the cholera plague in London. Germ theory was still a controversial thing, they thought it was neighbors. So, go vets! Real doctors treat more than one species.
Kimothy: So, if you haven’t inferred already, we’re going to give you a snapshot of Salmonella today. Salmonella enterica, specifically.
Christian: Yeah, so…a query sir. As I was sifting through literature, I didn’t see a lot of mention of enterica early in the investigation of Typhoid fever. Can you summarize how Salmonella enterica became the catch-all for all the varieties of Salmonella?
Kimothy: Yeah, it’s a bit unusual because as you said, Christian, the initial outbreak investigation resulted in named in Salmonella typhi and now we have Salmonella enterica.
It’s important to remember that science naming conventions are like kaleidoscopes – the contents remain the same, but the picture and how it’s described change depending on who’s holding the instrument. Such has been the reshuffling with Salmonella. Most of the scientific community now breaks Salmonella into two species Salmonella bongori and Salmonella enterica into 6 subspecies and over 2600 serotypes. But essentially it comes down to two groups – Salmonella that causes gastroenteritis and then those that cause enteric fevers.
Christian: Which patient populations are most at risk for acquiring Salmonella?
Kimothy: The CDC estimated that Salmonella causes 1.2 million illnesses and 450 deaths annually in the US. Anyone can become infected with the bacteria – fecal-oral and food & water are the most common routes. The populations at greatest risk are typical demographic we’ve discussed for all our opportunistic pathogens – those under the age of 5 and over the age of 65, and those with weakened immune systems.
Christian: And how does it present?
Kimothy: So, the gastrointestinal infection that results when you ingest the bacteria is Salmonellosis, and it presents exactly how you would expect for a pathogen that survives in your GI tract – fever, abdominal cramps, and diarrhea. Symptoms manifest within about 12-72 hours and typically last about a week. You can take antibiotics, but most people will be able to recover without pharmaceutical intervention. Typhoid fever is, as you might expect, slightly different. Patients become symptomatic gradually and once a fever presents it is accompanied by extreme fatigue, usually a skin rash or skin discoloration, headaches, abdominal pain, and constipation. Without medical intervention, the fever can be fatal. But it can easily be treated with antibiotics, such as azithromycin.
Christian: And if you really believe in preventative medicine folks, you can always get the vaccine. Also, Typhoid fever shouldn’t be confused be typhus, right? Two totally different pathologies. Typhus is caused by Rickettsia, a different gram-negative bacterium that spreads itself around to humans hitching a ride on lice and fleas. I digress. Tell me about Cell morphology and other unique descriptions associated with Salmonella.
Kimothy: Gram-negative rods, motile with flagella, about 0.4 - 0.7 micron in size.
Christian: Quick question before I let you go: do both varieties of Salmonella transmit the same?
Kimothy: So, good question. No, they do not. The variety that causes Typhoid fever is spread from human to human only and the variety that results in gastroenteritis is transmitted in food or water.
Christian: Copy that, so we’re in the clear for acquiring Typhoid fever a la hospital drinking fountains. Kimothy, as always, thanks so much for the chat today.
Kimothy: You bet, Christian.
Ready to think twice about the filtration used to treat your water for consumption? Ready or not, our hosts are exploring the gut microbe, Campylobacter jejuni. This gram-negative bacterium is about 0.2um – 0.5um in size. Small, but mighty enough to warrant the use of a 0.05um filter if you want to catch this bug and potentially avoid some stomach souring symptoms.
More about Campylobacter jejuni:
What is Campylobacter infection?
Safewater.org | Campylobacter Fact Sheet
Stay tuned for more episodes, posting on the first Thursday of each month. Subscribe to our show wherever you get your podcasts and find more info at weebeastiespodcast.com
The Wee Beasties podcast is a production of Nephros, Inc., a company committed to improving the human relationship with water through leading, accessible technology.
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Campylobacter jejuni, Campylobacter, biosurveillance, microorganisms, biotechnology, PremisePlumbing, AntonVanLeeuwenhoek, WeeBeastiesPodcast, season1, origins, CDC, pathogens, OpportunisticWaterbornePathogen
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SHOW TRANSCRIPT:
Christian: I am back with Dr. Kimothy Smith. Kimothy, welcome back!
Kimothy: Thanks, Christian.
Christian: All right…how are we doing today Kimothy?
Kimothy: Doing well, Christian. Just recovering.
Christian: Recovering from what?
Kimothy: All of the candy corn I had to pick up in my front yard this weekend. The local monsters and ghouls decided it was imperative that my lawn be seeded with candy corn so they could apparently revive a Children of the Corn montage for Halloween. Of course, nothing was going to grow except the number of birds and bugs on my lawn, so I found myself bent over cleaning that crap up all day on Sunday. Sigh.
Christian: Well, hey, out of the Steven King flicks to choose from that was probably the best. I mean, at least they didn’t choose to revive the film It, your front yard would have been littered with psychopathic clowns with red hair and pointy teeth. It can always be worse, Kimothy. It can always be worse. Well, enough with the candy corn and clowns…what is our pathogen for today?
Kimothy: Campylobacter jejuni
Christian: Campylobacter is always associated with camping and environmental infections for me. I just remember the camp in Campy and immediately remember that these infections are uncommon for treated water networks, but more likely found in untreated settings like stagnant environmental samples.
Kimothy: Yeah, Christian, this bacterium doesn’t tend to survive in treated water systems very well; and, if it does, it is in a viable but non-culturable state. This is a gut microbe and it’s primarily transmitted through birds, cattle, and other livestock feces – but, poultry mainly, such as chickens and turkeys. Feces from these animals shed campylobacter in into streams, rivers, lakes, and reservoirs. The most common route of infection is through ingestion (fecal-oral), whether that is untreated water or contaminated food. The result is campylobacteriosis – an acute illness that causes nausea, abdominal pain, fever, cramping, and diarrhea. The abdominal pain can be so debilitating that it is often confused with appendicitis.
Christian: Alright, so, in treated water there is less of a concern, but it’s still possible to become infected in untreated water sources. What about its cellular structure and behavior; is this something I can easily filter out of the water supply I’m drinking from?
Kimothy: Well, this is another gram-negative, spiral, and rod-shaped bacterium that is about 0.2um – 0.5um in size, so you’ll want a 0.05-micron filter if you want to catch this bug before using the water for consumption. Its motile by a single flagellum, and is not a good biofilm producer, so it’s constantly on the move for nutrient sources. It’s most happy in intestinal tracts of animals, like I mentioned early, so livelihood is challenging for it in bulk water systems. That said, it doesn’t take much ingestion to make you symptomatic and acutely sick. I believe Safewater.org reports that less than 500 cells consumed will result in symptoms. To that end, I’d like to deviate just for a moment and emphasize Campylobacter is the most common bacterial cause of diarrhea in the U.S., affecting 1.5 million residents a year.1 And, a not well-known mode of transmission for shedding Campylobacter is our pets, in particular, our dogs.
Christian: Ahhh, so all those people out there that are convinced your dog licking your face is OK, and just a warm sign of affection and love – it's probably true, but it comes with the bonus of acute diarrhea and cramps! Nice. Well, pooches aside, which patient populations are most at risk for acquiring Campylobacter?
Kimothy: So, nothing surprising here, Christian. Immunosuppressed or compromised patients are at greatest risk (think cancer and AIDS patients), but also pediatrics -- specifically those under the age of five are highly susceptible because of their lower developed immunity and inability to cope with the hypovolemia and accompanying diarrhea. There are a few rare circumstances possible when acquiring this bacterium that are worth noting also (although these are highly improbable): About one in every 1,000 cases of infection results in Gullian-Barre Syndrome (GBS). GBS is an autoimmune disorder that causes weakness in the extremities and sometimes paralysis. Most people recover, but permanent nerve damage is possible in rare cases. Also, strangely, according to the CDC, about 1-5% of those infected with Campylobacter will develop arthritis – non-age dependent.
Christian: Bizarre…I wouldn’t have suspected that outcome. Tell me about the treatment. I assume since this is another bacterial pathogen that the best treatment is an antibiotic regimen.
Kimothy: Actually, no. This is rarely fatal, and symptoms will usually resolve on their own in most patient populations within about three weeks. Except for those patients most at risk, that I mentioned earlier, you really are just treating the diarrhea here – so taking extra effort to drink lots of fluids and combat the dehydration and cramps is really most of what needs to be done.
Christian: Alright, well it’s good to hear that this isn’t a pathogen with a high mortality rate. It does seem quite easy to acquire in untreated water or contaminated food, but if you do acquire it, symptoms resolve quickly. And the worst-case scenario you must get an antibiotic treatment if you’re part of a high-risk patient population. And you said earlier that these little guys don’t survive well in bulk water systems and that treated water usually kills them or puts them into a VBNC state. So, there seem to be two easy solutions – use a point-of-use 0.05-micron filter or treat your water – also don’t kiss your dog – and you’re well on your way to preventing this bacterial infection!
Kimothy: Usually it does just come down to the basics. This one is an “easier” one to address, but it still is ubiquitous and it’s important to recognize small inputs and changes that really aren’t that cumbersome can reduce the infection rate of this opportunistic pathogen.
Christian: Alright, Kimothy, another one down, Campylobacter jejuni. I made it through all of that without being campy – well, maybe a little with the dog bit.
Kimothy: Yes, a man of true restraint!
Christian: Kimothy, as always, thanks so much for the chat today.
Kimothy: You bet, Christian.
1 https://www.cdc.gov/campylobacter/faq.html
Time to talk about the most widespread infection in the world, Helicobacter pylori. Following the accidental abandonment of incubated plates, H. Pylori colonies were discovered, launching a larger investigation into the microbiology of the human stomach. More research is needed on this disease-causing gram-negative bacterium, but our hosts provide the basics of its characteristics, transmission routes, and prevention in this episode.
More about Helicobacter pylori:
Stay tuned for more episodes, posting on the first Thursday of each month. Subscribe to our show wherever you get your podcasts and find more info at weebeastiespodcast.com
The Wee Beasties podcast is a production of Nephros, Inc., a company committed to improving the human relationship with water through leading, accessible technology.
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SHOW TRANSCRIPT:
Christian: I am back with Dr. Kimothy Smith. Kimothy, welcome back!
Kimothy: Thanks, Christian.
Christian: All right…how are we doing today Kimothy? How’s life?
Kimothy: I’m feeling a lot of stress, and I’ve got a pain in my stomach. I think I’m getting an ulcer.
Christian: Today’s the right day to have this conversation, I think. We’re talking about pathogens on this podcast, so I hear?
Kimothy: Cool! Let’s go.
Christian: I was watching that documentary, Human Nature, last night. Have you seen it yet? It’s about genomics, personalized medicine using CRISPR cas9 and the scope of genetic and molecular engineering to cure disease, but also do wild projects like bringing back a wooly mammoth. Cool stuff. Worth a watch if you have some time.
Kimothy: I’ll check it out, but I tend to be a bit old school. And, I don’t mean to go too deep on the old school stuff here, but, have you seen Jurassic Park? Do you really want to bring back a wooly mammoth?
Christian: What is that line from Jeff Golblum in Jurassic Park? “Your scientists were so preoccupied with whether or not they could, they didn’t stop to think if they should?”
Kimothy: Yeah, definitely.
Christian: Well, what’s our next waterborne pathogen?
Kimothy: Apropos to my ulcer generation, it is Helicobacter pylori.
Christian: H. pylori, I’m not super familiar with this one, but if memory serves this is spiral-shaped bacteria that makes a home in your stomach and can cause ulcers and even stomach cancer in some cases, right?
Kimothy: Yeah, you’re on the right track, Christian. According to a 2013 report1 in Nature, H. pylori is the most widespread infection in the world, infecting at least half of the global population. The World Health Organization (WHO) recognized H. pylori as a group 1 carcinogen in 1994, but the backstory on this little bug isn’t that straight forward. H. pylori was discovered more recently, in comparison to the other microorganisms we’ve discussed – it was discovered in 1983 – and, interestingly enough, it was first found as a colony in the human stomach in a really unexpected stroke of luck after two doctors were trying to demonstrate a connection between the severity of gastric distress experienced by their patients and the number of bacteria present. In part, this discovery prompted scientists to begin a larger investigation into the microbiology of the human stomach using 16S rRNA analysis – and now we know that the stomach and the rest of the human gut has an extraordinarily diverse microbiome of bacteria which is critical to our immune response and other autonomic faculties. And I must tell you, Christian, as a side note, I’ve heard an urban legend that your microbiome can determine if you have a sweet tooth or not. Have you heard that?
Christian: I have not, but I’ve got a horrible sweet tooth. I’m always wanting sweets. So, I’m sort of wondering if we should run a 16S rRNA analysis of my gut biopsy.
Kimothy: Keep your microbiome to yourself, please.
Christian: Yeah, so this was part of what catalyzed the gut microbiome frenzy in the 90’s. But wait, what was the stroke of luck? And, if good bacteria is so critical to our gut and immune response how is H. pylori, a pathogenic bacterium, able to stay alive in there?
Kimothy: Yeah, Christian, I’m glad you asked. So, the stroke of luck was in the successful culture. The two Australian doctors credited with the discovery just mistakenly left a plate in the incubator a lot longer than they had intended, and they just happen to get H. pylori colonies on it. Those that have worked with H. pylori before will know just how persnickety the bacteria is – it is exceedingly difficult to grow outside of its habitat.
Christian: And why is that?
Kimothy: Well, let me get into the weeds a bit here. So, like many of the other pathogens we’ve discussed, H. pylori is a gram-negative bacterium, which means it has that extra LPS (lipopolysaccharide) barrier on its outer membrane. So, for starters, its more protected simply by its composition as a gram-negative bacterium. However, H. pylori has a really cool mechanism that allows it to transform its shape when it’s under stress – examples of stress may include a change in pH or salinity, or an increase in the gases present – like nitrogen, carbon dioxide, and oxygen.
Christian: Uh huh…so what does it change its shape to?
Kimothy: Well, as I was saying a moment ago, H. pylori is hard to grow on a plate outside its ideal habitat. It turns out that even in its ideal habitat, the stomach, the bacterium only thrives in these really specific conditions of pH and gas and any deviation from those conditions will cause the cells to become dormant and actually change shape. So check this out: H. pylori is spiral or helix-shaped (that’s where the name comes from, Helico-bacter) and form follows function here, so it needs to burrow into the epithelium in the stomach lining in order to survive, so it uses its spiral shape and several flagella to literally corkscrew itself into our stomach to take residence. But, if the cell becomes stressed because a change in any of those conditions – pH, salt, gas, or temperature – it will slow down its metabolic machinery and change from its spiral shape and into a coccoid form. It’s still unclear if this transformation under stress is a selected adaptation or something else. Several studies point to H. pylori’s transformation as an evolutionary adaptation to cope with stress and others show no relationship. There need to be more experiments to tease this out, but it is clear that a VBNC state is common with H. pylori, which again makes this a very, very difficult organism to culture from biopsies.
Christian: OK, we did get pretty deep there, let me just recap real quick: H. pylori is a gram-negative pathogen that is spiral (helix-shaped) with several flagella, which make it very motile; it is really selective about its environment (which is the stomach) and it doesn’t grow well at all outside of that environment, in fact it usually enters a VBNC state if it becomes stressed in any way and when it’s stress it changes shape into a coccoid form – this is a smaller spherical shape, right? I think the etymology of coccoid is actual berry in Greek, right? So, it transforms from a rod-spiral to a berry-shape? Lastly, and most importantly H. pylori results in the host ultimately getting stomach ulcers and even cancer, right? OK, but we’ve been talking a lot about this pathogen living in stomachs, H. pylori is also in bulk water, though.
Kimothy: Yes, so the route of infection for H. pylori is still a bit mysterious and not always well-characterized to researchers. Contaminated water sources are certainly a means of infection, but so is fecal-oral and mucous-oral routes. This can result from living in close quarters with a large community and just not have access to proper disinfectants on touchable surfaces. Once one person in a close-quarters household acquires H. pylori the R0 in that sample size will increase over time according to a Stanford Medical School manuscript in 2006. R0 is just a term we use to describe the rate of infection to other individuals.
Christian: So the good news, if there is good news, is that educating people on transmission routes and increasing access to disinfectants can likely really disrupt or lower the R0.
Kimothy: That’s right, Christian. I’d like to come back to bulk water and liquid biopsies though if I may for a moment. Because H. pylori is so challenging to culture one of the best and most reliable ways to detect and study H. pylori is by using molecular diagnostic tools such as NGS using 16S rRNA and qPCR. We’ve talked about pathogens that cause pneumonia and acute respiratory infections, we’ve talked about pathogens that infect the blood, and now we have a pathogen that infects your gut with little to no indication of infection in most patients. And although worldwide infection rates are going down, largely because of what you mentioned – access to clean water and surface disinfectants, the best way we can track and surveil this bug is by using these new diagnostic tools. Culturing for this bug is just too time consuming, unreliable, and not specific enough. It’s analog in a digital world.
Christian: All right, well H. pylori…the peptic ulcer disease-causing gram-negative bacterium. One more thing before we go – I know you’re not a medical doctor, but how is H. pylori usually treated? Just a super dose of antibiotics?
Kimothy: Yeah, bacterium is very susceptible to antibiotic regimens, so it can usually be eradicated with a high-powered antibiotic.
Christian: Well, cool deal. We’ll put some links in the show notes to some of these manuscripts we’ve mentioned in case you’re interested. Kimothy, as always, thanks so much for the chat today.
Kimothy: You bet, Christian.
This month, Dr. Kimothy Smith and Christian Railsback explore a well-known pathogen to healthcare facilities worldwide, Legionella pneumophila (Lp). Premise plumbing systems serve as the coziest of homes to this harmful and sometimes deadly bug, making routine biosurveillance efforts a must. Our hosts take a deep dive into the metabolic and cellular composition, preferred habitats, harmful effects, and preventative measures of Legionella pneumophila. A transcript of the conversation appears below.
More about Legionella pneumophila:
Stay tuned for more episodes, posting on the first Thursday of each month. Subscribe to our show wherever you get your podcasts and find more info at weebeastiespodcast.com .
The Wee Beasties podcast is a production of Nephros, Inc., a leading water technology company providing filtration and pathogen detection solutions to the medical and commercial markets.
In this episode our hosts are joined by Dr. Paul Sturman, Research Professor and Industrial Coordinator at the Center for Biofilm Engineering (CBE), to discuss biofilms and their relationship to the CDC’s list of opportunistic pathogens. This season, Dr. Kimothy Smith and Christian Railsback have been dissecting this list of pathogens, specifically those that cause disease. Biofilms are a big part of the microbiome of premise plumbing systems and the different concentrations of bulk water pathogens. Dr. Sturman’s extensive research and knowledge of these slimy communities of microorganisms offer insightful points about biofilms, pathogens, and how they affect the systems in which they grow.
More about biofilm consortiums:
National Biofilms Innovation Centre
Singapore Centre for Environmental Life Sciences Engineering
Costerton Biofilm Center
Center for Biofilm Engineering
Stay tuned for more episodes, posting on the first Thursday of each month. Subscribe to our show wherever you get your podcasts and find more info at weebeastiespodcast.com
The Wee Beasties podcast is a production of Nephros, Inc., a leading water technology company providing filtration and pathogen detection solutions to the medical and commercial markets.
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SHOW OUTLINE:
Today’s episode features a conversation with Dr. Paul Sturman, a Research Professor and Industrial Coordinator at the Center for Biofilm Engineering (CBE). Dr. Paul Sturman began his impressive line of work in Forestry, operating in the wood products industry before pursuing his master’s in environmental engineering at Montana State University. While completing post-grad bioremediation work of soil and groundwater and working as research faculty at MSU, Dr. Sturman received project funding through the U.S. Environmental Protection Agency (EPA), allowing him to advance his environmental engineering education by obtaining his PhD. Currently, Dr. Sturman serves as Research Professor and Industrial Coordinator at the Center for Biofilm Engineering (CBE) in Bozeman, MT. He currently works on a NASA-funded project, attempting to answer how biofilm growth compromises the wastewater system.
Our discussion covers:
In this episode, Dr. Kimothy Smith and Christian Railsback discuss Klebsiella – a gram-negative bacteria that causes various healthcare-associated infections. Though Klebsiella has a broad scope at the species and sub-species levels, this episode concentrates on common characteristics, environments, and levels of drug resistance. A transcript of the conversation appears below.
More about Klebsiella:
CDC’s Opportunistic Pathogens of Premise Plumbing list
Klebsiella pneumoniae in Healthcare Settings
Klebsiella Pneumonia
Stay tuned for more episodes, posting on the first Thursday of each month. Subscribe to our show wherever you get your podcasts and find more info at weebeastiespodcast.com
The Wee Beasties podcast is a production of Nephros, Inc., a leading water technology company providing filtration and pathogen detection solutions to the medical and commercial markets.
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SHOW TRANSCRIPT:
Christian: I am back with Dr. Kimothy Smith. Kimothy, welcome back!
Kimothy: Thanks, Christian.
Christian: So, what’s our bug for today?
Kimothy: Klebsiella.
Christian: Klebsiella. Reminds me of something I would get whacked with by my grandmother.
Kimothy: Well, Christian, Klebsiella is likely slightly more insidious than your grandmother, it can lead to meningitis. But I don’t know I never met your grandmother.
Christian: You’re right, that’s slightly more insidious than my grandmother. Okay, I’m really interested to hear how Klebsiella leads to meningitis or other pathologies of similar mortality and morbidity. But let’s start small today. Let’s make this easily digestible. This is a waterborne pathogen like the previous pathogens we’ve discussed. How do we differentiate this bug?
Kimothy: Let me first say the genus, Klebsiella, has a fairly broad scope and extensive list at the species and sub-species levels. For the purpose of remaining very clear I’ll limit my descriptions to the most clinically significant species and sub-species. Namely, K. pneumoniae and K. oxytoca. Both of which can be pronounced in different ways, by different people. Part of the justification for limiting to just these two is that 90% of the waterborne pathogen infections caused by Klebsiella are these two species.
Christian: Okay, so that means the microbiologists out there are going to express scorn for our unwillingness to spend the full day discussing the catalogue of attributes across the genus, right? So, keeping in mind this is a 30,000’ discussion, what’s at the cellular level, what kinds of characteristics stand out?
Kimothy: Well, Klebsiella’s most immediate visual cue is its rod-shape and capsule. Its capsule is meant, in part, to protect it from hostile environments. Klebsiella thrives in the gastrointestinal tracts of a wide range of animals, including our own. And consequentially it’s also found in wastewater, soil, and then of course therefore, fruits and vegetables as well. Since it predominates these areas, it easily integrates into the water cycle and in particular municipal water networks. The capsules also promote biofilm development which allows it to better protect itself and easily persist in water distribution systems despite heavy chlorination. Like the other pathogens we’ve discussed this too is a gram-negative bacterium. And it’s non-motile, so it really depends on the biofilm for protection and nutrients.
Christian: Biofilms keep coming up. I assume it’s not a coincidence that the CDC is emphasizing non-motile biofilm producers on its list of most concerning waterborne pathogens?
Kimothy: Yes, that’s right, Christian. And I’ll just add that another common feature we’ll begin to see many of these bacteria share is the ability to resist antibiotics. Klebsiella is no exception. It is among the most resistant to antibacterial agents. Most recently to a class of antibiotics known as carbapenems.
Christian: This is I suspect, in part, why we see so many healthcare-associated infections resulting from Klebsiella. Long-term care facilities, hospitals, clinics, and places where antibiotics are used, I imagine that’s why Klebsiella persists so much. So, tell me a little about the epidemiology. What kinds of illnesses are caused?
Kimothy: So, I mentioned earlier that Klebsiella does exist in the human GI tract, but this does not cause disease. Klebsiella really only becomes a problem when it’s (like meningitis) transmitted in the blood or inhaled. So, serious blood infections and acute pneumonia are the biggest concerns. Particularly, patients needing long-term, recurring infusions or patients on ventilators are most susceptible. Also, individuals with liver disease and are hospitalized are known to get liver abscesses as a result of Klebsiella.
Christian: Okay, so if I’ve got this right, I’ve got Klebsiella in my gut right now, but it’s essentially benign there because it really can’t take root and cause disease, but if it’s in my blood or if it enters my lungs that’s really where things start to go badly. So, I’ve seen some headlines, well more headlines than one would expect, highlighting Klebsiella outbreaks around the United States. Why do you think there has been a spike in outbreaks? Is this in some way correlated to our overuse of antibiotics in healthcare settings?
Kimothy: Insightful question, Christian. Klebsiella is ubiquitous in the environment. It finds its way into many places where humans will run into it, and of course, one of those places is hospitals or healthcare centers. But your point highlights the importance of antibiotic stewardship, or the judicious use of antibiotics to fight bacterial infections in healthcare settings. One of the interesting features of gram-negative bacteria, like Klebsiella is that they can share genes – they can share plasmids. In these plasmids they can carry antibiotic resistance genes that can be shared with other bacterium – passed on from one group to another. And so, when they grow, the resistance to antibiotics can grow exponentially. Bacteria can carry, and “collect” multiple antibiotic resistance factors in their DNA, which makes them hugely dangerous, particularly in a healthcare setting where you have immunosuppressed patient populations.
The topic of antibiotic stewardship has reached a level of importance to warrant discussion and policy adoption at the World Health Organization (WHO). Even some at CDC and Health and Human Services consider this an issue that deserves a broader national discourse in the United States.
We have a limited number of antibiotics with which to fight infections, and we are losing many of those options because of the way the bacteria are adapting. Consequently, it is harder for pharmaceutical companies to develop novel antibiotics. I didn’t intend to wax so philosophical on this topic, but you brought up such an important issue, I wanted to give it the attention it deserves.
Christian: I really appreciate it. It seems to me this is a problem we are not well prepared to mitigate. Namely, you’ve got a waterborne pathogen here that has a rigid exterior, it’s protected in a biofilm, it’s resistant to the effects of chlorination, it’s ubiquitous in water supplies, and there is no way to mitigate it from entering our water supply; and, to top it all off it’s incredibly resistant to antibiotics while outpacing our ability to manufacture better antibiotics. It seems like we’re getting outmatched here and one of the things we could be doing better is monitoring water using biosurveillance.
Kimothy: Absolutely, I couldn’t agree with you more. Better surveillance, better detection and diagnostics, particularly at the point of care / point of need, combined with fastidious cleanliness and sterilization in healthcare settings, and judicious use of antibiotics in healthcare settings. And finally, sharing this information across healthcare provider networks – educating communities.
Christian: Yeah, I couldn’t agree with you more, education seems to be the best thing we could do to begin the fight. Again, this fascinating stuff, Kimothy. What else do we need to mention today?
Kimothy: I think that’s probably it. I think we’ve scared our audience today – hopefully not too much. We’ve given some hope and some appropriate measures to take, so I think that’s enough.
Christian: Well, again, thanks so much! This is always a pleasure.
Kimothy: Likewise, Christian.
In this episode, Dr. Kimothy Smith and Christian Railsback discuss non-tuberculosis mycobacterium (NTM) and how it differs from a gram-negative bacterium, like Pseudomonas. Cell structure, metabolic Mycobacterium avium performance, exploiting biofilms, and culturable but non-viable cells are among the high points on the pathogen odyssey today. A transcript of the conversation appears below.
More about Mycobacterium:
Stay tuned for more episodes, posting on the first Thursday of each month. Subscribe to our show wherever you get your podcasts and find more info at weebeastiespodcast.com
The Wee Beasties podcast is a production of Nephros, Inc., a leading water technology company providing filtration and pathogen detection solutions to the medical and commercial markets.
***
SHOW TRANSCRIPT:
Christian: I am back with Dr. Kimothy Smith. Kimothy, welcome back!
Kimothy: Thanks, Christian.
Christian: So, what’s our bug for today?
Kimothy: Non-tuberculosis mycobacterium. (NTM)
Christian: Okay, NTM. What is NTM?
Kimothy: NTM actually includes 125 different species of mycobacteria. Essentially all of the mycobacteria that do not cause tuberculosis or leprosy, also known as Hansen’s disease are included in the NTMs.
Christian: Interesting, so it seems like there could be a lot of ground to cover here. Are there certain types of this mycobacteria that are more likely to exist in potable water and cause infections?
Kimothy: Yes, it’s actually very complex and more than we can cover in this podcast. But, we can get a start and a little bit of a taste, so to speak, for NTM. In NTM’s, the one most likely to cause a health issue in water is called Mycobacterium avium — it is actually a complex, Mycobacterium avium complex (MAC). It can be found in fresh and saltwater, as well as in soil or dust, too. Like Pseudomonas, these are biofilm producers, and they use this as a niche to colonize. Particularly because they can take advantage of protozoa and amoebae that are motile. MAC behave as intercellular parasites and use them to colonize.
Christian: And at the cellular level, what kinds of characteristics stand out?
Kimothy: Well, different from our last bug, Pseudomonas, MAC is a gram-positive bacterium and non-motile. But it is rod-shaped, like Pseudomonas was. Perhaps one of the most notable features at the cellular level is its slow growth rate and slow cellular metabolism. Where some bacteria might reproduce every 20 minutes, the mycobacteriums are usually measured in hours, and sometimes even a day or more, for them to reproduce. So, this is really slow. This is noteworthy because it allows the bacterium to gradually uptake and process any antibiotics and disinfectants in its habitat, resulting in the bug being very resilient in an environment treated with antimicrobial agents. It also produces mycolic acids that coat the cell surface in a kind of wax, increasing its cellular defense – antibiotics and disinfectants can’t penetrate it as easily.
Christian: It sounds like it’s a pretty difficult bacteria to kill. Would one be able to use chloramine or superheating to address NTM in their water supply?
Kimothy: Many remediation methods are not effective in removing NTM from building plumbing. In fact, some remediation methods may remove competing microbes and result in increased concentrations of NTM in the water. So they take advantage of the depression of the other bacteria in the community and they fill that void. Still, other methods such as treating water with chlorine or chloramine are ineffective, too.
Christian: The bug has a waxy protective coating, a slow metabolic engine that allows it to resist antibiotics, and it’s really tolerant to chlorine and chloramine treatments. This is an impressive set of defenses. Is there anything else?
Kimothy: Well, two more things, actually. Remember that I mentioned MAC produces mycolic acid as an additional protective barrier on its cell membrane? Well, that is also an essential component to the formation of biofilms, which it uses to both protect itself and enhance colonization and translocation, so when pieces of the biofilm break off. Lastly, MAC is sometimes not easy to culture because the cells enter a state of VBNC, or Viable but Non-Culturable. This is usually because several treatment modalities have been used in the water or nutrients are in short supply, so the cell operates in a dormant, but a still viable condition. This is one of those worst-case scenarios because when you send samples to a lab to be cultured there is no indication pathogens are in your premise plumbing. So, yes, this is a really complex bug to get rid of – it has a tough cell membrane, it hides in biofilms, it can resist anti-biotics, it can survive chloramine and chlorine treatments, and it can remain undetectable in VBNC state.
Christian: Wow, okay. How does one become infected with NTM and what are the consequences of becoming infected?
Kimothy: MAC enters the body when individuals inhale or swallow the bacteria, say through a water source, so this could be a shower, steam rising, or drinking water. But most people, however, will not become ill or acquire an infection if they have healthy immune systems. Those at greatest risk for infection are individuals with compromised immune systems. Mostly, patients acquire progressive respiratory distress that eventually leads to an acute pulmonary infection. People with HIV/AIDS for example, or COPD or emphysema patients; very young or very old; cancer and organ transplant patients are most susceptible. Patients who are infected are not thought to be contagious at all, you can’t pass this infection by touching or being within proximity of an infected person. Although the lungs are the most likely organ system to be affected, MAC can also affect the integumentary and lymphatic systems, resulting in lesions and inflammation.
Christian: Fascinating stuff, Kimothy. Well, is there anything else before we close today?
Kimothy: I’d just like to point out some resources, in case individuals are interested in learning more. The CDC’s Opportunistic Pathogens of Premise Plumbing list was the inspiration for our molecular assays at Nephros. I recommend people start there if they are wanting to know more.
Christian: Well, again, thanks so much! This is always a pleasure.
Kimothy: Likewise, Christian.
In this episode, Christian Railsback and co-host Dr. Kimothy Smith one another’s virtues and conduct a shallow dive into the molecular machinery, persistence, and epidemiology of Pseudomonas aeruginosa, the first of several waterborne pathogens discussed this season. A transcript of the conversation appears below.
More about Pseudomonas aeruginosa:
Infection risk, spread, and treatment
Drinking water and outbreak surveillance
Additional opportunistic pathogens of premise plumbing
Stay tuned for more episodes, posting on the first Thursday of each month. Subscribe to our show wherever you get your podcasts and find more info at weebeastiespodcast.com
The Wee Beasties podcast is a production of Nephros, Inc., a leading water technology company providing filtration and pathogen detection solutions to the medical and commercial markets.
***
SHOW TRANSCRIPT:
Christian: I am here with Dr. Kimothy Smith. Kimothy, welcome!
Christian: Kimothy, you are currently the Vice President of the Pathogen Detection Systems division at Nephros, but you have a pretty rich history. Can you give our listeners a summary of your professional life and what you’re currently working on with Nephros?
Kimothy: DVM, PhD, Biodefense, Consulting, Academia/DRI, Nephros, Pathogen Detection in potable water systems.
Christian: So, the current technology that Nephros incorporates in its risk management portfolio identifies waterborne pathogens, but there must dozens, possibly hundreds of pathogens to identify? I imagine most people don’t know these pathogens by name; maybe they’ve heard them mentioned, but are likely not acquainted with the specifics -- cellular structure, diseases they cause, target populations which are vulnerable, and recent outbreaks, etc. This series is meant to share information about waterborne pathogens and make otherwise unpalatable information about microorganisms more accessible.
Kimothy: Yes, that’s right Christian. There is an entire catalog of pathogens and it can get overwhelming quickly. It’s difficult to know exactly where to start directing your attention. I thought we might start with pathogens that have been in the headlines as it pertains to outbreaks, but that people aren’t screening for or aren’t aware is a potential problem at all.
Christian: Great; what should we start with?
Kimothy: I was thinking Pseudomonas aeruginosa might be a good place to start.
Christian: I realize there are other species of Pseudomonas that are important, but, what kind of waterborne pathogen is Pseudomonas aeruginosa and what kind of infection does it cause?
Kimothy: This is a gram-negative, opportunistic pathogen, that can infect the blood and lungs and lead to pneumonia. It thrives in moist environments, so soil or water is where it’s most commonly found.
Christian: I’d like to get to the population of individuals most susceptible to this infection, but before we go there can you give everyone a sense of what type of bug this is at the cellular level?
Kimothy: Sure, it’s a motile, rod-shaped, gram-negative bacterium. It takes on a blue-green color when grown on a plate and has relatively low nutritional requirements. It can grow anaerobically, which means it does not use oxygen. It also produces a biofilm which combined with its highly adaptive environmental response makes this a fairly resilient bug.
Christian: What do you mean by that?
Kimothy: Well, the cell can modify itself very quickly to an antimicrobial environment. The cell’s ability to modify its DNA (through mutation or from genes from other bacteria) allows it to resist most anti-microbial climates, while less robust microorganisms will die. The bacteria’s efficiency in rapid adaptation combined with being able to obfuscate itself in biofilms makes it very difficult to eradicate. It can also provide a home for other microbes to establish themselves and live. This is why we have seen this bug among the more rapidly trending outbreaks when it comes to nosocomial infections.
Christian: Okay, so nosocomial infections? These are infections that are acquired in healthcare environments, like hospitals, clinics, or long-term care facilities?
Kimothy: That’s right.
Christian: Okay, so let’s come back to my question from earlier – what kind of population of individuals are most susceptible to acquiring Pseudomonas aeruginosa?
Kimothy: Well, the bacterium takes advantage of the vulnerable epithelium (i.e. skin). That is, a patient that has degraded, or underdeveloped epithelial tissue is going to be highly susceptible to Pseudomonas aeruginosa. Babies in the PICU/NICU, for instance, or burn patients in particular. But anyone with a preexisting acute or chronic respiratory issue is also vulnerable. Ironically, since hospitals are where you find antibiotics and antimicrobial agents, antibacterial-resistant Pseudomonas aeruginosa strains find hospitals to be a favorable environment. Medical equipment, such as ventilators or catheters are good locations to harbor Pseudomonas.
Christian: I see, so given the persistent and lethal nature of this bug, why are we still seeing it as a problem not being addressed in hospitals and healthcare facilities? For example, we know that if water isn’t treated or filtered you can acquire cholera and die, so now we treat or filter the water and don’t get sick. Why isn’t the same approach taken to address Pseudomonas aeruginosa?
Kimothy: Here in the United States, there is not a strict regulatory requirement to test water for pathogens other than for Legionella, so many facilities don’t realize they have Pseudomonas aeruginosa in their water supply.
Christian: Couldn’t facilities just treat or filter the water without screening for it? In other words, isn’t it unnecessary to know what’s in the water if you implement methods to eliminate nosocomial infections, such as water treatment and filters?
Kimothy: I think unfortunately it’s slightly more nuanced than what you’ve described. Just like there is not one or two solutions your physician gives you when you go to the doctor when you’re sick, there is no panacea to treat building water networks. Just like a physician, if you want to practice good medicine and develop a sound patient care plan, you need to know what you’re dealing with before you start treating. Physicians run blood tests and take images -- x-ray, MRI, etc. We are doing something similar are Nephros. We are taking water samples and testing them using molecular assays and gene sequencing technology. This allows us to have, or give our clients, a clear picture of the building health. Treatment outcomes for the building – filters, UV, chlorine, copper, silver nitrate, etc. – largely depend on what we are diagnosing the problem to be.
Christian: So, Pseudomonas aeruginosa, for example, isolated to a burn unit or NICU, may require a more robust remediation strategy for an Infectious Disease staff than say E. coli or addressing certain coliforms?
Kimothy: That’s right, Christian. And may I add that what we’re doing is allowing the screening and diagnosis to occur in the field, on-site, which doesn’t confine clients to only using feedback from lab cultures – which can take several days or weeks to get results.
Christian: And that’s PluraPath you’re talking about there, correct?
Kimothy: Correct
Christian: Alright folks, well that was a nice little overview of Pseudomonas aeruginosa. We’ll see you next time for our next Pathogen Podcast here at Nephros. Thanks, Kimothy!
Kimothy: You bet; thank you, Christian.
On Origins is a prologue episode offering some brief history of Anton Van Leeuwenhoek, and how his clever description of the "cavorting" specimens beneath his microscope as "wee beasties" inspired the name for our podcast. Our first season focuses on the CDC list of opportunistic waterborne pathogens; our first regular episode dives into Pseudomonas aeruginosa.
Stay tuned for more episodes, posting on the first Thursday of each month. Subscribe to our show wherever you get your podcasts and find more info at weebeastiespodcast.com
The Wee Beasties podcast is a production of Nephros, Inc., a leading water technology company providing filtration and pathogen detection solutions to the medical and commercial markets.
The podcast currently has 10 episodes available.