166: Pasteurella multocida: capsular groups and more

Welcome to Let's Talk Micro. Hello my dear audience, welcome to another episode of Let's Talk Micro as always. I hope you had a great week. And if you're listening to this and you celebrate Thanksgiving, happy Thanksgiving. I hope you're having a wonderful time with your family and loved ones or friends or whoever you normally celebrate with. But

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These resources include cheat sheets, practice tests, games and more and they are being used by thousands of people worldwide and may be helpful for you or your colleagues. And of course these are some great resources from Dr. Timothy Gothier, a very passionate pharmacist.

If you haven't listened to the previous episode of Let's Talk Micro, please go ahead and do so. It was a great episode where Ranim Pallora, who's a pharmacist at the University of Utah in Salt Lake City, she joined the podcast. And in the episode she talked about an article that she co wrote and it was about an N D M variant that was seen in E. coli. An N D M five variant actually.

And of course we started with an overview of what are betalactams, betalactamases, uh penicillin binding proteins. And one of the betactamases is New Delhi metallobetalactamas or NDM. And those of you that work in micro and microbiologists, pharmacists, you know, ID physicians, you know that NDM actually affects the activity of better lactam drugs with the exception of Estronem.

And in the episode she talks about that this variant and how, you know, it has a a PvP alteration and how this affects antibiotics. So it was definitely a great episode, so please check it out if you haven't already. Okay, so let's go ahead and talk about today's episode.

So those of you that listen to the podcast regularly you know that I recently re released an episode that I had done last year about veterinary microbiology where Kelly Maddock and Sarah Gerfrow They joined the podcast to talk about what's microbiology like in a veterinary lab. And it was definitely a great episode. So in today's episode I am joined by Dr. Kelly Maddox, so she returns to the podcast.

And she is the section head at the North Dakota State University Veterinary Diagnostic Laboratory. And she came to the podcast to talk about my favorite organism, which is Pastorella multosida. And you know if you if you have been following the podcast for a while, you know that At the beginning in twenty twenty one I did an episode about this organism and why do I love it so much?

So in the episode Kelly starts going over an overview, like a historical overview of Pastorella Multosida, and then she moves on to talk about the capsular types. And in the episode she also talks about her doctoral project that she did, which the link to the to the that study, you know, it's in the show notes. And in the study they use Malditoff MS. As a rapid way to look for hemorrhagic septicemia types of pastoral amaltos,

And in the episode she explains how they did that, you know, she talks about hemorrhagic septicemia and it was such a great episode. I definitely love talking about Pastorella. I really love that Kelly also that is her favorite organism. And one interesting fact that she mentions in the episode is actually that Moltosida means killer of many. So once again, so great having Kelly back. All in all, a great episode, so let's go ahead and listen to it.

Well, today is a great day at the Let's Talk Micro Podcast. Those of you that have been listening for a while, do you know that my favorite organism is pastorella? So if you like it too and maybe if you don't, definitely stay and listen to this episode because it's great. We're gonna talk about pastorella. So with me today, I have a guest, and she was a guest before. If you haven't enjoyed the episode about veterinary microbiology, I definitely invite you to check it out.

But in the episode, I had Kelly Maddock and Sarah Gerfrow. So with me today, we have the now Dr. Kelly Maddock. Uh Kelly, welcome to Let's Talk Micro. Thanks. I'm excited to be here. My pleasure. And and you know, we talked about this off off screen before, but you know, once again it's definitely as someone that's about to finish his masters and and

I know the hard work that goes into that with you know with a full time job you just completed your degree not too long ago. So definitely congratulations. Thanks. Okay, so it has been a while since you've been here and and and So maybe if we can start with a quick introduction so if someone is just listening and haven't listened to the previous episode so they have an idea of what you do.

Yeah, uh I'm Kelly Madoc. I am section head of the Microbiology and Biosafety Level Three Laboratories at the North Dakota State University Veterinary Diagnostic Laboratory. I'm a medical laboratory scientist by training with my bachelor's and masters in medical laboratory science. And as Louise just said, I just finished up uh with my doctorate in public health from the University of South Florida.

Um, very passionate about uh one health and the human animal interface when it comes to bacteria too. Yeah, definitely. And and I always get good feedback from the episode that we did did before, you know, people working in the clinical lab and especially medical lab scientists and and seeing things, you know, happening on a different population, which in your case is a veterinary. So I think, you know, it definitely had a lot of good feedback.

Um, so let's go ahead and as I said, you know, we're gonna talk about pastorella more specifically, pastorella mutosera. So maybe let's go ahead and start with a historical overview. Yeah, so Pastorella, as you can imagine with the name uh Pasture snuck in there, uh Louis Pasture had a hand in

um identifying this bacteria. Of course, disease caused by what we presume would be pastoral and maltosid at the time had been described before. But Louis Pasteur essentially identified it as the causative agent of foul collar. Laura? So that's a disease in birds.

Um, and also through this, of course, those happy accidents and miscommunications, uh, the the culture wound up being left out for a month um and it wound up becoming an attenuated vaccine. So there were some initial vaccine studies done with Pastorella Maltosida. Um, that's about eighteen seventy nine. And over the years, um, many different animal diseases were described as being caused um by this bacillus, as they would call it at the time.

Um, and as time went on, other diseases such as hemorrhagic septicemia were described um in about the eighteen eighties. Early nineteen hundreds uh wound up with the more of that

recognition of the various animal diseases. Um, but then there was also a lot of debate on what was actually causing the disease'cause they'd find different bacteria, which I think they later figured out was this another Pastorellaceaea, that Manheimia hemolytica. Um And in 1912, again, this hemorrhagic septicemia, we can go into more of what that is, um, first thought to occur in North America.

Um nineteen twenty two first confirmed case in North America of this hemorrhagic septicemia and the bacteria um isolated from that outbreak. was eventually used for challenge studies um and a lot of research um that occurred in a bison herd in Yellowstone. Um Then in the nineteen fifties and nineteen sixties, I really think this was kind of the heyday for a lot of research on Pastorella Maltosita.

With uh Namioca and Carter initially describing some capsular typing systems. Uh there are five different capsular types of pastorella maltosita. Um, so these two independently um described some different methods for potentially typing these. Uh the predominating system is was developed by G.R. Carter. Um and then in the 60s, um, Carter and Holmes ended up uh attempting to characterize uh the different capsular types.

of pastoral maltosida isolated from human infections. So it was recognized at that time as potentially a zoonotic illness. Uh so they they talked about the different capsular types and um potential animal hosts. Um and at the time capsular types A and D were most frequently identified, but um and and a lot of non-typable strains were noticed at at that time, but

uh no type F strains had been described at that time either. So more than likely that was what was going on. Um in the nineteen seventies and nineteen eighties, um, they ended up coming up with serotypic methods. So um identifying or characterizing that somatic antigen um in nineteen eighty seven then was when that type F strain. So um more than thirty years from the original capsular typing methods being described, that final fifth capsular type was described.

Um, and it really is an important uh human pathogen. I think we've all probably run into it in the lab. Um, it can seem kind of innocuous because it tends to be very susceptible to like the beta-lactams. Acquired resistance is pretty rare for those. Um but an article in twenty twenty two noted that more than three hundred and thirty uh case studies

were on human patients with pastoral maltosita infections. So it is a pretty important cause of disease. Of course, I'm sure there are more in the literature since that article was written. But yeah, very very significant in terms of it it affects all animal species. Multosita literally translates out to killer of many.

Um, and of course, pretty much any animal species and humans could be impacted. And something that really struck me as I was going through old literature, I feel like the people that are interested in pastoral amaltosata tend to be very passionate about it and um How many bacteria have you heard as being described as enigmatic or fascinating in like a literature review that popped up multiple times? Um, I really appreciated that about the bacteria.

Wow, that's such a great uh historical overview and and a lot of things that I that I I wasn't aware of. Um so definitely thank you for that and So one thing, you know, and then as you touch on it when my pastorella, if you're a medical lab scientist and you work with cultures, you know, um at some point in time I'm sure you have seen it. And it's typically right, you you see that typical presentation where maybe you get in a wound

Um, you know, you can always have all the cases where then maybe spreads out and you can have it like in bacteria or something like that. But typically the most classic one is you're sitting working on a wound culture and you see it there. And then uh You always check the history and you see okay, yeah, dog bite, cat bite, depending on on the species, you know, like in the the most exciting one for me was pastoral erogenes and you know, history, pig bite wow. In Orlando.

Um, so that was definitely very fascinating. But maybe, you know, as someone that I don't have any any pets and I haven't worked with veterinary microbiology, but besides that I don't think much about it and the way that I know that, you know, it's it's it's part of the commensal, you know, in some organisms.

But beyond that, thinking about diseases and and and animals, you know, I haven't given much thought. So maybe if you can talk to the audience and tell them more about pastorella motosida and disease in animals. Yeah. Uh so actually and I th this was shocking to me, I guess, when I moved over to vetmed, but um Of course there's bovine respiratory disease complex. So that's primarily caused by bacteria and viruses, with most of the bacteria belonging to those pastoraliaceae family.

So there's that Manheimia hemolytica, pastorella maltosida, and Histophilous somni. And globally it's estimated that um this respiratory illness costs over a billion dollars. um just because of the expense of um managing it with antimicrobial treatment and uh death loss of animals. So it is a very significant cause of respiratory disease in cattle.

Um, in cats and dogs, you can get respiratory and often those bite wound infections might be more of like the pastorella canus or some of those more minor species of pastorella. Um in rabbits, it sounds super cute, but they get what it is commonly uh termed as snuffles. It's a respiratory illness in rabbits.

Um goats, sheep, even elem elephants and other ruminants can wind up with it. I'm sure any animal species has it could be described as having an infection with pastoral maltosida, but similar to humans. Um would often expect it so if the animal is stressed or immunocompromised or if you have those bite wounds. Um

So pretty common there. And of course in humans we realize that um we'll often see them, as you had mentioned, in those skin and soft tissue infections, uh potentially more invasive infections and respiratory um illnesses. Um and you'll usually see those in the young elderly or immunocompromised, but of course a bite wound. Um, I I think that's pretty commonly associated with with those cats. So um not infrequent in immuno immunocompiment um competent individuals.

Yeah, and I think for some reason, I mean, it's just it's just something that making that connection and up to this day, you know, I have seen many and and I don't know. It just you know, you see the it growing on the plate and you're like, Let me check that history, you know, see if I see that bite, like you're always making that connection and you know that more than likely that's where it's coming from, but it's always

I don't know, it's it's just I don't know how else to say it, you know, it's kinda like fascinating and and so we always go back and check. Um

So right, so um you know, you you touch you talk about, you know, about the capsular types of of of pastorella uh multosida, and you mentioned some examples and you also, you know, mentioned hemorrhagic fever. So maybe if you can go over those, maybe you know, to expand on the types and animals associated with each type and things like that.

Uh yeah, so there are five different capsular types. Uh there's type A, B, D, E, and F. Type A would be the most commonly seen capsular type in humans for sure from several different papers. Um, but also the most common for foul cholera, which I forgot to mention in those animal diseases, um, recap, but um also that bovine respiratory disease and then often in other um other ruminants like um sheep and goats. Um capsular types B and E uh cause that hemorrhagic septicemia. And that's a

actually a really problematic disease primarily in Asian and African countries or developing countries primarily. Um, it causes really rapid death loss in cattle. And um it's really characteristic um in that it causes edema in the neck and like in the chest region or brisket region is how it's usually described. And then there's just prolific hemorrhage throughout the body.

for these animals. Um, so it can be really devastating for those countries where there's a lot of dependence on uh cattle economically and of course for food. And um Then we have capsulety D, which is most commonly associated with uh pigs, so it causes what's called um atrophic rhinitis. Which essentially um there's a toxin produced that ends up um destroying the nasal turbidance in the pig.

But that type can also cause bovine respiratory disease. And then there's capsular type F, which is more minor. It is one of from my experience the more common uh capsular types seen from human infections, but I think it's uh probably pretty often seen in cats, if we were to to characterize more of those. But then also poultry.

But really any of those capsular types can can jump around and cause disease in the different animal species and different areas, but those are the primary characteristics of those types. You know, I have worked in different labs and I know that uh When it comes to a lot of time a lot of times when it comes to things like you know, like like capsular typing and things like that, it sounds like maybe something that

Maybe it will be done like by some sort of reference lab or or like a state lab of sorts. Um so I don't think it's something that but might be routinely available in the labs. Is that correct? That is correct. Of course it's an esoteric test test method, so it wouldn't often be performed. Um maintaining the antecera is really difficult. Um and

I think as late as two thousand and one it was noted that maybe two labs in the world maintained that reference SIRA. And I know for sure like our va national veterinary services lab in the US stopped routinely producing those. Um, and of course something we think of all the time is that diagnostic stewardship. If it's not actively going to help you treat something better or characterize the disease is probably not practical.

Um, so where I see it being most practical is in cases when we're expecting like that hemorrhagic septicemia that would be unusual. Um Primarily, but it is really interesting when you kinda wanna get a little bit deeper into some of that epidemiology and potentially there could be more virulence associated with some of those different capsular types. So it is it is very impractical for routine use. Um there is uh PCR methods for the capsular typing.

And you can also use whole genome sequencing. There's actually some really great databases that will take the sequences and tell you the the capsular types um pretty rapidly. And it's um Really friendly for folks that don't have a lot of bioinformatics experience like myself. Uh really great point and click option. Yeah, I like that you mentioned yeah, I I I recent not recently, like last year, I took a bioinformatics class and oh my goodness, you know, I learned a lot.

But definitely was a lot of information and and very you know, the labs had like a lot of steps and and I enjoyed it, but definitely like a lot of information and something that I wasn't familiar with because You know, when it comes to things like you know, like sequencing and as as you know, definitely it's trending now. Now you hear more research on it and maybe some labs might be starting to bring it.

But it's something that up to now, uh like routinely, you know, us l medical lab scientists, you know, we haven't worked with in in the lab, especially in microbiology, so we might not be familiar with some of those things. And then then brings me to Maldituff. You know, side note I definitely enjoy how the feel has been changing and and from the traditional culture reading, then we started bringing Moldy Tov. Now there's talks about, you know, gene sequencing and things like that.

You know, I have done episodes about Malditov. I have I love some things about it. I do not love some things about it. Um but here, you know, there's some model that was developed to use Molditoff MS for differentiating hemorrhagic from non-hemorrhagic strains. Can you talk more about that? Yeah, so that uh that manuscript was part of a project uh that I wrote for um one of my uh my products for my doctoral project.

Um, very much owe a debt of gratitude just off the top uh to Doctors Stanger, Loy, Wynne, Clausen, and Roberts. Those are my co-authors on that paper. So this method was developed so that we'd have a rapid way of looking for those hemorrhagic septicemia strains in the lab. We see so many pastoral EACA, it would not be practical, as we'd mentioned, to actually do the capsular typing on those.

basically just using other models. Um, there there are some papers out about uh looking at different genotypes, say of that Manhamia hemolytica, which is again that bovine pathogen. But also Haemophilus influenza type B. There's a paper that's described to be able to differentiate that from the other type.

And so using that same thought process, uh, tried to develop a Malditoff MS method for um capsular typing the different types of pastorella. Well, it became very apparent that there was a lot of over overlap between the capsular types A, D, and F. Um and so it made it really difficult to actually find a good biomarker. So those um mass mm um mass spectra peaks or the main spectral profiles that your Malty Top is using to actually identify

the the different bacteria, you can actually find those different biomarkers and potentially associate it with genomic differences. And that's where you get into that nitty-gritty with the different capsular types. So um it was really hard to differentiate those alike strains and so wound up looking to see if I combine the kinds that cause hemorrhagic septicemia and compare them against ones that do not. Is there a distinguishing peak?

that would actually help differentiate those. And fortunately there was um a mass spectral peak uh commonly found um in all of the hemorrhagic septicemia strains. Uh was that seven seven to nine uh mass to charge ratio.

Um, there are some trickier strains that are I think emerging in North America and elsewhere in the world, but they might be our more predominating strains. Um, an extra peak in there a an an intensity difference between the non hemorrhagic septicemia strains and the hemorrhagic septicemia strains really help um identify those further. So we can do it with a model and software that would do it automatically if you were to pull the spectra from your MALD and put it through that.

Or you can actually, I know on my research use only or the RUO Bruker model that I have, I'm able to actually look at it directly in the software to see if that peak is present or not. Um, and seeing those peaks, I would then be able to decide should I actually pursue sequencing or some other kind of characterization? Because this is a reportable disease for animals in the United States.

Um, so it's one that we keep track of. Um, so it would actually give us a tool. Um these strains, of course, if you've seen them in the lab, you might see ones that are uh more mucoid than others. Some will be a little bit more dry or shiny looking.

Um, but you can't just look at it and be like that's a hemorrhagic septicemia strain. So it's just a really useful tool. It doesn't necessarily cost extra money because you can look at your direct spots that you're normally doing in the lab. You could potentially do your formic acid overlay. Or you could do a f full formic acid tube extraction with that tube extraction being the most sensitive and producing the the crispest peaks that you could possibly have.

So just kind of a more integrated way to examine these uh capsulars. You know, it's always something interesting how you know, like I use the Vitech MS and and When we talk about the formic acid, you know, with the Vitech it's only used for for uh fun yeah, like if you have yeast. So when it comes to this uh model, you know, are there any ex step any next steps for this or that's about it or?

My next dream would uh to be you uh to use Fourier transform infrared mic um m microscopy or um mass spectrometry. Uh FTIR. My next goal would be to use FTIR to be able to actually get more granular examination of the different capsular types. I think that's really the only other way to go about it. um for creating a a better model that wouldn't be something genomic or s or sequencing. Um but, you know, in the meantime it would be additional um

typing potentially of these strains using that whole genome sequencing. Um, I do related to this project, have a couple of other manuscripts that'll be coming out. So we're describing potentially the first two um cases of hemorrhagic septicemia in cattle in North America or in the United States since nineteen ninety three.

So it is very rarely described. And then we also have another manuscript, both just submitted, um describing pastoral maltosita strains that were collected from uh human patients. So describing those. um more granularly. So just some interesting things. And we also typed those human strains using Malditoff MS. And of course, as expected, most were those A, D, and F strains, or all of them I should say. Um, that is something I don't think I mentioned. There have yet to be reported human cases.

of hemorrhagic septicemia, but I think that would potentially be more towards um resource limitations or um potentially just people not thinking of them being different, especially if you're in those developing countries and you have these other strains. Um

So I think that would be really interesting is to actually find out from humans that are getting pastoral and moltosida infections in those endemic countries. Um, are we actually seeing those strains? Is that something that's potentially impacting folks? In those areas. Well I'm definitely looking forward to to those publications and be able to read them and um when it comes to this one with the the model, has this been published already that maybe the listeners can look at it?

Yes, actually it just published in the Journal of Microbiological Methods and Uh it is titled Development of a Malditoff MS model for differentiating hemorrhagic septicemia causing strains of pastorella maltocida from other capsular groups, if folks want to check that out.

Perfect. And I'll go ahead and put a link on the show notes. So if you want to check it out as you're listening to this episode, once you listen to it, if you want to go ahead and take a look at it, it's gonna be there for you to access. Um so right when I'm and you told me you listened to it and and I did an episode, you know, when I was starting the podcast about why I like it so much and

And I also and you m mentioned this when you were in your introduction, but so it is also your favorite, right? So you also like it as much as I do. So can you tell the audience why is Pastorella Moltosita your favorite organism?

Uh well at this point after spending so much of the last two years really researching this bug, uh it would be really hard not to love it. I think it's imprinted on my soul at this point. Uh but as a young med tech it was one of my favorites to get. Just really similar to you. You end up

uh for me it you're flipping through your different culture plates, you see the growth on the blood and the chocolate auger, then nothing on CNA or Mac. And I know as a young tech I was like, this seems like any coli But it's weird that it's not growing on Mac and you end up going through your indole and oxidase, realizing those are both positive, and then it would click in my head. I should look at um the record and see if there was animal contact of some sort.

Now knowing more about the literature, there's a lot more where we're seeing with those immunocompromised patients, just them having a a pet and being really close and maybe cuddling, maybe they're going through cancer treatments, they become colonized and th it can then be a problem.

Um, but just it of course, even just that interaction of the human animal bond then contributing to a disease. Um, I also just love that it's really susceptible for antimicrobials. For some reason that's a charming quirk for me on that. Um But yeah, it's it's just a great bug. Um it's predictable, but also has its unusual little quirks there too in the different um colony types. So just kind of a fun bacterium for a while.

Indeed. And and you know, like I always tell the text, you know, if it's not growing on the Mac, you know, stop and think, do a gram stain, you know. you I have seen people go through the worst outcome, which is, you know, you assuming that it's positive and then you put it in an instrument, you get an ID and so many things going wrong that way. So

Take your time. But it's still, you know, and to this day, I know when I'm looking at on my all my plates and sometimes, you know, from the get-go I see the Makonki that is not growing and or I see Gram stain, gram negative runs and I see the two plates, you know, it still makes me smile. It's like the same thing with Hemophilus influenza. When I look at that blood and I don't see anything and then I flip that chocolate and those tan colonies are fully grown in there. Oh man.

I don't know, I guess it it just it brings the nerdiness in me. So but definitely wow what a what a what a great episode and learning so much about about Pastorella and like I mentioned before, yeah, you don't maybe you might think about it in the terms of You know, you see that wound in the lap and and something like that, but all those things that you have brought to light about.

Patient maybe is immunocompromised, you have a pet, you might get colonized with it, you know, and really puts a lot of things in perspective. And and of course with all the antimicrobial resistance that we're seeing, it's always nice when you look at a uh uh organism the profile is nice and susceptible. It definitely, you know, it's it's a good thing. Well Calino, as we are coming to the end of the episode, is there anything else that you want to tell the audience?

Uh, I just really hope you gained an extra appreciation for this cool bug. It is such an interesting pathogen and it has such an interesting history. That was another thing I absolutely loved about researching it. There's so many papers and debates. I feel like I know the people that um researched it in the past to an extent. It's one that I feel like has been built upon.

many, many times over the decades since it was first described by Pasteur. So it's really fun to be a part of that legacy. Um I I just hope you can join in that passion and maybe appreciate it a little more the next time you isolate it in in your benchwork. Well thank you for that. And uh so and for the listeners, if you haven't as I said before, if you haven't listened to the episode about veterinary microbiology, it was recently re-released as part of the Throwback Thursday series.

So if you have your catalog set up on the order of release, you should be able to see it kind of right at the top. So check it out. Well you know Kelly, once again it was it was so great. You know, I enjoyed the first time that we talked I talked to you and Sarah and definitely I I truly had a great time recording this. So thank you so much for taking the time to be in Let's Talk Micro. Thanks for having me back. It was great. My pleasure.

And that my dear audience, it's the end of this episode. I hope you enjoy learning more about Pastorella, like capsular types, a little bit of a historical overview, and more. As always, I enjoy sharing this information with you. And so great, you know, having um Dr. Madd again and talking about pastorella, my favorite organism. So

As always, continue bringing that passion to what you do. It's so important. You do such great work. And stay tuned. Great things coming your way. Thank you so much for the support. So As always, stay motivated, stay safe, and of course, continue talking micro until the next time. Bye!