Scientist explains why the FDA hasn't found cyclospora source

[00:00:00]So, I want to go over the three points that make this so hard to to kind of open up in a lab. The reason I'm I'm on camera one today is because I brought some visual aids. So, >> step one to what your email said, to get the DNA, you got to break open the cell.

[00:00:18]Correct.

[00:00:19]>> Yeah. So, the well, as we talked about last time, there's a lot of challenges related to the incubation time uh working with this pathogen in the lab, which is really tricky. So step one, we need DNA. We need that molecular confirmation. And to do that, relative to other things that cause food born illness, this one's notoriously difficult and challenging.

[00:00:38]>> You want to see the parasite in a sample and be able to study that.

[00:00:43]>> Uh if we're trying to confirm that that product is positive for said uh pathogen, then yes, that is uh that would give us the scientific evidence.

[00:00:53]>> Okay. So say this bagel is the product.

[00:00:56]We have the bagel. We like to see a lot of the sesame seeds representing what we're trying to find the parasite. We want to see a lot of them on the bagel.

[00:01:05]We want them to be big enough to be able to take off and split open. Correct. And it's sesame a sesame seed is possible to break open.

[00:01:14]>> Yeah, in a way that's that's one way to look at it. Remember this is a microorganism. So it's a totally different scale. uh there are uh but that first step is we need chemical reaction physical reaction to try to break open the DNA of that cell and then eventually amplify that DNA and confirm that that is what we indeed think it is because it has a cycllosphor gene for example >> and these are harder to break open than than we might expect.

[00:01:42]So the parasite is physiologically different. It has a thicker cell wall, a different kind of membrane. The chemistry is going to be a little bit different. Um, traditionally with other foodborne pathogens as well, when things are present at low abundance, of course the sesame seeds on your bagel, there's many of them. But, uh, when we think of when something is actually present in a product or in nature, it's more often than not at a very low concentration that approaches what we call like the detection limit. So traditionally we want to amplify those things and enrich for them. So we grow them up in the lab and then we do our molecular confirmation. So with salmonella for example if that's in iceberg lettuce we would take that sample we would rinse it with some kind of buffers and reagents and then we would uh enrich that in some media nutrient media that's specific to that organism grow it up to a certain detectable level then we can run our molecular tests. With cycllospora there's no media where we can actually do that. So that is what creates part of this challenge as well.

[00:02:42]>> So there's no way to replicate these to make it like you know like a poppy seed like a ton of them on a thing. There's no way to do that. We're getting plain bagels.

[00:02:52]>> So the alternative approach is to really concentrate our sample. So there are technical methods where we can spin down at a certain gravitational pool and and separate cells based on their size or their density. use different chemicals to try to um isolate or concentrate what we think is our target and then we can try to break that DNA open. And even when we get to that point, again, like you said, this one has a shell that's a little bit different than other microbes that we're interested in uh for these similar causing similar problems um in the context of food safety. And it's just hard to study overall, >> right? And for those watching at home, that is maybe you could break open a sesame seed, but try breaking open a poppy seed. You can't even can't even really see one of them, especially when you don't have a poppy seed bagel. You have something that looks more like a plain bagel because you can't get uh enough.

[00:03:47]>> All right, so it's a tough nut to crack.

[00:03:50]>> Let's talk about >> Well, if you go back to the farm too, just just real quick, if you go back to the farm too, it's not just going to be the many poppy seeds or the many sesame seeds. looking for a small dozen maybe on a whole farm or something in some context in some cases when it gets diluted in the environment. So if people are getting sick a doctor can take a clinical specimen that and there's suspicion based on the symptoms the syndrome that they have this uh illness then they can look at in the stool sample and the clinical sample and then confirm that with food sample maybe that's diluted because remember this is transmitted uh through fecal oral route.

[00:04:26]So, it's going to be diluted as it moves through the environment, whether it goes into water or other food. Um, or maybe it's local to a specific farm or even a very specific location within a farm.

[00:04:36]>> So, a lot bigger than a bagel and in many cases a lot grosser it seems as we're trying to take these samples out.

[00:04:43]So, about what the FDA, what may have happened here, uh, Senator Blumenthal this morning from Connecticut said that it may have been due to short staffing at the FDA. You know, there there were all kinds of angles to this. Now, from your scientific whole genome perspective, what do you think may have happened here that would have registered a false positive and linked this to Taylor Farms?

[00:05:10]>> I think so. From the scientific perspective, when we think of what is a false positive when we do any of these tests, it's really essential that in the lab, we have what we call standards and controls. So, we need to have a sample that is a known cycllospora, that would be our positive control, and a sample that has no cycllopppor in it, that would be our negative control. Uh, you can think back to the pandemic when you had to take the swab and you ran on the um on on the enzyme assay. If the line wasn't there for the control and you got a line or you didn't get a line, you can't conclude that result. You need to have a very thorough set of controls.

[00:05:45]Um, it also has to be validated. So, if we're trying to point uh blame or in one direction or another, it's more likely than not that the the it should be isolated in, you know, more than one sample. And if we can only see it here.

[00:05:59]And if that sample uh was in question by any means based on the controls uh in some way uh then we lack enough scientific evidence to really pinpoint that cause. Uh per Senator Blumenthal's comment, I do think that it's challenging to uh meet the the need for uh traceability and and tracking uh to try to solve this problem with limited resources. That that is >> Go ahead.

[00:06:27]Yeah, I was just going to say you need resources to do it.

[00:06:29]>> Yes. Uh do you think this story is going to end up where it's traced to one farm?

[00:06:36]You know, it was so the Taco Bell iceberg lettuce answer was so like, you know, people latched on to it. People were like, "Of course it was Taco Bell iceberg lettuce." Do you think it's going to be one source or a lot?

[00:06:48]I think that we don't know, but it's more likely than not that there are multiple small outbreaks that kind of go on in uh when we think of food safety, microbiology. Uh for example, this is really centralized to the region in the Midwest right now. I think case numbers are way up in Michigan and Ohio, but around here in the Washington DC area, I think that those numbers are more in a normal range. Um and part of and this is all going to reflect like where's the supply chain. I do think that there's a lot of epidemiological data that can still point and and help um our um federal partners and state health agencies try to figure this out. Uh but I do think that yeah, I think that it's very complicated.

[00:07:30]>> Once again, thank you so much for breaking this down for us, Dr. Ryan Blousein, associate professor at the University of Maryland. And uh we might have to call you back next week, so so stay in touch.

[00:07:42]Yeah, I think it's we just have to be careful. Um, and this is a unique situation. So, thanks again, Joey.

[00:07:47]>> Yep. We'll be right back.