MIC: More Infection Chat
The British Infection Association's podcast, incorporating the Journal of Infection and Clinical Infection in Practice
MIC: More Infection Chat
How has Haemolytic Uraemic Syndrome and STEC epidemiology changed? And trainee matters: looking at the recent survey outcomes
You can read the article on the epidemiology of Haemolytic Uraemic Syndrome here https://www.journalofinfection.com/article/S0163-4453(25)00145-8/fulltext
And the workforce survey of Infection Trainees is here https://www.sciencedirect.com/science/article/pii/S2590170225001153
Thanks for listening to MIC! Feedback is appreciated, email us at journalpodcast@britishinfection.org
Our logo was kindly created by Gabriella Petruso; check out her website at www.gabriellapetruso.com
Welcome to MIC More Infection Chat, the podcast for the BIA highlighting articles from the Journal of Infection and Clinical Infection in practice with me, Dr. Amy Bellfield. And me Dr. Michael Blank. And we're both infection trainees in the uk.
Today we'll be looking at the changing epidemiology of hemolytic uremic syndrome and how diagnostics have changed surveillance. We'll also be discussing the results of the UK Infection Training survey, which looks at how changes to training has impacted resident doctors and. First, let's turn to the epidemiology of hemolytic uremic syndrome.
Michael:Hello and welcome to Dr. Luke McGough, And Dr. Surya Bagram, who are the authors of the paper in Journal of Infection, the Epidemiology of Hemolytic Uremic Syndrome in England, 2009 to 2023, an analysis of national surveillance data. Welcome to the podcast.
Luke McGeoch:Hi Michael. Thanks so much for having us on. We're looking forward to discussing this paper.
Michael:So I thought maybe you could start by telling us a bit more about the problem of hemolytic uremic syndrome or HUS and why is it significant? What led you to do this research?
Luke McGeoch:Yes, of course. So hemolytic uremic syndrome or HUS is a severe disease. Characterized by the triad of microangiopathic, hemolytic anemia, renal thania, and thrombocytopenia. It's mainly seen in young children, particularly children under five. And the majority of cases are caused by infection with sugar toxin producing ecoline or Aztec bacteria, although there are other infectious and non-infectious causes. HOS, although rare is a severe disease with patients frequently requiring renal replacement therapy. For intensive care about 30% of patients will experience long-term disease consequences, including longstanding renal dysfunction and an ongoing requirement for renal replacement therapy. And the case fatality rate is about between one and 5%. Reports vary in in different papers. So you know, this is a severe disease.
Michael:What, what was the rationale for carrying out this research?
Luke McGeoch:Yeah, so a number of studies have previously been conducted in England using national surveillance data to examine the characteristics of HOS and the risk factors for HOS. However the last of these was conducted using data. To 2014, so over a decade ago. And since that time, we know that local laboratories in England have largely introduced PCR testing for EC bacteria, enabling them to detect serial groups other than oh 1 57, which is most widely recognized serial group and previously the only one that most labs could pick up. At the same time the National Reference Laboratory in kHSA has introduced whole genome sequencing for AEC bacteria. And the combination of these things means that we have a much better understanding of the microbiology of Aztec now, which, as I've already mentioned, is the main cause of HQS. At the same time the microbiology of Aztec detected in both human and animal samples across Europe and globally has been shifting over the past decade with a move towards increasing identifications of non oh 1 57 Aztec zero groups. As a result of these changes, we wanted to understand whether there had been any change in the instance or characteristics of HUS or in the factors that appear to be associated with an elevated risk of progressing to HUS.
Michael:What, what did you do in your paper? What, what did your research entail?
Luke McGeoch:So perhaps if I start with where this data actually came from. So we are fortunate in the UK to have a national enhanced surveillance system for ESTEC and HUS cases, which aims to capture all patients with these diseases that are notified to UK Health Security Agency. And that surveillance system includes microbiological information. From our national reference laboratory as well as clinical and epidemiological information collected from every patient by UK HSA. So that includes data on factors such as demographics, symptoms, travel, and key environmental food, and animal exposures. In the week before disease onset.
Michael:The level of granularity in your data is quite impressive, so I wonder if you could share some of your results that you found.
Luke McGeoch:we were able to identified a, a number of key findings, really. The first of these was that the instance of HUS does not appear to have increased in England over the past 15 years, despite the fact that detections of. ESTEC have been increasing, and that probably reflects the fact that widespread introduction of PCR use in labs in England has enabled better detection of more mild Aztec cases that do not progress to severe disease outcomes like HUS. Secondly, we were able to identify that it's been a marked shift in the microbiology of Aztec bacteria detected in HUS cases in England over time. So in 2009, the vast majority of HUS cases had Aztec zero group oh 1 5 7 detected the. Partly reflecting biases in testing available at that time. By 2023, around half of HUS cases at Estec Serial Group oh two six detected compared to less than one sixth of Estec cases without HUS. So a marked rise in detections of serial group oh two six in particular. Over the same timeframe. We also saw a marked reduction in the number of HOS cases with serial group oh 1 5 7 detected. And these findings are also mirrored in results coming from other countries across Europe and globally. Finally we looked at factors associated with HUS among people with stech using multi-variable ate regression model. And we identified that the characteristics that appear to elevate at risk of HUS were broadly consistent with those reported in previous literature. So particularly age under five years at presence of the virulence factors, sugar toxin subtype two A or 2D, and intermittent presence of bloody diarrhea or vomiting. In at some with Aztec and to some extent antibiotic use. So one of the associations we observed in our multi-variable logistic regression model was a relatively strong relationship between vomiting among Aztec patients and HUS. Now it's unclear whether this particular symptom precedes the onset of HUS or is simply a, a symptom of HUS itself. But either way, it's worth maintaining a degree of suspicion around HUS in a patient with Estec who is vomiting. And this association has been reported in a number of previous studies but is not as widely recognized as, as some of the other factors associated with progression to HUS. So those were our key findings in this paper.
Michael:Could you suggest why you think there's a decline in oh 1 5 7 causing hypnotic uremic syndrome?
Luke McGeoch:Yes. So I think there's potentially a few things going on here. So firstly I mentioned that the introduction of. PCR testing has led to increasing detections of non oh 1 5 7 serum groups over time. However that being said this change in testing practices alone would not account for the different patterns observed between stech cases with and without HUS, nor would it account, as you say, for a decline in the absolute number of HUS cases with STE oh 1 5 7 detected. So you know what else could be going on? Firstly there may be some degree of competition going on between different Aztec cereal groups within the animal reservoir. So we know that detections of Aztec, O2 six in animals food samples and humans. In England and across Europe have been increasing over time. And the virulence of the Aztec oh two six detected has also been increasing with, in particular, increasing detections of sugar toxin subtype two A, which is a key virulence factor and is associated with severe disease outcomes, including HU. There are also suggestions in the literature that the virulence of ESTEC oh 1 57 detected in the animal reservoir may simultaneously be decreasing. So it's likely that as well as changes in our testing practices, there are real changes in circulating estec oh two six and oh 1 5 7 strains in the animal reservoir going.
It is really interesting. One thing I noticed is you compare the epidemiology of HUS to other countries.
Michael:For example, in Argentina there's per a hundred thousand, which is over 10 times the incidents compared to the UK or, or other countries in Europe. do you think that's a true reflection or that more to do with the way data's collected?
Luke McGeoch:Yeah, it's a really good question. So I think, I think both things are probably true. So when you look at the instance of HUS, as you say, there are marked variations between countries, even between relatively similar countries within Europe, for instance, and England seems tends to sit somewhere in the middle of the pack. On the one hand, there will be real differences in circulating Aztec trains and in dietary and agricultural practices and climatic conditions that bring people into contact with Aztec. But at the same time, there are very likely to be artifactual differences. In instance, rates reported reflecting variations in things like. Clinical criteria and diagnostic practices around HUS notification of HUS to national public health systems, surveillance systems and study designs. And it's quite difficult to disentangle real differences in circulating Aztec from those kind of artifactual contributing factors.
Sooria:also going to be Diagnostic practices in particular PCR use of PCR. When you test.
I wonder if you could describe for me some of the limitations of your research, and maybe that can go on to a discussion about future research too.
Luke McGeoch:Yes, of course. So there, there are two key limitations really in the, in the data that we used in this research that are worth noting. So firstly, we know that, that the majority of HOS cases in England are not notified to UK Health Security agency and therefore not included in our surveillance system. And that. Really limits the, you know, the picture that we're able to look at in terms of the epidemiology of HUS. And in fact there's an ongoing study which suggests that as many as half to two thirds of HUS cases may not be notified. And it's really important that those cases are notified to us'cause that guides clinical and public health management. The second key limitation is that just over a third of HUS cases in our study did not have Aztec identified. In reality, we know that many of those patients will have been infected with Aztec, but either will not have been tested or would've been tested after delay or after receiving antibiotics. So again, it's important that HUS cases are tested promptly for Aztec including using a rectal swab if a fecal sample isn't available. So as well as those limitations, it's also worth noting that we were using a surveillance data set. And surveillance data comes with limitations. So there are certain variables that are not collected. There is also limited completeness of data for certain variables. That being said it's an incredibly rich resource that allowed us to look at the national epidemiology of HS over a 15 year.
Michael:Thanks. And maybe we could discuss future research directions that the gaps from your research have highlighted.
Luke McGeoch:So I think you 1, 1, 1 key area is the nature of this relationship between Stech Serial Group O2 six. And HUS. So we know that there are some reasons why the presence of this particular Aztecs group may be associated with an elevated risk of HUS. For instance, Aztec O2 six is disproportionately seen in young children as compared with other serial groups. We know that young children are at higher risk of HUS. Secondly, we know that Ssec, O2 six is commonly positive for some of the key virulence factors associated with HUS, including the presence of sugar toxin subtype two A. But that being said, in our multi-variable regression model, even after we controlled for these factors it appeared that. Presence of SSEC Serial Group oh two six was still associated with an increased risk of HUS. And it's not clear why that might be. We know for instance, that there are unmeasured variance factors that we didn't look at in this study that could be contributing. So it'd be really interesting to further explore what exactly is driving the dominance of, estec Sero group O2 six among HS cases. We were weren't able to look at those factors in this study because we didn't have the data required. But that would be an interesting area of research.
Sooria:Thing I'd like to emphasize is the importance of notification, the previous point around limitations and we are trying to encourage as much as possible testing and notifying HUS and Stech.
And do you have any insights into the future direction of HUS?
Sooria:I think we need to be just mindful of future trends whether or not, The, the changes we see will persist or you know, I mean, you, we don't know what the future holds. It looks like there's a trend of increasing all juice six which is very. Very characteristic of what happened when Owen five seven first came to the scene. But as I said, so we do need to keep an eye on how, you know, the, the changes go, go go forward.
I know many people who are listening to this podcast will be wondering about antibiotics, and although you say that your paper doesn't look at it specifically, I wonder if it would be helpful to talk about the gaps in our knowledge about antibiotics and antibiotics impact on HUS. Do either of you have any insight into that?
Luke McGeoch:So our current national public health guidance for ESTEC and HUS states that antibiotic use is contraindicated in patients with sst e owing to an elevated risk of HUS. And there are a variety of studies and meta-analysis that have been conducted demonstrating an association between use of beta lactams and co amaz in particular and. HUS. That being said, there are other studies reporting protective associations between certain antibiotics and HUS among Estec patients, including use of antibiotics like phosphomycin. So to some extent the jury stood out, although, as I say antibiotics are contraindicated and England and several other countries in estec patients. There's also some emerging evidence around the selective use of antibiotics among young children with prolonged shedding of Aztec. Although that is a, is a more niche indication. In this study we did not have data on the indication or timing of antibiotic use or specific antibiotic classes used. So we were limited in the information we could provide, although we did demonstrate a weak association between antibiotic use among EC patients and HUS.
Michael:And do either of you want to talk about any future research that you are already conducting or involved with
Sooria:I think other elements of research that we are looking at, for example, looking at clusters of estec and whether there's seasonality to them. Secondly, looking at HUS and comparing notifications versus what's at the hospital episode system. So NHS hospital admissions to quantify how much there is that's not notified, and whether it's linked with the age or any other characteristic.
Well, we look forward to reading about that soon, and thank you both for coming on the podcast. I'm sure our listeners will be fascinated to hear about your research. I.
Luke McGeoch:Thanks very much, Michael.
I am very excited for our next speaker, Dr. Amy Bellfield, who not only has been working incredibly hard on this podcast, but also has, uh, been working with the British Infection Association on asking trainees what they think about their trainee program. She has recently published the UK Infection Trainees Workforce Survey in the Clinical Infection and Practice Journal. I'm very excited to discuss this paper with you, Amy.
Amy:Yeah, great. I am excited to talk about it. I think it's, it's good for, particularly for UK trainees who filled in the survey to be able to hear the results of the survey, and so hopefully this is an easier way of them getting the information, spreading the, spreading the news.
Michael:Great. I wonder if you could tell us, uh, what is the background to your research and what. What was it that led you to conduct it?
Amy:Yeah, sure. So I think since, around 2014 infection training changed and so combined infection training. Came into fruition. so then we had trainees who did both infectious diseases and microbiology, for example. and infectious diseases and medical virology. and that resorted in less people were doing single specialty for med micro and med virology. And as people have been sort of coming through training. We wanted to see, what sort of jobs they then wanted at the end of their training. So did they want to do ID and Med Micro or were people just still doing Med microbe, but they had training in ID as well. Um, and so. We were kind of keen, we being the J-R-C-P-T-B, so the Joint Royal Colleges of Physicians Training Board, um, RC PA, the Royal College of Pathologists and the British Infection Association. we were keen to sort of see why did trainees choose a specialties that they chose and what specialties did we think they are going to work in when they. CCT. so when they get their compensation certificate of training, because that can help plan the workforce moving forward. So that was, that was why we did it.
Michael:And what were the broad ideas that you were asking about in your survey?
Amy:So, It was hopefully not too much of an arduous survey for people to complete. So I'm really grateful to everybody who did. The initial questions were your standard demographic questions. What specialties are you doing, currently, but then we went in to sort of ask whether or not people had. Done different specialties. Had they ever planned to do different specialties, have they ever considered changing specialty? And that could be either within infection or out with infection. And then we tried to get a bit more information, a bit more qualitative data around why. So if you've changed specialty, why did you do that? If you thought about changing it, why did you do that? or, Are you still thinking of doing that? and why have you ultimately not? Why are you still in the specialty that you're in? And then we asked, where do you see yourself being as a consultant? Um, so what specialty do you see yourself being in? And then we've said. Do you see yourself working less than full-time? And we've compared that to how many trainees currently work less than full-time to, so they, they were kind of the broad trics of what we were after.
Michael:And who answered it was that a representative sample?
Amy:Yeah, so, 72 people responded. two people didn't live in the uk so unfortunately we couldn't include them So we had 70 responses that we could analyze. Um, whether or not it's representative is an interesting question. The eagle eyed amongst people reading the paper or realize that I didn't actually write anywhere how many infection trainees there are in the uk and that's because there's. No firm number at the time of writing. Um, and so because of dual training and the way our portfolios work, there's probably a lot of duplication of numbers. So, because I wasn't a hundred percent sure on how many trainees there are, I couldn't say how many trainees there are in the paper. So all grades were represented, um, including someone who was due to start as the survey was done, and then all, deanaries. Um, but there were no respondents from Northern Ireland sadly. But otherwise, most regions were represented as well. Um, and then in terms of specialties that people do, Most specialties were represented, we didn't have any respondents from tropical medicine. Internal medicine? Tropical medicine medical virology or single specialty medical virology. And they're all much smaller training programs, which is probably why we didn't get any representation from those.
Michael:Were the key takeaways from the survey. And did were, were there any surprises?
Amy:So I think one of the big things for me was about the amount of trainees that currently work less than full-time, and the number of trainees that see themselves working less than full-time when they CCT, because that's obviously going to potentially take a lot of. Hours of work away, um, for people to maintain their work life balance. And so, 23 out of the 70 trainees currently work less than full-time. However, 38 outta 70 trainees see themselves working less than full-time post CCT. So that's over half of us see ourselves working as some full-timers consultants, which I. I dunno. I don't know if I was surprised about. I think I was surprised about that, but now I've reflected on it. I completely understand it. I work less than full-time, so I completely get it. I don't know if you are surprised by that.
Michael:Well, do you think people once they're less than, less than full-time, can't go back? It's like a you. You've got used to the good life and you don't want to go back to the full-time life.
Amy:Yeah. Yeah. But I did wonder if then when people Became consultants if that they would. Change and go back to full time. But it seems like actually people just want to get through training and then are happy to go less than full time thereafter. so yeah, I thought that was interesting. are I, I think the other thing that I found really interesting was, which I didn't go into too much in the results, but how really. Great infection. Trainees are so, there's so, so many people have done so many interesting things to get where they are. And so many people had taken time out of training and time out of program to do so much additional work. So whether that's research PhDs outer program experiences, whether they'd worked abroad for a bit, yeah, there was just so many strings to people's bows and I thought that was really impressive. And as a group, I think, yeah, well done is I think that's really, really good.
Michael:Sorry, do you think that's exceptional compared to other specialties?
Amy:Do you know what? I have no idea, but I like to think that we are all exceptional, so I'm gonna take it. Um, and yeah, and lots of people taking time out for parental leave as well, which is. Just really great. So congratulations everybody who have had, infection babies over their training. and then I think in terms of sort of have people considered changing specialty, I guess that's the nitty gritty of the survey and I was really intrigued to see what people were going to put, and I'm really grateful that people were so honest actually in their responses, so that we could kind of get a slightly better understanding of why people have considered changing. So a third of trainees have essentially considered changing specialty, Two of those trainees have considered completely moving out of the infection specialty. and the rest have basically wanted to move, within infection specialties. and for those who wanted to do that, mainly they were keen to drop their subspecialty. So, usually wanting to drop. internal medicine or med micro for example. and the reason being was to get a better work life balance, but also because there was a lot of concerns around job prospects. and I think interestingly that. Around job prospects, no matter what specialty you were about to CCT in, everyone was worried about job prospects and whether or not there was going to be a job for them at the end of training. I think that was. Felt more by people not doing microbiology component. but on the whole, everyone was worried about not getting a job, or not getting the job that they wanted, which I thought was interesting
Michael:I mean, I, I can speak from personal experience that it, it, it is a, a source of anxiety, um, that we, we are guaranteed jobs for such a long period of time, and then become a consultant and there's no guarantee anymore.
Amy:and you kind of have to see what's out there and what PAs you can kind of scrabble together. And I think what, what I've realized is that talking to people about that is the best kind of way forward with that. I think there are, I don't know, I don't know if you know of anybody, but I don't know of anybody who's CCT and hasn't got a job. And it might not be their perfect job as soon as they CCT, but eventually they, they find their feet. But I think it is a worry that we need to reassure people of,
Michael:one thing that I'm struck, uh, as I'm reading the survey results is that, um, might be infection departments where consultants have had completely different training to other consultants. So, uh, you know, a perhaps a senior consultant might be, um, single specialty microbiology, um, but would be expected to support maybe a junior consultant who is dual trained. you know, it's an interesting dynamic, and interesting to think about how infection departments might change in in the next few years.
Amy:Yeah, so I think that's kind of why. we felt that this was an important thing to ask to see where do people wanna be? Where do what specialties do people want to work in? and I guess the other thing out of that is reassuringly. 41 out of 70 people do want to work in a specialty that they're currently training in. So we actually are quite good at knowing what we want and we do just want to do that In terms of, yeah, being supervised by different specialists or seniors in different areas, I think Each place is going to be so different. Right. Um, so each, the makeup of each unit across the UK is gonna be so different. But I guess what I'm trying to say is that. There's always gonna be somebody who has trained in your specialty. There's always gonna be a microbiologist. There's always gonna be a virologist. There's always gonna be an infection specialist. At least in your area. So even if in the trust that you are working in, nobody has the exact credentials that you ccd in there is going to be a senior consultant somewhere in the region who has those skills and that can continue to mentor you as a junior consultant. and I think. Perspectives will shift over time, and I think that they've changed in different parts of the UK quicker maybe than others. And the merging of an infection specialty as a whole seems to be sort of. More likely to come into fruition than everybody staying in the specialist silos. But I, I, I think that's so different across the uk. I don't know you obviously work in a different part of the uk To me, I, I don't know how, how differently it works down south.
Michael:Yeah, I mean, I, I guess you're right, which is that in, in infection departments there's often people with, uh, lots of different skill sets and usually can find someone that will match your own.
Amy:Yeah.
Michael:Is there anything that your survey failed to capture, do you think?
Amy:Yeah. so I think there's a couple of limitations, I guess not to, um, not to draw attention to it again, but not knowing how many infection trainees are in the uk, does mean that it's hard to, to know how representative. It was, I sent out the survey via the BIA mailing list. So it's only people who are BIA, trainees, who could have responded'cause only they got the email. and I guess the other thing is that. If you've already left infection training, you're not gonna get that email. So I've only spoken to people, or people who have only responded who have thought about leaving or have maybe changed specialty within infection. for people who have left infection training, I have no idea what made them leave, and I guess that would be really interesting. What is it? That wasn't right for you, and is there anything we can, can sort of do about that? and a, as we've mentioned, the differences between the structure of infection services is really. Interesting. And I don't know if we got the granular detail on kind of what region has what and how that might impact people's worries about job prospects, for example, in the future. so that would've been interesting. I guess the other thing to say is that we have recently surveyed. People who have just CC'd. So who have CC'd in the last five years to see, what jobs they are actually working in. And if they actually are currently working less than full time to see how that kind of correlates with this work. Um, and if people are working in the jobs that they, That they were training in and is it the job that they wanted? So that, that's an extra bit of work, which is ongoing.
Michael:Gonna say an another group that you, you don't include is the scientist training program, participants. So the sort of, the people doing clinical microbiology, but maybe from a biomedical science, background. Um, I'm curious how the, how that group are influencing training and, clearly there's a big overlap with their training programs and, and the jobs that they will be seeking. Sorry, I sprung that question on you outta nowhere.
Amy:So actually Michael, there was one HSST respondent to the survey and I did include them in. The data, but obviously they were underrepresented in the survey since there was only one person who responded. Um, and I think it would be really interesting to see, where,'cause I think different regions will have different sort of pathways and different proportions of higher specialist scientific trainees, and I think that would be really interesting to look into, from their training perspective, but also to see how that influences, job availability. for medical trainees and I think those roles are so complimentary to each other. And so I've worked with a few HSST trainees and they've been exceptional and I think it would be really interesting to see Yeah. How that, how that fits together. I dunno if that answers your question though.
Michael:Yeah. No, it does. Yeah.
Amy:So in terms of the results, um, in the actual paper itself, we've broken down. In more detail, who wants to swap to what and the reasons for that. So if anybody does want to sort of get a more granular understanding, then it is all in there in the paper for them to sort of look through. cause I think it is quite interesting, and again, thank you to, everybody who responded and who was. Honest and candid about their reasoning.'cause I think it's really useful to help shape training, but also to shape, post CCT jobs in the future,
Michael:Well, thanks
Amy:yeah.
Michael:your findings with us and, uh, I'm sure you'll be back on to share the consultant findings in the future.
Amy:That would rely on me writing it up and publishing it. Michael, that one might just stay in house. Thanks.