Marcel Behr
Clinician-scientist. Epidemiology and pathogenesis of mycobacterial infections.
- Always a treat to see the owl while cross country skiing on Mount Royal. Doesn't seem bothered by -12C
- Ha! And yes. But are sponges the host, or are they just sponges, doing what sponges do?
- It might be the sponges! Or might not be. Plenty to search for still regarding ancestors. @tstinear.bsky.social journals.plos.org/plospathogen...
- I agree with everything said by @mycolates.bsky.social in this thread, except the penultimate sentence. To my eyes, figure shows that Mtb diverged from animal lineages after the blue box (loss of spacers). Whether their common ancestor was Mtb is uncertain. Prefer to call this 'MTBCo '.
- Reposted by Marcel BehrHow likely is ‘likely’? Does ‘likely’ have a higher probability than ‘probable’? I put together a quick quiz so you can see how you interpret probability phrases, then see how you compare with others: probability.kucharski.io
- Thanks Gabriele!
- Cool! In case I missed it ....can you post the link to article?
- 👇Great thread on TB strain concordance/strain discordance among household contacts. If I read correctly, findings from a 1998 small series from San Francisco consistent with the much greater analysis. ++ Implications for transmission and management of contacts.
- Not as cold as much of Canada. And yes to the postdoc opportunity!
- Are there positive and negative control tissues, eg from mouse or guinea pig infections, that can be used to pre-validate FISH before studying human samples? Without this, how does one know whether an assay is fit for purpose?
- To see bacteria by FISH, does this imply at least 10(4) per g, akin to the threshold to detect Mycobacterium tuberculosis by Auramine staining (5000-10,000 per mL)?
- Excited to see the PhD work led by Sarah Danchuk published today. Virulence hierarchies within the Mycobacterium tuberculosis complex. Thanks to all the authors and collaborators, and especially kudos to Sarah: www.pnas.org/doi/10.1073/...
- It has been often observed that TB rates go up from childhood to adolescence, suggesting that children under 14 are relatively resistant and/or adolescents are more susceptible. Could the rise in incidence be explained instead by transmission effects you report?
- Starting conversation for mycobacteria researchers. 1) mycobacteria have strange cell wall, 2) mycobacterial infections are hard to treat. Is 1) the CAUSE of 2)? For broad spectrum antibiotics that work (rifampin, levofloxacin, linezolid), do they get into mycobacteria at lower concentrations?
- I thought it was going outside in winter without a hat....
- Sihem Belhocine put this quote at the start of her thesis: "If many remedies are prescribed for an illness, you may be certain that the illness has no cure." Anton Chekhov, The Cherry Orchard, 1904 (the year he died of tuberculosis). Does this adage hold true in 2025?
- Amazing thesis work led by Sarah Danchuk now submitted for review and posted as preprint: ssrn.com/abstract=51598…. Short summary: M. bovis & M. orygis manifest enhanced virulence compared to M. tuberculosis in natural host model (calves) and small animal model (mice).
- Question to academics: I've been on several editorial boards before, but until now, never been asked by to sign a 16-page legal contract, including a section on my obligations. Unpaid role. Is this the new norm?
- Hi Peter, A further point. It's brilliant that UK publishes its M. Bovis data. Now that WHO and WOAH recognize that definition of zoonotic TB extends to M. Orygis as well, I would be curious to see the same type of data for M. Orygis cases. So far, just scattered case series, nothing systematic.
- Thanks!
- Hi Peter. I don't know about exposure. Harder to do in immigrants to e.g., Canada, Australia asking about exposure in country of birth. Maybe can be done in places where local exposure? Are there good data in the UK?
- Compelling analysis suggesting that M:F difference in TB rates driven by differences in rates of Mtb infection. Consistent with old (2000) analysis of genotypic clustering (PMID: 10654640). But why do zoonotic TB series often have flipped ratios? doi: 10.1093/infdis/jiae124
- I believe most isolates from pre-2020. Resistance developing or already established?
- ⚠️ Bit of an alarm bell to MDR-TB regimen BPaL/M - resistance to constituent antibiotics developing and transmission of such strains already occurring #TBSky #IDSky @nejm.org www.nejm.org/doi/10.1056/...
- Agree with treating Legionella. Where are the best data on macrolide treatment and outcome of CAP due to Mycoplasma?
- Reposted by Marcel Behr[Not loaded yet]
- Pre-XDR Mycobacterium tuberculosis in cattle. Plus some M. orygis academic.oup.com/ofid/advance...
- Sarah Danchuk at PhD defense, presenting her favourite figure contrasting the host reservoirs of Mycobacterium tuberculosis complex.
- Here is the reference for macrolide susceptibility of certain BCG strains PMID: 14693532
- In addition to standard M. bovis drugs, 'late' BCG strains are macrolide susceptible because of deletion of rv1988, in the RD2 region. This gives another therapeutic option if it was oncoTice
- In much of medicine, new drugs are twinned with companion diagnostics. Blood pressure monitoring for antihypertensives; bone densitometry for osteoporosis drugs, etc. How can we ensure drug susceptibility testing is developed and deployed for the next TB antibiotic?
- Natural experiments, although imperfectly controlled, can be more creative, and therefore more informative, than the experiments we design in the lab. Agree/disagree/both?
- They are also evaluated differently, generally using randomized responders rather than treat-through studies. Detailed in: www.gastrojournal.org/article/S001...
- Do urine tests offer a useful sample in PWHIV because they have unrecognized renal TB? Or is there a DNAemia / LAMemia that is filtered through the glomeruli into the urine?
- International observations consistent with what we saw across subgroups in San Francisco. But is it gender or sex or a bit of both? pubmed.ncbi.nlm.nih.gov/10654640/
- Agree we need better data on infection. Will data drive the need for a test to distinguish cleared from current infection? Or is a test needed first to generate firm estimates? Would be ++ helpful in clinic to know who is infected today, before writing a prescription.
- Reposted by Marcel Behr[Not loaded yet]
