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Marcel Behr

@mbehr-mcgill.bsky.social
2K followers 218 following 42 posts

Clinician-scientist. Epidemiology and pathogenesis of mycobacterial infections.

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Reposted by Marcel Behr
Rebecca Clark @raclark18.bsky.social · 15/06/2026
New publication now out in @lancetgh.bsky.social! New #TB #vaccines are being trialled in older adolescents and adults, and we comment on the advantages and challenges of including younger adolescents who have historically been excluded. www.thelancet.com/journals/lan...
thelancet.com
Inclusion of young adolescents in policy development for new tuberculosis vaccines
The infant tuberculosis vaccine, BCG, prevents severe tuberculosis disease, but protection is rarely durable beyond childhood. New tuberculosis vaccines are being developed for the prevention of infec...
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Marcel Behr @mbehr-mcgill.bsky.social · 27/04/2026
www.medrxiv.org/content/10.6... New work led by Ori Solomon on resistant Mycobacterium tuberculosis isolate from the VQUIN study. Lots of drug resistance across classes and across regions.
medrxiv.org
Molecular epidemiology of rifampicin resistant Mycobacterium tuberculosis in Vietnam
Background: Vietnam is a top 20 burden country for multi-drug resistant/rifampicin-resistant tuberculosis (MDR/RR-TB), with nearly 10,000 cases a year. With the emergence of new diagnostic assays for ...
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Reposted by Marcel Behr
Patrick Moynihan @pmoyniha.bsky.social · 27/03/2026
We've been we've been working on this for quite a while now (hopefully published soon). Grateful to @proftracypalmer.bsky.social for concinving me & @lislowe.bsky.social that mycobacteria produce inter-bacterial toxins. Team science, led by @sambenedict5.bsky.social www.biorxiv.org/content/10.6...
biorxiv.org
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Marcel Behr @mbehr-mcgill.bsky.social · 24/03/2026
Passed by the Saranac laboratory on world TB day. Looking forward to TB science at the Trudeau institute.
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Marcel Behr @mbehr-mcgill.bsky.social · 15/02/2026
Some global estimates regarding clinical versus microbiologically confirmed TB in this article: PMID: 41501491 DOI: 10.1038/s41591-025-04097-5
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Reposted by Marcel Behr
Alvaro Schwalb @aschwalbc.bsky.social · 13/02/2026
1/📢 In our new publication, we estimate that in 2022, 134 million people worldwide had a recent Mycobacterium tuberculosis (Mtb) infection and were at high risk of progressing to TB disease. Read the full paper in PLOS Medicine (tinyurl.com/mtbinfection). #TBSky
tinyurl.com
Estimating the global burden of viable Mycobacterium tuberculosis infection: A mathematical modelling study
Alvaro Schwalb and colleagues conducted a mathematical modelling study to estimate the global burden of viable Mycobacterium tuberculosis--that which can cause disease and be transmitted--to help guid...
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Marcel Behr @mbehr-mcgill.bsky.social · 09/02/2026
Congrats to @aschwalbc.bsky.social for bringing this work to the finish line!
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Reposted by Marcel Behr
PLOS Medicine @plosmedicine.org · 09/02/2026
In this mathematical modeling study, Alvaro Schwalb and colleagues estimate the global burden of viable Mycobacterium tuberculosis—that which can cause disease and be transmitted—to help guide disease prevention efforts 🧪 #tuberculosis #MedSky plos.io/4aqzIQV
plos.io
Estimating the global burden of viable Mycobacterium tuberculosis infection: A mathematical modelling study
Alvaro Schwalb and colleagues conducted a mathematical modelling study to estimate the global burden of viable Mycobacterium tuberculosis--that which can cause disease and be transmitted--to help guid...
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Marcel Behr @mbehr-mcgill.bsky.social · 31/01/2026
Always a treat to see the owl while cross country skiing on Mount Royal. Doesn't seem bothered by -12C
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Marcel Behr @mbehr-mcgill.bsky.social · 06/01/2026
Ha! And yes. But are sponges the host, or are they just sponges, doing what sponges do?
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Marcel Behr @mbehr-mcgill.bsky.social · 06/01/2026
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 '.
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Reposted by Marcel Behr
Adam Kucharski @adamjkucharski.bsky.social · 03/01/2026
How 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
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Marcel Behr @mbehr-mcgill.bsky.social · 02/01/2026
Thanks Gabriele!
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Marcel Behr @mbehr-mcgill.bsky.social · 02/01/2026
Cool! In case I missed it ....can you post the link to article?
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Marcel Behr @mbehr-mcgill.bsky.social · 20/12/2025
👇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.
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Marcel Behr @mbehr-mcgill.bsky.social · 02/12/2025
Not as cold as much of Canada. And yes to the postdoc opportunity!
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Marcel Behr @mbehr-mcgill.bsky.social · 22/11/2025
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?
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Marcel Behr @mbehr-mcgill.bsky.social · 22/11/2025
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)?
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Marcel Behr @mbehr-mcgill.bsky.social · 16/10/2025
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/...
pnas.org
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Marcel Behr @mbehr-mcgill.bsky.social · 12/10/2025
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?
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Marcel Behr @mbehr-mcgill.bsky.social · 11/10/2025
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?
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Marcel Behr @mbehr-mcgill.bsky.social · 07/07/2025
I thought it was going outside in winter without a hat....
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Marcel Behr @mbehr-mcgill.bsky.social · 12/04/2025
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?
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Marcel Behr @mbehr-mcgill.bsky.social · 04/03/2025
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).
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Marcel Behr @mbehr-mcgill.bsky.social · 18/02/2025
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?
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Marcel Behr @mbehr-mcgill.bsky.social · 30/01/2025
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.
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Marcel Behr @mbehr-mcgill.bsky.social · 29/01/2025
Thanks!
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Marcel Behr @mbehr-mcgill.bsky.social · 29/01/2025
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?
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Marcel Behr @mbehr-mcgill.bsky.social · 10/01/2025
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
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Marcel Behr @mbehr-mcgill.bsky.social · 05/01/2025
I believe most isolates from pre-2020. Resistance developing or already established?
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Marcel Behr @mbehr-mcgill.bsky.social · 28/12/2024
Agree with treating Legionella. Where are the best data on macrolide treatment and outcome of CAP due to Mycoplasma?
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Reposted by Marcel Behr
NEJM.org @nejm.org · 20/12/2024
In this report, investigators assessed the efficacy of levofloxacin for the prevention of secondary cases of tuberculosis among household contacts of persons with multidrug-resistant tuberculosis. Full VQUIN MDR trial results: nej.md/41BHEf5 #MedSky #IDSky
A diagram of the screening and randomization process for household contacts included in the trial.
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Marcel Behr @mbehr-mcgill.bsky.social · 20/12/2024
Pre-XDR Mycobacterium tuberculosis in cattle. Plus some M. orygis academic.oup.com/ofid/advance...
academic.oup.com
Recovery of Mycobacterium tuberculosis complex isolates including pre-XDR strains from Cattle at a Slaughterhouse in Chennai, India
AbstractBackground. India has the highest global burden of human tuberculosis (TB) and the largest cattle herd with endemic bovine TB. However, the extent
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Marcel Behr @mbehr-mcgill.bsky.social · 09/12/2024
Sarah Danchuk at PhD defense, presenting her favourite figure contrasting the host reservoirs of Mycobacterium tuberculosis complex.
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Marcel Behr @mbehr-mcgill.bsky.social · 02/12/2024
Here is the reference for macrolide susceptibility of certain BCG strains PMID: 14693532
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Marcel Behr @mbehr-mcgill.bsky.social · 02/12/2024
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
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Marcel Behr @mbehr-mcgill.bsky.social · 01/12/2024
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?
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Marcel Behr @mbehr-mcgill.bsky.social · 26/11/2024
Natural experiments, although imperfectly controlled, can be more creative, and therefore more informative, than the experiments we design in the lab. Agree/disagree/both?
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Marcel Behr @mbehr-mcgill.bsky.social · 26/11/2024
They are also evaluated differently, generally using randomized responders rather than treat-through studies. Detailed in: www.gastrojournal.org/article/S001...
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Marcel Behr @mbehr-mcgill.bsky.social · 21/11/2024
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?
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Marcel Behr @mbehr-mcgill.bsky.social · 19/11/2024
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/
pubmed.ncbi.nlm.nih.gov
Sex differences in the epidemiology of tuberculosis in San Francisco - PubMed
The ongoing transmission of tuberculosis in the US-born population is one of the factors that explains the difference in sex-specific rates of disease in San Francisco. Observed differences in tubercu...
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Marcel Behr @mbehr-mcgill.bsky.social · 19/11/2024
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.
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Reposted by Marcel Behr
Peter MacPherson @petermacp.bsky.social · 18/11/2024
Read this amazing preprint today: ~2% (156M) of the world recently infected with #tb. Between 4.9%~7.7% have viable infection. But emphasises we need +++ data on Mtb infection @aschwalbc.bsky.social @kchorton.bsky.social @petedodd24.bsky.social @reinhouben.bsky.social @hannahrickman.bsky.social
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Marcel Behr @mbehr-mcgill.bsky.social · 17/11/2024
NGS can help make cryptic diagnoses. But to be clinically useful for CNS infections, there needs to be fast turnaround time. How long from lumbar puncture to report in different countries? Evenings and weekends included. Curious to hear your experiences.
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Marcel Behr @mbehr-mcgill.bsky.social · 14/11/2024
Great to see this written up Alvaro. Good luck with the presentation in Bali. I'm curious to know how people respond to these estimates and their implications.
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Marcel Behr @mbehr-mcgill.bsky.social · 12/11/2024
One of the indications to treat is 'during an epidemic'. Presumably for public health reasons, because disease should not be more severe? Is there evidence for treatment limiting community spread? Or is this recommendation based on different spectrum of disease during epidemics?
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Marcel Behr @mbehr-mcgill.bsky.social · 11/11/2024
Got it! Did not expect such a low yield for simply obtaining sputum, but good to have this data point. Thanks!
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Marcel Behr @mbehr-mcgill.bsky.social · 11/11/2024
Not all places have radiology. Should we be insisting on bringing in the machines (or sending people to the machines) or can we jump straight to sputum, which is sensitive and specific? Context dependent choices, perhaps?
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Marcel Behr @mbehr-mcgill.bsky.social · 11/11/2024
In 2024, would this be done with Xpert? Xpert + CXR? Other?
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