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Posts by Mona Johannessen

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The anatomy and molecular inventory of Staphylococcus aureus abscesses Staphylococcus aureus is an opportunistic pathogen that infects practically every body site despite differences in nutritional environment, immune milieu, and mode of inoculation. S. aureus abscesses are pathophysiological structures wherein host-derived extracellular matrix and immune cells form layers surrounding a S. aureus colony. Staphylococcal abscess communities seed staphylococcal abscesses, which are associated with worse S. aureus infection outcomes. Abscesses are also an example of the host–S. aureus interface, wherein host and pathogen adaptations define the spatial and temporal features of pathogenesis as well as the outcomes of infection. This review discusses recent discoveries in abscess formation made across organ systems and highlights findings involving host and pathogen determinants of abscess formation that improve our understanding of S. aureus pathogenesis.

The anatomy and molecular inventory of Staphylococcus aureus abscesses

4 weeks ago 5 3 0 0

Lovely work driven by Lizzie Ledger in the group: a new but druggable mechanism by which Staphs produce biofilm using components of human serum. First polysaccharides, then protein, then eDNA, now lipids too!

bsky.app/profile/bior...

1 month ago 12 8 0 0
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Microbiome-mediated colonization resistance to and countermeasures of Klebsiella pneumoniae - Nature Communications Yang et al. summarize that Klebsiella pneumoniae affects infectious and non-infectious disease via gut colonization; commensals provide colonization resistance, but K. pneumoniae adapts via multiple m...

The incomparable Zong roped @wvschaik.bsky.social and I into a comment for Nature Comms on microbiome mediated colonisation resistance to combat Klebsiella

www.nature.com/articles/s41...

2 months ago 16 6 0 0
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The Mannose Phosphotransferase System in Enterococcus lactis Is Essential for Gastrointestinal Colonization Enterococcus lactis, a recently established species that was previously classified as Enterococcus faecium clade B. Given its recent taxonomic classification, studies on this bacterium are scarce, an...

Interesting new paper on Enterococcus lactis (the species formerly known as Clade B E. faecium)

'The Mannose Phosphotransferase System in Enterococcus lactis Is Essential for Gastrointestinal Colonization'

onlinelibrary.wiley.com/doi/abs/10.1...

3 months ago 15 10 0 0
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Staphylococcus aureus induces Gasdermin A-dependent keratinocyte pyroptosis - Nature Communications The cell death effector Gasdermin A is only known to be activated by Streptococcus pyogenes. This work discovers a mechanism for its activation by Staphylococcus aureus, and shows a conserved role in ...

Happy to see our collaboration with @larocklab.com in print! Great work from @larocklab.com group to show that Staphopain A cysteine protease (ScpA) of S. aureus initiates pyroptosis in keratinocytes through proteolytic processing of Gasdermin A. www.nature.com/articles/s41...

4 months ago 1 2 1 0
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Navigating the Challenges in Staphylococcus aureus Bloodstream Infection: A Practical Guide to Management

New article about how to manage Staphylococcus aureus bacteremia. Led by Hadar Mudrik-Zohar. Includes @seanong.bsky.social @drtoddlee.bsky.social
#IDSky #SNAP_trial

www.sciencedirect.com/science/arti...

4 months ago 14 6 0 0
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Reversible phenotypic resistance to phage infection via capsule downregulation in Klebsiella pneumoniae Molecular biology; Microbiology; Cell biology

😳
Reversible phenotypic resistance to phage infection via capsule downregulation in Klebsiella pneumoniae
#phage #phageky

www.cell.com/iscience/ful...

4 months ago 13 8 0 0

Really excited to be part of this project!

#KlebClub

4 months ago 4 1 1 0
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Competitive fitness of Staphylococcus aureus against nasal commensals depends on biotin biosynthesis and acquisition Abstract. The human nasal microbiome can serve as a reservoir for pathogens. In particular, the opportunistic pathogen Staphylococcus aureus can be a membe

Really happy to see the final version of this published in @isme-microbes.bsky.social. We show that production of and competition for biotin shapes S. aureus fitness in the context of nasal commensals doi.org/10.1093/isme...
Work lead by the amazing Kevser Bilici!

4 months ago 27 14 1 1
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Export by a quorum sensing–controlled drug exporter underlies rifampicin’s strong activity against staphylococcal biofilms Rifampicin is more effective against biofilm infections because it targets biofilm-forming mutants that are highly resistant to other antibiotics.

S. aureus has an intrinsic rifampicin resistance mechanism! See the recent study by M. Otto's lab with important clinical implications:

Export by a quorum sensing–controlled drug exporter underlies rifampicin’s strong activity against staphylococcal biofilms | www.science.org/doi/10.1126/...

5 months ago 7 3 0 0

Growing Staphylococcus aureus in Synthetic Cystic Fibrosis Medium Promotes Colonization in a Murine Pneumonia Model www.biorxiv.org/content/10.1101/2025.10....

6 months ago 1 2 0 0
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A host-directed adjuvant sensitizes intracellular bacterial persisters to antibiotics - Nature Microbiology The authors developed a screen to find compounds that modulate intracellular Staphylococcus aureus metabolism and discovered KL1, which sensitizes persisters to antibiotics by reversing host-induced tolerance.

Delighted to share our latest paper - A host-directed adjuvant sensitizes intracellular bacterial persisters to antibiotics. Excellently led by Dr. Kuan-Yi Lu. We think it's a great proof-of-concept that altering immune cell behavior can make antibiotics work better www.nature.com/articles/s41...

6 months ago 29 17 0 1
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Thinking about a postdoc in microbiome science?
Our lab at the MPI for Biology (Tübingen) builds on the culture I established at Cornell: collaborative, creative, and internationally diverse. Postdocs lead their own projects with secure funding. Join us!
#PostdocJobs #HostMicrobe #AcademicJobs

6 months ago 30 27 2 0
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Nasal Staphylococcus aureus carriage promotes depressive behaviour in mice via sex hormone degradation - Nature Microbiology Nasal colonization by Staphylococcus aureus is linked with depression in a human cohort and shown in a mouse model to cause decreased serotonin and dopamine in the brain.

#NewResearch

Nasal colonisation by S. aureus is linked with depression in a human cohort and shown in a mouse model to cause decreased serotonin and dopamine in the brain

#MicroSky #Depression

www.nature.com/articles/s41...

6 months ago 22 14 1 2

Congrats, @ronimiah.bsky.social with your newly published work.

7 months ago 2 0 0 0
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Fishing out AIEC with FimH capturing microgels for inflammatory bowel disease treatment - Nature Communications Inflammatory bowel disease (IBD) is a chronic immune-mediated condition. This study presents a drug-free treatment strategy for IBD that targets bacterial adhesion, utilizing mannan oligosaccharide-lo...

New in Nat Comm

Pathogenic E. coli use protein FimH to grab onto the gut lining

New microgels mimic the mannose binding sites—acting as “decoys” to drag bacteria away and protect the intestine in IBD

Adherent-invasive E. coli (AIEC), enriched in Crohn’s disease, are a key target for this strategy

7 months ago 31 9 1 1

Good opportunity here to work with a super talented new PI.

7 months ago 1 2 1 0
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Job opportunity Postdoctoral Researcher (m/f/div) in Gut Microbiome Metabolomics at Leibniz HKI Jobportal Wissenschaft/Forschung in Jena

We’re hiring a Postdoc in Gut Microbiome Metabolomics!

Help us decode microbial metabolism and its impact on human health @leibniz-hki.de , Jena 🇩🇪

🔗 jobs.hki-jena.de/jobs/Postdoc...

8 months ago 19 30 1 0
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Regulation of airway fumarate by host and pathogen promotes Staphylococcus aureus pneumonia - Nature Communications This study reveals how the pathogen Staphylococcus aureus adapts to the lung microenvironment, rich in host metabolites fumarate and itaconate, by using a key enzyme, FumC, to support its metabolic fi...

Pleased to share our latest study @natcomms.nature.com! We show that the host metabolites fumarate and itaconate impose selective pressure on Staphylococcus aureus, driving its adaptation via the enzyme FumC. Grateful to all who contributed to this work!
www.nature.com/articles/s41...

8 months ago 25 11 0 1
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Staphylococcus aureus: a model for bacterial cell biology and pathogenesis | Journal of Bacteriology When talking about Staphylococcus aureus, one usually has in mind the diseases that can be caused by this bacterium, ranging from mild skin and soft tissue infections, such as abscesses and furuncles,...

"Among all bacterial species, S. aureus ranks second only to E. coli in the number of scientific publications."
It was a pleasure to contribute to this review, with @pinholab.bsky.social and Friedrich Götz
journals.asm.org/doi/10.1128/...

8 months ago 12 8 0 0

Staphylococcus aureus exhibits spatiotemporal heterogeneity in Sae activity during kidney abscess development www.biorxiv.org/content/10.1101/2025.07....

9 months ago 2 3 0 1
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Staphylococcus haemolyticus is a reservoir of antibiotic resistance genes in the preterm infant gut Staphylococcus haemolyticus is an important cause of sepsis in preterm infants, with gut colonization being recognized as a risk factor for infection. To better understand the diversity of S. haemo...

I am delighted that our manuscript 'Staphylococcus haemolyticus is a reservoir of antibiotic resistance genes in the preterm infant gut' is now published.

www.tandfonline.com/doi/full/10....

Big thank you to all co-authors, particularly @lisalamberte.bsky.social and @halllab.bsky.social

9 months ago 72 21 2 4

www.biorxiv.org/content/10.1.... New pre-print of the lab in which we dive deep into Klebsiella-macrophage interface. High structural resolution of the lipid A produced by Klebsiella within the Klebsiella containing vacuole governed bt TLR4 signaling. Superb job led PhD student Toby Bartholomew

10 months ago 11 7 0 0
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Assessing the safety of microbiome perturbations Everyday actions such as eating, tooth brushing or applying cosmetics inherently modulate our microbiome. Advances in sequencing technologies now facilitate detailed microbial profiling, driving inten...

(1/6) 🌟 Excited to share our new paper!
Advancing microbiome safety assessments: opportunities, challenges & recommendations 🧫🦠

This work came out of an academic–industry workshop hosted by @microbiologysociety.org in early 2024.

🔗 www.microbiologyresearch.org/content/jour...

10 months ago 39 18 2 1
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Great news for postdocs! 🎉

Looking for your next big career move in microbiology? Explore a range of exciting postdoctoral positions now available on the #FEMSOpportunitiesBoard.

Find your perfect fit and advance your research journey. Apply today👇

buff.ly/CSwBDPl

#CareerOpportunity

10 months ago 7 6 1 0
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Powerful new tool against Malaria (𝘕𝘢𝘵𝘶𝘳𝘦)

Instead of killing mosquitoes, bed nets coated with ELQs (endochin-like quinolones) KILL THE MALARIA PARASITES INSIDE THE INSECTS. Infected mosquitoes land, absorb the drug through their legs, and are rendered parasite-free

www.nature.com/articles/s41...

10 months ago 74 21 2 0
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Secretory IgM regulates gut microbiota homeostasis and metabolism - Nature Microbiology Rainbow trout with depleted secretory IgM reveal interesting insights into the elusive role of this immunoglobulin in maintaining gut microbiota.

🚨 Out now!

Rainbow trout with depleted IgM reveals interesting insights into its role in maintaining the gut microbiota 🐟

#MicroSky #IgM #MicrobiomeSky 🦠

www.nature.com/articles/s41...

10 months ago 9 3 0 0
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I am happy to share our latest preprint, spearheaded by Laura Camus. We show that tyrosin-dependent interactions can foster integration of S. aureus into the nasal microbiome. @cmfi.bsky.social @lmumuenchen.bsky.social
www.biorxiv.org/content/10.1...

11 months ago 33 19 2 2
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Important stuff

Microbes that weather chemo may help cancer patients do the same

Turnbaugh Lab (UCSF) find preTA+ bacteria detoxify 5-FU, reduce side effects

Probiotic supplements to protect patients during cancer therapy?

Works in mouse colorectal cancer model

www.science.org/doi/10.1126/...

11 months ago 32 7 2 1

Yeah! 7 more years for @cmfi.bsky.social
So many people to thank... We are a fantastic team!

10 months ago 34 6 3 1