Kim Walker

Kim Walker

@drwalkermsbanta.bsky.social

Associate Prof at UNC-Chapel Hill studying Klebsiella virulence.

1K followers240 following22 posts

Kim Walker
@drwalkermsbanta.bsky.social

Very elegant work!

George O'Toole (he/him/his)@geiselbiofilm.bsky.social

New in JB: Harrison, Chen et al., using CRISPRi and imaging, describe the "order of operation" of divisome assembly in C. difficile, an organism lacking some of the canonical cell division proteins. journals.asm.org/doi/10.1128/... @asm.org #JBacteriol @microsky.bsky.social

Kim Walker reposted

Yunn-Hwen Gan
@yunnhwengan.bsky.social

Our new paper is online and describes how antibiotic treatment #AMR versus osmotive laxative pre-exposure alters the gut environment leading to different colonization outcomes and evolutionary fates of hypervirulent #Klebsiella pneumoniae! onlinelibrary.wiley.com/share/CJFYDB... #Microsky #UTIsky

onlinelibrary.wiley.comDifferent gut microbiome dysbioses impact the evolutionary fate of hypervirulent Klebsiella pneumoniaeReader environment loaded
Kim Walker
@drwalkermsbanta.bsky.social

Really cool story!! Check it out!

Rita Tamayo@ritatamayo.bsky.social

New from the lab--C. diff uses phase variation to initiate infection in a virulent state but that phenotype presents a fitness cost as disease develops. A programmed reset mechanism primes Clostridioides difficile virulence at the onset of infection | Science Advances www.science.org/doi/10.1126/...

science.orgA programmed reset mechanism primes Clostridioides difficile virulence at the onset of infectionClostridioides difficile is a major cause of antibiotic-associated diarrhea. This pathogen produces toxins essential for disease and flagella that promote intestinal colonization. Flagella and toxins ...
Kim Walker
@drwalkermsbanta.bsky.social

A must-read for anyone interested in #Klebsiella or metal acquisition!

Ammar Zafar@azmicro.bsky.social

Study from my Lab detailing how Aerobactin-mediated iron acquisition is critical for hypervirulent Klebsiella to disseminate from the gut to cause invasive disease. Tour de Force work led by my wonderful Grad student, Giovanna Hernandez! #PLoSPathogens #Klebsiella journals.plos.org/plospathogen...

journals.plos.orgAerobactin is a key driver of hypervirulent Klebsiella pneumoniae translocation and virulenceAuthor summary The emergence of hypervirulent Klebsiella pneumoniae (hvKP) poses a significant public health threat due to its capacity to cause severe, often fatal, systemic infections. Of further co...
Kim Walker
@drwalkermsbanta.bsky.social

This is a really neat story. Excited to see it out!!

George O'Toole (he/him/his)@geiselbiofilm.bsky.social

New in JB: Weiss, Tamayo et al. describe a very cool microbial interaction wherein Enterococcus faecalis, an opportunist found in the inflamed gut, impacts phase-variation noted by chaining & rough colony morphology of C. diff. journals.asm.org/doi/10.1128/... @asm.org #JBacteriology

Kim Walker reposted

Juan David Valencia Bacca
@juanvalenciabacca.bsky.social

journals.asm.org/doi/10.1128/... Proud to see our work published in mBio! We uncover how C3 and C4 provide layered immune protection against Klebsiella pneumoniae. Grateful for my incredible mentors Dr. Ammar Zafar @azmicro.bsky.social, Dr. Karen Haas and supportive colleagues.

journals.asm.orgDivergent roles for complement components C3 and C4 in controlling Klebsiella pneumoniae gut colonization and systemic dissemination | mBioKlebsiella pneumoniae, a major public health threat, resists antibiotics and can spread from the gut to the bloodstream, causing severe infections. Our study reveals how the immune system uses complement proteins C3 and C4 to block this spread. C3 limits bacterial growth in the gut through two potential mechanisms: (i) coating K. pneumoniae with fragments that signal bacteria-eating phagocytic cells to destroy it and (ii) recruiting more phagocytes into the gut. C3 also helps clear bacteria that escape into the blood. However, when antibiotic-resistant strains overgrow, C3 alone is insufficient. In these cases, C4 becomes critical, likely by enhancing C3’s ability to tag bacteria for elimination. This two-layered defense highlights new immune pathways that could be targeted to prevent bloodstream infections, especially in vulnerable patients or those colonized with drug-resistant bacteria. These insights open doors to innovative strategies against life-threatening Klebsiella infections.
Kim Walker
@drwalkermsbanta.bsky.social

Looks to be yet another excellent seminar series!

Klebsiella Club@klebclub.bsky.social

We’re excited to kick off a new season of the Klebsiella Seminar Series, held on Thursdays in April 🧫🧬! We have 3 sessions on pathogenesis, pediatric Klebsiella & translational approaches. We will also have an open session. Registration is mandatory & FREE in this link forms.gle/LhJu11WQN6Yy... 🔁

Kim Walker
@drwalkermsbanta.bsky.social

The latest in our quest to understand the role of HMV and hypercapsule in convergent Klebsiella is out! So thankful to this team for making this project really fun! @stphnslsbry.bsky.social @leslieannaerobe.bsky.social @margaretlam.bsky.social @katholt.bsky.social journals.asm.org/doi/10.1128/...

journals.asm.orgThe acquisition of rmpADC can increase virulence of classical Klebsiella pneumoniae in the absence of other hypervirulence-associated genes | mBioKlebsiella pneumoniae is a global pathogen, and gene exchange between hypervirulent (hvKp) and classical (cKp) strains is a rising threat. It is essential to understand how hvKp genes impact virulence phenotypes and identify the cKp strain backgrounds most amenable to enhanced virulence. Hypermucoviscosity (HMV) is a critical virulence factor in hypervirulent K. pneumoniae, conferred by the rmpADC locus. The rmp genes are encoded on mobile genetic elements and have been detected in convergent antibiotic-resistant K. pneumoniae strains of concern. In this study, we explored the impact of rmp acquisition in a broad set of classical clinical isolates. We observed that HMV appears necessary, but not sufficient, for increased virulence. Sequence type, capsule type, and HMV capacity could not predict which classical isolates gain an rmp-dependent colonization benefit. These insights increase our understanding of the distinctions between cKp and hvKp and further our ability to identify and treat new strains of concern.
Kim Walker
@drwalkermsbanta.bsky.social

Really excited to be part of this project! #KlebClub

AMR-kleb/staph@s-rowe-conlon.bsky.social

Thrilled to share our latest paper on antibiotic treatment failure of Klebsiella pneumoniae liver abscesses www.pnas.org/doi/full/10.... @drwalkermsbanta.bsky.social

pnas.orgAntibiotics accumulate in Klebsiella pneumoniae liver abscesses but fail to eliminate antibiotic-tolerant populations | PNASLiver abscesses caused by hypervirulent Klebsiella pneumoniae (hvKp) can lead to severe metastatic complications, with mortality rates ranging from...

Kim Walker reposted

Juan David Valencia Bacca
@juanvalenciabacca.bsky.social

currentprotocols.onlinelibrary.wiley.com/doi/10.1002/... Our new article in Current Protocols is out: Microbiologists, immunologists, host-pathogen folks: this one’s for you 🧬🦠 #Klebsiella #HostPathogen #Microbiology Huge thanks to my mentor @azmicro.bsky.social for the guidance and support!

currentprotocols.onlinelibrary.wiley.comMurine Models of Klebsiella pneumoniae Gastrointestinal InfectionKlebsiella pneumoniae (Kpn) is a Gram-negative opportunistic pathogen and a leading cause of hospital-acquired infections. The gastrointestinal (GI) tract serves as a critical site for Kpn colonizati....

Kim Walker reposted

Kelly Wyres
@kelwyres.bsky.social

So excited that this is now online. It's been a huge collaborative effort to estimate the prevalence of capsule and O antigens associated with #klebsiella neonatal sepsis in Africa and South Asia. The first step to prioritising antigens for a vaccine to protect 1000s of newborns. #MicroSky #AMR

Kat Holt@katholt.bsky.social

I'm super happy to share this preprint on ‘Distribution of capsule and O types in #Klebsiella pneumoniae causing neonatal sepsis in Africa and South Asia: meta-analysis of genome-predicted serotype prevalence and potential vaccine coverage’ doi.org/10.1101/2025...

doi.orgDistribution of capsule and O types in Klebsiella pneumoniae causing neonatal sepsis in Africa and South Asia: meta-analysis of genome-predicted serotype prevalence and potential vaccine coverageBackground: Klebsiella pneumoniae causes ~20% of sepsis in neonates, with ~40% crude mortality. A vaccine administered to pregnant women, protecting against 70% of K. pneumoniae infections, could aver...
Kim Walker
@drwalkermsbanta.bsky.social

Very excited to see this in print form! It was quite a journey and I learned ton along the way!

Ammar Zafar@azmicro.bsky.social

Our comprehensive review on bacterial transmission is out today in MMBR @asm.org, which took us ~2 years to put together. Thanks to Kim Walker @drwalkermsbanta.bsky.social and my graduate student, Giovanna Hernandez, for all the hard work they put into this review! journals.asm.org/eprint/JIVRR...

journals.asm.orgMechanisms of bacterial host-to-host transmission | Microbiology and Molecular Biology ReviewsSUMMARYBacterial pathogens must navigate complex host environments to thrive, replicate, and ultimately transmit to new hosts. Effective transmission is critical for pathogen propagation and often requires overcoming host defenses and exploiting ...
Kim Walker
@drwalkermsbanta.bsky.social

Very useful indeed

Vaughn Cooper@vscooper.micropopbio.org

When times are tough I default to Vaclav Havel, on hope. I think that our trust and belief in the value of science is similar. We are scientists because we believe it is the best way to discover anything lasting and durable, headwinds be damned. I hope this quote is useful for you.

Kim Walker reposted

Caity Holmes
@caityholmes.bsky.social

It's that time of year! Registration and abstract submission for the 6th Klebsiella Seminar Series is now open. Participation is free and abstracts are due by February 16th. See the link below for details, and reach out to the organizers with any questions: forms.gle/gxbvaC6FjzuS... #KlebClub

forms.gleKlebsiella Seminar Series 2025This form can be used to register only or register+submit an abstract for the 2025 Klebsiella Seminar Series. By registering, you will receive a Zoom Webinar link for attendance prior to the event. Re...

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