Kim Walker

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

Divergent roles for complement components C3 and C4 in controlling Klebsiella pneumoniae gut colonization and systemic dissemination | mBio Klebsiella 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.

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.

📢 Our latest paper is now in @infectionimmunity.bsky.social

We asked: How different are classical (cKp) vs hypervirulent (hvKp) Klebsiella pneumoniae bloodstream isolates if they are all the same K type (K2)?

📄 doi.org/10.1128/iai....

#KlebClub #MicroTwitter

Looks to be yet another excellent seminar series!

Our latest collaboration with Karthik Hullahalli's team on bacterial barcoding is now out! We developed a way to measure dissemination dynamics that controls for independent colonization events. This more accurately assesses how bacteria spread between tissues.

journals.asm.org/doi/10.1128/...

The acquisition of rmpADC can increase virulence of classical Klebsiella pneumoniae in the absence of other hypervirulence-associated genes | mBio Klebsiella 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.

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/...

Really excited to be part of this project!

#KlebClub

Murine Models of Klebsiella pneumoniae Gastrointestinal Infection Klebsiella 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....

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!

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

Can’t wait to see the updates😃!

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

One of my favorite meetings!

Congrats Valeria!!!

Out fighting for my job with many “colleagues” in Raleigh, NC.
And thanks to @shonmcbride.bsky.social for the poster inspiration!

#StandUpForScience

I started to suggest that! We also use that phrasing frequently.

Agreed!! I guess this is just one of those circumstances where you can’t use similar phrasing 🫤. But I must add that I admire your attempt to find that similarity!

How about “plasmid-borne genes”?

Very useful indeed

Congrats Michael!

Klebsiella Seminar Series 2025 This 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...

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

MAMPM February 2-4, 2025 Wintergreen Resort, Virginia

Last call! Abstracts are due Dec. 8 for the 2025 Mid-Atlantic Microbial Pathogenesis Meeting (MAMPM), which will be held Feb. 2-4, 2025. Lot's of short talk opportunities for trainees. Join us at the wonderful Wintergreen Resort for two days of great science! Please repost!

Some stunning contaminants found on old plates in the back of the cold room 😍🧫

Let's increase #klebclub chatter on 🔵🦋!
Klebsiella aficionados add your handle below and we will build a starter pack.

🔁 to spread the word

Do you love Klebsiella?! Check this out!

Wow! Congrats 🎉!!

Do you ❤️ capsules? Come learn NEW & INTERESTING things about capsules at our #ASMMicrobe2024  symposium! 4 talks to be selected from abstracts. Please spread the word! Abstracts are due soon!
www.abstractsonline.com/pp8/#!/20188...

KlebClub Klebsiella Virtual Seminar Series

KlebClub registration is now open for the 5th annual Klebsiella Seminar Series! Follow the link below and register to attend (for free!) or submit an abstract.
We are excited for another great line up of keynote speakers this year!
Follow @klebclub.bsky.social !
sites.google.com/view/klebclu...