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Sean Czerwinski

@sczerwinski.bsky.social

510 followers 950 following 34 posts

Ph.D. Candidate at GSU with @jamesgurney.bsky.social - Phage researcher that is open to losing a capsid and genome on occasion. Evolutionary medicine in the face of AMR #PhageSteering #HAs
Avid concert goer. Footy fan. Phage phan.

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Sean Czerwinski

@sczerwinski.bsky.social

I made a phage… I think it’s in LB

Long contractile tailed bacteriophage in a yellow-gold environment.

November 11, 2025 at 10:50 PM

Sean Czerwinski

@sczerwinski.bsky.social

Incredible conversations at #ASMicrobe2025! Thank you to everyone who stopped by to talk phages, evolution, and the potential of phage steering in complex infections! @asm.org #PhageSky #PhageSteering

June 23, 2025 at 6:46 PM

Sean Czerwinski

@sczerwinski.bsky.social

We found SNPs in pilR and pilZ, key regulators of T4P biogenesis. One line had a SNP in pqsR, a transcriptional regulator of quorum sensing in PA, because is it ever not quorum sensing? These mutations conferred resistance to the phage and attenuated T4P function!

Mutations in key regulatory factors of T4P biogenesis confer phage resistance. (A) PilR serves as the response regulator of pilA transcription. The sensor kinase, PilS, phosphorylates PilR, activating it, which, in turn, activates transcription of pilA, which encodes for the major pilin subunit, PilA. (B) PilZ regulates T4P biogenesis. By binding to the extension ATPase, PilB activates shaft polymerization. PilZ and FimX are necessary for PilB activation. (C) Without PilZ binding, PilB remains inactive, and energy is not generated for shaft assembly. (D) Defective PilR does not activate transcription of pilA, no PilA subunits are synthesized, and thus, the shaft is not assembled.

June 10, 2025 at 9:13 PM

Sean Czerwinski

@sczerwinski.bsky.social

Curiously, lines evolved in the presence of S. aureus showed greater SNP diversity conferring resistance to the phage. See the bold SNPs...

Chromosomal single-nucleotide polymorphisms (SNPs) defined for all co-evolution condition replicates and the ancestral PAO1. SNPs were determined using breseq (version 0.31). SNPs of two variations in 5 out of 5 (5/5) +Luz19 co-evo replicates and 3/5 +SA+Luz19 co-evo replicates. In all but one of these replicate sequences, the SNP in pilR is C192Y (TGC → TAC). Replicate B of the +Luz19 condition had a different SNP in pilR, P189Q (CCG → CAG). Of the replicates in the two conditions that were subject to co-evolution with Luz19, two lacked an SNP in pilR, both in the +SA+Luz19 condition. Replicate B instead had a 197 bp deletion in pilZ. Replicate A of +SA+Luz19 was the only replicate co-evolved alongside Luz19 that sequencing did not reveal a pil gene mutation; instead, a PQS system mutation was identified in pqsR.

June 10, 2025 at 8:43 PM

Sean Czerwinski

@sczerwinski.bsky.social

It’s my first time in Alaska and I’m enthralled. The temperate rainforest and rapid ecosystem shift as you move from coastline to jagged peaks is fascinating

Valley with steep mountains in the background and a frozen river running through the foreground

Plants covered in ice, carried in by the dense mist

Middle of the day, around 12:30 PM, the sun barely reaches above the peaks

November 26, 2024 at 8:21 PM

Sean Czerwinski

@sczerwinski.bsky.social

Spending time with family and found the remaining exoskeleton of a dead wheel bug in the garage. They don’t appreciate my fascination with the wheel and piercing mouth part, but maybe someone on here will.