Sam Manna
@sammanna.bsky.social
61 followers 70 following 11 posts
Microbiologist/postdoc working on #pneumococcus. Former Lecturer. Ex-mitochondrial geneticist. Vice President of Communications for @aussocmic.bsky.social Views are my own.
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sammanna.bsky.social
Very excited to unveil the latest serotype to join the #pneumococcus family - introducing you to serotype 33H (see thread below for summary) pneumonia.biomedcentral.com/articles/10....
sammanna.bsky.social
Great to see this finally out there!
biorxiv-microbiol.bsky.social
Streptococcus pneumoniae vaccine serotype persistence following 13-valent pneumococcal conjugate vaccine introduction in Mongolia: investigating changes in epidemiology, immunology and virulence https://www.biorxiv.org/content/10.1101/2025.09.23.678142v1
Reposted by Sam Manna
biorxivpreprint.bsky.social
SeroBA(v2.0) and SeroBAnk: a robust genome-based serotyping scheme and comprehensive atlas of capsular diversity in Streptococcus pneumoniae https://www.biorxiv.org/content/10.1101/2025.04.16.648953v1
sammanna.bsky.social
They have different mutations and are different genetic lineages so definitely independent events
sammanna.bsky.social
Together, we provide the requisite genetic, serological and biochemical evidence to support 33G-like be designated as a new serotype, which we have named 33H. So far, we have seen this new serotype in Mongolia and South Africa - very excited to see where else it might be!
sammanna.bsky.social
Lastly, to confirm the lack of acetylation in the 33G-like capsule due to the loss of wciG, we conducted 1H NMR on the capsular polysaccharide, which showed that in contrast with 33G capsule, the 33G-like capsule lacks any acetyl residues.
sammanna.bsky.social
To verify that inactivation of wciG was responsible for the change in the quellung result, we constructed an 'artificial 33G-like' by deleting wciG in a 33G strain. Indeed, this changed the quellung result from 10B and 33B to 10B and 33F.
sammanna.bsky.social
We also conducted deep-sequencing and PCR from the nasopharyngeal swabs themselves to confirm the presence of the mutations in vivo (suggesting they were unlikely to have occurred during laboratory culture)
sammanna.bsky.social
When we examined the capsule locus, the 33G-like capsule locus was identical to that of 33G except for one difference - all the 33G-like isolates had frameshift mutations in a capsule gene called wciG, which encodes an acetyltransferase.
sammanna.bsky.social
During our pneumonia surveillance program in adults in Mongolia, we isolated pneumococcal variants in nasopharyngeal swabs that resembled serotype 33G. Where 33G yields the serotype result of 10B and 33B by quellung, these variants (which we called 33G-like) would give the result of 10B and 33F.
sammanna.bsky.social
Very excited to unveil the latest serotype to join the #pneumococcus family - introducing you to serotype 33H (see thread below for summary) pneumonia.biomedcentral.com/articles/10....
sammanna.bsky.social
Interested in a PhD focusing on Streptococcus pneumoniae or pyogenes? Our group is looking for new PhD students to join our lab! Apply here: career10.successfactors.com/sfcareer/job...
Career Opportunities: PhD Student - Microbiology (42694)
career10.successfactors.com
Reposted by Sam Manna