Streptococcus pyogenes M1UK Variant-Associated Sartorius Muscle Necrotizing Soft Tissue Infection: A Case Report and Literature Review
Bibliographic record
Abstract
Necrotizing soft tissue infections (NTSIs) represent a concept of necrotizing infections involving the skin, subcutaneous tissue, fascia, and muscle, and it is a potentially fatal disease. Early exploratory incision is strongly recommended for both the diagnosis and treatment of necrotizing soft tissue infections. Treatment of necrotizing soft tissue infections requires the administration of appropriate antimicrobial agents and adequate surgical debridement. The emergence of M1UK-lineage Streptococcus pyogenes (S. pyogenes) is recently reported in the UK, Canada, the USA, and the Netherlands. We report a Japanese case of sartorius muscle (SM) NTSI caused by M1UK-lineage S. pyogenes. A 34-year-old man developed redness and swelling of his right thigh anterior compartment with fever in October 2024. The closed and deep effusions by active exploratory incision/debridement on hospital days one to three yielded the presence of Gram-positive cocci, although two sets of blood cultures upon admission revealed no bacterial growth; its species identification results indicated S. pyogenes. Clinical and pathological diagnosis was streptococcal SM NTSI (without toxic shock syndrome (TSS)). Negative pressure wound therapy with instillation and dwelling (NPWTi-d) to promote his soft tissue cure was performed along with antimicrobial regimens. The patient recovered and received micrografting (carrier: artificial dermis made from collagen sponge and silicon film, Pelnac Gplus® (Gunze Limited, Osaka, Japan) using the Rigenera® system (Rignera HBW, Candiolo, Italy). Thereafter, he developed bronchitis: the sputum yielded S. pyogenes growth: he recovered uneventfully. Split-thickness skin grafting (STG) was performed. Split-thickness skin grafting was fully engrafted, and the wounds achieved complete healing. The patient could walk by himself. Microbiological genetic analyses using both DNAs from effusion/sputum-origin strains revealed the emm1.0 and speA-speB-smeZ profiles. rofA-gldA-pstB sequencing results indicated M1UK-specific single-nucleotide polymorphisms. The streptococcal inhibitor of the complement-mediated lysis gene allele was the streptococcal inhibitor of the complement-mediated lysis-1.02 allele. Micrografting using the Rigenera® system and STG following NPWTi-d can be beneficial approaches. Clinicians should perform cultures using sterile specimens (deep effusions/tissues) from infection foci through exploratory incision/debridement, along with two sets of blood cultures, when examining patients with/without underlying medical conditions.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.009 | 0.008 |
| Science and technology studies | 0.002 | 0.002 |
| Scholarly communication | 0.002 | 0.004 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.003 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".