Activity of Dapsone versus Community and Hospital Pathogens from the CANWARD Study.
Bibliographic record
Abstract
BACKGROUND: Topical dapsone gel is a sulfone antibiotic approved for acne treatment. No microbiology studies were conducted during dapsone gel clinical trials and it is unclear whether 1) dapsone has antimicrobial activity that may be of clinical relevance in dermatology and 2) dapsone could affect the normal microbiome of facial skin where it is most commonly applied. This study assessed the in vitro activity of dapsone versus Gram-positive and Gram-negative bacterial pathogens obtained from patients with infections. METHODS: CANWARD is a national, annual, and ongoing surveillance system to assess the patterns of antibiotic-resistant pathogens in Canada. In 2014, 15 tertiary care medical centers collected 3,511 isolates from blood, respiratory tract, urine, and wounds. Antimicrobial susceptibility was assessed using CLSI broth microdilution method. RESULTS: Dapsone demonstrated relatively poor activity versus Gram-negative bacilli with most MIC50, MIC90 in the range of 512μg/mL and >512μg/mL, respectively. In contrast, dapsone demonstrated activity versus Gram-positive cocci, such as Staphylococcus (including methicillin-resistant S. aureus [MRSA], methicillin-sensitive S. aureus [MSSA]), Streptococcus, and Enterococcus-several strains of S. epidermidis had MICs of 32 and 64μg/mL; there were strains of E. faecalis with MICs of 8, 16, 32, and 64μg/mL; and several strains of S. agalactiae and S. pyogenes demonstrated dapsone MICs of 4, 8, 16, 32, and 64μg/mL. CONCLUSION: Dapsone has demonstrated antimicrobial activity in vitro. Whether this activity is part of the mechanism of action of topical dapsone in acne remains unknown. There are limited cutaneous pharmacokinetic data with topical dapsone including skin concentrations achieved with topical dapsone therapy; however, topical dapsone as a 2% nanoemulsion has shown very high (1196-3837.34μg/cm(2)) local skin concentrations. At these high concentrations, topical dapsone would be expected to affect the skin flora of patients with acne (especially Gram-positive cocci, such as Staphylococcus and Streptococcus). These concentrations are multiple times higher (20x-1000x) than the dapsone MICs found for many MSSA, MRSA, S. epidermidis, S. agalactiae, and S. pyogenes, any of which may be present on the skin of acne patients. Whether this results in resistance to dapsone or more importantly results in resistance to chemically unrelated antimicrobials is currently unknown.
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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 | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
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".