A phenotypic and molecular comparison of community-associated and hospital-associated methicillin-resistant Staphylococcus aureus in Canada
Notice bibliographique
Résumé
Methicillin resistan| staphylococcus an¿reus (MRSA) was first described in 1961 only one year after methicillin was introduced clinically.MRSA was initially restricted to the healthcare settings, but recently has become prevalent in the community setting.community-associated MRSA (CA-MRSA) is generally sensitive to most non-B-lactam a¡timicrobials and commonly causes skin and soft tissue infections however, GA-MRSA has been linked to severe infections such as necrotizing pneumonia.CA-MRSA strains typically contain Staphylococcal cassefte chromosome n¡e c (sccmec) type rv and the Panton-Valentine leukocidin (PVL) toxin.One hundred sixteen methicillin-sensitive S. aarzzs (MSSA) and 26 MRSA were collected fiom east-central saskatchewan as part ofan on-going case control sfudy.Previously characterized MRSA ÍÌom the region were also included in antimicrobial resistance investigations.Newly collected strains were characterized by antimicrobial susceptibility testing, DNA fingerprinting using pulse-field gel electrophoresis (pFGE) and PCR to detect the genes responsible for PVL.pcR was used to detect eryth¡omycin resistance genes and a D-test was used to confirm inducible clindamycin resistance in all erythromycin resistant strains.PCR was also used to detect the pre sence of the mupA mupirocin resistant gene.MSSA strains possessed a low level of antimicrobial resistance overall with 52% of strains sensitive to all antimicrobials tested.However, erythromycin resistance was of notable levels.Among the erythromycin resistant MSSA, pcR results revealed an even distributton of ermA, erntc and ntsrA resistance determinants, which is reflective of the large amount of diversity of pFGE pattems.Two MSSA strains were determined to be PVL positive, which is not unexpected, as pv]is known to exist in a small number of MSSA.kr both the new and previously characterized MRSA from the region, erythromycin resistance was hìgh being present in 53% ofstrains.Ofthe erythromycin resistant MRSA, 61% were constitutively or induciblely clindamycin resistant due to the presence of ennC, The remaining erythromycin resistant strains contained msrA and were sensitive to clindamycin.When erythromycin resistance in MRSA from Saskatchewan was compared to that of MRSA strains collected from Canadian Nosocomial Infection Surveillance (CNISP) sites, the level of erythromycin resistance was found to be lower in strains fiom Saskatchewan.Among the CMRSA2 from Saskatchewan ermC, was the most prevalent resistance gene while in CMRSA2 from CNISP sifes ermA, was the most prevalent.CMRSAT from CNISp sites was found to have a lower amount of erythromycin resistance as well as a lower amount of inducible clindamycin resistance.A high r ate (55%) of mupirocin resistance was observed in all MRSA from the region.Mupirocin resistance in MRSA was found to be due to rnupA, which was shown to be carried on at least two distinct plasmids through plasmid restriction analysis and Southem blotting.During routine investigation of PVL in CA-MRSA from CNISp sites, pVL was found to be absent in 31 of 76 CA-MRSA strains that had indistinguishable pFGE pattems.The strains were Canadian PFGE type 0142, which is indistinguishable from MW2ruSA400 CA-MRSA strain.It was found that a homologous phage that does not contain PVL was inserted into the same site.There does not appear to be a difference in the number ofinfections versus colonizations or in the types ofinfections among the pvlpositive and PVL negative strains suggesting that PVL may not be as important in milder infections as previously thought.vi, List of Abbreviations Ala Alanine ATP Adenine Tri-Phosphate bp
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,002 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,002 | 0,003 |
| Études des sciences et des technologies | 0,003 | 0,001 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,003 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».