Characterization of extended-spectrum beta-lactamases (ESBLs) in North America
Notice bibliographique
Résumé
Extended-spectrum beta-lactamases (ESBLs) are a growing concern both in the hospital and community settings.These ESBLs have frequently been repofted among Escherichia coliand K/ebsiel/a spp.but have also been described in Salmonel/a spp.Many isolates that harbour ESBLs are multi-drug resistant and can therefore limit therapeutic options.This reporl describes ESBLs in three different studies, ESBLs identified from Canadian Sa/monella isolates, ESBLs produced by E. coli in a long term care facility, and ESBLs identified in fluoroquinolone resistant strains o'f E. coliin a North American study.The methodologies from all three projects are described below.Susceptibilities were determined using the automated Sensititer System and ESBLs were confirmed using disk diffusion (CLSI).PCR and sequence analysis was used to identify blalç¡¡, b/asHv, and blaçyy-n¡.Strains were subtyped using pulsed-field gel electrophoresis and analysed for similarity using BioNumerics v3.5.Plasmid DNA was transferred to E. coliDH10B using electroporation and plasmid fingerprinting and size estimation was carried out using Bglll and Hpal.Salmonella strains from human cases were identified from the Canadian lntegrated Program for Antimicrobial Resistance Surveillance (CIPARS) over a 2.5 year period beginning January 2003.Twenty-five (0.33%) of 7618 Salmonella isolates were identified among ten different serovars over the 2.5 year period as ESBL-producers.ESBL rates per year were: 2003, 0.26% (n=B/3056); 2004, 032% (n=10/31 47); January 2005 to June 30, 2005, 0.49% (n=711415).Genotype distribution included blas¡v-zu1t"ì=13, 52o/o), blasnv-tz(n=2, Bo/o), blactx-M-14 (n=2, Bo/o), blactx-M-1s (n=1 , 4%) and seven (28%) strains contained unknown resistance mechanisms.Plasmid fingerprinting suggested an indistinguishable SHV-2a containing plasmid may have spread between serovars.Over a two year period, starting January 2002 and ending April 20O4, all E. coli displaying reduced susceptibility to CLS I recommended beta-lactams isolated from a long term care facility (LTCF) in Manitoba were submitted to Cadham Provincial Laboratory.Sequence analysis of the 40 confirmed ESBLproducers revealed 29 (72.5%)CTX-M-1 4, 10 (25%) CTX-M-15, and one (2.5%)SHV-S gene.PFGE subtyping revealed two major clusters distributed among the LTCF.Majority of isolates were multidrug resistant and were resistant to ciprofloxacin (n=39, 97 .5o/o),naladixic acid (n=39 , 97 .5o/o),tetracycline (n=39, 97 .5%),trimethoprim/sulfamethoxazole (n=15, 37 .5%),kanamycin (n=9, 22.5%) and gentamicin (n=11 ,27.5%).Statistical analysis revealed patients with multiple isolates were more likely to have had multiple courses of antibiotics.As well patients harbouring CTX-M-14 were more likely to have had a gastrostomy. As paft of the North American Urinary Tract lnfection CollaborativeAlliance Quinolone Resistant (NAUTICA-QR) study 30 medical centres in the United States and 10 medical centres in Canada collected consecutive outpatient QR-E coli mid-stream urine (MSU) isolates.ESBL distribution of the 59 confirmed ESBl-producers included 31 (52.5%)b/acrx-rr¡-rs, 21 (35.6o/o)blactx-r¡- 14, ore (1 .7%)blactx-¡t-zq, three (5.1%)blasnv-tz, one (1 .7%)blarc¡4-1 and one (1.7%)blaqx-t¿-zs.A total of 66% of the isolates were multidrug resistant.The three studies presented here have shown very different results among ESBL-producing bacteria.For instance SHVtype ESBLs were frequently seen
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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 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,002 | 0,002 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 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 ».