Toxigenic diphtheria rarely detected amid rising cases of nontoxigenic <i>Corynebacterium diphtheriae</i> infections in Ontario, Canada, 2011–2023
Notice bibliographique
Résumé
ABSTRACT Diphtheria remains a major public health threat in areas of the world where diphtheria toxoid-containing vaccine programs are not successfully implemented or maintained. In countries with high vaccine coverage, diphtheria is well-controlled with occasional travel-related cases eliciting a robust public health response to limit transmission. While classic diphtheria is caused by toxigenic Corynebacterium diphtheriae and rarely by other species, such as Corynebacterium ulcerans , infections due to nontoxigenic C. diphtheriae (not covered by the vaccine) are increasingly being reported. We describe the genomic epidemiology of toxigenic and nontoxigenic C. diphtheriae in Ontario, Canada, based on isolates submitted to the Public Health Ontario Laboratory. Of 146 cases, four cases (2.7%) involved toxigenic C. diphtheriae , three of which were associated with travel from endemic countries. Most isolates were nontoxigenic (97.2%) and from cutaneous sources (84.9%), with an increase in submission of nontoxigenic C. diphtheriae isolates from one in 2016 to 65 in 2023. Based on whole-genome sequencing and BIGSdb-Pasteur core genome multi-locus strain typing, most nontoxigenic isolates were categorized into three highly related genetic clusters from sublineages 32 and 76, suggesting epidemiologically linked cases indicative of local transmission. Apart from intermediate susceptibility to penicillin in 98.0% of isolates, antimicrobial resistance was rarely detected. Because infections with nontoxigenic C. diphtheriae are not prevented by vaccination and do not cause classic diphtheria, healthcare professionals should be aware of these trends, given the clinical, public health, and infection control implications when C. diphtheriae is identified in the microbiology laboratory prior to knowledge of toxigenicity. IMPORTANCE Infections by toxigenic and nontoxigenic Corynebacterium diphtheriae cause vastly different diseases requiring different treatment and public health responses. Healthcare practitioners should be aware of the complexities of diphtheria from a global perspective. Toxigenic C. diphtheriae remains prevalent in regions that do not have well-established vaccination programs, while vaccine hesitancy and compliance issues challenge countries that do require childhood vaccination. These factors, coupled with the propensity for human travel and migration, heighten the risk of cases and outbreaks in non-endemic countries and designate diphtheria as a relevant re-emerging threat. Further complicating public health decisions is the increasing incidence of nontoxigenic C. diphtheriae infections identified among highly vaccinated populations. An excessive public health response in these cases would be burdensome and expensive. Our findings will aid public health departments and hospitals with local risk assessments of the likelihood that a laboratory identification of C. diphtheriae represents a case of toxigenic diphtheria by raising awareness of the disproportionately small number of toxigenic C. diphtheriae recovered from clinical specimens compared to the vast majority of nontoxigenic isolates. Genomic analysis suggests local transmission of nontoxigenic strains, while isolation of toxigenic C. diphtheriae from among a highly vaccinated population remains associated with travel to endemic regions.
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 distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 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 tête enseignante, 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 ».