JP Rodriguez Ruiz, Qiang Lin, Ch Lammens, PR Smeesters, S van Kleef-van Koeveringe, V Matheeussen, S Malhotra-Kumar.

Increase in bloodstream infections caused by emm1 group A Streptococcus correlates with emergence of toxigenic M1UK, Belgium, May 2022 to August 2023.

Eurosurveillance, Vol 28, Issue 36, September 2023

Many European countries have recently reported upsurges in invasive group A Streptococcus (iGAS) infections mainly caused by emm1 Streptococcus pyogenes specifically the toxigenic M1UK lineage. We present the epidemiology of emm1 causing iGAS in Belgium during 2018–August 2023 and describe an emergence of the toxigenic M1UK lineage in Belgium in mid-2022 that was observed as an increase in bloodstream infections caused by emm1 S. pyogenes that continued into 2023.

https://www.eurosurveillance.org/docserver/fulltext/eurosurveillance/28/36/eurosurv-28-36-3.pdf?expires=1731411465&id=id&accname=guest&checksum=A457DA98D76D38CCFC0A8304113901C8

S van Kleef – van Koeveringe, Dr. S De Koster, prof. dr. V Matheeussen

National reference centre for invasive β-hemolytic streptococci non group B.

Report 2012-2023 

This report describes the activities performed by the National Reference Centre (NRC) for invasive β-hemolytic Streptococci non group B from 2012 until 2023, including species identification via MALDI-TOF MS, detection of virulence genes and/or macrolide/tetracycline resistance genes by Whole Genome Sequencing (WGS) and emm typing using Sanger sequencing or WGS. This report aims to follow up on the epidemiological trends of invasive β-hemolytic streptococci over the past decade, highlighting changes in strain distribution, resistance patterns, and the emergence of new virulence factors. Streptococcus pyogenes (group A streptococcus, GAS) and Streptococcus dysgalactiae (groups C and G streptococci, GCS and GGS) are capable of causing a wide range of infections. These range from superficial infections such as pharyngitis and impetigo, to severe invasive infections like necrotizing fasciitis, bacteremia, and streptococcal toxic shock syndrome. Invasive infections are associated with significant morbidity and mortality, particularly in vulnerable populations.The virulence of these organisms is largely attributed to a variety of factors, including the M proteins (encoded by the emm or stG genes), which help the bacteria evade the immune system. Given the significant burden of invasive streptococcal infections, vaccine development has been a subject of interest, particularly targeting the M protein due to its role in pathogenesis and surface accessibility. Although no vaccine is currently available, ongoing research explores the potential for vaccine strategies to prevent infections by S. pyogenes and S. dysgalactiae..

https://www.sciensano.be/sites/default/files/report_2012-2023_streptococci_v1.0.pdf

L Cornelissen  S van Kleef-van Koeveringen , V Matheeussen

Surveillance épidémiologique des infections invasives causées par les streptocoques du groupe A S. pyogenes – 2017 à 2023

Sciensano, rapport épidémiologique 2017-2023, infections invasives causées par les streptocoques du groupe A

Messages clés:

• Toutes les sources de données (laboratoires vigies, Centre National de Référence et déclaration obligatoires) indiquent les mêmes tendances générales : la fréquence de l’iGAS a été faible pendant les années pandémiques 2020-2021 et a fortement augmenté à partir de la fin de 2022, avec des chiffres très élevés en 2023.
• Le pic du nombre de cas signalés a été atteint au tournant de l’année 2022-2023 : décembre ‘22 selon les chiffres du Centre national de référence (CNR) et les laboratoires vigies, janvier ‘23 selon les chiffres de la déclaration obligatoire (DO).
• Il est difficile de déterminer l’ampleur exacte de l’augmentation relative par rapport aux années précédentes en raison des limites des différentes sources de données.
• Le génotype le plus courant pendant le pic 2022-2023 était M1.
• On ne sait pas exactement ce qui a provoqué ce pic, mais il est probable qu’une combinaison de facteurs joue un rôle : une faible circulation pendant la pandémie entraînant une réduction de l’immunité chez les jeunes enfants, une augmentation soudaine des contacts étroits et des autres infections virales (qui sont un facteur de risque pour l’iGAS) après la levée des mesures d’hygiène, et peut-être aussi un génotype plus virulent.
• Les groupes d’âge les plus touchés sont les enfants de moins de 5 ans et les adultes de plus de 65 ans.
• Il s’agit d’infections graves qui nécessitent presque toujours une hospitalisation et sont associées à une mortalité élevée. Toutefois, les chiffres exacts relatifs à la mortalité ne sont pas disponibles en raison de problèmes d’encodage des données (pour les certificats de décès et les données du Résumé Hospitalier Minimal), de l’enregistrement au moment de l’infection aiguë, sans suivi dans le temps (données du CNR), ou d’une couverture limitée (déclaration obligatoire).

https://www.sciensano.be/en/health-topics/invasive-group-a-streptococcal-infection#prevention

Nicolas Yin, Charlotte Michel, Nadia Makki, Ariane Deplano, Alisha Milis, Benoit Prevost, Veronique Yvette Miendje-Deyi, Marie Hallin, Delphine Martiny, National reference centre for Staphylococcus aureus.

Emergence and spread of a mupirocin-resistant variant of the European epidemic fusidic acid-resistant impetigo clone of Staphylococcus aureus, Belgium, 2013 to 2023

Eurosurveillance, 29, 19, May 2024

Background
Antimicrobial resistance to mupirocin and fusidic acid, which are used for treatment of skin infections caused by Staphylococcus aureus, is of concern.

Aim
To investigate resistance to fusidic acid and mupirocin in meticillin-susceptible S. aureus (MSSA) from community-acquired skin and soft tissue infections (SSTIs) in Belgium.

Methods
We collected 2013–2023 data on fusidic acid and mupirocin resistance in SSTI-associated MSSA from two large Belgian laboratories. Resistant MSSA isolates sent to the Belgian Staphylococci Reference Centre were spa-typed and analysed for the presence of the eta and etb virulence genes and the mupA resistance gene. In addition, we whole genome sequenced MSSA isolates collected between October 2021 and September 2023.

Results
Mupirocin resistance increased between 2013 and 2023 from 0.5-1.5% to 1.7-5.6%. Between 2018 and 2023, 91.4% (64/70) of mupirocin-resistant isolates were co-resistant to fusidic acid. By September 2023, between 8.9% (15/168) and 10.1% (11/109) of children isolates from the two laboratories were co-resistant. Of the 33 sequenced isolates, 29 were sequence type 121, clonal and more distantly related to the European epidemic fusidic acid-resistant impetigo clone (EEFIC) observed in Belgium in 2020. These isolates carried the mupA and fusB genes conferring resistance to mupirocin and fusidic acid, respectively, and the eta and etb virulence genes.

Conclusion
We highlight the spread of a mupirocinresistant EEFIC in children, with a seasonal trend for the third quarter of the year. This is of concern because this variant is resistant to the two main topical antibiotics used to treat impetigo in Belgium.

Ariane Deplano, Marie Hallin, Natalia Bustos Sierra, Charlotte Michel, , Benoit Prevos, Delphine Martiny and Nicolas Yin

Persistence of the Staphylococcus aureus epidemic European fusidic acid-resistant impetigo clone (EEFIC) in Belgium.

J Antimicrob Chemother 2023; 78: 2061–2065

Objectives
In August 2018, a public health alert was issued in Belgium regarding clusters of impetigo cases caused by the epidemic European fusidic acid-resistant impetigo clone (EEFIC) of Staphylococcus aureus. As a result, the Belgian national reference centre (NRC) was commissioned to update the epidemiology of S. aureus causing community-onset skin and soft tissues infection (CO-SSTI) to assess the proportion of EEFIC among them.

Methods
For 1 year, Belgian clinical laboratories were asked to send their first three S. aureus isolated from CO-SSTI each month. Isolates were tested for antimicrobial susceptibility to oxacillin, mupirocin and fusidic acid.
Resistant isolates were also spa typed and tested for the presence of the genes encoding the Panton–Valentine leucocidin, the toxic shock syndrome toxin and the exfoliatins A and B. MLST clonal complexes werededuced from the spa types.

Results
Among the 518 S. aureus strains analysed, 487 (94.0%) were susceptible to oxacillin. Of these, 79(16.2%) were resistant to fusidic acid, of which 38 (48.1%) belonged to the EEFIC. EEFIC isolates were mostlyisolated from young patients with impetigo and showed a seasonal late summer peak.

Conclusions
These results suggest the persistence of EEFIC in Belgium. Furthermore, its prevalence may lead toreconsideration of the treatment guidelines for impetigo.
The primary risk assessment of the RAG (risk assessment group) concerning a cluster of fusidic acid-resistant Staphylococcus aureus in Flanders (Turnhout) can be found on the Sciensano website through the following link : https://www.sciensano.be/sites/default/files/pra_impetigo_09042019_v2.1_1.pdf