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  • Publication
    Interlaboratory validation trial report on multiplex real-time PCR method for molecular serotyping and identification of the 30 major clonal complexes of circulating in food in Europe.
    (2025-05-22) Capitaine, Karine; Te, Sandrine; Asséré, Adrien; Plodková, Hana; Michel, Valerie; Sabrou, Pauline; Bourdonnais, Erwan; Gillot, Guillaume; Mouhali, Nassim; Brauge, Thomas; Dumaire, Cécile; Feurer, Carole; Houry, Baptiste; Lueth, Stefanie; Sréterné Lancz, Zsuzsanna; Centorotola, Gabriella; Guidi, Fabrizia; Torresi, Marina; Mathisen Fagereng, Tone; Skjerdal, Taran; Guedes, Hugo; Nieto Almeida, Gonçalo; Mihai Ciupescu, Laurentiu; Ågren, Paula; Ricão, Monica; Marti, Elisabet; Jacobs-Reitsma, Wilma; van Hoek, Angela; Félix, Benjamin
    The performance of a new method developed in 2021 by the European Union Reference Laboratory (EURL) for based on 12 multiplex real-time PCR, allowing the identification of the molecular serotype and the 30 major multilocus sequence typing clonal complexes (CC), was assessed through a European interlaboratory validation trial (ILVT). This ILVT was adapted from ISO standard 16140 part 6. Overall, 98 blinded pure strains of (s or spp.), previously characterized by the EURL, were sent to 15 laboratories distributed in 11 countries. The molecular serotype had to be identified for 20 strains of the ILVT panel, while CC identification had to be performed for the whole panel. The results of the 12 multiplex real-time PCR were reproducible between the participating laboratories with high individual concordance values for molecular serotyping (100%) and CC identification (90.8%-100%) irrespective of DNA extraction protocols, PCR master mixes, and thermocycler diversity. Master mixes identified as incompatible with some of the multiplex real-time PCR were excluded from the method. The overall concordance of the results was sufficient for the method to be confidently applied in other laboratories involved in typing.IMPORTANCEThis interlaboratory validation trial, coordinated by the European Union Reference Laboratory for , was the final step to assess the performance of the multiplex real-time PCR method developed and published by B. Félix, K. Capitaine, S. Te, A. Felten, et al. (Microbiol Spectr 11:e0395422, 2023, https://doi.org/10.1128/spectrum.03954-22). Different combinations of parameter settings were applied in 15 French and European laboratories involved in typing. It was a prerequisite to establish this new real-time PCR method as a standard for rapid molecular serotyping and clonal complex identification. The accuracy and reproducibility of the results obtained on the panel of 98 strains of sent to the participants proved that the real-time PCR was suitable for use in their conditions. Rapid screening of strains is therefore now possible, and the method provides a valuable tool for epidemiological investigations to identify food-associated strains during listeriosis outbreaks.
  • Publication
    Setting off on the right path: make your research regulatory relevant.
    (2025-06-16) Pohl, Anna; Morel, Elise; Bleeker, Eric A J; Kelly, Sean; Smith, Rachel; Svendsen, Claus; Kuhlbusch, Thomas A J; Heunisch, Elisabeth
    Scientifically well-established methods do not automatically get used in regulations. Even when there is an urgent need for regulatory relevant test methods, methods need to pass through a so-called standardization process. This involves following specific agreed processes, which define the timeline and requirements (e.g., validation, documentation, approval) before the method can be integrated in regulatory oriented standards or Test Guidelines from the Organization of Economic Cooperation and Development (OECD). The process is often seen as too complex or too resource (and time) consuming by the scientific community, which inhibits method developers from translating their scientific methods and protocols into standards or OECD Test Guidelines. Numerous incentives exist for scientists to be (more) active in the standardization process and allow regulation to keep up with new scientific developments. These include an increase in research impacts, an expansion and diversification of the international expert network, and an access to more fundings. This paper shows scientists how to reach such outcomes, by providing guidance on how to navigate successfully through the standards and OECD Test Guidelines development processes. Especially the requirements for method validation, which is a prerequisite in this process and common across the different standardization bodies. For further details and insights, readers are invited to consult the various freely available resources generated by the NanoHarmony EU project. These are compiled in the OECD Test Guideline Process Mentor (https://testguideline-development.org/). The active participation of scientists along the entire process toward standards and OECD Test Guidelines is key. Only then can their methods be expanded into a wider, regulatory application toward a safer world.
  • Publication
    Investigating setting-specific superspreading potential and generation intervals of COVID-19 in Hong Kong.
    (2025-07-01) Chen, Dongxuan; Adam, Dillon C; Lau, Yiu-Chung; Wang, Dong; Lim, Wey Wen; Ho, Faith; Tsang, Tim K; Lau, Eric H Y; Wu, Peng; Wallinga, Jacco; Cowling, Benjamin J; Ali, Sheikh Taslim
    Superspreading is an important feature of COVID-19 transmission dynamics, but few studies have investigated this feature stratified by transmission setting. Using detailed clustering data comprising 8647 COVID-19 cases confirmed in Hong Kong between 2020 and 2021, we estimated the mean number of new infections expected in a transmission cluster ( ) and the degree of overdispersion (k) by setting. Estimates of ranged within 0.4-7.1 across eight settings, with highest in the close-social indoor setting that an average of seven new infections per cluster was expected. Transmission was most heterogeneous (k = 0.05) in retail setting and least heterogeneous (k = 1.1) in households, where smaller k indicates greater overdispersion and superspreading potential. Point-estimates of the mean generation interval (GI) ranged within 4.4-7.0, and settings with shorter mean realized GIs were associated with smaller cluster sizes. Here, we show that superspreading potential and generation intervals can vary across settings, strengthening the need for setting-specific interventions.
  • Publication
    Modeling lesion transition dynamics to clinically characterize patients with clade I mpox in the Democratic Republic of the Congo.
    (2025-07-02) Nishiyama, Takara; Miura, Fuminari; Jeong, Yong Dam; Nakamura, Naotoshi; Park, Hyeongki; Ishikane, Masahiro; Yamamoto, Shotaro; Iwamoto, Noriko; Suzuki, Michiyo; Sakurai, Ayana; Aihara, Kazuyuki; Watashi, Koichi; Hart, William S; Thompson, Robin N; Yasutomi, Yasuhiro; Ohmagari, Norio; Kingebeni, Placide Mbala; Huggins, John W; Iwami, Shingo; Pittman, Phillip R
    Coinciding with the global outbreak of clade IIb mpox virus (MPXV), the Democratic Republic of the Congo (DRC) recently experienced a rapid surge in mpox cases with clade I MPXV. On 14 August 2024, the World Health Organization declared the continued cross-border spread of this clade in Africa a public health emergency of international concern (PHEIC). Clade I MPXV is known to be more fatal than clade IIb, but its clinical characteristics and prognosis differ between patients. Here, we used mathematical modeling to quantify temporal changes in total lesion counts during clade I MPXV infections, using data from a large cohort of patients with mpox in the DRC from 2007 to 2011. We further analyzed individuals' clinical data to explore predictive biomarkers of high lesion counts. Our analysis indicates that patients with clade I mpox can be stratified into two groups according to lesion severity and that viral load in peripheral blood at symptom onset may serve as a predictor for this classification [area under the curve (AUC) = 0.70]. Our estimates also suggest substantial individual heterogeneity in the time period during which patients have lesions, ranging from 20 to 65 days. Understanding the severity and duration of lesions in different patients, as characterized by our approach, may contribute to more tailored treatment strategies and control measures in ongoing clade I mpox outbreaks.
  • Publication
    Determinants of COVID-19-related hospital and ICU admissions in the region Haaglanden, The Netherlands: a cross-sectional study.
    (2025-07-02) Bingöl, K B; Meulman, I; Wassing, K R M; Meer, I M van der
    The COVID-19 pandemic has been a global health crisis since late 2019. By the end of 2021, the Netherlands reported over 3 million cases, leading to significant hospital and Intensive Care Unit (ICU) admissions. This study investigated the impact of demographic, socio-economic, health, including vaccination coverage, and neighborhood characteristics on COVID-19-related hospital and ICU admissions, with a focus on neighborhood differences in the region Haaglanden, the Netherlands.

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