Increase in invasive group A streptococcal infections and emergence of novel, rapidly expanding sub-lineage of the virulent Streptococcus pyogenes M1 clone, Denmark, 2023

Funding Information: We would like to thank Karina Kaae, Lanni Fugl Niebuhr Nielsen and Joan Nevermann Jensen for their laboratory expertise, and acknowledge the great effort by clinicians and laboratory technicians at hospitals across Denmark and at Landspítali, Reykjavik, in securing samples and data essential for WGS-based surveillance efforts, as well as the dedicated technical staff maintaining and developing the registries and epidemiological databases at the core of national surveillance in Denmark. Publisher Copyright: © 2023 European Centre for Disease Prevention and Control (ECDC). All rights reserved.A highly virulent sub-lineage of the Streptococcus pyogenes M1 clone has been rapidly expanding throughout Denmark since late 2022 and now accounts for 30% of the new invasive group A streptococcal infections. We aimed to investigate whether a shift in variant composition can account for the high incidence rates observed over winter 2022/23, or if these are better explained by the impact of COVID-19-related restrictions on population immunity and carriage of group A Streptococcus. An increase in incidence rates of invasive (iGAS) and non-invasive (nGAS) group A Streptococcus infection has been reported by several countries across Europe during the 2022/23 winter season [1-3]. Through analysis of all whole genome sequencing (WGS) data acquired for national surveillance of iGAS in Denmark since 2018, we aimed to investigate current genomic developments and the impact of emerging lineages on iGAS incidence rates in 2023. In Denmark, iGAS is not notifiable except in case of meningitis, however, test results from all 10 Departments of Clinical Microbiology (DCMs) are submitted to the Danish Microbiology Database (MiBa) [4] and can be used to monitor incidence rates. Iceland also experienced a higher iGAS incidence in early 2023, and we also present Icelandic WGS data on iGAS isolates from 2022 and 2023.Peer reviewe

Investigation of a monophasic Salmonella Typhimurium outbreak linked to chocolate products as part of wider international outbreak: A matched case–control study, Ireland, 2022

Abstract Background In March 2022, an outbreak investigation was initiated in Ireland after identifying a cluster of monophasic Salmonella Typhimurium cases, affecting primarily small children. Microbiological investigations revealed that the cluster was part of a wider international outbreak. Methods A total of 18 Irish outbreak cases were identified. We undertook a matched case–control study using the case–case method to determine if exposure to the implicated products was associated with illness. Results In univariable analysis, the highest odds of disease due to monophasic S. Typhimurium versus other gastrointestinal disease were obtained for a chocolate Product A of Brand A [matched odds ratio (mOR) = 7.77, 95% confidence intervals (CI): 0.89–67.20]. When grouping the implicated products in a composite variable, the odds of disease due to monophasic S. Typhimurium versus other gastrointestinal disease were 10.5 times higher with a consumption of at least one of the implicated products [mOR = 10.50, 95% CI: 1.24–88.60, p = 0.031]. Conclusion This analytical study supported the internationally generated hypothesis which led to the implementation of control measures. Owing to the high levels of chocolate purchasing with Easter approaching, early outbreak identification and involvement in the internationally coordinated investigation was essential to an efficient response and to minimise the risk of further harm to a particularly vulnerable population group

Investigation of an international outbreak of multidrug-resistant monophasic Salmonella Typhimurium associated with chocolate products, EU/EEA and United Kingdom, February to April 2022

International audienceAn extensive multi-country outbreak of multidrug-resistant monophasic Salmonella Typhimurium infection in 10 countries with 150 reported cases, predominantly affecting young children, has been linked to chocolate products produced by a large multinational company. Extensive withdrawals and recalls of multiple product lines have been undertaken. With Easter approaching, widespread product distribution and the vulnerability of the affected population, early and effective real-time sharing of microbiological and epidemiological information has been of critical importance in effectively managing this serious food-borne incident