EurosurveillancePub Date : 2025-03-01DOI: 10.2807/1560-7917.ES.2025.30.11.2500173
Anca Vasiliu, Veronica Cristea, Krista Stoycheva, Senia Rosales-Klintz, Christoph Lange, Dominik Zenner, Csaba Ködmön
{"title":"Shifting tuberculosis dynamics in the EU/EEA: geographical and drug resistance trends among people of foreign origin, 2019 to 2023.","authors":"Anca Vasiliu, Veronica Cristea, Krista Stoycheva, Senia Rosales-Klintz, Christoph Lange, Dominik Zenner, Csaba Ködmön","doi":"10.2807/1560-7917.ES.2025.30.11.2500173","DOIUrl":"10.2807/1560-7917.ES.2025.30.11.2500173","url":null,"abstract":"<p><p>We observed shifting trends in tuberculosis (TB) epidemiology in the EU/EEA between 2019 and 2023. In 2023, TB notifications among people of foreign origin increased by 24.6% after decreasing between 2019 and 2020. The majority originated from African and East Mediterranean regions, with a 316.4% upsurge in TB among Ukrainians in 2022-23. Rifampicin-resistant/multidrug-resistant TB increased by ≥ 60% in 2019-23, mainly among Ukrainians. Rapid response to shifting epidemiological patterns is crucial for efficient TB prevention and control within the EU/EEA.</p>","PeriodicalId":12161,"journal":{"name":"Eurosurveillance","volume":"30 11","pages":""},"PeriodicalIF":9.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11927073/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143669548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
EurosurveillancePub Date : 2025-03-01DOI: 10.2807/1560-7917.ES.2025.30.11.2400393
Céline M Gossner, Luisa K Hallmaier-Wacker, Harold Noel, Beatriz Fernández Martínez, Danai Pervanidou, Maria Tseroni, Julia Enkelmann, Daniela Boccolini, Diamantis Plachouras
{"title":"Healthcare-associated malaria: a systematic review, 1997 to 2023.","authors":"Céline M Gossner, Luisa K Hallmaier-Wacker, Harold Noel, Beatriz Fernández Martínez, Danai Pervanidou, Maria Tseroni, Julia Enkelmann, Daniela Boccolini, Diamantis Plachouras","doi":"10.2807/1560-7917.ES.2025.30.11.2400393","DOIUrl":"10.2807/1560-7917.ES.2025.30.11.2400393","url":null,"abstract":"<p><p>BackgroundMalaria is primarily transmitted through mosquito bites; occasionally, direct transmission through blood has been reported. Healthcare-associated infections refer to infections acquired in a hospital or another healthcare setting.AimThis systematic review aims to explore determinants of healthcare-associated malaria (HAM) cases.MethodThis review follows the PRISMA guidelines and was registered in PROSPERO (CRD42022309701). We searched five databases for publications on HAM cases published between 1 January 2000 and 7 December 2023. We initiated a data call for HAM cases to public health authorities from 37 European countries. We performed a backward and forward search, reviewed health authorities' websites, performed searches on Google and the European Scientific Conference on Applied Infectious Disease Epidemiology (ESCAIDE) conference abstracts book.ResultsWe identified 37 studies on HAM comprising 55 HAM cases, of which 35 (64%) were infected in Europe, primarily in Spain (nine cases), France and Italy (seven cases each). All cases were infected with <i>Plasmodium falciparum</i> except one individual. Fifty HAM cases were hospital inpatients and five were healthcare workers. Five patients died. Flushing of vascular catheters with contaminated heparin/saline solution and manipulation of intravenous catheters were the most frequently reported procedures leading to infection among patients.ConclusionsWhile rare, HAM transmission can be fatal. Healthcare-associated malaria is preventable through strict adherence to infection prevention and control procedures. Despite extensive investigations, the procedure leading to infection often remained unknown, highlighting the complexity of investigations. Guidance and protocols for conducting investigations may improve the success rate of such inquiries.</p>","PeriodicalId":12161,"journal":{"name":"Eurosurveillance","volume":"30 11","pages":""},"PeriodicalIF":9.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11927069/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143669533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Increase in tuberculosis among children and young adolescents, European Union/European Economic Area, 2015 to 2023.","authors":"Veronica Cristea, Csaba Ködmön, Joana Gomes Dias, Senia Rosales-Klintz","doi":"10.2807/1560-7917.ES.2025.30.11.2500172","DOIUrl":"10.2807/1560-7917.ES.2025.30.11.2500172","url":null,"abstract":"<p><p>As tuberculosis (TB) in children is an indicator of ongoing transmission, we analysed surveillance data to understand the increase in notified TB cases among individuals aged < 15 years in the European Union/European Economic Area countries between 2015 and 2023. Several factors may have contributed to this increase, such as improved diagnosis and reporting, migration and the COVID-19 pandemic. The observed increasing trend, albeit low in absolute numbers, emphasises the importance of early case finding and timely prevention.</p>","PeriodicalId":12161,"journal":{"name":"Eurosurveillance","volume":"30 11","pages":""},"PeriodicalIF":9.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11927071/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143669536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
EurosurveillancePub Date : 2025-03-01DOI: 10.2807/1560-7917.ES.2025.30.10.2400038
Matilda Berkell, Anna Górska, Mathias Smet, Delphine Bachelet, Elisa Gentilotti, Mariana Guedes, Anna Maria Franco-Yusti, Fulvia Mazzaferri, Erley Lizarazo Forero, Veerle Matheeussen, Benoit Visseaux, Zaira R Palacios-Baena, Natascia Caroccia, Aline-Marie Florence, Charlotte Charpentier, Coretta van Leer, Maddalena Giannella, Alex W Friedrich, Jesús Rodríguez-Baño, Jade Ghosn, Samir Kumar-Singh, Cedric Laouénan, Evelina Tacconelli, Surbhi Malhotra-Kumar
{"title":"Quasi-species prevalence and clinical impact of evolving SARS-CoV-2 lineages in European COVID-19 cohorts, January 2020 to February 2022.","authors":"Matilda Berkell, Anna Górska, Mathias Smet, Delphine Bachelet, Elisa Gentilotti, Mariana Guedes, Anna Maria Franco-Yusti, Fulvia Mazzaferri, Erley Lizarazo Forero, Veerle Matheeussen, Benoit Visseaux, Zaira R Palacios-Baena, Natascia Caroccia, Aline-Marie Florence, Charlotte Charpentier, Coretta van Leer, Maddalena Giannella, Alex W Friedrich, Jesús Rodríguez-Baño, Jade Ghosn, Samir Kumar-Singh, Cedric Laouénan, Evelina Tacconelli, Surbhi Malhotra-Kumar","doi":"10.2807/1560-7917.ES.2025.30.10.2400038","DOIUrl":"10.2807/1560-7917.ES.2025.30.10.2400038","url":null,"abstract":"<p><p>BackgroundEvolution of SARS-CoV-2 is continuous.AimBetween 01/2020 and 02/2022, we studied SARS-CoV-2 variant epidemiology, evolution and association with COVID-19 severity.MethodsIn nasopharyngeal swabs of COVID-19 patients (n = 1,762) from France, Italy, Spain, and the Netherlands, SARS-CoV-2 was investigated by reverse transcription-quantitative PCR and whole-genome sequencing, and the virus variant/lineage (NextStrain/Pangolin) was determined. Patients' demographic and clinical details were recorded. Associations between mild/moderate or severe COVID-19 and SARS-CoV-2 variants and patient characteristics were assessed by logistic regression. Rates and genomic locations of mutations, as well as quasi-species distribution (≥ 2 heterogeneous positions, ≥ 50× coverage) were estimated based on 1,332 high-quality sequences.ResultsOverall, 11 SARS-CoV-2 clades infected 1,762 study patients of median age 59 years (interquartile range (IQR): 45-73), with 52.5% (n = 925) being male. In total, 101 non-synonymous substitutions/insertions correlated with disease prognosis (severe, n = 27; mild-to-moderate, n = 74). Several hotspots (mutation rates ≥ 85%) occurred in Alpha, Delta, and Omicron variants of concern (VOCs) but none in pre-Alpha strains. Four hotspots were retained across all study variants, including spike:D614G. Average number of mutations per open-reading-frame (ORF) increased in the spike gene (average < 5 per genome in January 2020 to > 15 in 2022), but remained stable in ORF1ab, membrane, and nucleocapsid genes. Quasi-species were most prevalent in 20A/EU2 (48.9%), 20E/EU1 (48.6%), 20A (38.8%), and 21K/Omicron (36.1%) infections. Immunocompromised status and age (≥ 60 years), while associated with severe COVID-19 or death irrespective of variant (odds ratio (OR): 1.60-2.25; p ≤ 0.014), did not affect quasi-species' prevalence (p > 0.05).ConclusionSpecific mutations correlate with COVID-19 severity. Quasi-species potentially shaping VOCs' emergence are relevant to consider.</p>","PeriodicalId":12161,"journal":{"name":"Eurosurveillance","volume":"30 10","pages":""},"PeriodicalIF":9.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11912139/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143624098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
EurosurveillancePub Date : 2025-03-01DOI: 10.2807/1560-7917.ES.2025.30.12.2500189
Pierre Bessière, Jessie Brun, Brandon Hayes, Amélie Marchand, Laura Lebouteiller, Sébastien-Mathieu Soubies, Marie-Christine Cadiergues, Jean-Luc Guérin
{"title":"Cats as sentinels of mammal exposure to H5Nx avian influenza viruses: a seroprevalence study, France, December 2023 to January 2025.","authors":"Pierre Bessière, Jessie Brun, Brandon Hayes, Amélie Marchand, Laura Lebouteiller, Sébastien-Mathieu Soubies, Marie-Christine Cadiergues, Jean-Luc Guérin","doi":"10.2807/1560-7917.ES.2025.30.12.2500189","DOIUrl":"10.2807/1560-7917.ES.2025.30.12.2500189","url":null,"abstract":"<p><p>Circulation of clade 2.3.4.4b highly pathogenic avian influenza H5Nx viruses has intensified in recent years, increasing epizootics and mammalian exposure. Cats, bridging wild and domestic environments, are key for studying cross-species transmission. To assess their exposure in France, we screened 728 outdoor cats (December 2023-January 2025). Seropositivity was 2.6% (19/728), with an estimated seroprevalence at 1.8%. Absence of hunting behaviour was a significant protective factor. These findings highlight high recent exposure and the need for targeted surveillance in cats.</p>","PeriodicalId":12161,"journal":{"name":"Eurosurveillance","volume":"30 12","pages":""},"PeriodicalIF":9.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11951414/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143742380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Enhanced influenza vaccines impact effectiveness in individuals aged 65 years and older, Denmark, 2024/25 influenza season up to 4 March 2025.","authors":"Hanne-Dorthe Emborg, Palle Valentiner-Branth, Ramona Trebbien, Amanda Bolt Botnen, Tyra Grove Krause, Bolette Søborg","doi":"10.2807/1560-7917.ES.2025.30.12.2500174","DOIUrl":"10.2807/1560-7917.ES.2025.30.12.2500174","url":null,"abstract":"<p><p>During the 2024/25 influenza season, enhanced and standard-dose influenza vaccines were available for individuals aged 65 and older. Compared with the standard-dose quadrivalent influenza vaccine (QIV), the adjuvanted QIV was significantly more effective, with an overall vaccine effectiveness (VE) of 48% (95% CI: 42-52) vs 33% (95% CI: 24-41) when considering both non-hospitalised and hospitalised patients. The high-dose QIV demonstrated similar effectiveness to the adjuvanted QIV. These findings support the inclusion of enhanced influenza vaccines in future vaccination programmes.</p>","PeriodicalId":12161,"journal":{"name":"Eurosurveillance","volume":"30 12","pages":""},"PeriodicalIF":9.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11951413/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143742394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Infants needed to immunise with nirsevimab to prevent one RSV hospitalisation, Spain, 2023/24 season.","authors":"Roberto Pastor-Barriuso, Olivier Núñez, Susana Monge","doi":"10.2807/1560-7917.ES.2025.30.6.2500040","DOIUrl":"10.2807/1560-7917.ES.2025.30.6.2500040","url":null,"abstract":"<p><p>Using real-life data from Spain between October 2023 and March 2024, the number needed to immunise (NNI) with nirsevimab and the cost to prevent one RSV hospitalisation were estimated at 90 infants (95% CI: 77-108) and 19,700 EUR for catch-up immunisation, and 41 infants (95% CI: 35-50) and 9,000 EUR for at-birth immunisation. By month of birth, NNI and cost were lowest in infants born shortly before the RSV epidemic peak, with impact decreasing gradually for earlier or later births.</p>","PeriodicalId":12161,"journal":{"name":"Eurosurveillance","volume":"30 6","pages":""},"PeriodicalIF":9.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11914966/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143412929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
EurosurveillancePub Date : 2025-02-01DOI: 10.2807/1560-7917.ES.2025.30.7.2400344
Anders Boyd, Colette Smit, Annemiek A van der Eijk, Hans Zaaijer, Bart Ja Rijnders, Berend van Welzen, Mark Aa Claassen, Katalin Pogány, Theodora Ems de Vries-Sluijs, Eline Op de Coul, Marc van der Valk
{"title":"Low coverage of hepatitis D virus testing in individuals with hepatitis B virus and HIV, the Netherlands, 2000 to 2022.","authors":"Anders Boyd, Colette Smit, Annemiek A van der Eijk, Hans Zaaijer, Bart Ja Rijnders, Berend van Welzen, Mark Aa Claassen, Katalin Pogány, Theodora Ems de Vries-Sluijs, Eline Op de Coul, Marc van der Valk","doi":"10.2807/1560-7917.ES.2025.30.7.2400344","DOIUrl":"10.2807/1560-7917.ES.2025.30.7.2400344","url":null,"abstract":"<p><p>BackgroundSince 2009, European guidelines recommend individuals with hepatitis B virus (HBV) and HIV be tested for hepatitis D virus (HDV).AimTo analyse HDV testing in individuals with HBV/HIV during routine practice in the Netherlands.MethodsWe assessed data from the ATHENA cohort of people with HIV who were ever HBV surface antigen-positive, aged ≥ 18 years and attended one of 24 HIV treatment centres in the Netherlands during 2000-22. Using longitudinal analysis, we estimated the percentage of individuals ever tested for HDV (antibody or RNA test) over time. In cross-sectional analysis, determinants for ever being tested by end of follow-up were assessed using relative risk regression.ResultsWe identified 1,715 individuals with HBV/HIV; 1,460 (85.1%) and 255 (14.9%) were male and female at birth, respectively (median age: 52 years; IQR: 42-59). Only 249 (14.5%) had an HDV test. The percentage tested increased from 5.0% (95% CI: 3.4-7.3) in 2000 to 17.0% (95% CI: 14.9-19.3) in 2022. In 2022, 16.2% (95% CI: 13.7-19.1) of men who have sex with men, 25.0% (95% CI: 9.7-50.9) of persons who inject(ed) drugs and 18.1% (95% CI: 14.6-22.3) of heterosexual/others were tested. In multivariable analysis, ever having an HDV test was associated with detectable HBV DNA viral load (p < 0.001), ever presenting with elevated alanine aminotransferase (ALT) levels (p = 0.023), advanced fibrosis/cirrhosis (p = 0.001) and being overweight/obese (p = 0.043).ConclusionsHDV testing coverage in the Netherlands is low for individuals with HBV/HIV. Although testing was more common in those with advanced liver disease, a considerable proportion at risk of HDV still need testing.</p>","PeriodicalId":12161,"journal":{"name":"Eurosurveillance","volume":"30 7","pages":""},"PeriodicalIF":9.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11843617/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143467473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
EurosurveillancePub Date : 2025-02-01DOI: 10.2807/1560-7917.ES.2025.30.7.2500074
François Blanquart, Vincent Vieillefond, Benoit Visseaux, Claire Nour Abou Chakra, Marta C Nunes, Alexandra Jacques, Stephanie Haim-Boukobza, Laurence Josset, Valentin Wehrle, Guillaume Deleglise, Thomas Duret, Marie Anne Rameix-Welti, Bruno Lina, Vincent Enouf, Antonin Bal
{"title":"Influenza vaccine effectiveness against detected infection in the community, France, October 2024 to February 2025.","authors":"François Blanquart, Vincent Vieillefond, Benoit Visseaux, Claire Nour Abou Chakra, Marta C Nunes, Alexandra Jacques, Stephanie Haim-Boukobza, Laurence Josset, Valentin Wehrle, Guillaume Deleglise, Thomas Duret, Marie Anne Rameix-Welti, Bruno Lina, Vincent Enouf, Antonin Bal","doi":"10.2807/1560-7917.ES.2025.30.7.2500074","DOIUrl":"10.2807/1560-7917.ES.2025.30.7.2500074","url":null,"abstract":"<p><p>Influenza circulates at high levels in Europe since November 2024. Using a test-negative study based on data from French community laboratories between October 2024 and February 2025, we estimated vaccine effectiveness (VE) against PCR-detected influenza infection (44,420/15,052; positive/negative individuals). For all age groups, the overall VE was 42% (95% CI: 37-46%), with 26% (95% CI: 18-34%) against influenza A and 75% (95% CI: 66-82%) against influenza B. Among individuals ≥ 65-year-olds VE was 22% (95% CI: 13-30%) and among 0-64-year-olds, 60% (95% CI: 56-65%).</p>","PeriodicalId":12161,"journal":{"name":"Eurosurveillance","volume":"30 7","pages":""},"PeriodicalIF":9.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11843621/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143467466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
EurosurveillancePub Date : 2025-02-01DOI: 10.2807/1560-7917.ES.2025.30.5.2400291
Arne Michael Taxt, Vegard Eldholm, Nicola Isabelle Kols, Maria Schei Haugan, Niclas Raffelsberger, Anne Mette Asfeldt, André Ingebretsen, Anita Blomfeldt, Kristin Stenhaug Kilhus, Paul Christoffer Lindemann, Horst Bentele, Jeanette Stålcrantz, Liz Ertzeid Ødeskaug, Thale Cathrine Berg
{"title":"A national outbreak of <i>Serratia marcescens</i> complex: investigation reveals genomic population structure but no source, Norway, June 2021 to February 2023.","authors":"Arne Michael Taxt, Vegard Eldholm, Nicola Isabelle Kols, Maria Schei Haugan, Niclas Raffelsberger, Anne Mette Asfeldt, André Ingebretsen, Anita Blomfeldt, Kristin Stenhaug Kilhus, Paul Christoffer Lindemann, Horst Bentele, Jeanette Stålcrantz, Liz Ertzeid Ødeskaug, Thale Cathrine Berg","doi":"10.2807/1560-7917.ES.2025.30.5.2400291","DOIUrl":"10.2807/1560-7917.ES.2025.30.5.2400291","url":null,"abstract":"<p><p>We report a national outbreak of <i>Serratia marcescens</i> complex type 755 (ct755) in Norway, with 74 cases identified between June 2021 and February 2023. Careful reviews of patient journals and interviews were performed, involving 33 hospitals throughout Norway. All available clinical isolates of <i>S. marcescens</i> collected between January 2021 and February 2023 (n = 455, including cases) from all involved hospitals were whole genome sequenced. Cases displayed a pattern of opportunistic infections, as usually observed with <i>S. marcescens</i>. No epidemiological links, common exposures or common risk factors were identified. The investigation pointed to an outbreak source present in the community. We suspect a nationally distributed product, possibly a food product, as the source. Phylogenetic analysis revealed a highly diverse bacterial population containing multiple distinct clusters. The outbreak cluster ct755 stands out as the largest and least diverse clone of a continuum, however a second cluster (ct281) also triggered a separate outbreak investigation. This report highlights challenges in the investigation of outbreaks caused by opportunistic pathogens and suggests that the presence of identical strains of <i>S. marcescens</i> in clinical samples is more common than previously recognised.</p>","PeriodicalId":12161,"journal":{"name":"Eurosurveillance","volume":"30 5","pages":""},"PeriodicalIF":9.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11803742/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143364162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}