Eurosurveillance - Volume 30, Issue 40, 09 October 2025

Escherichia coli (EC) is the leading cause of bloodstream infections (BSI). The emergence of extended-spectrum beta-lactamase (ESBL) production in EC is concerning, as it may worsen infection outcomes.

We aimed to assess the incidence and outcome of ESBL-EC and non-ESBL-EC BSIs in Finland in 2018–2023 and identify factors associated with death.

Data from national registers were used to identify EC BSIs and to determine infection origin, patient comorbidities and death within 30 days. Isolates resistant or susceptible with increased exposure to third-generation cephalosporins were defined as ESBL-producing. Trends were analysed using a binomial regression model with log link. Factors associated with 30-day case-fatality were evaluated using a multivariable logistic regression model.

In total, 33,586 EC BSIs were identified, of which 1,916 (5.7%) were ESBL-EC BSIs. The annual incidence of ESBL-EC BSIs decreased from 7.2/100,000 to 4.9/100,000, being 3.3-fold larger for healthcare-associated than community-acquired ESBL-EC BSIs. Non-ESBL-EC BSIs showed similar but weaker trends. The 30-day case-fatality rate was 1.3-fold higher for ESBL-EC than non-ESBL-EC BSIs and 1.7–3.2-fold higher for healthcare-associated than community-acquired BSIs. Factors associated with 30-day case-fatality included age, comorbidity, male sex, and healthcare association and ESBL in patients with no or less severe comorbidities.

We observed a decline in EC BSIs in Finland in 2018-2023, especially those caused by ESBL-EC and healthcare-associated BSIs. ESBL-EC BSIs were associated with 30-day case-fatality only among patients with low comorbidity, a phenomenon requiring further investigation. Continuous surveillance of BSI pathogens, also covering BSI outcome, is essential.

The Danish respiratory virus sentinel surveillance system has monitored influenza-like illness and influenza virus activity for over 30 years. During the last decade, additional virus groups were added. In 2021, the system was updated to include SARS-CoV-2, collect detailed symptomatic data, and transitioned to year-round surveillance.

To explore the first two seasons of year-round respiratory virus surveillance and the first symptomatic data collected in the Danish primary care sentinel surveillance system.

In 2021/22 and 2022/23 seasons, 156 and 147 participating general practitioners, respectively, reported influenza-like illness consultation rates, collected symptomatic data and swabbed patient volunteers. Swabs were sent to Statens Serum Institut for multiplex PCR analysis, with additional characterisation using high-throughput sequencing or type-specific PCR assays for viruses such as influenza, SARS-CoV-2 and respiratory syncytial virus (RSV).

During the two seasons, 4,391 and 6,034 swabs, respectively, were collected and analysed. Year-round surveillance detected an unusually early wave of RSV during 2022/23. While present in nearly all weeks, SARS-CoV-2 showed waves with increased detection. Year-round surveillance also highlighted consistent patterns, such as continuous presence of entero-/rhinoviruses and endemic coronaviruses, as well as parainfluenza virus appearing after influenza virus. Symptom data showed differences by both sex and virus type, e.g. headaches were more commonly reported by women with RSV.

Our findings highlight the value of year-round respiratory virus surveillance in identifying both atypical virus activity and consistent patterns outside the winter season. Symptom data suggest the need for further research into sex-specific symptom patterns.