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

Penicillin-susceptible Staphylococcus aureus : susceptibility testing, resistance rates and outcome of infection

Background: Staphylococcus aureus (SA) is an important human pathogen that causes both superficial and invasive infections. Penicillin is now rarely used in the treatment of SA infections due to widespread resistance and a concern about the accuracy of existing methods for penicillin susceptibility testing. The aims of the present study were to determine the frequency of penicillin-susceptible SA isolates from blood and wound cultures in Lund, Sweden, and to evaluate methods for penicillin testing in SA. We also wanted to investigate if penicillin-susceptible isolates are associated with higher mortality. Methods: Hundred blood culture isolates collected 2008/2009, 140 blood culture isolates from 2014/2015, and 141 superficial wound culture strains from 2015 were examined. Penicillin susceptibility was tested with disk diffusion according to EUCAST guidelines, and results were confirmed with a cloverleaf assay and PCR amplification of the BlaZ gene. Patient data for all bacteraemia cases were extracted from medical records. Results: The disk diffusion method with assessment of both zone size and zone edge appearance had high accuracy in our study. About 57% of bacteraemia isolates from 2008/2009 were sensitive to penicillin compared to 29% in 2014/2015 (p < .0001). In superficial wound cultures, 21% were penicillin susceptible. There was no difference in co-morbidity or mortality rates between patients with penicillin resistant and penicillin sensitive SA bacteraemia. Conclusion: Disk-diffusion is a simple and reliable method to detect penicillin resistance in SA, and susceptibility rates are significant. Penicillin has many theoretical advantages and should be considered in the treatment of SA bacteraemia when susceptible

Comparison of antibiotic prescribing and antimicrobial resistance in urinary tract infections at the municipal level among women in two Nordic regions

Objectives: To describe and compare the prescribing of antibiotics used for urinary tract infections and its correlation with resistance in Escherichia coli in urinary samples across two adjacent regions - the Capital Region and the Skaane Region - and their municipalities in Denmark and Sweden. Methods: The Capital Region consists of 29 municipalities and 725 960 female inhabitants aged ≥18 years and the Skaane Region consists of 33 municipalities and 515 668 female inhabitants aged ≥18 years. Aggregated data from outpatient care on the prescribing of pivmecillinam, trimethoprim and nitrofurantoin from both regions were analysed. The Department of Clinical Microbiology in both regions provided data on E. coli resistance in urinary samples from women aged ≥18 years. Data were measured as the number of prescriptions/1000 women/year, number of DDDs/1000 women/year and DDDs/prescription. Correlation analyses between antibiotic prescribing and antibiotic resistance rates were performed. Results: Antibiotic prescribing and resistance rates were significantly higher in the Capital Region compared with the Skaane Region. Large variations in prescription and resistance rates were found at the municipal level, but there were no correlations between the antibiotic prescription and resistance rates when each region was analysed separately. Conclusions: Although closely related, there are large differences in antibiotic prescribing and antibiotic resistance. It is suggested that the regional guidelines are an important driver and explanatory factor for the variations; however, further research is needed in this new field and factors such as the influence of cultural aspects should be the target of further research