Genome analysis of Neisseria gonorrhoeae in Norway 2016-2023

The incidence of gonorrhea has increased significantly in Norway over the past 10 years. The emergence of antimicrobial resistance and potential for increased rates of future treatment failure make epidemiological surveillance of Neisseria gonorrhoeae a top priority. Here we combine epidemiological data and genomic analyses of isolates from cases in Norway between January 2016 and May 2023, to identify genomic clusters and antimicrobial resistance patterns. We describe how the epidemiology of N. gonorrhoeae has changed before and after the COVID-19 pandemic and the lockdown restrictions of the Norwegian society. A total of 4096 isolates, representing 39% of all the cases recorded by the Norwegian Surveillance System for Communicable Diseases, were analyzed by whole genome sequencing. Forty-one clusters, 12 of which encompassed more than 100 isolates, were identified. As seen in other countries, the lockdown of the society in 2020-2021 led to a dramatic reduction of the cases of gonorrhea. Import cases likely outweighed local transmission during that period, as shown by the high strain diversity. With the lift of the restrictions, one cluster, dominated by sequence type (ST)-1580, rapidly expanded among young, heterosexual men and women. A significant increase in the fraction of female patients was observed through the study period. An increase in number of isolates resistant to azithromycin was observed throughout the study period, while the proportion of ciprofloxacin and cefixime resistance remained stable. A single ceftriaxone resistant isolate was identified.