Genomic epidemiology and population structure of Neisseria gonorrhoeae in Norway, 2016-2017

This study presents the nationwide epidemiology of Neisseria gonorrhoeae, using whole genome sequencing of all culture positive cases which comprise roughly half of all cases of gonorrhea reported in Norway from 2016 - 2017. Isolates are assigned to sequence type clusters and variation in genes coding for antibiotic resistance is linked to phenotypic resistance data. The study also includes isolates from taken from the same patients from different anatomical sites at one time point and/or at different time points. Comparing these isolates allow for observation of patterns of infections, i.e. multiple reinfections of genetically related clones vs. reinfections of genetically distant clones, and quantification of the genomic variation of closely related isolates from samples taken from a patient within the same day. Demographically, the patients in the study could be split into two groups; one group of patients being urban with a high proportion of men who have sex with men (MSM), and another consisting of young adults with transmission primarily between males and females from outside the capital. The genomes clustered according to the two demographic groups. Pairwise comparison of multiple isolates from the same patients revealed that most were reinfected with different clones. Observations of frequent reinfections in patients is a concern and should be taken into account in the development of improved information and treatment guidelines.