Utility of whole genome sequencing in assessing and enhancing partner notification of Neisseria gonorrhoeae infection

BACKGROUND Gonorrhea is a sexually transmitted infection of global concern. We investigated whole-genome sequencing (WGS) as a tool to measure and enhance partner notification (PN) in gonorrhea management. METHODS Between May and November 2018, all N. gonorrhoeae isolated from patients attending Leeds Sexual Health, United Kingdom, underwent WGS. Reports listing sequences within 20 single-nucleotide polymorphisms (SNPs) of study isolates within a database containing select isolates from April 1, 2016, to November 15, 2018, were issued to clinicians. The proportion of cases with a potential transmission partner identified by PN was determined from patient and PN data. The WGS reports were reviewed to identify additional cases within 6 SNPs or less and verified for PN concordance. RESULTS Three hundred eighty isolates from 377 cases were successfully sequenced; 292 had traceable/contactable partners and 69 (18%) had a potential transmission partner identified by PN. Concordant PN and WGS links were identified in 47 partner pairs. Of 308 cases with no transmission partner by PN, 185 (60%) had a case within 6 SNPs or less; examination of these cases' PN data identified 7 partner pairs with previously unrecognized PN link, giving a total of 54 pairs; all had 4 or less SNP differences. The WGS clusters confirmed gaps in partner finding, at individual and group levels. Despite the clinic providing sexual health services to the whole city, 35 cases with multiple partners had no genetically related case, suggesting multiple undiagnosed infections. CONCLUSIONS Whole-genome sequencing could improve gonorrhea PN and control by identifying new links and clusters with significant gaps in partner finding.