Novel approach using automated target enrichment enables culture-independent accurate whole-genome sequencing of Neisseria gonorrhoeae directly from clinical urogenital and extragenital specimens.

Abstract

Objectives: Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is compromising gonorrhoea treatment, and enhanced N. gonorrhoeae AMR and genome-based epidemiological surveillance is imperative. Molecular tests are replacing N. gonorrhoeae culture internationally, excluding possibilities to perform WGS. We describe and evaluate a novel approach using a custom SureSelectXTHS Target-Enrichment probe panel automated on the Magnis NGS Prep System and Illumina sequencing to generate accurate N. gonorrhoeae genomes directly from clinical urogenital and extragenital specimens.

Methods: One hundred thirteen clinical N. gonorrhoeae-positive APTIMA Combo 2 (AC2) specimens (with 89 linked N. gonorrhoeae isolates) were included. DNA was extracted using QIAsymphony DSP Virus/Pathogen kit. Amplisens multiplex RT-PCR assay (AM-PCR) identified 105 (92.9%) of the AC2 specimens as N. gonorrhoeae positive, which were further examined. Sequence libraries for AC2 specimens were prepared on the Magnis NGS Prep System using the Magnis SureSelectXTHS Reagent kit for Illumina paired-end platforms. Paired-end sequencing was performed on Illumina platforms.

Results: Seventy-four of the 105 (70.5%) AC2 samples remained N. gonorrhoeae positive with a cycle threshold <20 in the AM-PCR and subjected to SureSelectXTHS target enrichment and subsequently Illumina WGS. Seventy-two (97.3%) of all target-enriched specimens were successfully genome-sequenced. All linked AC2 specimens and N. gonorrhoeae isolates from the same anatomical site had identical AMR determinants and molecular epidemiological sequence types.

Conclusions: We show that custom SureSelectXTHS target enrichment automated on the Magnis NGS Prep System, followed by Illumina sequencing, enables culture-independent genome-based surveillance of N. gonorrhoeae AMR and molecular epidemiology. This novel methodological advancement provides an efficient and accurate WGS of N. gonorrhoeae directly from clinical urogenital and extragenital NAAT specimens.