Reflex Detection of Ciprofloxacin Resistance in Neisseria gonorrhoeae by Use of the SpeeDx ResistancePlus GC Assay.

Vesna De Petra,Benjamin P Howden,Darren Y J Lee,Christopher K Fairley,Catriona S Bradshaw,Melinda M Ashcroft,Shivani Pasricha,Nathan A Ledeboer,David M Whiley,Deborah A Williamson,Michelle Sait,Eric P F Chow,Marlene Tschaepe,Sigrid Lange,George Taiaroa,Marcus Y Chen

doi:10.1128/jcm.00089-21

Abstract

Resistance-guided therapy (RGT) for gonorrhea may reduce unnecessary use of broad-spectrum antibiotics. When reflexed from the Aptima Combo 2 assay, the ResistancePlus GC assay demonstrated 94.8% sensitivity and 100.0% specificity for Neisseria gonorrhoeae detection. Of the 379 concordant N. gonorrhoeae-positive samples, 86.8% were found to possess the gyrA S91F mutation, which was highly predictive for ciprofloxacin resistance and stable across 3,144 publicly available N. gonorrhoeae genomes. Our work supports the feasibility of implementing RGT for gonorrhea into routine molecular workflows.

Highlights

IntroductionGonorrhoea has been treated before antibiotic susceptibility results are known, according to local treatment guidelines which are generally based on the local prevalence of antimicrobial resistance (AMR)
The increasing incidence of gonorrhoea globally is a major public health threat
Compared to Aptima nucleic acid amplification test (NAAT), the overall sensitivity and specificity of the ResistancePlus GC assay for detection of N. gonorrhoeae was 94.8%

Summary

Introduction

Gonorrhoea has been treated before antibiotic susceptibility results are known, according to local treatment guidelines which are generally based on the local prevalence of antimicrobial resistance (AMR). With recent reports of increasing resistance, individualized therapy based on the molecular detection of resistance determinants (resistance-guided therapy; RGT) has been suggested as a way of improving antimicrobial stewardship and delaying the emergence of AMR [2, 3]. The aims of this study were: (i) to assess the performance characteristics of a recently introduced commercial assay for ciprofloxacin RGT against a widely used nucleic acid amplification test (NAAT) for N. gonorrhoeae, and (ii) to determine the genomic stability of molecular determinants of ciprofloxacin resistance in a large collection of publicly available

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