WGS of Commensal Neisseria Reveals Acquisition of a New Ribosomal Protection Protein (MsrD) as a Possible Explanation for High Level Azithromycin Resistance in Belgium.

Tessa De Block,Irith De Baetselier,Sheeba Santhini Manoharan-Basil,Chris Kenyon,Dorien Van Den Bossche,Christophe Van Dijck,Jolein Gyonne Elise Laumen,Said Abdellati

doi:10.3390/pathogens10030384

Abstract

In this study, we characterized all oropharyngeal and anorectal isolates of Neisseria spp. in a cohort of men who have sex with men. This resulted in a panel of pathogenic Neisseria (N. gonorrhoeae [n = 5] and N. meningitidis [n = 5]) and nonpathogenic Neisseria (N. subflava [n = 11], N. mucosa [n = 3] and N. oralis [n = 2]). A high proportion of strains in this panel were resistant to azithromycin (18/26) and ceftriaxone (3/26). Whole genome sequencing (WGS) of these strains identified numerous mutations that are known to confer reduced susceptibility to azithromycin and ceftriaxone in N. gonorrhoeae. The presence or absence of these known mutations did not explain the high level resistance to azithromycin (>256 mg/L) in the nonpathogenic isolates (8/16). After screening for antimicrobial resistance (AMR) genes, we found a ribosomal protection protein, Msr(D), in these highly azithromycin resistant nonpathogenic strains. The complete integration site originated from Streptococcus pneumoniae and is associated with high level resistance to azithromycin in many other bacterial species. This novel AMR resistance mechanism to azithromycin in nonpathogenic Neisseria could be a public health concern if it were to be transmitted to pathogenic Neisseria. This study demonstrates the utility of WGS-based surveillance of nonpathogenic Neisseria.

Highlights

Neisseria gonorrhoeae has developed antimicrobial resistance (AMR) to every class of antimicrobials used to treat it [1]
We reported the antimicrobial resistance-associated mutations detected in these Neisseria species with a focus on those implicated in macrolide and extendedspectrum cephalosporin resistance
In the present study, screening by BIGSdb was used in species identification. This resulted in a Neisseria panel with a composition of pathogenic Neisseria: N. gonorrhoeae (n = 5) and N. meningitidis (n = 5) and nonpathogenic Neisseria: N. subflava (n = 11), N. mucosa (n = 3) and N. oralis (n = 2)

Summary

Introduction

Neisseria gonorrhoeae has developed antimicrobial resistance (AMR) to every class of antimicrobials used to treat it [1]. Of particular concern are the rapid increases in azithromycin resistance and the emergence of combined ceftriaxone and high-level azithromycin resistance [1,2,3,4]. Much of these resistance mechanisms are acquired via horizontal gene transfer (HGT) from commensal Neisseria [5,6,7,8]. The importance of this pathway for the emergence of AMR has been well established for extended spectrum cephalosporins, such as ceftriaxone. HGT played an important role in the genesis of AMR to macrolides such as azithromycin [8]

Methods

Results

Conclusion