Introduction

In 2021, the Robert Koch-Institute in Germany reinforced the Gonococcal Resistance Surveillance for Antimicrobial Resistance (Go-Surv-AMR) program to address the urgent issue of rising resistance in Neisseria gonorrhoeae (NG). Increased resistance to Azithromycin and stability in resistance to the cephalosporins Cefixime and Ceftriaxone have been reported. The off-label use of doxycycline for sexually transmitted infection (STI) prophylaxis (Doxy-PEP), not licensed in Germany, is anticipated to play a critical role in impacting and altering the resistance patterns in NG. This aspect is now closely monitored within the surveillance efforts.

Methods

DNA of NG isolates was extracted and the genomes were sequenced using Illumina technology. The web-based platform Pathogenwatch was used for genotyping and to predict resistance genes.

Results

Between 2020 and 2022, 1739 NG isolates were sequenced, unveiling 116 known Sequence Types (STs) and 15 new STs. Phylogenetic analysis identified globally distributed groups associated with reduced susceptibility to azithromycin (ST9363), cefixime (ST7363), and ceftriaxone (ST7827). Genetic patterns associated with reduced susceptibility to Penicillin were identified in 95.6% of isolates and for Tetracycline in 89.8%. Regarding isolates with the co-occurrence of patterns for both antibiotics, additional patterns associated with reduced susceptibility towards Azithromycin were identified in 20.2%. In contrast, for these isolates with simultaneous genotypic resistance to Penicillin and Tetracycline, patterns associated with reduced susceptibility to Cefixime and Ceftriaxone were rarely identified (<1%).

Summary

The impact of Doxy-PEP on the emergence of AMR in NG warrants specific attention, especially considering the co-occurrence of azithromycin resistance genes. Some of these genes are known to contribute to cephalosporin resistance while also conferring a fitness benefit. Moreover, current surveillance of AMR in STIs in Germany primarily focuses on NG. Expanding the monitoring efforts to include the emergence of resistance to other antimicrobials and other bacterial species would be beneficial.