Impact of National Antibiotic Use on Neisseria gonorrhoeae Resistance in Norway

Overview

This study analyzed Norwegian Neisseria gonorrhoeae susceptibility data from 2003 to 2024 alongside national antibiotic consumption. Significant positive correlations were found between consumption of penicillins and tetracyclines and increased gonococcal resistance, highlighting the influence of population-level antibiotic use on antimicrobial resistance (AMR). Novel metrics, SIPI and WIPI ratios, were introduced to better characterize MIC distribution shifts within susceptible and wild-type isolates.

Background

Neisseria gonorrhoeae has developed resistance to all antibiotics used for its treatment, posing a threat to effective management of gonorrhea. In Norway, gonorrhea incidence is rising, but fewer cases are acquired abroad, suggesting national antibiotic stewardship could impact AMR development. Many resistance genes in N. gonorrhoeae originate from commensal Neisseria species exposed to antibiotics consumed by the population, facilitating horizontal gene transfer. Previous European studies showed unexpected high resistance levels in Norway despite low antibiotic consumption, warranting further investigation.

Data Highlights

Key Findings

• Strong positive correlations exist between national consumption of penicillins and tetracyclines and increased geometric mean MICs for benzylpenicillin and tetracycline in N. gonorrhoeae.
• Penicillin consumption is significantly associated with betalactamase plasmid carriage, suggesting horizontal gene transfer from commensal Neisseria species.
• Norway exhibits high gonococcal resistance levels despite relatively low overall antibiotic consumption compared to other European countries.
• The novel SIPI and WIPI ratios effectively describe shifts in MIC distributions within susceptible and wild-type isolate populations, capturing subtle resistance trends.
• Population-level antibiotic use likely exerts selective pressure on commensal Neisseria, facilitating resistance gene transfer to N. gonorrhoeae.

Clinical Implications

These findings emphasize the importance of national antibiotic stewardship programs in managing gonococcal AMR, even in low-consumption settings like Norway. Monitoring MIC distribution shifts using SIPI and WIPI ratios can enhance surveillance sensitivity and inform timely interventions. Clinicians should be aware of the potential for resistance development linked to community antibiotic use and consider this in treatment guidelines.

Conclusion

Norwegian antibiotic consumption patterns significantly influence gonococcal antimicrobial resistance, potentially via gene transfer from commensal Neisseria. Novel MIC distribution metrics provide valuable tools for ecological AMR surveillance and may guide future stewardship efforts.

References

1. Kenyon et al 2024 -- Impact of National Antibiotic Usage on Antibiotic Resistance in Neisseria Gonorrhoeae in Norway
2. Norwegian Public Health Institute (NIPH) -- MSIS Reporting System
3. European Committee on Antimicrobial Susceptibility Testing (EUCAST) 2022 -- MIC Breakpoints and ECOFFs