Enhanced molecular surveillance for gonococcal resistance during doxycycline post-exposure prophylaxis implementation.

OBJECTIVE

The introduction of doxycycline post-exposure prophylaxis (doxy-PEP) as a strategy to reduce the risk of bacterial sexually transmitted infections has raised concerns about the potential for rapid selection of tetracycline resistance and the emergence of ceftriaxone-resistant strains. This study aimed to develop a molecular surveillance method to monitor antimicrobial resistance (AMR) in Neisseria gonorrhoeae (NG) during doxy-PEP implementation.

METHODS

We developed a high-resolution melting (HRM) analysis-based molecular assay, termed HRM-doxyPEP, to enhance surveillance of NG AMR. Validation was conducted with strains of known susceptibility profiles, and further evaluation was performed on clinical samples, comparing HRM results with quantitative PCR, whole-genome sequencing, and PCR-sequencing.

RESULTS

The HRM-doxyPEP assay demonstrated high analytical specificity and a detection limit of 20 copies/reaction, enabling the detection of low levels of target DNA in clinical samples. Validation with strains of known susceptibility profiles showed 84% consistency with antimicrobial susceptibility testing results. Clinical sample testing revealed 100% sensitivity and specificity for identifying NG infection, tracking ceftriaxone-resistant FC428-like strains, and detecting tetM associated with tetracycline resistance.

CONCLUSIONS

The HRM-doxyPEP assay offers an accurate, affordable, and scalable tool for enhanced molecular surveillance of AMR in NG during doxy-PEP implementation.