Review of Methods for Detecting Antimicrobial Resistance of Neisseria gonorrhoeae

Neisseria gonorrhoeae (GC) rapidly develops antimicrobial resistance, complicating treatment and surveillance. Although interest in resistance-guided therapy is increasing, most infections are treated empirically. Culture-based antimicrobial susceptibility testing (AST) remains essential but is limited by the fastidious nature of GC. Molecular AST shows promise but is constrained by incomplete validation of resistance determinants.

We conducted a systematic review of phenotypic and molecular AST methods for GC using predefined search strategies across Medline, Embase, Cochrane, CINAHL, and Scopus (2009-2024). Of 3136 unique manuscripts identified, 80 met inclusion criteria. Data extraction captured test methods, performance characteristics, and reported strengths and limitations.

Agar dilution remains the gold standard for GC AST, though its labor-intensive workflow limits routine use. Disk diffusion, gradient diffusion, and broth microdilution offer feasible alternatives but show method- and drug-dependent variability compared with agar dilution, influenced by media and manufacturer differences. Molecular assays reliably predict ciprofloxacin susceptibility via the gyrA S91F mutation, whereas predictive accuracy for other antibiotics is limited due to multigenic resistance mechanisms. Next-generation sequencing expands detection of resistance determinants but is not yet practical for rapid clinical decision-making.

Culture-based AST remains the most reliable approach for detecting GC resistance. Molecular methods have targeted utility, primarily for ciprofloxacin, and require broader validation. Standardizing alternative phenotypic methods, improving molecular marker characterization, and strengthening surveillance capacity will be essential to support resistance-guided therapy.