Purpose: Neisseria gonorrhoeae , resistant to the first-line treatment option ceftriaxone, is widespread in China from 2016. Nowadays, diverse reagents of disks and strips for rapid gonococcal antimicrobial susceptibility tests used in clinics are culture-based disks diffusion and gradient strips methods. This study aimed to evaluate the accuracy, quality, and availability of almost all disks and strips acquired in the Chinese market and serve as a reference for clinical selection.
Methods: We tested the performance of 15 commercial disks and 9 commercial gradient strips acquired in China, compared with traditional agar dilution method. The overall performance was evaluated by the categorical agreement. The reagent accuracy of gradient strips was assessed by the essential agreement.
Results: A total of 167 gonococcal isolates were used to evaluate antimicrobial disks from three brands. The overall categorical agreements were 71.7% to 81.8% for ceftriaxone, less than 58% for cefixime, 100% for spectinomycin, over 98% for ciprofloxacin, below 70.5% for penicillin, and 73.3% to 81.8% for tetracycline. A total of 81 isolates were tested for different gradient strips. Categorical agreements were over 96% for ceftriaxone, 86.2% for azithromycin, 62.3% to 67.1% for penicillin, 41.9% to 67.5% for tetracycline, and 95% for ciprofloxacin. Essential agreements were 57.7% to 87.3% for ceftriaxone, 70% for azithromycin, 64.9% to 68.4% for penicillin, 51.8% to 71.2% for tetracycline, and 91.3% for ciprofloxacin.
Conclusion: Rapid test reagents of disks and strips based on gonococcal culture have suboptimal performance. Disk diffusion for spectinomycin or ciprofloxacin can be recommended for clinical individualized prescription. The gradient strips are of great value to identify ceftriaxone-resistant gonococcal strains. Furthermore, abundant improvements are required for many reagents to further optimize their accuracy till the fulfillment of molecular detection.
Keywords: Neisseria gonorrhoeae , disk diffusion test, gradient strip test, antimicrobial susceptibility