Gonorrhea caused by Neisseria gonorrhoeae is diagnosed in a 24-year-old male using NAAT on urethral swab. The isolate (on culture) is tested for antibiotic susceptibility. Ceftriaxone MIC is 0.125 µg/mL (resistance breakpoint >0.125 µg/mL per EUCAST). What does this represent?
- A Intermediate susceptibility to ceftriaxone — ceftriaxone 500 mg IM single dose remains the recommended treatment but minimum inhibitory concentrations are rising and surveillance is critical ✓
- B Full susceptibility — MIC 0.125 µg/mL is well below resistance breakpoints
- C Ceftriaxone resistance — patient must be treated with spectinomycin
- D MIC of 0.125 µg/mL indicates a hypersusceptible strain; dose reduction is possible
Correct answer: A. Intermediate susceptibility to ceftriaxone — ceftriaxone 500 mg IM single dose remains the recommended treatment but minimum inhibitory concentrations are rising and surveillance is critical
Explanation
Per EUCAST 2023 breakpoints for N. gonorrhoeae, ceftriaxone MIC ≤0.125 µg/mL is categorised as susceptible at standard dosing (S) — not resistant. However, WHO global surveillance (GASP) has documented rising ceftriaxone MICs worldwide, with MICs at 0.125 µg/mL representing the highest end of susceptible range; this warrants continued surveillance for emergence of resistance. Current WHO/CDC-recommended treatment is ceftriaxone 500 mg (or 1g) IM single dose plus azithromycin or doxycycline. Spectinomycin is an alternative for ceftriaxone-allergic patients.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
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