Neisseria gonorrhoeae antimicrobial susceptibility trends in Bangkok, Thailand, 2015-21: Enhanced Gonococcal Antimicrobial Surveillance Programme (EGASP)

Objectives Rising antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a global public health concern. Many ceftriaxone-resistant cases have been linked to Asia. In the WHO/CDC global Enhanced Gonococcal Antimicrobial Surveillance Programme (EGASP), we conducted AMR surveillance at two clinical sites in Bangkok, Thailand, 2015-21.Methods Urethral discharge samples, from males with urethral discharge and/or dysuria, were Gram-stained and cultured. ETEST was performed to determine AMR. EGASP MIC alert values, CLSI and EUCAST breakpoints were used.Results In 2015-21, gonococcal isolates were cultured from 1928 cases; most (64.1%) were males reporting having sex with females. The sensitivity and specificity of Gram-stained microscopy compared with culture for detection of gonococci were 97.5% and 96.6%, respectively. From 2015 to 2021, the azithromycin MIC90 increased from 0.125 to 1 mg/L, and the MIC90 of ceftriaxone and cefixime increased from 0.008 and <= 0.016 mg/L to 0.032 and 0.064 mg/L, respectively. Eight EGASP MIC alert values (in seven isolates) were identified. Five alert values were for cefixime (all resistant according to EUCAST breakpoints) and three for azithromycin (all resistant according to EUCAST breakpoints). The average annual resistance to ciprofloxacin during 2015-21 was 92%.Conclusions A continuous high susceptibility to ceftriaxone, Thailand's first-line gonorrhoea treatment, was found. However, the increasing MICs of ceftriaxone, cefixime and azithromycin are a substantial threat, especially considering these are the last remaining options for the treatment of gonorrhoea. To monitor AMR, continuous and quality-assured gonococcal AMR surveillance such as the Thai WHO/CDC EGASP, ideally including WGS, is imperative globally.