Demographic and behavioural factors associated with antimicrobial susceptibility to azithromycin and ceftriaxone in Neisseria gonorrhoeae

Abstract

Antimicrobial resistance of Neisseria gonorrhoeae (NG) is of global public health concern. The aim of this study was to explore demographic and behavioural factors associated with antimicrobial susceptibility of NG to ceftriaxone and azithromycin. Gonococcal isolates (n = 391) from clients attending the Auckland Sexual Health Service, New Zealand, from July 2014 – June 2015 (n = 206), and July 2017 – June 2018 (n = 185), were tested for susceptibility to ceftriaxone and azithromycin. Laboratory data were linked with behavioural and demographic data. Geometric mean azithromycin MICs increased across the two time periods (0.239 mg/L in 2014/15 to 0.347 mg/L in 2017/18, p < 0.001), and ceftriaxone MICs decreased (0.007 mg/L in 2014/15 to 0.005 mg/L in 2017/18, p < 0.001). Demographic and behavioural factors were not associated with differences in ceftriaxone MICs; however azithromycin MICs were higher in men who have sex with men (0.356 mg/L) compared with the heterosexual study population (0.192 mg/L, p < 0.001) and were lower in Pacific peoples (0.201 mg/L, p < 0.001) and Māori (0.244 mg/L, p = 0.05) compared with those of European ethnicity (0.321 mg/L). Our findings show that azithromycin MICs increased in our region between 2014 and 2018; associations were seen with sexual orientation and ethnicity.