Antimicrobial Resistance of Neisseria gonorrhoeae Isolates from High-Risk Men in Johannesburg, South Africa

Abstract

Neisseria gonorrhoeae antimicrobial drug resistance has emerged worldwide; however, the situation in sub-Saharan Africa is not well documented. We investigated the molecular epidemiology and occurrence of antimicrobial resistance in Neisseria gonorrhoeae infections in two core transmission groups of men in Johannesburg, South Africa. We recruited men who have sex with men (MSM) presenting with urethral discharge and men with recurrent episodes of urethral discharge. Molecular testing and culture for N. gonorrhoeae were performed, followed by antimicrobial susceptibility testing. Whole-genome sequencing (WGS) was used to identify resistance-conferring mutations and to determine the genetic relatedness of the isolates. In all, 51 men were recruited; 42 (82%) had N. gonorrhoeae infections. Most gonococcal isolates were resistant to ciprofloxacin (78%) and tetracycline (74%); 33% were penicillin resistant. All gonococcal isolates were susceptible to cephalosporins and spectinomycin. Azithromycin resistance was observed in 4 (15%) isolates (epidemiological cutoff), all with mutations in the mtrR promoter region. Most of the isolates (19/27) harbored the gonococcal genetic island, which is associated with antimicrobial resistance. WGS revealed a diverse epidemic with mostly novel NG-STAR (70%) and NG-MAST (70%) sequence types. Thus, we demonstrate a high prevalence of antimicrobial resistance in Neisseria gonorrhoeae strains obtained from high-risk men in South Africa. The introduction of diagnostics and scale-up of surveillance are warranted to prevent the emergence of multidrug-resistant infections.

Keywords: Africa; Neisseria gonorrhoeae; antimicrobial resistance; azithromycin; ceftriaxone; ciprofloxacin; core transmission groups; men who have sex with men; whole-genome sequencing.