Diagnostics for gonococcal antimicrobial resistance
Gonorrhoea is the second most common bacterial sexually transmitted infection, resulting in substantial morbidity and economic cost globally. WHO estimates that in 2020, 82.4 million new infections with Neisseria gonorrhoeae occurred among adults aged 15 to 49 year worldwide. Prevalence of gonorrhoea is highest among men who have sex with men, sex workers, transgender women and adolescents and young people in high burden countries. Coinfection with chlamydia is detected in 10–40% of people with gonorrhoea.
WHO has identified N. gonorrhoeae as a high-priority pathogen due to widespread antimicrobial resistance to penicillin, tetracyclines, macrolides (including azithromycin), sulphonamides, trimethoprim and quinolones – including emergent resistance to the last line extended-spectrum cephalosporins cefixime and ceftriaxone. The emergence of decreased susceptibility of N. gonorrhoeae to extended-spectrum cephalosporins, together with already-existing resistance to other antibiotics, makes N. gonorrhoeae a multidrug-resistant organism.
As multiple organizations push to develop new drugs, and WHO simultaneously recommends the AWaRe approach (Access, Watch and Reserve) for antibiotic stewardship, countries will need diagnostic tools to guide treatment choices, ensure current therapies remain effective for as long as possible, and preserve new drugs from rapid development of resistance by overuse. In 2023 and 2024, two new therapies have shown promising results: Zoliflodacin developed by the Global Antibiotic Research and Development Partnership, and Gepotidacin.
The gold standard for diagnosing gonorrhoea are molecular tests, which can be laboratory-based or at the point-of-care. One United States Food and Drug Administration-approved molecular diagnostic test is available to distinguish between Chlamydia trachomatis and N. gonorrhoeae infections; however, the turnaround time to results is too long for use at the point-of-care, the cost remains prohibitive for use in primary health care settings for most countries, and uptake remains limited to reference-level laboratories. Currently, there is no quality-assured rapid diagnostic test available to identify N. gonorrhoeae. Recent technology advances may facilitate development of a low-cost rapid diagnostic test for N. gonorrhoeae detection alone – or for combined N. gonorrhoeae/C. trachomatis detection and differentiation – would enable widescale uptake at primary health care level, especially in low- and middle-income countries.
New diagnostics are needed to help guide diagnosis and treatment decisions to foster antibiotic stewardship of existing and new antibiotics. If syndromic management remains the primary approach to guide treatment of sexually transmitted infections, there is a significant risk of misdiagnosis and antibiotic overuse, which has been shown to contribute to antimicrobial resistance. The inclusion of the potential new diagnostics within the overall clinical algorithms of syndromic management will narrow the diagnoses options and thus extensively limit antibiotic overuse.