The past, present and future of molecular testing for Neisseria gonorrhoeae in Australia: still challenging

Abstract

Nucleic-acid amplification tests (NAATs) for Neisseria gonorrhoeae, particularly earlier generation tests, have been beset with specificity problems associated with cross reaction with commensal neisseriae. This is a particular problem for extragenital samples such as pharyngeal swabs, which are loaded with commensal Neisseria species and also a common site of infection for N. gonorrhoeae. To address the specificity issues, supplementary testing (whereby samples testing positive in a screening NAAT are reflexively tested with a secondary NAAT) has been widely implemented, with associated guidelines in place in Australia since 2005. Unlike earlier generation tests, modern commercial N. gonorrhoeae NAATs are (for the most part) much improved in terms of sensitivity and specificity and some now include testing claims for oropharyngeal and anorectal sites. This has raised questions over the ongoing utility of N. gonorrhoeae supplemental testing (particularly for urogenital sites) and left supplemental testing needing to play ‘catch-up’ in terms of sensitivity compared to newer commercial NAATs. More recently, supplemental testing has found added clinical utility with the addition of antimicrobial resistance (AMR) markers. Here I present the current N. gonorrhoeae testing guidelines, recent improvements in N. gonorrhoeae NAATs, discuss the changing role of supplemental testing and future sexually transmitted infection (STI) testing needs.