Transport time, not transport method, predicts Neisseria gonorrhoeae culture yield in an urban setting

Abstract

Antimicrobial resistance (AMR) in Neisseria gonorrhoeae poses a pressing public health threat. Current surveillance programs via antimicrobial susceptibility testing (AST) depend on successfully cultivating the organism via bacterial culture. However, AST is more challenging in extragenital sites and in remote clinical settings where there is a delay between sample collection and testing. This study evaluated whether an enhanced specimen transport system involving direct plating of samples onto selective agar with carbon dioxide enrichment (Bio-Bag^TM Type C, Becton Dickinson) improved N. gonorrhoeae recoverability compared to the standard method of rayon swabs in Amies gel (Transystem^TM, Copan Diagnostics). Men with urethral or rectal gonorrhoea confirmed by nucleic acid amplification testing were consecutively recruited from an urban Sydney clinic. Among 33 rectal samples, enhanced transport yielded a slightly higher culture positivity rate (72.7%) than the standard method (69.7%), though this difference was not statistically significant (p  = 0.790). Notably, rectal specimens arriving at the laboratory within five hours had significantly higher culture yields (100%) than those with longer transport times (61.5%; p = 0.049). Future studies of the impact of enhanced transport in rural and remote settings are critical to enhance AMR surveillance.