Trends and Risk Factors for Antimicrobial-Resistant Neisseria gonorrhoeae, Melbourne, Australia, 2007 to 2018

Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a major public health problem. Traditionally, AMR surveillance programs for N. gonorrhoeae have focused mainly on laboratory data to describe the prevalence and trends of resistance. However, integrating individual-level risk factors (e.g., sexual orientation or international travel) with laboratory data provides important insights into factors promoting the spread of resistant N. gonorrhoeae. Here, over a 12-year period, we assessed the trends and risk factors for resistant N. gonorrhoeae in individuals attending a large publicly funded sexual health center in Melbourne, Australia. A total of 7,588 N. gonorrhoeae isolates were cultured from 5,593 individuals between 1 January 2007 and 31 December 2018. The proportion of isolates with penicillin resistance decreased from 49.5% in 2007 to 18.3% in 2018 (p(trend) < 0.001) and from 63.5% in 2007 to 21.1% in 2018 for ciprofloxacin resistance (p(trend) < 0.001). In contrast, the proportion of isolates displaying decreased susceptibility to ceftriaxone increased from 0.5% in 2007 to 2.9% in 2018 (p(trend) < 0.001), with a significant increase in low-level azithromycin resistance, from 2.5% in 2012 to 8.2% in 2018 (p(trend) < 0.001). Multivariate analysis identified risk factors for multidrug-resistant (MDR) N. gonorrhoeae, namely, female sex and country of birth, with MDR isolates more common in individuals born in northeast Asia, further highlighting the importance of this region and international travel as factors in the cross-border transmission of MDR N. gonorrhoeae. Future surveillance work should incorporate additional epidemiological and genomic data to provide a comprehensive overview of the emergence and spread of resistant N. gonorrhoeae.