Drug-resistant strains of gonorrhoea are spreading across NSW as health authorities grow increasingly concerned about the diminishing effectiveness of antibiotics to treat the common sexually transmitted infection.
There have been 16 cases of multi-drug resistant gonorrhoea diagnosed so far this year, compared to 41 cases last year, NSW Health said on Tuesday.
This includes two cases showing high-level resistance to both the first-line treatment (ceftriaxone) and a host of other drugs, including penicillin. These cases are sometimes called “gonorrhoea superbugs” or “super gonorrhoea”.
Most of the cases were in Sydney, said NSW Health’s Dr Vicky Sheppeard.
“If we do get a predominance of drug resistance, we might need to give people intravenous antibiotics … there may not be antibiotics available,” Sheppeard said. “So to try to control this now, when the numbers are relatively small, is ideal.”
Cases occurred mostly in heterosexual people, including recent cases linked to female sex workers, NSW Health said in an alert sent to doctors earlier this month.
Gonorrhoea can occur without symptoms, meaning it can spread easily among people who do not know they are carrying the infection. Untreated, it can cause long-term reproductive issues such as infertility, pelvic inflammatory disease, and complications during pregnancy.
The antibiotic injection ceftriaxone is the recommended first-line treatment against gonorrhoea, but since 2014 doctors have been advised to give it in combination with another antibiotic, azithromycin, because bacteria had begun to show signs of being resistant to ceftriaxone alone.
Strains that are resistant to multiple antibiotics are increasingly common. Extensively drug-resistant gonorrhoea was first reported in Australia and the UK in 2018, and again in 2022.
A report released this week by the Australian Centre for Disease Control found community cases surged between 2022 and 2024, coinciding with the relaxation of COVID-19 travel restrictions.
In 2024, high-level resistance to azithromycin was identified in a record 46 cases of Neisseria gonorrhoeae, compared to 27 isolated cases in 2023, the report found.
Drug-resistant forms of gonorrhoea represent a fraction of the total number of cases recorded in Australia every year, but their ability to rapidly build resistance to treatment make them an emerging global health threat.
These drug-resistant forms of infection have been declared a high-priority global threat by the World Health Organisation.
There have been 1614 gonorrhoea notifications in NSW so far this year.
The total number of gonorrhoea cases in Australia doubled in a decade to 44,210 in 2024, according to the latest surveillance data from the Kirby Institute. Men accounted for two-thirds of all notifications.
Associate Professor Tanya Applegate, chief investigator at the UNSW’s Kirby Institute antimicrobial resistance hub, said more research was needed into new drugs to fight the ever-changing threat.
The institute is working with the CSIRO on artificial intelligence models that can analyse patterns in the genome sequence of gonorrhoea isolates, and how they react to antibiotics.
Angus Thomson is a reporter covering health at The Sydney Morning Herald.Connect via X or email.