New warning over antibiotic-resistant gonorrhoea

Strains of Neisseria gonorrhoeae - the bacterium behind common STI gonorrhoea - have developed resistance to a wide range of antimicrobials. Photo / 123RF

The bacterium behind a common sexually transmitted infection (STI) has now grown resistant to many antibiotics - and researchers say clinicians need to be wary.

In New Zealand, gonorrhoea is mostly detected in men and women under the age of 25, and is generally easily treated with antibiotics.

But in a paper published today in the New Zealand Medical Journal, researchers said strains of Neisseria gonorrhoeae (NG) had developed resistance to a wide range of antimicrobials.

Furthermore, the now-widespread use of molecular detection for gonorrhoea and other STIs had led to a reduction in samples submitted for culture, making it harder for clincians to optimise treatment for individual patients.

That made population-level data, like that collected through surveillance programmes, essential for guiding treatment regimes.

A team from Auckland Hospital and Auckland Sexual Health Service aimed to reveal whether there was any pattern to antimicrobial resistance among nearly 2000 surveyed patients.

They found resistance rates to certain antibiotics decreased between 2013 and 2016, but many remained too high to be reliable treatments.

As at 2016, around 31 per cent and 22 per cent of samples respectively proved resistant to commonly used ciprofloxacin and tetracycline, while a further seven per cent were resistant to penicillin.

Over a wider period, from 2008 to 2016, resistance rates were higher at 42 per cent for tetracycline, 22 per cent for ciprofloxacin, and 21 per cent for penicillin.

Those figures put all of the treatments well above threshold under which the World Health Organisation recommended clinicians could use them based on their own experiences in dealing with cases.

While resistance rates appeared to have dropped over the eight-year period, the study authors pointed out that the number of strains of NG harbouring resistance, and with the capacity to spread, was likely to be increasing.

That was evident by the increasing number of reports of clones associated with treatment failure, which the authors said was placing "significant pressure on our limited antibiotic options for this organism".

With increasing reports of treatment failure worldwide, they said it was essential clinicians didn't become complacent about the risks and consequences of widespread resistance to the current antibiotic options, which ranged from rising rates of pelvic inflammatory to neonatal eye disease.

The researchers also argued that better methods were ultimately needed to rapidly pick up antibiotic resistance, ensuring patients were getting the best treatment.

"In the future, developments in point of care testing may allow rapid, individualised therapy for patients in STI clinics."

In the most recent reported quarter, the three months to June last year, there were 23 cases of gonorrhoea per 100,000 New Zealanders, in line with the same period the year before.

The highest rates were recorded in Auckland, the Tairāwhiti region, which covered Gisborne, and Northland.