Sexual health experts are urging people with symptoms such as painful urination to get checked for a lesser-known STI.
Mycoplasma genitalium is rarely diagnosed but up to 400,000 Australians could have it, according to The Age.
In people with uteruses it can lead to pelvic inflammatory disease, miscarriage or infertility.
The bug is often resistant to first-line antibiotics such as azithromycin, meaning specialist care can be needed to get rid of the infection.
Until recently only a few general practitioners have had access to testing for Mycoplasma, despite its estimated prevalence of about 1 to 2 per cent in the population.
A new Australian-developed test being made widely available to doctors shows whether people have the infection, as well as whether they have an azithromycin-resistant strain, reducing the need for trial and error in treatment.
Professor Susan Garland from Melbourne’s Royal Women’s Hospital said resistance to first-line treatment was now about 60 per cent, with about 10 per cent of cases also resistant to second-line medications.
“MG is not [monitored] and we are running out of drugs to treat it,” she said.
Like chlamydia, Mycoplasma is most common among people aged in their 20s.
Associate Professor Catriona Bradshaw of the Melbourne Sexual Health Centre said that at present testing and treatment is only recommended for people with symptoms.
“Once we have better information about the infection’s impact and a better-tolerated, highly effective treatment, we can recommend widespread screening,” she said.
For people who need to be checked for Mycoplasma, the test is a simple urine test or genital swab.