The authors report that the latest data indicates an increase in resistance to both first and second-choice drugs for treating a common sexually transmitted infection (STI) caused by Mycoplasma genitalium. Currently, limited evidence supports the effectiveness of third-choice drugs.

In the journal Sexually Transmitted Infections, doctors indicate that an oral antibiotic pill used to treat common eye infections may be an effective therapy for a sexually transmitted bug that has developed resistance to the standard treatment.

With chloramphenicol, they were able to successfully treat a young man’s Mycoplasma genitalium (non-gonococcal) urethritis.

According to the authors, data from the UK Health Security Agency shows that antimicrobial resistance is growing to the first and second-choice drugs used to treat this infection. At the moment, there isn’t much evidence for the third-choice drugs.

They present the case of a young man with recurring symptoms of non-gonococcal urethritis, a common sexually transmitted illness caused by Mycoplasma genitalium that has become more difficult to treat with the drugs now prescribed.

Two weeks after engaging in unprotected intercourse with a casual partner, the young guy presented himself at the clinic complaining of symptoms he’d been experiencing for just two days.

He was first given doxycycline for a week while waiting for test results to find out which bacteria caused his infection.

He tested positive for M genitalium infection, so his doctor gave him a different antibiotic, azithromycin. He was subsequently given the third antibiotic, moxifloxacin, after the lab examination confirmed that the strain was treatment-resistant.

But he continued to have symptoms five days after finishing all of the medication treatments. The authors opted to attempt chloramphenicol: 1g pill taken four times a day for 14 days after reviewing alternative possibilities that were ruled out because of cost, availability, or licensing concerns.

The evidence from test tube studies demonstrating chloramphenicol’s ability to effectively halt M genitalium, combined with the drug’s readily accessible nature, prompted their decision.

The young man’s symptoms had disappeared after 14 days of therapy, and lab testing revealed that he was no longer suffering from urethritis.

Remembering that this is a single occurrence, the results must be interpreted cautiously. However, the authors note that “When considering what to choose after first- and second-line treatment failure, there is a lack of novel agents readily available in the UK, and a paucity of data to underpin recommendations.”

They emphasize that chloramphenicol is often well tolerated and that major side effects are rare (1 in 30,000). And they advise additional research since there aren’t any feasible, efficient alternatives.

“Options for third-line therapies in treatment-resistant M genitalium are urgently required. Chloramphenicol may have an application in this scenario, and should be considered as a possible drug for investigation,” they write.

Source: 10.1136/sextrans-2022-055621

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