Oral chloramphenicol effective treatment option for resistant non-gonococcal urethritis: BMJ

UK: Non-gonococcal urethritis is a common sexually transmitted infection caused by Mycoplasma genitalium that has become increasingly difficult to treat with currently recommended antibiotics.

Researchers have reported novel use of oral chloramphenicol for treatment-resistant Mycoplasma genitalium (M. genitalium) infection in a 20-year-old heterosexual cisgender male presenting with recurrent symptomatic non-gonococcal urethritis.

The case study published in the journal Sexually Transmitted Infections has described the case of a man with Mycoplasma genitalium (non-gonococcal) urethritis who was successfully treated with chloramphenicol. 

"An oral antibiotic tablet used to treat common eye infections may prove an effective medicine for a sexually transmitted bug resistant to the usual recommended treatment," the researchers wrote in their study. 

Data from the UK Health Security Agency suggest rising antimicrobial resistance to first and second-choice drugs used to treat this infection. At the same time, there’s currently no strong evidence for third-choice options, say the authors.

The young man initially turned up at the clinic with 2-day-old symptoms a fortnight after having unprotected sex with a casual partner.

He was initially treated with a week’s course of doxycycline, pending test results to identify the exact bacterial cause of his infection.

The results showed that he was infected with M genitalium, and he has then prescribed another antibiotic, azithromycin. Once the lab analysis revealed that it was a treatment-resistant strain, he was given a third antibiotic, moxifloxacin.

But 5 days after completing all the courses of antibiotics, he still had symptoms. After considering other options dismissed due to cost, availability, or licensing issues, the authors decided to try chloramphenicol: 1g tablet taken four times a day for 14 days.

Their decision was prompted by test tube evidence showing that chloramphenicol stopped M genitalium in its tracks and the ready availability of the drug.

After 14 days of treatment, the young man’s symptoms had cleared up, and lab tests confirmed that he no longer had urethritis.

This is just one case; the findings should be taken in that context. But point out the authors: “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.”

Chloramphenicol is generally well tolerated, with the serious side effects rare (1 in 30,000), they highlight. And in the absence of viable effective alternatives, it merits further investigation, they suggest.

“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 conclude.

Reference:

Goodfellow JJ, Hughes S, Smith J, et alNovel use of oral chloramphenicol for treatment-resistant Mycoplasma genitalium Sexually Transmitted Infections Published Online First: 30 January 2023. doi: 10.1136/sextrans-2022-055621