By Rebecca Bowers

EXECUTIVE SUMMARY

Concerns about Mycoplasma genitalium, a sexually transmitted infection, are on the rise. The British Association of Sexual Health and HIV just released draft guidance in July 2018 regarding testing and treatment strategies. Public health officials cite concerns that the infection often is misdiagnosed as chlamydia and treated as such, which encourages antimicrobial resistance.

  • Mycoplasma genitalium is a major cause of urethritis in men. In a 2015 meta-analysis, M. genitalium infections were associated with about a two-fold increase in the risk of cervicitis, pelvic inflammatory disease, preterm delivery, and spontaneous abortion.
  • Research now indicates that treatment failure rates after azithromycin treatment have risen because of the emergence of macrolide resistance in the infection.

Concerns about Mycoplasma genitalium (MG), a sexually transmitted infection, are on the rise. The British Association of Sexual Health and HIV just released draft guidance in July 2018 regarding testing and treatment strategies.

What prompted the move? Public health officials cite concerns that the infection often is misdiagnosed as chlamydia. In treating as such, antimicrobial resistance is encouraged.

Mycoplasma genitalium is a major cause of urethritis in men. In a 2015 meta-analysis, M. genitalium infections were associated with about a two-fold increase in the risk of cervicitis, pelvic inflammatory disease, preterm delivery, and spontaneous abortion.1 Research now indicates that treatment failure rates following azithromycin treatment have risen because of the emergence of macrolide resistance in the infection.

In the draft guidance, the association calls for testing urine samples and swabs for antibiotic resistance, treating all partners, and testing of cure five weeks after treatment initiation. Azithromycin treatment should not be repeated, as such use could lead to antibiotic resistance. Condom use should be stressed, the guidance states.2

Get Up to Speed

Mycoplasma genitalium is a bacterium first identified in 1980 that infects the reproductive tract and is transmitted via sexual contact. Unlike most other bacteria, it is difficult to grow in culture, taking about six months to develop. Researchers were hampered in studying the epidemiology of M. genitalium infections until polymerase chain reaction tests were developed in the early 1990s. Antibiotic resistance has developed in the bacteria. Treatment of the infection is challenging because rates of resistance are high.

No Food and Drug Administration (FDA)-approved diagnostic test for M. genitalium is available currently in the United States. However, in April 2018, the FDA listed Sydney, Australia-based SpeeDx’s ResistancePlus MG Positive Control kit for sale in the United States. The assay received CE marking in 2016.

Research indicates that a single 1-gram dose of azithromycin is more effective against M. genitalium than doxycycline.3 However, resistance to azithromycin is increasing. In both men and women, the median cure rate is about 85%, but the most recent trial found it to be only 40%.4 Cure rates for moxifloxacin range from 70-100%. Fluoroquinolones other than moxifloxacin are not recommended for the treatment of M. genitalium, according to the Centers for Disease Control and Prevention.3

In Australia, for initial treatment of M. genitalium, clinicians are using 100 mg doxycycline for one week, followed by either azithromycin or moxifloxacin.

“If macrolide-sensitive MG is detected, then this can be treated with azithromycin with greater confidence,” said Tim Read, MBBS, PhD, a research fellow in the Central Clinical School at Melbourne, Australia-based Monash University in a press release. “We are hopeful, but less certain, that this reduction in bacterial load will also increase the likelihood of success with moxifloxacin treatment.”

Symptoms May Not Be Present

Detecting the presence of infection can be a challenge; about 40-75% of women and 70% of men are asymptomatic.5 Women may present with increased or altered vaginal discharge; urethritis that is acute, persistent, and recurrent; dysuria or urgency; occasional intermenstrual bleeding or post-coital bleeding; cervicitis; or lower abdominal pain. Men may have symptoms such as urethritis. dysuria, urethral discharge, and proctitis.5

How can science aid in better detection and treatment? Clinical trials are needed to find out whether to recommend widespread screening for M. genitalium that is asymptomatic and treatment. More effective antibiotics also must be identified to treat infections. Clinicians need diagnostic tests that can detect resistance genes to a range of antibiotic drug classes. Additional research is needed to assess potential new antibiotics, determine potential vaccine targets, and understand the lifecycle of M. genitalium in the reproductive tract.6

REFERENCES

  1. Lis R, Rowhani-Rahbar A, Manhart LE. Mycoplasma genitalium infection and female reproductive tract disease: A meta-analysis. Clin Infect Dis 2015;61:418-426.
  2. Soni S, Horner P, Rayment M, et al. 2018 BASHH UK National Guideline for the Management of Infection With Mycoplasma genitalium. Available at: https://bit.ly/2mcd7zv. Accessed July 19, 2018.
  3. Workowski KA, Bolan GA; Centers for Disease Control and Prevention. Sexually transmitted diseases treatment guidelines, 2015. MMWR Recomm Rep 2015;64(No. RR-03):1-137.
  4. Manhart LE, Gillespie CW, Lowens MS, et al. Standard treatment regimens for nongonococcal urethritis have similar but declining cure rates: A randomized controlled trial. Clin Infect Dis 2013;56:934-942.
  5. Sethi S, Zaman K, Jain N. Mycoplasma genitalium infections: Current treatment options and resistance issues. Infect Drug Resist 2017;10:283-292.
  6. Martin DH, Manhart LE, Workowski KA. Mycoplasma genitalium from basic science to public health: Summary of the results from a National Institute of Allergy and Infectious Diseases technical consultation and consensus recommendations for future research priorities. J Infect Dis 2017;216(suppl_2):S427-S430.