Clinical evaluation of the ResistancePlus MG FleXible test on the GeneXpert Infinity-48s instrument: a near-patient assay for simultaneous detection of Mycoplasma genitalium and macrolide resistance

Treatment of bacterial sexually transmitted infections in Europe: gonorrhoea, Mycoplasma genitalium, and syphilis

This review explores the therapeutic challenges of sexually transmitted infections (STI) in Europe, which include increasing antimicrobial resistance and limited progress in drug discovery. We primarily focus on gonorrhoea, Mycoplasma genitalium, and syphilis infections. For gonorrhoea with escalating resistance rates we explore the possibility of combining ceftriaxone with another antibiotic or using alternative antibiotics to mitigate resistance emergence, and we provide insights on the ongoing evaluation of new antimicrobials, like gepotidacin and zoliflodacin. In the case of M. genitalium, which exhibits high resistance rates to first and second-line treatments, we emphasize the importance of resistance-guided therapy in regions with elevated resistance levels, and highlight the limited alternative options, such as pristinamycin and minocycline. Furthermore, we address the challenges posed by syphilis, where the primary treatment consists of penicillin or doxycycline, with challenges arising in neurosyphilis, allergy, pregnancy, and supply shortages and discuss the ongoing evaluation of alternative antimicrobials (e.g., ceftriaxone, cefixime, linezolid). Our findings identify priority actions and provide concrete solutions for long-term effective management of STIs and antimicrobial resistance mitigation.

Latest Advances in Laboratory Detection of Mycoplasma genitalium

Mycoplasma genitalium is an important sexually transmitted pathogen affecting both men and women. Its extremely slow growth in vitro and very demanding culture requirements necessitate the use of molecular-based diagnostic tests for its detection in clinical specimens. The recent availability of U.S. Food and Drug Administration (FDA)-cleared commercial molecular-based assays has enabled diagnostic testing to become more widely available in the United States and no longer limited to specialized reference laboratories. Advances in the knowledge of the epidemiology and clinical significance of M. genitalium as a human pathogen made possible by the availability of molecular-based testing have led to updated guidelines for diagnostic testing and treatment that have been published in various countries. This review summarizes the importance of M. genitalium as an agent of human disease, explains the necessity of obtaining a microbiological diagnosis, describes currently available diagnostic methods, and discusses how the emergence of antimicrobial resistance has complicated treatment alternatives and influenced the development of diagnostic tests for resistance detection, with an emphasis on developments over the past few years.

Clinical Performance of Three Commercial Molecular Diagnostic Assays for the Detection of Fluoroquinolone Resistance-Associated Mutations in Mycoplasma genitalium

The high prevalence of macrolide resistance in Mycoplasma genitalium results in an increased reliance on moxifloxacin, the second-line treatment; however, moxifloxacin resistance has also emerged. Because assays that can detect fluoroquinolone resistance-associated mutations will be useful for the management of macrolide-resistant M. genitalium infections, we evaluated the performance of three commercial assays (the Allplex MG & MoxiR Assay [Seegene], LightMix Modular parC kit [TIBMOLBIOL], and MGMO qPCR [NYtor) in comparison with parC gene Sanger sequencing used as the reference. Between January 2018 and December 2020, remnants of M. genitalium-positive clinical specimens received at the French National Reference Center for Bacterial Sexually Transmitted Infections were collected if a Sanger sequencing result was obtained for the parC gene. Overall, 368 M. genitalium-positive specimens were assessed. The clinical sensitivities for the detection of the ParC mutations that are likely of clinical significance were 91.8% (95% CI = 83.2 to 96.2), 98.6% (95% CI = 92.4 to 99.8), and 94.4% (95% CI = 86.6 to 97.8) for the Allplex MG & MoxiR, LightMix Modular parC, and MGMO qPCR kits, respectively, with no significant difference between the three kits. The clinical specificity of the Allplex MG & MoxiR and MGMO qPCR kits was 100% (95% CI = 97.7 to 100 and 98.7 to 100, respectively), which was significantly higher than the specificity of the LightMix Modular parC kit of 95.4% (95%CI = 92.3 to 97.3), for which the interpretation of melting curves may be misleading. These kits should be useful for the selection of antimicrobials in macrolide-resistant M. genitalium infections, although further developments may be necessary because parC mutations involved in fluoroquinolone resistance have not been precisely determined.

Mycoplasma genitalium: A new superbug

Mycoplasma genitalium (MG) is an emerging sexually transmitted pathogen. It is an important cause of nongonococcal urethritis in men and is associated with cervicitis and pelvic inflammatory disease in women, putting them at risk of infertility. Multiple factors that aid pathogenesis of MG include its ability of adhesion, gliding motility, and intracellular invasion by means of the tip organelle. Through intracellular localization and antigenic variation, MG could result in treatment-resistant chronic infection. There are limited data on the prevalence of MG in Indian patients with urogenital syndromes. Recently, a high prevalence of extra genital infection with MG has been reported. Molecular assays are the major diagnostic techniques of MG infection. Antimicrobial agents such as macrolides, along with fluoroquinolones, are the treatment of choice for MG infections. The issue of drug resistance to azithromycin and fluoroquinolones in MG is rising globally. As molecular tests are becoming available for MG, both for the diagnosis and the detection of antimicrobial resistance, any patient with MG infection should then be tested for antimicrobial resistance. Consideration of MG as a cause of sexually transmitted disease in the Indian population is crucial in diagnostic algorithms and treatment strategies. The purpose of this review is to understand the prevalence of MG in different clinical scenarios, molecular mechanisms of pathogenesis, current status of antimicrobial resistance, and its impact on MG treatment.

Performance of Three Commercial Molecular Diagnostic Assays for the Simultaneous Detection of Mycoplasma genitalium and Macrolide Resistance

The increasing frequency of macrolide resistance is an emerging issue in the treatment of Mycoplasma genitalium infection. Because evaluation of new commercial kits detecting M. genitalium and macrolide resistance is needed, we evaluated the performance and handling characteristics of the Allplex MG & AziR (Seegene), the Macrolide-R/MG ELITe MGB (ELITechGroup), and the ResistancePlus MG FleXible (SpeeDx-Cepheid) kits in comparison with those of an in-house real-time PCR and 23S rRNA gene sequencing used as the reference. A total of 239 urogenital specimens (135 M. genitalium-positive and 104 M. genitalium-negative specimens) collected between April and December 2019 at the French National Reference Center for Bacterial Sexually Transmitted Infections were assessed. The overall agreement for M. genitalium detection of the three commercial kits compared with the in-house real-time PCR was 94.6 to 97.6%, and there was no significant difference. A total of 97 specimens were found to be M. genitalium positive with the three kits and were used to assess macrolide resistance detection. The clinical sensitivities for resistance detection were 74.5% (95% confidence interval, 61.7 to 84.2%), 96.2% (87.2 to 99.0%), and 92.8% (82.7 to 97.1%) for the Allplex MG & AziR, Macrolide-R/MG ELITe MGB, and ResistancePlus MG FleXible kits, respectively. The sensitivity of the Macrolide-R/MG ELITe MGB kit was significantly higher than that of the Allplex MG & AziR kit. The clinical specificity for resistance detection of the three kits was 97.4 to 97.6%. The random-access possibility, input sample volume, and DNA extract availability for detecting resistance to other antibiotics may also influence the selection of a commercial kit by diagnostic laboratories.