Use of Pristinamycin for Macrolide-Resistant Mycoplasma genitalium Infection

Treatment of Mycoplasma genitalium infection in pregnancy: A systematic review of international guidelines

BACKGROUND

Mycoplasma genitalium is an emerging pathogen, which has been linked to cervicitis, urethritis and pelvic inflammatory disease (PID). With the advent of multiplex polymerase chain reaction (PCR) panels for sexually transmitted infections, it is increasingly being identified in pregnant women.

OBJECTIVES

The aim was to review international guidelines, which had explicit recommendations for treatment of M. genitalium infection in pregnancy and breastfeeding.

SEARCH STRATEGY

PubMed, EMBASE and Cochrane databases were reviewed with no age, species, language or date restrictions.

SELECTION CRITERIA

Studies were included if they had an explicit recommendation for treatment of M. genitalium in pregnancy. Studies were excluded if there was no recommendation in pregnancy, if they referred to other international guideline recommendations or were historical versions of guidelines.

DATA COLLECTION AND ANALYSIS

References were manually reviewed and 50 papers were selected for review. Only four guidelines were included in the final analysis and they were from Europe, UK, Australia and Aotearoa New Zealand.

MAIN RESULTS

All studies recommended azithromycin as first-line treatment, and advised against moxifloxacin use. The dosing schedule of azithromycin, varied between guidelines, as did the utility/safety of pristinamycin for macrolide resistant infections. Safety data was generally reassuring for azithromycin but inconsistent for pristinamycin.

CONCLUSIONS

Azithromycin is the first-line treatment for macrolide susceptible or unknown resistance infections, but there is a lack of consistency regarding dosing of azithromycin or the utility/safety of pristinamycin for macrolide resistant infections in pregnancy/lactation.

Antimicrobial treatment and resistance in sexually transmitted bacterial infections

Sexually transmitted infections (STIs) have been part of human life since ancient times, and their symptoms affect quality of life, and sequelae are common. Socioeconomic and behavioural trends affect the prevalence of STIs, but the discovery of antimicrobials gave hope for treatment, control of the spread of infection and lower rates of sequelae. This has to some extent been achieved, but increasing antimicrobial resistance and increasing transmission in high-risk sexual networks threaten this progress. For Neisseria gonorrhoeae, the only remaining first-line treatment (with ceftriaxone) is at risk of becoming ineffective, and for Mycoplasma genitalium, for which fewer alternative antimicrobial classes are available, incurable infections have already been reported. For Chlamydia trachomatis, in vitro resistance to first-line tetracyclines and macrolides has never been confirmed despite decades of treatment of this highly prevalent STI. Similarly, Treponema pallidum, the cause of syphilis, has remained susceptible to first-line penicillin.

High cure rates of Mycoplasma genitalium following empiric treatment with azithromycin alongside frequent detection of macrolide resistance in Austria

BACKGROUND

Mycoplasma genitalium (MG) is an emerging sexually transmitted infection, often harboring resistance-associated mutations to azithromycin (AZM). Global surveillance has been mandated to tackle the burden caused by MG, yet no data are available for Austria. Thus, we aimed to investigate the prevalence of MG, disease characteristics, and treatment outcomes at the largest Austrian HIV-and STI clinic.

METHODS

All MG test results at the Medical University of Vienna from 02/2019 to 03/2022 were evaluated. Azithromycin resistance testing was implemented in 03/2021.

RESULTS

Among 2671 MG tests, 199 distinct and mostly asymptomatic (68%; 135/199) MG infections were identified, affecting 10% (178/1775) of all individuals. This study included 83% (1479/1775) men, 53% (940/1775) men who have sex with men (MSM), 31% (540/1754) HIV+, and 15% (267/1775) who were using HIV pre-exposure prophylaxis (PrEP). In logistic regression analysis, 'MSM' (aOR 2.55 (95% CI 1.65-3.92)), 'use of PrEP' (aOR 2.29 (95% CI 1.58-3.32)), and 'history of syphilis' (aOR 1.57 (95% CI 1.01-2.24) were independent predictors for MG infections. Eighty-nine percent (178/199) received treatment: 11% (21/178) doxycycline (2 weeks), 52% (92/178) AZM (5 days), and 37% ( 65/178) moxifloxacin (7-10 days) and 60% (106/178) had follow-up data available showing negative tests in 63% (5/8), 76% (44/58) and 85% (34/40), respectively. AZM resistance analysis was available for 57% (114/199)) and detected in 68% (78/114). Resistance-guided therapy achieved a cure in 87% (53/61), yet, empiric AZM-treatment (prior to 03/2021) cleared 68% (26/38).

CONCLUSIONS

Mycoplasma genitalium was readily detected in this Austrian observational study, affected predominantly MSM and often presented as asymptomatic disease. We observed a worryingly high prevalence of AZM resistance mutations; however, empiric AZM treatment cleared twice as many MG infections as expected.

Mycoplasma genitalium: Key Information for the Primary Care Clinician

Mycoplasma genitalium (MG) is an emerging sexually transmitted infection, which appears to be a cause of urethritis and cervicitis and has been associated with pelvic inflammatory disease (PID), epididymitis, proctitis, infertility, complications during pregnancy, and human immunodeficiency virus (HIV) transmission. Three Food and Drug Administration (FDA) approved tests are available. Testing should be focused to avoid inappropriate antibiotic use. The Center of Disease Control and Prevention (CDC) guidelines recommend testing for persistent male urethritis, cervicitis, and proctitis and state that testing should be considered in cases of PID. Testing is also recommended for sexual contacts of patients with MG. Testing is not recommended in asymptomatic patients, including pregnant patients, who do not have a history of MG exposure. Although resistance-guided therapy is recommended, there are currently no FDA approved tests for MG macrolide resistance, and tests are not widely available in the United States. The CDC recommends 2-step treatment with doxycycline followed by azithromycin or moxifloxacin. Moxifloxacin is recommended if resistance testing is unavailable or testing demonstrates macrolide resistance..

Mycoplasma genitalium infection among gay, bisexual and other men who have sex with men in Montréal, Canada

Background

The bacteria Mycoplasma genitalium has been identified as a causative agent of urethritis in men, especially in gay, bisexual and other men who have sex with men (gbMSM). Canadian clinic-based data have identified a high prevalence of M. genitalium and resistance to antibiotic treatments. This article estimates the prevalence of M. genitalium infections among Montréal gbMSM, explores correlates for M. genitalium infection and estimates the prevalence of mutations associated with antimicrobial resistance (AMR).

Methods

Engage Cohort Study is a multi-site longitudinal study on sexually active gbMSM, aged 16 years and older, recruited via respondent-driven sampling in Montréal, Toronto and Vancouver. Participants completed a questionnaire on behaviour and were tested for sexually transmitted and blood-borne infections at each visit. For this sub-study, Montréal participants with a follow-up visit that occurred between November 2018 and November 2019 were included.

Results

A total of 2,064 samples were provided by 716 participants. Prevalence of M. genitalium infection was 5.7% at rectal and/or urethral sites, 4.0% at rectal site and 2.2% at urethral site. Correlates for M. genitalium infection were younger age and reporting six or more sexual partners in the past six months. Prevalence of macrolide resistance associated mutations (MRAM), quinolone resistance associated mutations (QRAM) and either MRAM or QRAM, was 82%, 29% and 85%, respectively.

Conclusion

This first population-based study among gbMSM in Canada documents a high prevalence of urethral and rectal M. genitalium infection and high levels of AMR. Our results highlight the importance of access to testing and AMR detection when indicated.

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.

Sexually transmitted infections in Spain: Current status

Sexually Transmitted Infections (STI) are a major public health problem. The problems inherent to their diagnosis, treatment and prevention have to do not only with their nature, but also with organizational issues and overlapping competencies of the different health authorities in Spain. The real situation of STI in Spain, at present, is poorly known. For this reason, the Scientific Committee on COVID and Emerging Pathogens of the Illustrious Official College of Physicians of Madrid (ICOMEM) has formulated a series of questions on this subject which were distributed, not only among the members of the Committee, but also among experts outside it. The central health authorities provide very high and increasing figures for gonococcal infection, syphilis, Chlamydia trachomatis infection and lymphogranuloma venereum (LGV). Both HIV infection and Monkeypox are two important STI caused by viruses in our environment, to which it should be added, mainly, Herpes simplex virus (HSV) and Human papillomavirus (HPV) infections. Emerging microorganisms such as Mycoplasma genitalium pose not only pathogenic challenges but also therapeutic problems, as in the case of N. gonohrroeae. The pathways that patients with suspected STI follow until they are adequately diagnosed and treated are not well known in Spain. Experts understand that this problem is fundamentally managed in public health institutions, and that Primary Care and Hospital Emergency Services, together with some institutions that deal monographically with this problem, are the recipients of most of these patients. One of the most serious difficulties of STI lies in the availability of the microbiological tests necessary for their diagnosis, particularly in this era of outsourcing of microbiology services. Added to this is the increased cost of implementing the latest generation of molecular techniques and the difficulties of transporting samples. It is clear that STI are not diseases to which the entire population is equally exposed and it is necessary to have a better knowledge of the risk groups where to focus the necessary interventions adapted to their characteristics. It should not be forgotten that STI are also a problem in the pediatric age group and that their presence can be a marker of sexual abuse with all that this implies in terms of health care and medicolegal activity. Finally, STI are infections that are associated with a high cost of care for which we have very little information. The possibility of expanding the automatic performance of laboratory tests for STI surveillance through laboratory routines is encountering ethical and legal problems that are not always easy to solve. Spain has created a ministerial area of specific attention to STI and there are plans to improve the diagnosis, treatment and prevention of these problems, but we still lack the necessary evidence on their impact. We cannot forget that these are diseases that transcend the individual and constitute a Public Health problem.

Efficacy of Minocycline for the Treatment of Mycoplasma genitalium

Background

High levels of macrolide resistance and increasing fluoroquinolone resistance are making Mycoplasma genitalium increasingly difficult to treat. Minocycline is an alternative treatment for patients with macrolide-resistant M genitalium infections that have failed moxifloxacin, or for those with fluoroquinolone contraindications or resistance. Published efficacy data for minocycline for M genitalium are limited.

Methods

We evaluated minocycline 100 mg twice daily for 14 days at Melbourne Sexual Health Centre (MSHC). Microbial cure was defined as a negative test of cure within 14-90 days after completing minocycline. The proportion cured and 95% confidence intervals (CIs) were calculated, and logistic regression was used to explore factors associated with treatment failure. We pooled data from the current study with a prior adjacent case series of patients with M genitalium who had received minocycline 100 mg twice daily for 14 days at MSHC.

Results

Minocycline cured 60 of 90 (67% [95% CI, 56%-76%]) infections. Adherence was high (96%) and side effects were mild and self-limiting. No demographic or clinical characteristics were associated with minocycline failure in regression analyses. In the pooled analyses of 123 patients, 83 (68% [95% CI, 58%-76%]) were cured following minocycline.

Conclusions

Minocycline cured 68% of macrolide-resistant M genitalium infections. These data provide tighter precision around the efficacy of minocycline for macrolide-resistant M genitalium and show that it is a well-tolerated regimen. With high levels of macrolide resistance, increasing fluoroquinolone resistance, and the high cost of moxifloxacin, access to nonquinolone options such as minocycline is increasingly important for the clinical management of M genitalium.

Update in Epidemiology and Management of Mycoplasma genitalium Infections

Mycoplasma genitalium is a frequent cause of urogenital syndromes in men and women and is associated with adverse sequelae in women. M genitalium also infects the rectum, and may cause proctitis, but rarely infects the pharynx. Diagnosis requires nucleic acid amplification testing. Antibiotic resistance is widespread: more than half of infections are resistant to macrolides and fluoroquinolone resistance is increasing. Resistance-guided therapy is recommended for symptomatic patients, involving initial treatment with doxycycline to reduce organism load followed by azithromycin for macrolide-sensitive infections or moxifloxacin for macrolide-resistant infections. Neither screening nor tests of cure are recommended in asymptomatic persons.

Mycoplasma genitalium antibiotic resistance-associated mutations in genital and extragenital samples from men-who-have-sex-with-men attending a STI clinic in Verona, Italy

Background

Mycoplasma genitalium (MG) is one of the most warning emerging sexually transmitted pathogens also due to its ability in developing resistance to antibiotics. MG causes different conditions ranging from asymptomatic infections to acute mucous inflammation. Resistance-guided therapy has demonstrated the best cure rates and macrolide resistance testing is recommended in many international guidelines. However, diagnostic and resistance testing can only be based on molecular methods, and the gap between genotypic resistance and microbiological clearance has not been fully evaluated yet. This study aims at finding mutations associated with MG antibiotic resistance and investigating the relationship with microbiological clearance amongst MSM.

Methods

From 2017 to 2021, genital (urine) and extragenital (pharyngeal and anorectal swabs) biological specimens were provided by men-who-have-sex-with-men (MSM) attending the STI clinic of the Infectious Disease Unit at the Verona University Hospital, Verona, Italy. A total of 1040 MSM were evaluated and 107 samples from 96 subjects resulted positive for MG. Among the MG-positive samples, all those available for further analysis (n=47) were considered for detection of mutations known to be associated with macrolide and quinolone resistance. 23S rRNA, gyrA and parC genes were analyzed by Sanger sequencing and Allplex™ MG and AziR Assay (Seegene).

Results

A total of 96/1040 (9.2%) subjects tested positive for MG in at least one anatomical site. MG was detected in 107 specimens: 33 urine samples, 72 rectal swabs and 2 pharyngeal swabs. Among them, 47 samples from 42 MSM were available for investigating the presence of mutations associated with macrolide and quinolone resistance: 30/47 (63.8%) showed mutations in 23S rRNA while 10/47 (21.3%) in parC or gyrA genes. All patients with positive Test of Cure (ToC) after first-line treatment with azithromycin (n=15) were infected with 23S rRNA-mutated MG strains. All patients undergoing second-line moxifloxacin treatment (n=13) resulted negative at ToC, even those carrying MG strains with mutations in parC gene (n=6).

Conclusion

Our observations confirm that mutations in 23S rRNA gene are associated with azithromycin treatment failure and that mutations in parC gene alone are not always associated with phenotypic resistance to moxifloxacin. This reinforces the importance of macrolide resistance testing to guide the treatment and reduce antibiotic pressure on MG strains.

Australian sexually transmitted infection (STI) management guidelines for use in primary care 2022 update

The 'Australian Sexually Transmitted Infection (STI) Management Guidelines For Use In Primary Care' (www.sti.guidelines.org.au ) provide evidence-based, up-to-date guidance targeted at use in primary care settings. A major review of the guidelines was undertaken in 2020-22. All content was reviewed and updated by a multi-disciplinary group of clinical and non-clinical experts, and assessed for appropriateness of recommendations for key affected populations and organisational and jurisdictional suitability. The guidelines are divided into six main sections: (1) standard asymptomatic check-up; (2) sexual history; (3) contact tracing; (4) STIs and infections associated with sex; (5) STI syndromes; and (6) populations and situations. This paper highlights important aspects of the guidelines and provides the rationale for significant changes made during this major review process.

Mycoplasma genitalium infection in the female reproductive system: Diseases and treatment

Mycoplasma genitalium is a newly emerged sexually transmitted disease pathogen and an independent risk factor for female cervicitis and pelvic inflammatory disease. The clinical symptoms caused by M. genitalium infection are mild and easily ignored. If left untreated, M. genitalium can grow along the reproductive tract and cause salpingitis, leading to infertility and ectopic pregnancy. Additionally, M. genitalium infection in late pregnancy can increase the incidence of preterm birth. M. genitalium infections are often accompanied by co-infection with other sexually transmitted pathogens (Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis) and viral infections (Human Papilloma Virus and Human Immunodeficiency Virus). A recent study suggested that M. genitalium plays a role in tumor development in the female reproductive system. However, few studies endorsed this finding. In recent years, M. genitalium has evolved into a new "superbug" due to the emergence of macrolide-and fluoroquinolone-resistant strains leading to frequent therapy failures. This review summarizes the pathogenic characteristics of M. genitalium and the female reproductive diseases caused by M. genitalium (cervicitis, pelvic inflammatory disease, ectopic pregnancy, infertility, premature birth, co-infection, reproductive tumors, etc.), as well as its potential relationship with reproductive tumors and clinical treatment.

Preparation and evaluation in vitro and in vivo of pristinamycin enteric-coated granules based on albumin nanoparticles

CONTEXT

The purpose of this study was to prepare enteric-coated particles based on albumin nanoparticles (NPs) using a mixture of PI_A albumin NPs freeze-dried powder (PA-PI_A) and PII_A albumin NPs freeze-dried powder (PA-PII_A) to improve the bioavailability effect of pristinamycin.

OBJECTIVE

This is the first study on the preparation of pristinamycin into enteric-coated granules based on albumin NPs, and our study has effectively improved the bioavailability of pristinamycin and ensured its safety.

METHODS

Pristinamycin albumin enteric-coated granules (PAEGs) were prepared by hybrid wet granulation. The characterizations of albumin NPs were performed by in vitro and in vivo studies of PAEGs. The assays were analyzed using zeta-sizer, transmission electron microscopy, high-performance liquid chromatography, and a fully automated biochemical index analyzer.

RESULTS

The morphology of NPs was close to spherical. PI_A-NPs and PII_A-NPs respectively had a zeta potential of (-24.33 ± 0.75) mV and (+7.30 ± 0.27) mV and mean size of (251.91 ± 19.64) nm and (232.83 ± 22.61) nm. The release of PI_A and PII_A from PAEGs in the artificial gastrointestinal fluid was as high as 58.46% and 87.79%. In the experimental group of oral PAEGs, PI_A and PII_A were AUC_(0-t) (3.68 ± 0.58) mg·L^-1·h^-1 and (2.81 ± 1.06) mg·L^-1·h^-1. The results of aspartate aminotransferase and alanine aminotransferase biochemical indices showed that there was no significant difference between the experimental and normal groups of oral PAEGs.

CONCLUSION

The PAEGs significantly increased the release of PI_A and PII_A in simulated intestinal fluid and improved the bioavailability. The oral administration of PAEGs may not damage the liver of rats. We hope that our study will promote its industrial development or clinical application.

Prevalence of fluoroquinolone resistance-associated mutations in Mycoplasma genitalium among clients of two sexual health centres in the Netherlands: a cross-sectional study

OBJECTIVE

This study aimed to determine the prevalence of fluoroquinolone resistance-associated mutations (QRAMs) in Mycoplasma genitalium (MG) among clients of two sexual health centres (SHCs) in the Netherlands.

DESIGN

A cross-sectional study.

SETTING AND PARTICIPANTS

Between 2018 and 2019, 669 clients with MG were included from two previous studies: 375 male clients with urethritis from the SHC in Amsterdam; and 294 clients (male and female) from the SHC in Amsterdam and The Hague. Urogenital and anal samples (705 in total) that tested positive for MG by nucleic acid amplification tests were selected.

OUTCOME MEASURES

The presence of QRAM was detected by an MG-QRAM PCR targeting four mutations in the parC gene and investigated by sequence analysis of relevant regions of the gyrA and parC genes. Possible risk factors for the presence of QRAM were investigated.

RESULTS

We found QRAM in 58 of 669 (9%) clients with an MG infection: 36 of 375 (10%) in the study population of men with urethritis and 22 of 294 (7%) in the study population of other clients (including both men and women; p=0.334). Most prevalent mutations in the parC gene were S83I and D87N, occurring in 31 of 60 (52%) and 20 of 60 (33%) samples, respectively. Factors associated with the presence of QRAM were: men who have sex with men (adjusted OR (aOR) 3.4, 95% CI 1.7 to 6.9) and Asian origin (aOR 2.5, 95% CI 1.2 to 5.6). Multidrug resistance (QRAM plus macrolide resistance-associated mutations) was found in 46 of 669 (7%) clients.

CONCLUSIONS

Nine per cent of MG-positive clients from two Dutch SHCs had QRAM. New treatment strategies and antibiotics are needed to treat symptomatic patients with multidrug-resistant MG.

Novel probe-based melting curve assays for the characterization of fluoroquinolone resistance in Mycoplasma genitalium

BACKGROUND

Mycoplasma genitalium infection is a sexually transmitted infection that has rapidly become resistant to mainstay treatments. While individualized treatment approaches have been recommended and adopted for macrolides, individualized therapy for fluoroquinolones has not yet been explored, due to a lack of commercial molecular assays and a lack of confidence in specific mutations associated with resistance. In another recent study, we defined a clear role and diagnostic utility in focusing on the absence of resistance mutations to inform microbial cure with fluoroquinolone antimicrobials.

METHODS

We developed two proof-of-concept molecular tests that focus on detection of M. genitalium and characterization of WT parC sequences that are strongly linked to fluoroquinolone susceptibility.

RESULTS

We screened a total of 227 M. genitalium-positive samples using novel molecular beacon and dual hybridization probe assays. These assays were able to detect M. genitalium and characterize fluoroquinolone susceptibility in 143/227 (63%) samples, based on clear differences in melting peak temperatures. The results of these molecular assays were in 100% agreement with 'gold standard' Sanger sequencing. Additionally, WT parC sequences were readily distinguished from M. genitalium samples harbouring parC mutations of known or suspected clinical significance. The ability of the assays to successfully characterize fluoroquinolone susceptibility and resistance was reduced in low M. genitalium load samples.

CONCLUSIONS

These proof-of-concept assays have considerable potential to improve individualized treatment approaches and rationalize tests of cure for M. genitalium infection. The ability to initiate individualized treatment in up to two-thirds of cases will enhance antimicrobial stewardship for this challenging pathogen.

Impact of 16S rRNA Single Nucleotide Polymorphisms on Mycoplasma genitalium Organism Load with Doxycycline Treatment

Doxycycline targets the 16S rRNA and is widely used for the treatment of sexually transmitted infections. While it is not highly effective at eradicating Mycoplasma genitalium infections, it can reduce organism load. The aim of this study was to investigate the association between single nucleotide polymorphisms (SNPs) in the 16S rRNA gene of M. genitalium and change in organism load. M. genitalium samples were collected from 56 men prior to commencing doxycycline and at a median of 13 of 14 doses. These were sequenced for the 16S rRNA, and the association between 16S rRNA SNPs and change in organism load was determined. 16S rRNA sequences were available for 52/56 (92.9%) M. genitalium-infected men, of which 20 (38.5%) had an undetectable load, 26 (50.0%) had a decrease in M. genitalium load (median change of 105-fold), and 6 (11.5%) had an increase in load (median change of 5-fold). The most common SNPs identified were A742G (10/52 [19.2%]), GG960-961TT/C (7/52 [13.5%]), and C1435T (28/52 [53.8%]) (M. genitalium numbering). None were associated with a change in organism load (P = 0.76, 0.16, and 0.98, respectively). Using pooled published data from 28 isolates, no clear relationship between the SNPs and doxycycline MIC was identified. In conclusion, the low efficacy of doxycycline against M. genitalium does not appear to be due to variation in the 16S rRNA gene.

2021 European guideline on the management of Mycoplasma genitalium infections

Mycoplasma genitalium infection contributes to 10-35% of non-chlamydial non-gonococcal urethritis in men. In women, M. genitalium is associated with cervicitis and pelvic inflammatory disease (PID) in 10-25%. Transmission of M. genitalium occurs through direct mucosal contact.

CLINICAL FEATURES AND DIAGNOSTIC TESTS

Asymptomatic infections are frequent. In men, urethritis, dysuria and discharge predominate. In women, symptoms include vaginal discharge, dysuria or symptoms of PID - abdominal pain and dyspareunia. Symptoms are the main indication for diagnostic testing. Diagnosis is achievable only through nucleic acid amplification testing and must include investigation for macrolide resistance mutations.

THERAPY

Therapy for M .genitalium is indicated if M. genitalium is detected. Doxycycline has a cure rate of 30-40%, but resistance is not increasing. Azithromycin has a cure rate of 85-95% in macrolide-susceptible infections. An extended course of azithromycin appears to have a higher cure rate, and pre-treatment with doxycycline may decrease organism load and the risk of macrolide resistance selection. Moxifloxacin can be used as second-line therapy but resistance is increasing.

RECOMMENDED TREATMENT

Uncomplicated M. genitalium infection without macrolide resistance mutations or resistance testing: Azithromycin 500 mg on day one, then 250 mg on days 2-5 (oral). Second-line treatment and treatment for uncomplicated macrolide-resistant M. genitalium infection: Moxifloxacin 400 mg od for 7 days (oral). Third-line treatment for persistent M. genitalium infection after azithromycin and moxifloxacin: Doxycycline or minocycline 100 mg bid for 14 days (oral) may cure 40-70%. Pristinamycin 1 g qid for 10 days (oral) has a cure rate of around 75%. Complicated M. genitalium infection (PID, epididymitis): Moxifloxacin 400 mg od for 14 days. MAIN CHANGES FROM THE 2016 EUROPEAN M.

GENITALIUM GUIDELINE

Due to increasing antimicrobial resistance and warnings against moxifloxacin use, indications for testing and treatment have been narrowed to primarily involve symptomatic patients. The importance of macrolide resistance-guided therapy is emphasised.

Combination therapy for Mycoplasma genitalium, and new insights into the utility of parC mutant detection to improve cure

BACKGROUND

Mycoplasma genitalium (MG) infection is challenging to cure due to rising antimicrobial resistance and limited treatment options.

METHODS

This was a prospective evaluation of the efficacy and tolerability of resistance-guided combination antimicrobial therapy for MG-treatment at Melbourne Sexual Health Centre (August 2019-December 2020). All patients received 7-days doxycycline prior to combination therapy based on the macrolide-resistant profile. Macrolide-susceptible infections received combination doxycycline+azithromycin (1g day-1, 500mg days-2-4) and macrolide-resistant infections combination doxycycline+moxifloxacin (400mg daily 7-days). Adherence and adverse effects were recorded at test-of-cure, recommended 14-28-days after antimicrobial completion. Sequencing was performed to determine the prevalence of single nucleotide polymorphisms (SNPs) in the parC gene and their association with moxifloxacin-treatment outcomes in macrolide-resistant infections.

RESULTS

Of 100 patients with macrolide-susceptible MG treated with doxycycline+azithromycin, 93 were cured (93.0%; 95%CI:86.1%-97.1%). Of 247 patients with macrolide-resistant MG receiving doxycycline+moxifloxacin, 210 were cured (85.0%; 95%CI:80.0%-89.2%). parC sequencing was available for 164 (66%) macrolide-resistant infections; 29% had SNPs at parC S83 or D87 (23% S83I). The absence of SNPs at parC S83/D87 was associated with 98.3% cure (95%CI:93.9-99.8%) following doxycycline+moxifloxacin. The presence of the parC S83I-SNP was associated with failure in 62.5% (95%CI:45.8-77.3%). Side-effects were common (40-46%) and predominantly mild and gastrointestinal.

CONCLUSION

Combination doxycycline+azithromycin achieved high cure for macrolide-susceptible infections. However, in the context of a high prevalence of the parC S83I mutation (23%) in macrolide-resistant infections, doxycycline+moxifloxacin cured only 85%Infections that were wildtype for S83/D87 experienced high cure following doxycycline+moxifloxacin, supporting the use of a parC-resistance/susceptibility testing strategy in clinical care.

Evaluation of treatment with two weeks of doxycycline on macrolide-resistant strains of Mycoplasma genitalium: a retrospective observational study

BACKGROUND

Increasing macrolide resistance makes treatment of Mycoplasma genitalium infections challenging. The second-line treatment is moxifloxacin, an antibiotic drug best avoided due to the potential of severe side effects and interactions. This study evaluates the effects of treatment with doxycycline 100 mg twice daily for 2 weeks as an alternative to moxifloxacin.

METHODS

This retrospective observational study examined the medical records of patients testing positive for macrolide resistant Mycoplasma genitalium from January 1st, 2016 to September 1st, 2019 in Trondheim, Norway. Information regarding symptoms as well as clinical and microbiological cure was collected.

RESULTS

263 infections from 259 patients (161 females/98 males) were examined. 155 (58.9%) had a negative test of cure following treatment. 34.7% of symptomatic patients not achieving microbiological cure experienced symptom relief or clearance. There was no statistical difference between bacterial loads in symptomatic versus asymptomatic patients. The mean difference was 1.6 × 105 copies/ml (95% CI - 1.4 × 105-4.8 × 105, p = 0.30) for women and 1.4 × 106 copies/ml (95% CI -4.0 × 105-3.2 × 106, p = 0.12) for men.

CONCLUSIONS

The cure rate of doxycycline in this study is higher than previously reported. This adds support to doxycycline's role in treatment before initiating treatment with less favorable drugs such as moxifloxacin.

Initial Failure of Pristinamycin Treatment in a Case of Multidrug-Resistant Mycoplasma genitalium Urethritis Eventually Treated by Sequential Therapy

ABSTRACT

We present a case of persistent Mycoplasma genitalium urethritis with documented macrolide and fluoroquinolone resistance, and we describe the A2062T mutation in the 23S rRNA gene, possibly associated with pristinamycin resistance. After several treatment failures and loss of the A2062T mutation, M. genitalium urethritis was finally cured by a sequential antibiotic treatment including minocycline.

Testing as Prevention of Resistance in Bacteria Causing Sexually Transmitted Infections-A Population-Based Model for Germany

Prescribed antibiotic treatments which do not match the therapeutic requirements of potentially co-existing undetected sexually transmitted infections (STIs) can facilitate the selection of antibiotic-drug-resistant clones. To reduce this risk, this modelling assessed the potential applicability of reliable rapid molecular test assays targeting bacterial STI prior to the prescription of antibiotic drugs. The modelling was based on the prevalence of three bacterial STIs in German heterosexual and men-having-sex-with-men (MSM) populations, as well as on reported test characteristics of respective assays. In the case of the application of rapid molecular STI assays for screening, the numbers needed to test in order to correctly identify any of the included bacterial STIs ranged from 103 to 104 for the heterosexual population and from 5 to 14 for the MSM population. The number needed to harm—defined as getting a false negative result for any of the STIs and a false positive signal for another one, potentially leading to an even more inappropriate adaptation of antibiotic therapy than without any STI screening—was at least 208,995 for the heterosexuals and 16,977 for the MSM. Therefore, the screening approach may indeed be suitable to avoid unnecessary selective pressure on bacterial causes of sexually transmitted infections.

High prevalence of circulating dual-class resistant Mycoplasma genitalium in asymptomatic MSM in Tokyo, Japan

Objectives

To assess the prevalence and antibiotic resistance profile of Mycoplasma genitalium detected from urogenital/rectal swab samples obtained from MSM in Tokyo, Japan.

Methods

We performed PCR-based screening for M. genitalium urogenital/rectal infection in 982 asymptomatic MSM between 1 January 2019 and 5 November 2020. Mutations in the antibiotic resistance-associated genes gyrA and parC and the 23S rRNA of M. genitalium were analysed.

Results

The prevalence of M. genitalium infection was 6.1%: the prevalence of rectal and urogenital infection was 4.7% and 1.4%, respectively. Among the cases, 48 were successfully analysed for 23S rRNA, 41 for parC mutations and 37 for gyrA mutations. Macrolide- and quinolone-resistance associated mutations (23S rRNA and parC mutations) were observed in 43 (89.6%) and 28 (68.3%) cases, respectively. The quinolone-resistance associated mutation-harbouring variants also harboured macrolide-resistance associated mutations. The S83I mutation in the parC gene was most commonly identified (24 cases, 58.5%), and its combination with M95I or D99N mutation in the gyrA gene was observed in 9 of 36 successfully analysed cases (25.0%). No significant association was observed between the presence of antibiotic resistance and antibiotic exposure for either macrolides or fluoroquinolones (P = 0.785 and 0.402, respectively).

Conclusions

In Tokyo, there is an alarmingly high prevalence of M. genitalium harbouring macrolide and/or quinolone resistance-associated mutations in MSM, irrespective of antibiotic exposure. The high prevalence of M. genitalium strains with both parC and gyrA mutations limits the efficacy of sitafloxacin. Therefore, suitable alternatives are required to treat such M. genitalium infections.

Doxycycline and Sitafloxacin Combination Therapy for Treating Highly Resistant Mycoplasma genitalium

Antimicrobial-resistant Mycoplasma genitalium is becoming increasingly common and creating major treatment challenges. We present early data on combination therapy with doxycycline and sitafloxacin to treat highly resistant M. genitalium. We found the regimen was well tolerated and cured 11/12 infections that had failed prior regimens with moxifloxacin and pristinamycin.

Retrospective analysis of infection and antimicrobial resistance patterns of Mycoplasma genitalium among pregnant women in the southwestern USA

BACKGROUND

Mycoplasma genitalium is a sexually transmitted infection (STI) pathogen. There have been no published studies concerning symptomatology, prevalence data, antibiotic resistance profiling or reports of co-infection with other STI in pregnant women.

OBJECTIVE

To describe these characteristics among pregnant women attending prenatal clinics in a large tertiary care centre.

DESIGN

Remnant genital samples collected from pregnant women between August 2018 and November 2019 were tested for M. genitalium and Trichomonas vaginalis by the transcription-mediated amplification technique. Specimens with detectable M. genitalium RNA were sequenced for 23S rRNA mutations associated with azithromycin resistance and parC and gyrA mutations associated with resistance to moxifloxacin. Demographic, obstetric and STI co-infection data were recorded.

RESULTS

Of the 719 samples, 41 (5.7 %) were positive for M. genitalium. M. genitalium infection was associated with black race, Hispanic ethnicity and young age (p=0.003, p=0.008 and p=0.004, respectively). M. genitalium infection was also associated with T. vaginalis co-infection and Streptococcus agalactiae (group B Streptococcus) colonisation (p≤0.001 and p=0.002, respectively). Of the 41 positive samples, 26 (63.4%) underwent successful sequencing. Eight (30.8%) had 23S rRNA mutations related to azithromycin resistance. One of 26 (3.8%) positive samples with sequencing results had the gyrA gene mutation and 1 of 18 sequenced samples (5.6%) had the parC gene mutation associated with moxifloxacin resistance.

CONCLUSIONS

Prevalence rates of M. genitalium in pregnant women was 5.7%. M. genitalium infection disproportionately affects young black women co-infected with T. vaginalis. Pregnant women remain at risk for persistent infection with M. genitalium due to decreased azithromycin susceptibility.

Resistance-Guided Antimicrobial Therapy Using Doxycycline-Moxifloxacin and Doxycycline-2.5 g Azithromycin for the Treatment of Mycoplasma genitalium Infection: Efficacy and Tolerability

BACKGROUND

Macrolide resistance in Mycoplasma genitalium (MG) exceeds 50% in many regions, and quinolone resistance is increasing. We recently reported that resistance-guided therapy (RGT) using doxycycline followed by sitafloxacin or 2.5 g azithromycin cured 92% and 95% of macrolide-resistant and macrolide-susceptible infections, respectively. We present data on RGT using doxycycline-moxifloxacin, the regimen recommended in international guidelines, and extend data on the efficacy of doxycycline-2.5 g azithromycin and de novo macrolide resistance.

METHODS

Patients attending Melbourne Sexual Health Centre between 2017 and 2018 with sexually transmitted infection syndromes were treated with doxycycline for 7 days and recalled if MG-positive. Macrolide-susceptible cases received 2.5 g azithromycin (1 g, then 500 mg daily for 3 days), and resistant cases moxifloxacin (400 mg daily, 7 days). Test of cure was recommended 14-28 days post-antimicrobials.

RESULTS

There were 383 patients (81 females/106 heterosexual males/196 men who have sex with men) included. Microbial cure following doxycycline-azithromycin was 95.4% (95% confidence interval [CI], 89.7-98.0) and doxycycline-moxifloxacin was 92.0% (95% CI, 88.1-94.6). De novo macrolide resistance was detected in 4.6% of cases. Combining doxycycline-azithromycin data with our prior RGT study (n = 186) yielded a pooled cure of 95.7% (95% CI, 91.6-97.8). ParC mutations were present in 22% of macrolide-resistant cases.

CONCLUSIONS

These findings support the inclusion of moxifloxacin in resistance-guided strategies and extend the evidence for 2.5 g azithromycin and presumptive use of doxycycline. These data provide an evidence base for current UK, Australian, and European guidelines for the treatment of MG.

Resistance-guided treatment of Mycoplasma genitalium infection at a UK sexual health centre

We evaluated the ResistancePlus® MG assay in providing macrolide resistance-guided treatment (RGT) for Mycoplasma genitalium infection at a UK sexual health centre. M. genitalium-positive samples from men with urethritis and women with pelvic inflammatory disease (PID) were tested for macrolide resistance-mediating mutations (MRMMs). MRMM-positive infections were given moxifloxacin 400 mg; otherwise 2 g azithromycin (1 g single dose and then 500 mg OD) was given. Among 57 M. genitalium-positive patients (32 men and 25 women), MRMMs were detected in 41/57 (72% [95% confidence interval (95% CI) 58-83%). Thirty-two of 43 patients given RGT attended for test of cure. Treatment failure rate was significantly lower at 1/32 (3%) than 10/37 (27%) before RGT (n = 37 [men = 23 and women = 17]; p = 0.008). Treatment failure was lower in male urethritis (0/15 vs. 7/21 p = 0.027) but not in female PID. There was a trend of a shorter time to negative test of cure (TOC) in male urethritis (55.1 [95% 43.7-66.4] vs. 85.1 [95% CI CI 64.1-106.0] days, p = 0.077) but not in female PID. Macrolide resistance is higher than previous UK reports and higher than expected. RGT reduces overall treatment failure and is particularly beneficial in M. genitalium urethritis. Fluoroquinolone resistance will continue to rise with increasing fluoroquinolone use, and RGT is critical to direct appropriate azithromycin use and prevent overuse of moxifloxacin.

Pharmacokinetic considerations regarding the treatment of bacterial sexually transmitted infections with azithromycin: a review

Rates of bacterial sexually transmitted infections (STIs) continue to rise, demanding treatments to be highly effective. However, curing infections faces significant challenges due to antimicrobial resistance in Neisseria gonorrhoeae and Mycoplasma genitalium and especially treating STIs at extragenital sites, particularly rectal chlamydia and oropharyngeal gonorrhoea. As no new antimicrobials are entering the market, clinicians must optimize the currently available treatments, but robust data are lacking on how the properties or pharmacokinetics of antimicrobials can be used to inform STI treatment regimens to improve treatment outcomes. This paper provides a detailed overview of the published pharmacokinetics of antimicrobials used to treat STIs and how factors related to the drug (tissue distribution, protein binding and t½), human (pH, inflammation, site of infection, drug side effects and sexual practices) and organism (organism load and antimicrobial resistance) can affect treatment outcomes. As azithromycin is commonly used to treat chlamydia, gonorrhoea and M. genitalium infections, and its pharmacokinetics are well studied, it is the main focus of this review. Suggestions are also provided on possible dosing regimens when using extended and/or higher doses of azithromycin, which appropriately balance efficacy and side effects. The paper also emphasizes the limitations of currently published pharmacokinetic studies including oropharyngeal gonococcal infections, where very limited data exist around ceftriaxone pharmacokinetics and its use in combination with azithromycin. In future, the different anatomical sites of infections may require alternative therapeutic approaches.

In vitro activity of the first-in-class triazaacenaphthylene gepotidacin alone and in combination with doxycycline against drug-resistant and -susceptible Mycoplasma genitalium

Mycoplasma genitalium has developed resistance to first-line azithromycin and second-line moxifloxacin. Third-line pristinamycin is only 75% effective. Gepotidacin, a novel triazaacenaphthylene topoisomerase II inhibitor, blocks bacterial DNA replication. We determined the in vitro activity of gepotidacin alone and in combination with doxycycline against a diverse collection of Mycoplasma genitalium isolates (n = 54).

Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined by a Vero-cell culture method. Macrolide resistance was present in 31 (57%) isolates, fluoroquinolone resistance in 18 (33%) isolates, and 17 (31%) had dual resistance. Synergy testing was performed for gepotidacin and doxycycline by checkerboard analysis for two macrolide- and two dual-resistant isolates.

Gepotidacin was active against all 54 M. genitalium isolates with median and modal MICs of 0.125 mg/L and MIC₉₀ of 0.25 mg/L (range ≤0.016–0.5 mg/L). No difference in gepotidacin MIC between macrolide-resistant and -susceptible isolates (p = 0.24) or between fluoroquinolone-, dual-resistant and -susceptible isolates (p = 0.2) was demonstrated. Gepotidacin MBCs were available for 44 M. genitalium isolates with median MIC of 0.064 mg/L and median MBC of 0.125 mg/L. All isolates had ≤4-fold difference between MIC and MBC, suggesting bactericidal effect for gepotidacin. Checkerboard analysis indicated synergistic effect for gepotidacin in combination with doxycycline [fractional inhibitory concentration index (ΣFICI) of 0.5] for two isolates and additive/indifference (ΣFICI at 0.62 and 0.75) for two isolates.

Gepotidacin warrants further evaluation in clinical treatment trials for M. genitalium. Combination therapy with doxycycline should be clinically studied to assess effect and potential protection against development and/or spread of gepotidacin resistance.

Mycoplasma genitalium Antimicrobial Resistance in Community and Sexual Health Clinic Patients, Auckland, New Zealand

Our retrospective study compared genotypic antimicrobial resistance in Mycoplasma genitalium-positive specimens collected from 48 community and 33 sexual health clinic (SHC) patients. Macrolide resistance was similar in community (75%) and SHC (76%) patients. We observed no significant difference in fluoroquinolone resistance between community (19%) and SHC (27%) patients (p = 0.66).

Mycoplasma genitalium: A Review

Mycoplasma genitalium is a fastidious organism of the class Mollicutes, the smallest prokaryote capable of independent replication. First isolated in 1981, much is still unknown regarding its natural history in untreated infection. It is recognized as a sexually transmitted pathogen causing acute and chronic non-gonococcal urethritis (NGU) in men, with a growing body of evidence to suggest it also causes cervicitis and pelvic inflammatory disease in women. Its role in several other clinical syndromes is uncertain. The majority of people infected remain asymptomatic and clear infection without developing disease; asymptomatic screening is therefore not recommended. Prevalence rates are higher in patients attending sexual health clinics and in men with NGU. Limited availability of diagnostics has encouraged syndromic management, resulting in widespread antimicrobial resistance and given that few antimicrobial classes have activity against M. genitalium, there is significant concern regarding the emergence of untreatable strains. There is a need for wider availability of testing, which should include detection of macrolide resistance mediating mutations. Expertise in interpretation of microbiological results with clinical correlation ensures targeted treatment avoiding unnecessary antibiotic exposure. Public health surveillance nationally and internationally is vital in monitoring and responding to changing epidemiology trends. In this review, we summarize current knowledge of M. genitalium, including epidemiology, clinical and microbiological data, and discuss treatment challenges in the era of rising multidrug resistance.

Recent advances in understanding and combatting Mycoplasma genitalium

Mycoplasma genitalium has emerged over the last 30 years as a sexually transmitted infection (STI). As data have accumulated, our understanding of this pathogen and its role in disease continues to evolve. This in turn creates new challenges and complexities. Questions remain regarding the natural history of M. genitalium, its contribution to disease and long-term sequelae. A decline in cure rates for first-line anti-microbials has been observed. This is likely in part due to high usage of single-dose azithromycin in the sexual health field but also due to the intrinsic ability of M. genitalium to rapidly acquire anti-microbial resistance. Consequently, the term 'the new STI superbug' is not infrequently used by the media to describe this pathogen. Currently available antibiotics have side effects that, though rare, are potentially serious. This leads to inherent questions regarding the benefit of testing for and treating M. genitalium, particularly in asymptomatic individuals or in genital syndromes where the benefit of treatment is not well established. In this review, we summarize the most recent evidence and literature regarding M. genitalium and explore areas of research where disparities exist. We discuss the contribution of M. genitalium to genital syndromes, particularly those where data are conflicting, in order to inform indications for testing and treatment. Avoidance of increasing anti-microbial resistance with astute anti-microbial stewardship is paramount if we are to successfully manage M. genitalium infection. We examine the state of play regarding anti-microbial resistance and how to combat this, including currently available anti-microbials, resistance-guided therapy and novel therapeutic approaches. We aim to provide an overview of the current understanding of M. genitalium and the implications for current clinical practise and suggestions for future research.

A profile of the FDA-approved and CE/IVD-marked Aptima Mycoplasma genitalium assay (Hologic) and key priorities in the management of M. genitalium infections

INTRODUCTION

Mycoplasma genitalium (MG) causes frequently asymptomatic STIs. MG prevalence figures are lacking and management is complicated by the lack of etiological diagnostics and high antimicrobial resistance in many countries. Appropriately validated, quality-assured, and FDA-approved MG diagnostic assays have been lacking.

AREAS COVERED

The clinical and analytical performance characteristics of the Aptima® MG assay, the first FDA-approved MG nucleic acid amplification test (NAAT), are summarized. Key priorities in the management and control of MG infections are also discussed.

EXPERT OPINION

Highly sensitive, specific, and quality-assured MG NAATs, e.g. the Aptima MG assay on the automated and flexible Panther® platform, are imperative to improve the management and control of MG infections internationally. This testing, combined with macrolide-resistance testing (not yet available on the Panther platform), offers a rapid, high-throughput, and appropriate diagnosis of MG. Macrolide resistance-guided sequential treatment needs to be implemented for MG infections. Dual antimicrobial therapy, novel antimicrobials and, ideally, a vaccine may become essential.

A custom amplicon sequencing approach to detect resistance associated mutations and sequence types in Mycoplasma genitalium

BACKGROUND

Mycoplasma genitalium resistance to antibiotic treatments is increasing, with very limited treatment alternatives on the horizon. Surveillance via sequencing of multiple M. genitalium loci would allow: monitoring of known antibiotic resistance mutations, associations between resistance/treatment failure and specific mutations, and strain typing for epidemiological purposes. In this study we assessed the performance of a custom amplicon sequencing approach, which negates the cost of library preparation for next generation sequencing.

METHODS

Fifty-two M. genitalium positive samples (cervical, vaginal, anal and rectal swabs, and urine) were used. Three regions associated with M. genitalium antibiotic resistance (23S rRNA, parC and gyrA genes) were targeted, in conjunction with a locus used for differentiation of sequence types in the mgpB gene, and findings compared to Sanger sequencing.

RESULTS

Amplicon sequencing provided adequate sequence read coverage (>30×) for the majority of samples for 23S rRNA gene (96%) and mgpB (97%), parC (78%) and gyrA (75%). Single nucleotide polymorphisms (SNPs) were characterised in samples for 23S rRNA gene (94%), parC (56%) and gyrA (4%). Unlike Sanger sequencing, mixed mutations could be identified by the amplicon sequencing method, and ratios of mutation types determined. All results, with one exception, were concordant to Sanger sequence results. Sequence diversity in the mgpB region was represented by 15 sequence types, 4 being observed in multiple samples.

CONCLUSIONS

We have demonstrated the utility of this custom amplicon sequencing approach for generating highly informative datasets with the capacity to identify and determine ratios of mixed sequences. The use of this customisable amplicon sequencing method enables cost effective, scalable amplicon sequencing of multiple target regions of interest in M. genitalium.

Nonquinolone Options for the Treatment of Mycoplasma genitalium in the Era of Increased Resistance

In the era of increasing macrolide- and quinolone-resistant Mycoplasma genitalium (MG), we report the efficacy of 2 nonquinolone antimicrobials in patients with limited treatment options. Pristinamycin + doxycycline cured 75% (95% CI, 64%–85%), and minocycline cured 71% (95% CI, 54%–85%) of cases. These data provide useful estimates to inform clinical practice.

Optimising treatments for sexually transmitted infections: surveillance, pharmacokinetics and pharmacodynamics, therapeutic strategies, and molecular resistance prediction

Progressive antimicrobial resistance in Neisseria gonorrhoeae, Mycoplasma genitalium, and Trichomonas vaginalis has created a pressing need for treatment optimisations for sexually transmitted infections (STIs). In this Review, we aim to highlight urgent needs in global STI management, including: (1) improved surveillance to monitor antimicrobial resistance and clinical outcomes; (2) systematic pharmacokinetic and pharmacodynamic evaluations to ensure resistance suppression and bacterial eradication at all sites of infection; (3) development of novel, affordable antimicrobials; and (4) advancements in new molecular and point-of-care tests to detect antimicrobial resistance determinants. Antimicrobial resistance among STIs is a global public health crisis. Continuous efforts to develop novel antimicrobials will be essential, in addition to other public health interventions to reduce the global STI burden. Apart from prevention through safer sexual practices, the development of STI vaccines to prevent transmission is a crucial research priority.

Prevalence of mutations associated with resistance to macrolides and fluoroquinolones in Mycoplasma genitalium: a systematic review and meta-analysis

BACKGROUND

Mycoplasma genitalium is now recognised as an important bacterial sexually transmitted infection. We summarised data from studies of mutations associated with macrolide and fluoroquinolone resistance in M genitalium to establish the prevalence of resistance. We also investigated temporal trends in resistance and aimed to establish the association between resistance and geographical location.

METHODS

In this systematic review and meta-analysis, we searched PubMed, Embase, and MEDLINE for studies that included data for the prevalence of mutations associated with macrolide and fluoroquinolone resistance in M genitalium published in any language up to Jan 7, 2019. We defined prevalence as the proportion of M genitalium samples positive for key mutations associated with azithromycin resistance (23S rRNA gene, position 2058 or 2059) or moxifloxacin resistance (S83R, S83I, D87N, or D87Y in parC), or both, among all M genitalium samples that were successfully characterised. We used random-effects meta-analyses to calculate summary estimates of prevalence. Subgroup and meta-regression analyses by WHO region and time period were done. This study was registered with PROSPERO, number CRD42016050370.

RESULTS

Overall, 59 studies from 21 countries met the inclusion criteria for our study: 57 studies of macrolide resistance (8966 samples), 25 of fluoroquinolone resistance (4003 samples), and 22 of dual resistance to macrolides and fluoroquinolones (3280 samples). The summary prevalence of mutations associated with macrolide resistance among M genitalium samples was 35·5% (95% CI 28·8-42·5); prevalence increased from 10·0% (95% CI 2·6-20·1%) before 2010, to 51·4% (40·3-62·4%) in 2016-17 (p<0·0001). Prevalence of mutations associated with macrolide resistance was significantly greater in samples in the WHO Western Pacific and Americas regions than in those from the WHO European region. The overall prevalence of mutations associated with fluoroquinolone resistance in M genitalium samples was 7·7% (95% CI 4·5-11·4%). Prevalence did not change significantly over time, but was significantly higher in the Western Pacific region than in the European region. Overall, the prevalence of both mutations associated with macrolide resistance and those associated with fluoroquinolone resistance among M genitalium samples was 2·8% (1·3-4·7%). The prevalence of dual resistance did not change significantly over time, and did not vary significantly by geographical region.

INTERPRETATION

Global surveillance and measures to optimise the efficacy of treatments-including resistance-guided strategies, new antimicrobials, and antimicrobial combination approaches-are urgently needed to ensure cure in a high proportion of M genitalium infections and to prevent further spread of resistant strains.

FUNDING

Australian National Health and Medical Research Council.

Outcomes of Resistance-guided Sequential Treatment of Mycoplasma genitalium Infections: A Prospective Evaluation

Background

Rising macrolide and quinolone resistance in Mycoplasma genitalium necessitate new treatment approaches. We evaluated outcomes of sequential antimicrobial therapy for M. genitalium guided by a macrolide-resistance assay.

Methods

In mid-2016, Melbourne Sexual Health Centre switched from azithromycin to doxycycline (100 mg twice daily for 7 days) for nongonococcal urethritis, cervicitis, and proctitis. Cases were tested for M. genitalium and macrolide-resistance mutations (MRMs) by polymerase chain reaction. Directly after doxycycline, MRM-negative infections received 2.5 g azithromycin (1 g, then 500 mg daily for 3 days), and MRM-positive infections received sitafloxacin (100 mg twice daily for 7 days). Assessment of test of cure and reinfection risk occurred 14-90 days after the second antibiotic.

Results

Of 244 evaluable M. genitalium infections (52 women, 68 heterosexual men, 124 men who have sex with men) diagnosed from 20 June 2016 to 15 May 2017, MRMs were detected in 167 (68.4% [95% confidence interval {CI}, 62.2%-74.2%]). Treatment with doxycycline decreased bacterial load by a mean 2.60 log10 (n = 56; P < .0001). Microbiologic cure occurred in 73 of 77 MRM-negative infections (94.8% [95% CI, 87.2%-98.6%]) and in 154 of 167 MRM-positive infections (92.2% [95% CI, 87.1%-95.8%]). Selection of macrolide resistance occurred in only 2 of 76 (2.6% [95% CI, .3%-9.2%]) macrolide-susceptible infections.

Conclusions

In the context of high levels of antimicrobial resistance, switching from azithromycin to doxycycline for presumptive treatment of M. genitalium, followed by resistance-guided therapy, cured ≥92% of infections, with infrequent selection of macrolide resistance.

Long-term trends of Chlamydia trachomatis in a clinic population at the Royal Women's Hospital, Melbourne

BACKGROUND

Chlamydia trachomatis (C. trachomatis) prevalence has been reported to be increasing. Whether this is a true increase over time or confounded by increases in testing and/or use of more sensitive assays is to be determined.

MATERIALS AND METHODS

One laboratory service has been detecting C. trachomatis for the past 30 years within the Royal Women's Hospital Melbourne. We conducted a retrospective audit of records over the period 1986-2016 from a clinic population routinely offered chlamydia screening. These were women presenting for family planning advice (termination of pregnancy, intrauterine device insertion or considered at high risk), who underwent chlamydia testing in the context of various diagnostic assays used over this time period. Assays utilised included culture, enzyme immunoassay (EIA), DNA probe, and nucleic acid amplification testing (NAAT). Non-parametric test for trend was used to determine significant differences between prevalence estimates across ordered groups. Least squares regression was conducted to describe a linear trend matching known data points.

RESULTS

Overall, there was no significant change for chlamydia prevalence which was 2.2%, in the 30-year study period (P = 0.7). Over time diagnostic assays changed from culture, to EIA, DNA probe, to the more sensitive NAAT. The bulk of the positives were in women under 25 years of age (57%).

CONCLUSION

Chlamydia prevalence has been stable over 30 years, remaining a problem in young women. Screening for those at risk needs underscoring in a national sexual health program.

Symptoms, Sites, and Significance of Mycoplasma genitalium in Men Who Have Sex with Men

During 2016-2017, we tested asymptomatic men who have sex with men (MSM) in Melbourne, Australia, for Mycoplasma genitalium and macrolide resistance mutations in urine and anorectal swab specimens by using PCR. We compared M. genitalium detection rates for those asymptomatic men to those for MSM with proctitis and nongonococcal urethritis (NGU) over the same period. Of 1,001 asymptomatic MSM, 95 had M. genitalium; 84.2% were macrolide resistant, and 17% were co-infected with Neisseria gonorrhoeae or Chlamydia trachomatis. Rectal positivity for M. genitalium was 7.0% and urine positivity was 2.7%. M. genitalium was not more commonly detected in the rectums of MSM (n = 355, 5.6%) with symptoms of proctitis over the same period but was more commonly detected in MSM (n = 1,019, 8.1%) with NGU. M. genitalium is common and predominantly macrolide-resistant in asymptomatic MSM. M. genitalium is not associated with proctitis in this population.

British Association for Sexual Health and HIV national guideline for the management of infection with Mycoplasma genitalium (2018)

This is the first British Association for Sexual Health and HIV (BASHH) guideline for the diagnosis and management of Mycoplasma genitalium in people aged 16 years and older. The guideline is primarily aimed at level 3 sexually transmitted infection (STI) management services within the UK, although it could also serve as a reference guide for STI services at other levels.

The impact of sample storage on molecular-based detection of Mycoplasma genitalium

AIMS

Mycoplasma genitalium causes a common, sexually transmitted bacterial infection. This study assessed the detection of M. genitalium in stored urine samples to understand the impact of sample storage on M. genitalium detection.

METHODS

Aliquots of M. genitalium-positive urine (n = 20 patients) were stored at either room temperature (22°C) or 4°C, without a preservative. At weekly intervals, samples were tested using the commercial test ResistancePlus MG^® (SpeeDx^® , Australia). We report the analysis at 1 week, an acceptable collection-to-test turnaround time, with further analysis over 5 weeks to illustrate degradation trends.

RESULTS

After storing at 4°C, the proportion of specimens that remained positive for M. genitalium was 100% after 1 week and 95% after 4 weeks. Storage at 22°C led to more rapid decline in detection in the first 4 weeks, with 95% detected after 1 week and 85% at 2 weeks onwards. At 5 weeks, samples stored at both temperatures had an 85% M. genitalium detection rate, with increase in crossing points (Cq) of 0·72 (95% confidence interval (CI) 0·01-1·43; P-trend = 0·027) at 4°C, and 1·75 ((95% CI 0·79-2·71), P-trend <0·001) at 22°C.

CONCLUSIONS

Urine samples stored without preservative, and unfrozen, retained high M. genitalium detection levels over the short term (up to 5 weeks). To minimize degradation, storing at 4°C is recommended.

SIGNIFICANCE AND IMPACT OF THE STUDY

There is little known about the stability of clinical samples for M. genitalium detection. This study found that a high proportion (85-100%) of samples are still suitable for M. genitalium detection after storage for up to 5 weeks.

Looking at the positives: proactive management of STIs in people with HIV

Patients who are HIV-positive and co-infected with other sexually transmitted infections (STIs) are at risk of increased morbidity and mortality. This is of clinical significance. There has been a dramatic increase in the incidence of STIs, particularly syphilis, gonorrhoea, Mycoplasma genitalium and hepatitis C virus (HCV) in HIV-positive patients. The reasons for this are multifactorial, but contributing factors may include effective treatment for HIV, increased STI testing, use of HIV pre-exposure prophylaxis and use of social media to meet sexual partners. The rate of syphilis-HIV co-infection is increasing, with a corresponding increase in its incidence in the wider community. HIV-positive patients infected with syphilis are more likely to have neurological invasion, causing syndromes of neurosyphilis and ocular syphilis. HIV infection accelerates HCV disease progression in co-infected patients, and liver disease is a leading cause of non-AIDS-related mortality among patients who are HIV-positive. Since several direct-acting antivirals have become subsidised in Australia, there has been an increase in treatment uptake and a decrease in HCV viraemia in HIV-positive patients. The incidence of other sexually transmitted bacterial infections such as Neisseria gonorrhoeae and M. genitalium is increasing in HIV patients, causing urethritis, proctitis and other syndromes. Increasing antimicrobial resistance has also become a major concern, making treatment of these infections challenging. Increased appropriate testing and vigilant management of these STIs with data acquisition on antimicrobial sensitivities and antimicrobial stewardship are essential to prevent ongoing epidemics and emergence of resistance. Although efforts to prevent, treat and reduce epidemics of STIs in patients living with HIV are underway, further advances are needed to reduce the significant morbidity associated with co-infection in this patient setting.

Surveillance of the prevalence of macrolide and/or fluoroquinolone resistance-associated mutations in Mycoplasma genitalium in Japan

To clarify the status of macrolide and fluoroquinolone resistance of clinical strains of Mycoplasma genitalium in Japan, we amplified portions of the gyrA, parC, and 23S rRNA genes from DNAs in 627 first-voided urine specimens collected from men with M. genitalium-positive urethritis who visited clinics mainly in Sendai, Tokyo, and Osaka, Japan, from 2013 to 2017, by PCR and sequenced. The incidence of single amino acid changes at Met95 or Asp99 in GyrA increased chronologically and was approximately 10% from 2015 onward. The incidence of amino acid changes at Ser83 or Asp87 in ParC was approximately 50% in 2013 but increased to 60-70% from 2014 to 2017. The incidence of mutations at A2071 or A2072 in the 23S rRNA gene increased chronologically and reached over 70% in 2017. The prevalence of M. genitalium harboring alterations in ParC and mutations in the 23S rRNA gene increased and was approximately 50% in 2016 and 2017. The prevalence of M. genitalium with alterations in both GyrA and ParC and mutations in the 23S rRNA gene, which could be associated with treatment failures with the sitafloxacin and azithromycin regimens, were approximately 15% and 10% in 2016 and 2017, respectively. The prevalence of M. genitalium with genetic alterations associated with resistance to fluoroquinolones and/or macrolides is increasing rapidly in Japan. We must prevent the further selection of multi-drug-resistant M. genitalium so that M. genitalium infections will not become untreatable.