Treatment of mild-to-moderate pelvic inflammatory disease with a short-course azithromycin-based regimen versus ofloxacin plus metronidazole: results of a multicentre, randomised controlled trial.

OBJECTIVE: A multicentre, randomised non-inferiority trial compared the efficacy and safety of 14 days of ofloxacin and metronidazole (standard-of-care (SoC)) versus a single dose of intramuscular ceftriaxone followed by 5 days of azithromycin and metronidazole (intervention arm (IA)) in women with mild-to-moderate pelvic inflammatory disease (PID). METHODS: Women with a clinical diagnosis of PID presenting at sexual health services were randomised to the SoC or IA arms. Treating clinicians and participants were not blinded to treatment allocation but the clinician performing the assessment of primary outcome was blinded. The primary outcome was clinical cure defined as ≥70% reduction in the modified McCormack pain score at day 14-21 after starting treatment. Secondary outcomes included adherence, tolerability and microbiological cure. RESULTS: Of the randomised population 72/153 (47.1%) reached the primary end point in the SoC arm, compared with 68/160 (42.5%) in the IA (difference in cure 4.6% (95% CI -15.6% to 6.5%). Following exclusion of 86 women who were lost to follow-up, attended outside the day 14-21 follow-up period, or withdrew consent, 72/107 (67.3%) had clinical cure in the SoC arm compared with 68/120 (56.7%) in the IA, giving a difference in cure rate of 10.6% (95% CI -23.2% to 1.9%). We were unable to demonstrate non-inferiority of the IA compared with SoC arm. Women in the IA took more treatment doses compared with the SoC group (113/124 (91%) vs 75/117 (64%), p=0.0001), but were more likely to experience diarrhoea (61% vs 24%, p<0.0001). Of 288 samples available for analysis, Mycoplasma genitalium was identified in 10% (28/288), 58% (11/19) of which had baseline antimicrobial resistance-associated mutations. CONCLUSION: A short-course azithromycin-based regimen is likely to be less effective than the standard treatment with ofloxacin plus metronidazole. The high rate of baseline antimicrobial resistance supports resistance testing in those with M. genitalium infection to guide appropriate therapy. TRIAL REGISTRATION NUMBER: 2010-023254-36.

Mycoplasma genitalium Protein of Adhesion Induces Inflammatory Cytokines via Cyclophilin A-CD147 Activating the ERK-NF-κB Pathway in Human Urothelial Cells.

Mycoplasma genitalium protein of adhesion (MgPa) plays an important role in the process of adhesion and invasion of host cells by M. genitalium, and is thus significant for its pathogenic mechanisms in host cells. Our previous study has demonstrated that cyclophilin A (CypA) is the receptor for MgPa in human urothelial cells (SV-HUC-1) and can, therefore, mediate the adherence and invasion of M. genitalium into host cells by interacting with MgPa. However, the specific pathogenesis of M. genitalium to host cells and the possible pathogenic mechanism involved in the interaction of MgPa and CypA have never been clarified. The study aimed to elucidate the mechanism involved in the pathogenicity of MgPa. Recombinant MgPa (rMgPa) induced extracellular CypA (eCypA) was detected in SV-HUC-1 cells by ELISA, and the interaction between CypA and CD147 was validated using co-localization and co-immunoprecipitation assay. In addition, both extracellular signal-regulated kinases (ERK) phosphorylation and NF-κB activation evoked by rMgPa-induced eCypA were also demonstrated. The findings of this study verified that rMgPa could induce the secretion of eCypA in SV-HUC-1 cells and thus promote the protein and mRNA expression of IL-1ß, IL-6, TNF-α and MMP-9 via CypA-CD147 interaction and thus activating ERK-NF-κB pathway, which is beneficial to elucidate the pathogenesis and possible pathogenic mechanism of M. genitalium to host cells.

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.

Prevalence of Mycoplasma genitalium by anatomical site in men who have sex with men: a systematic review and meta-analysis.

OBJECTIVE: To systematically review and appraise published data, to determine the prevalence of Mycoplasma genitalium (MG) in men who have sex with men (MSM) tested at each anatomical site, that is, at the urethra, rectum and/or pharynx. DESIGN: Systematic review and meta-analysis. DATA SOURCES: Ovid Medline, PubMed, Embase were searched for articles from 1st January 1981 (the year MG was first identified) to 1st June 2018. REVIEW METHODS: Studies were eligible for inclusion if they reported MG prevalence in MSM tested at the urethra, rectum and/or pharynx, in at least 50 MSM, using nucleic acid amplification testing. Data were extracted by anatomical site, symptom and HIV status. Summary estimates (95% CIs) were calculated using random-effects meta-analysis. Subgroup analyses were performed to assess heterogeneity between studies. RESULTS: Forty-six studies met inclusion criteria, with 34 reporting estimates of MG prevalence at the urethra (13 753 samples), 25 at the rectum (8629 samples) and 7 at the pharynx (1871 samples). MG prevalence was 5.0% (95% CI 3.5 to 6.8; I2=94.0) at the urethra; 6.2% (95% CI 4.6 to 8.1; I2=88.1) at the rectum and 1.0% (95% CI 0.0 to 5.1; I2=96.0) at the pharynx. The prevalence of MG was significantly higher at urethral and rectal sites in symptomatic versus asymptomatic MSM (7.1% vs 2.2%, p<0.001; and 16.1% vs 7.5%, p=0.039, respectively). MG prevalence at the urethra was significantly higher in HIV-positive compared with HIV-negative MSM (7.0% vs 3.4%, p=0.006). CONCLUSION: MG was common in MSM, particularly at urethral and rectal sites (5% to 6%). MG was more commonly detected in symptomatic men at both sites, and more common in HIV-positive men at the urethra. MG was uncommonly detected in the pharynx. Site-specific estimates are similar to those for chlamydia and will be helpful in informing testing practices in MSM. PROSPERO REGISTRATION NUMBER: CRD42017058326.

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.

High prevalence of Mycoplasma genitalium infection and macrolide resistance in patients enrolled in HIV pre-exposure prophylaxis program.

OBJECTIVES: Limited data on Mycoplasma genitalium infection has been reported among PrEP users. The aim of this study was to estimate the prevalence and macrolide resistance of M. genitalium infection among enrollees in a French PrEP program. PATIENTS AND METHODS: M. genitalium infection screening was systematically and prospectively proposed to patients of the Bordeaux PrEP program (between January 2016 and February 2017). Macrolide resistance was evaluated in M. genitalium-positive patients. RESULTS: Among 89 clients, M. genitalium infection prevalence was 10% (mainly asymptomatic) with a high rate of macrolide resistance (58%). CONCLUSIONS: Because of a high level of macrolide resistance, a systematic search for M. genitalium macrolide resistance associated-mutations may be recommended in PrEP users before initiating the antibiotic therapy.

Mycoplasma genitalium adhesin P110 binds sialic-acid human receptors.

Adhesion of pathogenic bacteria to target cells is a prerequisite for colonization and further infection. The main adhesins of the emerging sexually transmitted pathogen Mycoplasma genitalium, P140 and P110, interact to form a Nap complex anchored to the cell membrane. Herein, we present the crystal structures of the extracellular region of the virulence factor P110 (916 residues) unliganded and in complex with sialic acid oligosaccharides. P110 interacts only with the neuraminic acid moiety of the oligosaccharides and experiments with human cells demonstrate that these interactions are essential for mycoplasma cytadherence. Additionally, structural information provides a deep insight of the P110 antigenic regions undergoing programmed variation to evade the host immune response. These results enlighten the interplay of M. genitalium with human target cells, offering new strategies to control mycoplasma infections.

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.

Establishment of Multiplex Loop-Mediated Isothermal Amplification for Rapid Detection of Genitourinary Mycoplasma.

BACKGROUND: Genitourinary Mycoplasma (Ureaplasma urealyticum, Mycoplasma hominis, and Mycoplasma genitalium) is a common pathogen among women, which can cause funisitis, spontaneous abortion, and low birth weight. However, current laboratory testing methods for genitourinary mycoplasma normally need complex processes, expensive devices, and qualified staffs, and there are many limits for application. Up to now, the LAMP method is a rapidly developing field because of the significance for clinical application and commercial value. Few studies have reported the use of mLAMP to detect UU, MH, and MG. In this study, a multiplex loop-mediated isothermal amplification system was developed for rapid detection of UU, MH, and MG, concurrently. METHODS: Three sets of multiplex LAMP primers were designed to specifically target urease of UU, 16S rRNA of MH, and mgpa of MG. The ratio of primer concentration was optimized. The specificity and sensitivity of multiplex LAMP were explored. Twenty-nine clinical samples were successfully used with mLAMP. RESULTS: In this study, the primer concentration in the mLAMP system was set to 1.3 µmol/L which could maintain reaction efficiency and avoid non-specific reaction. Multiplex LAMP can test UU, MG, and MH simultaneously with high specificity. Meanwhile, the sensitivity of multiplex LAMP was found to be 100 pg for UU, 100 pg for MH and 1 ng for MG, which was much higher than that of conventional PCR. Furthermore, among the 29 clinical samples, there were two positive samples determined by mLAMP, which was consistent with the PCR and sequencing results. CONCLUSIONS: The multiplex LAMP assay can potentially facilitate simultaneous detection of three kinds of mycoplasma in a large number of samples in clinic, which could be used as a primary screening method and as a supplementary method for classical methods.

Cyclophilin A is the potential receptor of the Mycoplasma genitalium adhesion protein.

The Mycoplasma genitalium adhesion protein (MgPa), the most important outer membrane protein of M. genitalium, plays a vital role in the adhesion to and invasion of host cells by M. genitalium. Identification of MgPa receptors will help elucidate the pathogenic mechanism of M. genitalium. However, the receptor protein of MgPa has not been reported to date. In this study, an MgPa-binding protein with a molecular weight of approximately 17 kDa was screened from SV-HUC-1 cell membrane proteins by a modified virus overlay protein binding assay (VOPBA). Liquid chromatography-mass spectrometry (LC-MS) was used to analyze the protein components of the 17-kDa protein. The results demonstrated that the MgPa-binding protein was most likely Cyclophilin A (CyPA). The binding activity and distribution of CyPA in SV-HUC-1 cells were detected using indirect ELISA, western blotting, far-western blotting and indirect immunofluorescence. We found that recombinant MgPa (rMgPa) could bind with CyPA from SV-HUC-1 cell membrane proteins and to recombinant CyPA, which indicated that CyPA was predominant component of the 17-kDa protein band and can interact with rMgPa. In addition, an indirect immunofluorescence assay showed that CyPA was partially distributed on the membrane surfaces of SV-HUC-1 cells and could partially inhibit the adhesion of rMgPa and M. genitalium to SV-HUC-1 cells. Co-localization assays further indicated that rMgPa and M. genitalium can interact with CyPA. These results suggested that the CyPA located on SV-HUC-1 cell membranes may be the potential receptor of MgPa, which could provide an experimental basis for elucidating the function of MgPa and the possible pathogenic mechanism of M. genitalium.

Cryo-electron tomography analyses of terminal organelle mutants suggest the motility mechanism of Mycoplasma genitalium.

The terminal organelle of Mycoplasma genitalium is responsible for bacterial adhesion, motility and pathogenicity. Localized at the cell tip, it comprises an electron-dense core that is anchored to the cell membrane at its distal end and to the cytoplasm at its proximal end. The surface of the terminal organelle is also covered with adhesion proteins. We performed cellular cryoelectron tomography on deletion mutants of eleven proteins that are implicated in building the terminal organelle, to systematically analyze the ultrastructural effects. These data were correlated with microcinematographies, from which the motility patterns can be quantitatively assessed. We visualized diverse phenotypes, ranging from mild to severe cell adhesion, motility and segregation defects. Based on our observations, we propose a double-spring ratchet model for the motility mechanism that explains our current and previous observations. Our model, which expands and integrates the previously suggested inchworm model, allocates specific functions to each of the essential components of this unique bacterial motility system.

Prevalence of Mycoplasma genitalium and other sexually transmitted infections causing urethritis among high-risk heterosexual male patients in Estonia.

BACKGROUND: We aimed to evaluate the prevalence of sexually transmitted infections (STI, including Mycoplasma genitalium, Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis) among high-risk heterosexual male patients and to clarify their potency to cause complaints and inflammation. METHODS: The study group included 825 men (18.0-49.5 y) consulting andrologist at Tartu University Hospital (Estonia) due to subjectively perceived risk of STI. Patients completed STI risk behaviour questionnaire. First voided urine was analysed for white blood cells and STIs. RESULTS: In total 193 (23.4%) patients were positive for one or multiple STI. The prevalence of C. trachomatis, M. genitalium, N. gonorrhoeae, T. vaginalis and combined STI was 14.3%, 4.4%, 2.7%, 0.7% and 1.3%, respectively. N. gonorrhoeae had the highest potency to generate inflammatory reaction in first voided urine (100%) followed by C. trachomatis (72.0%), M. genitalium (63.9%) and T. vaginalis (33.3%). N. gonorrhoeae and T. vaginalis caused the highest mean number of complaints while half of T. vaginalis cases and nearly fifth of M. genitalium and C. trachomatis cases were asymptomatic. CONCLUSIONS: C. trachomatis has the highest prevalence among Estonian high-risk men but M. genitalium holds an important second place. Prevalence of combined STIs is low. N. gonorrhoeae has the highest potency to generate urethral inflammation followed by C. trachomatis and M. genitalium. The highest number of complaints is also associated with N. gonorrhoeae while half of T. vaginalis cases and nearly a fifth of M. genitalium and C. trachomatis cases are asymptomatic.

Antimicrobial-resistant sexually transmitted infections: gonorrhoea and Mycoplasma genitalium.

The emergence of antimicrobial resistance (AMR) is a major concern worldwide and already compromises treatment effectiveness and control of several bacterial sexually transmitted infections (STIs). Neisseria gonorrhoeae and Mycoplasma genitalium are evolving into so-called superbugs that can become resistant, both in vitro and clinically, to essentially all antimicrobials available for treatment, causing exceedingly difficult-to-treat or untreatable STIs and threatening global public health. Widespread AMR in these bacteria is likely to persist and even worsen in the future, owing to the high number of infections, widespread and uncontrolled use of antimicrobials, limited surveillance of AMR and clinical failures, as well as the extraordinary capacity of these bacteria to develop AMR. This development would not only result in an increased prevalence of N. gonorrhoeae and M. genitalium infections but also in a considerably increasing number of severe complications affecting reproductive health. To combat this threat, clinicians need to be aware of the current guidelines on diagnostic procedures, recommended treatment regimens, as well as therapeutic options for multidrug-resistant bacteria. AMR testing needs to be more frequently performed, inform treatment decisions and elucidate how AMRs compromise treatment effectiveness, guiding research for effective future therapies.

A minimized motile machinery for Mycoplasma genitalium.

The cell wall-less bacterium Mycoplasma genitalium uses specialized adhesins located at the terminal organelle to adhere to host cells and surfaces. The terminal organelle is a polar structure protruding from the cell body that is internally supported by a cytoskeleton and also has an important role in cell motility. We have engineered a M. genitalium null mutant for MG491 protein showing a massive downstream destabilization of proteins involved in the terminal organelle organization. This mutant strain exhibited striking similarities with the previously isolated MG_218 null mutant strain. Upon introduction of an extra copy of MG_318 gene in both strains, the amount of main adhesins P140 and P110 dramatically increased. These strains were characterized by microcinematography, epifluorescence microscopy and cryo-electron microcopy, revealing the presence of motile cells and filaments in the absence of many proteins considered essential for cell adhesion and motility. These results indicate that adhesin complexes play a major role in the motile machinery of M. genitalium and demonstrate that the rod element of the cytoskeleton core is not the molecular motor propelling mycoplasma cells. These strains containing a minimized motile machinery also provide a valuable cell model to investigate the adhesion and gliding properties of this human pathogen.

Kinetics of Genetic Variation of the Mycoplasma genitalium MG192 Gene in Experimentally Infected Chimpanzees.

Mycoplasma genitalium, a human pathogen associated with sexually transmitted diseases, is capable of causing chronic infections, though mechanisms for persistence remain unclear. Previous studies have found that variation of the MgPa operon occurs by recombination of repetitive chromosomal sequences (known as MgPars) into the MG191 and MG192 genes carried on this operon, which may lead to antigenic variation and immune evasion. In this study, we determined the kinetics of MG192 sequence variation during the course of experimental infection using archived specimens from two chimpanzees infected with M. genitalium strain G37. The highly variable region of MG192 was amplified by PCR from M. genitalium isolates obtained at various time points postinfection (p.i.). Sequence analysis revealed that MG192 sequence variation began at 5 weeks p.i. With the progression of infection, sequence changes accumulated throughout the MG192 variable region. The presence of MG192 variants at specific time points was confirmed by variant-specific PCR assays and sequence analysis of single-colony cloned M. genitalium organisms. MG192 nucleotide sequence variation correlated with estimated recombination events, predicted amino acid changes, and time of seroconversion, a finding consistent with immune selection of MG192 variants. In addition, we provided evidence that MG192 sequence variation occurred during the process of M. genitalium single-colony cloning. Such spontaneous variation suggests that some MG192 variation is independent of immune selection but may form the basis for subsequent immune selection.

Management of Mycoplasma genitalium infections - can we hit a moving target?

Mycoplasma genitalium is an etiological agent of sexually transmitted infections, but due to its fastidious growth requirements, only a few M. genitalium strains are available for determination of the activity of currently used and new antimicrobial agents.Recent clinical trials have demonstrated that treatment with azithromycin has decreasing efficacy due to an increasing prevalence of macrolide resistance, which is likely to be attributed to the widespread use of 1 g single dose azithromycin. Second line treatment with moxifloxacin is similarly under pressure from emerging resistance. The era of single dose monotherapy for uncomplicated STIs such as M. genitalium and N. gonorrhoeae, while convenient for patients and physicians, has been associated with escalating resistance and treatment failure and is now drawing to a close. There is a critical need for trials of combinations of existing registered drugs and new antimicrobial compounds, implementation of diagnostic testing combined with molecular detection of resistance, and antimicrobial surveillance.

[Mycoplasma genitalium lipid-associated membrane proteins induce endocervical epithelial cells to express ß-defensin-2].

OBJECTIVE: To observe the expression of human ß-defensin-2 (hBD-2) induced by Mycoplasma genitalium-derived lipid-associated membrane proteins (LAMPs) and its potential mechanism. METHODS: Human endocervical epithelial End1/E6E7 cells were cultured in vitro and stimulated by different concentrations of LAMPs for 48 hours, and the expressions of hBD-2 mRNA and protein were detected by real-time RT-PCR and Western blotting, respectively. Toll-like receptor 2 (TLR2) and TLR6 neutralizing antibodies for End1/E6E7 cell cultivation, and dominant negative plasmids for cell transfection were used to analyze the roles of TLR2, TLR6 and MyD88 in mediating hBD-2 expression. Nuclear translocation of the nuclear factor κB (NF-κB) p65 subunit, and its DNA-binding activity were detected by Western blotting and electrophoretic mobility shift assay (EMSA), respectively. Pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-κB, was used to investigate the effect of NF-κB on hBD-2 expression. RESULTS: Mycoplasma genitalium-derived LAMPs induced the expressions of hBD-2 mRNA and protein in End1/E6E7 cells. The expressions could be abrogated by TLR2 and TLR6 neutralizing antibodies, or their dominant negative plasmids. In addition, dominant negative plasmids of MyD88 significantly decreased LAMPs-induced hBD-2 expression. Western blotting showed that p65 was translocated to the nucleus, and the DNA binding activity of NF-κB was enhanced after LAMPs treatment. Furthermore, PDTC treatment decreased LAMPs- induced hBD-2 expression. CONCLUSION: Mycoplasma genitalium-derived LAMPs can induce End1/E6E7 cells to express hBD-2, which may be involved in the TLR2, TLR6/Myd88/NF-κB pathways.

Treatment of Mycoplasma genitalium. Observations from a Swedish STD clinic.

OBJECTIVES: To evaluate therapy for Mycoplasma genitalium infection with doxycycline or azithromycin 1 g compared to five days of azithromycin (total dose 1.5 g). METHODS: A retrospective case study was performed among patients attending the STD-clinic in Falun, Sweden 1998-2005. All patients with a positive PCR test for M. genitalium were routinely offered a test of cure (toc). Response to doxycycline for 9 days, azithromycin 1 g single dose and extended azithromycin (500 mg on day 1 followed by 250 mg o.d. for 4 days) was determined. In patients with treatment failure after azithromycin, macrolide resistance was monitored before and after treatment. Furthermore, the rate of macrolide resistance was monitored for positive specimens available from 2006-2011. RESULTS: The eradication rate after doxycycline was 43% (48% for women and 38% for men), for azithromycin 1 g 91% (96% for women and 88% for men) and for extended azithromycin 99% (100% for women and 93% for men). Macrolide resistance developed in 7/7 examined (100%) of those testing positive after azithromycin 1 g, but in none of those treated with extended azithromycin. Macrolide resistance before treatment increased from 0% in 2006 and 2007 to 18% in 2011. CONCLUSIONS: These findings confirm the results from other studies showing that doxycycline is inefficient in eradicating M. genitalium. Although azithromycin 1 g was not significantly less efficient than extended dosage, it was associated with selection of macrolide resistant M. genitalium strains and should not be used as first line therapy for M. genitalium. Monitoring of M. genitalium macrolide resistance should be encouraged.