Evaluation of the Microbiological Efficacy of a Single 2-Gram Dose of Extended-Release Azithromycin by Population Pharmacokinetics and Simulation in Japanese Patients with Gonococcal Urethritis.

The objective of this study was to analyze the relationship between the pharmacokinetic (PK)/pharmacodynamic (PD) parameters of a single 2-g dose of extended-release formulation of azithromycin (AZM-SR) and its microbiological efficacy against gonococcal urethritis. Fifty male patients with gonococcal urethritis were enrolled in this study. In 36 patients, the plasma AZM concentrations were measured using liquid chromatography-tandem mass spectrometry, the AZM MIC values for the Neisseria gonorrhoeae isolates were determined, and the microbiological outcomes were assessed. AZM-SR monotherapy eradicated N. gonorrhoeae in 30 (83%) of the 36 patients. AZM MICs ranged from 0.03 to 2 mg/liter. The mean value of the area under the concentration-time curve (AUC), estimated by population PK analysis using a two-compartment model, was 20.8 mg · h/liter. Logistic regression analysis showed that the PK/PD target value required to predict an N. gonorrhoeae eradication rate of ≥95% was a calculated AUC/MIC of ≥59.5. The AUC/MIC value was significantly higher in patients who achieved microbiological cure than in patients who achieved microbiological failure. Monte Carlo simulation using this MIC distribution revealed that the probability that AZM-SR monotherapy would produce an AUC/MIC exceeding the AUC/MIC target of 59.5 was 47%. Furthermore, the MIC distribution for strains isolated in this study was mostly consistent with that for strains currently circulating in Japan. In conclusion, in Japan, AZM-SR monotherapy may not be effective against gonococcal urethritis. Therefore, use of a single 2-g dose of AZM-SR either with or without other antibiotics could be an option to treat gonococcal urethritis if patients are allergic to ceftriaxone and spectinomycin or are diagnosed to be infected with an AZM-sensitive strain.

Multidrug-resistant Neisseria gonorrhoeae infection with ceftriaxone resistance and intermediate resistance to azithromycin, Denmark, 2017.

We describe a multidrug-resistant Neisseria gonorrhoeae infection with ceftriaxone resistance and azithromycin intermediate resistance in a heterosexual man in Denmark, 2017. Whole genome sequencing of the strain GK124 identified MSLT ST1903, NG-MAST ST1614 and all relevant resistance determinants including similar penA resistance mutations previously described in ceftriaxone-resistant gonococcal strains. Although treatment with ceftriaxone 0.5 g plus azithromycin 2 g was successful, increased awareness of spread of gonococcal strains threatening the recommended dual therapy is crucial.

Multiplex Assay for Simultaneous Detection of Mycoplasma genitalium and Macrolide Resistance Using PlexZyme and PlexPrime Technology.

Mycoplasma genitalium is a cause of non-gonoccocal urethritis (NGU) in men and cervicitis and pelvic inflammatory disease in women. Recent international data also indicated that the first line treatment, 1 gram stat azithromycin therapy, for M. genitalium is becoming less effective, with the corresponding emergence of macrolide resistant strains. Increasing failure rates of azithromycin for M. genitalium has significant implications for the presumptive treatment of NGU and international clinical treatment guidelines. Assays able to predict macrolide resistance along with detection of M. genitalium will be useful to enable appropriate selection of antimicrobials to which the organism is susceptible and facilitate high levels of rapid cure. One such assay recently developed is the MG 23S assay, which employs novel PlexZyme™ and PlexPrime™ technology. It is a multiplex assay for detection of M. genitalium and 5 mutations associated with macrolide resistance. The assay was evaluated in 400 samples from 254 (186 males and 68 females) consecutively infected participants, undergoing tests of cure. Using the MG 23S assay, 83% (331/440) of samples were positive, with 56% of positives carrying a macrolide resistance mutation. Comparison of the MG 23S assay to a reference qPCR method for M. genitalium detection and high resolution melt analysis (HRMA) and sequencing for detection of macrolide resistance mutations, resulted in a sensitivity and specificity for M. genitalium detection and for macrolide resistance of 99.1/98.5% and 97.4/100%, respectively. The MG 23S assay provides a considerable advantage in clinical settings through combined diagnosis and detection of macrolide resistance.

2016 European guideline on the management of non-gonococcal urethritis.

We present the updated International Union against Sexually Transmitted Infections (IUSTI) guideline for the management of non-gonococcal urethritis in men. This guideline recommends confirmation of urethritis in symptomatic men before starting treatment. It does not recommend testing asymptomatic men for the presence of urethritis. All men with urethritis should be tested for Chlamydia trachomatis and Neisseria gonorrhoeae and ideally Mycoplasma genitalium using a nucleic acid amplification test (NAAT) as this is highly likely to improve clinical outcomes. If a NAAT is positive for gonorrhoea, a culture should be performed before treatment. In view of the increasing evidence that azithromycin 1 g may result in the development of antimicrobial resistance in M. genitalium, azithromycin 1 g is no longer recommended as first line therapy, which should be doxycycline 100 mg bd for seven days. If azithromycin is to be prescribed an extended course of 500 mg stat, then 250 mg daily for four days is to be preferred over 1 g stat. In men with persistent NGU, M. genitalium NAAT testing is recommended if not previously undertaken, as is Trichomonas vaginalis NAAT testing in populations where T. vaginalis is detectable in >2% of symptomatic women.

2015 UK National Guideline on the management of non-gonococcal urethritis.

We present the updated British Association for Sexual Health and HIV guideline for the management of non-gonococcal urethritis in men. This document includes a review of the current literature on its aetiology, diagnosis and management. In particular it highlights the emerging evidence that azithromycin 1 g may result in the development of antimicrobial resistance in Mycoplasma genitalium and that neither azithromycin 1 g nor doxycycline 100 mg twice daily for seven days achieves a cure rate of >90% for this micro-organism. Evidence-based diagnostic and management strategies for men presenting with symptoms suggestive of urethritis, those confirmed to have non-gonococcal urethritis and those with persistent symptoms following first-line treatment are detailed.

Efficacy of Antimicrobial Therapy for Mycoplasma genitalium Infections.

Mycoplasma genitalium has been causally linked with nongonococcal urethritis in men and cervicitis, pelvic inflammatory disease, preterm birth, spontaneous abortion, and infertility in women, yet treatment has proven challenging. To inform treatment recommendations, we reviewed English-language studies describing antimicrobial susceptibility, resistance-associated mutations, and clinical efficacy of antibiotic therapy, identified via a systematic search of PubMed supplemented by expert referral. Minimum inhibitory concentrations (MICs) from some contemporary isolates exhibited high-level susceptibility to most macrolides and quinolones, and moderate susceptibility to most tetracyclines, whereas other contemporary isolates had high MICs to the same antibiotics. Randomized trials demonstrated poor efficacy of doxycycline and better, but declining, efficacy of single-dose azithromycin therapy. Treatment failures after extended doses of azithromycin similarly increased, and circulating macrolide resistance was present in high levels in several areas. Moxifloxacin remains the most effective therapy, but treatment failures and quinolone resistance are emerging. Surveillance of M. genitalium prevalence and antimicrobial resistance patterns is urgently needed.

Management of non-gonococcal urethritis.

Non-gonococcal urethritis (NGU), or inflammation of the urethra, is the most common treatable sexually transmitted syndrome in men, with approximately 20-50 % of cases being due to infection with Chlamydia trachomatis and 10-30 % Mycoplasma genitalium. Other causes are Ureaplasma urealyticum, Trichomonas vaginalis, anaerobes, Herpes simplex virus (HSV) and adenovirus. Up to half of the cases are non-specific. Urethritis is characterized by discharge, dysuria and/or urethral discomfort but may be asymptomatic. The diagnosis of urethritis is confirmed by demonstrating an excess of polymorpho-nuclear leucocytes (PMNLs) in a stained smear. An excess of mononuclear leucocytes in the smear indicates a viral etiology. In patients presenting with symptoms of urethritis, the diagnosis should be confirmed by microscopy of a stained smear, ruling out gonorrhea. Nucleid acid amplifications tests (NAAT) for Neisseria gonorrhoeae, C. trachomatis and for M. genitalium. If viral or protozoan aetiology is suspected, NAAT for HSV, adenovirus and T. vaginalis, if available. If marked symptoms and urethritis is confirmed, syndromic treatment should be given at the first appointment without waiting for the laboratory results. Treatment options are doxycycline 100 mg x 2 for one week or azithromycin 1 gram single dose or 1,5 gram distributed in five days. However, azithromycin as first line treatment without test of cure for M. genitalium and subsequent Moxifloxacin treatment of macrolide resistant strains will select and increase the macrolide resistant strains in the population. If positive for M. genitalium, test of cure samples should be collected no earlier than three weeks after start of treatment. If positive in test of cure, moxifloxacin 400 mg 7-14 days is indicated. Current partner(s) should be tested and treated with the same regimen. They should abstain from intercourse until both have completed treatment. Persistent or recurrent NGU must be confirmed with microscopy. Reinfection and compliance must be considered. Evidence for the following recommendations is limited, and is based on clinical experience and guidelines. If doxycycline was given as first therapy, azithromycin five days plus metronidazole 4-500 mg twice daily for 5-7 days should be given. If azithromycin was prescribed as first therapy, doxycycline 100 mg x 2 for one week plus metronidazole, or moxifloxacin 400 mg orally once daily for 7-14 days should be given.

Sexually transmitted diseases treatment guidelines, 2015.

These guidelines for the treatment of persons who have or are at risk for sexually transmitted diseases (STDs) were updated by CDC after consultation with a group of professionals knowledgeable in the field of STDs who met in Atlanta on April 30-May 2, 2013. The information in this report updates the Sexually Transmitted Diseases Treatment Guidelines, 2010 (MMWR Recomm Rep 2010;59 [No. RR-12]). These updated guidelines discuss 1) alternative treatment regimens for Neisseria gonorrhoeae; 2) the use of nucleic acid amplification tests for the diagnosis of trichomoniasis; 3) alternative treatment options for genital warts; 4) the role of Mycoplasma genitalium in urethritis/cervicitis and treatment-related implications; 5) updated HPV vaccine recommendations and counseling messages; 6) the management of persons who are transgender; 7) annual testing for hepatitis C in persons with HIV infection; 8) updated recommendations for diagnostic evaluation of urethritis; and 9) retesting to detect repeat infection. Physicians and other health-care providers can use these guidelines to assist in the prevention and treatment of STDs.

Identification of treatment strategies for Mycoplasma genitalium-related urethritis in male patients by culturing and antimicrobial susceptibility testing.

Mycoplasma genitalium was first isolated from urethral swab specimens of male patients with non-gonococcal urethritis. However, the isolation of M. genitalium strains from clinical specimens has been difficult. Co-cultivation with Vero cells is one available technique for the isolation of M. genitalium. The strains that can be used for antimicrobial susceptibility testing by broth dilution or agar dilution methods are limited. Macrolides, such as azithromycin (AZM), have the strongest activity against M. genitalium. However, AZM-resistant strains have emerged and spread. Mutations in the 23S rRNA gene contribute to the organism's macrolide resistance, which is similar to the effects of the mutations in macrolide-resistant Mycoplasma pneumoniae. Of the fluoroquinolones, moxifloxacin (MFLX) and sitafloxacin have the strongest activities against M. genitalium, while levofloxacin and ciprofloxacin are not as effective. Some clinical trials on the treatment of M. genitalium-related urethritis are available in the literature. A doxycycline regimen was microbiologically inferior to an AZM regimen. For cases of treatment failure with AZM regimens, MFLX regimens were effective.

Recent perspectives in the diagnosis and evidence-based treatment of Mycoplasma genitalium.

Mycoplasma genitalium is a globally important sexually transmitted pathogen. Men infected with M. genitalium frequently present with dysuria, while women may present with or without urogenital symptoms. In some populations, M. genitalium is significantly associated with HIV-1 infection, and is also an etiological agent in pelvic inflammatory disease. However, there is insufficient evidence to establish a causative role of the organism in obstetric complications, including tubal factor infertility. Although several nucleic acid amplification tests offer rapid, sensitive methods for detecting M. genitalium, there is no standardized assay. Available evidence supports treatment of M. genitalium infections with an extended regimen of azithromycin and resistant strains respond to moxifloxacin. Accumulating evidence indicates growing fluoroquinolone resistance, including against moxifloxacin, emphasizing the need for new therapeutic strategies to treat M. genitalium infections.

[Which is the best empirical treatment in patients with urethritis?]. / ¿Qué tratamiento empírico es el más adecuado en pacientes con uretritis?

OBJECTIVE: To know the best empirical treatment of urethritis in patients at the City Center of Madrid. METHODS: 2.021 urethral exudates were analyzed in men between January 2003-December 2007. In addition to the traditional cultures, it was determined the presence of Chlamydia trachomatis, Ureaplasma urealyticum, Mycoplasma hominis, Trichomonas vaginalis and Herpes simplex. The susceptibility of N.gonorrhoeae and Haemophilus spp was performed by disk diffusion method and U. urealyticum by Mycoplasma IST. RESULTS: The percentage of positive samples was: 30.6%. The most frequently isolated microorganisms were: U. urealyticum 9.9%, N. gonorrhoeae 7.4%, C. trachomatis 5.1% and Haemophilus spp 3.8%. The resistance of N. gonorrhoeae in the first period was: penicillin 11.8%, tetracycline 5.9%, ciprofloxacin 8.8% and presence of betalactamase 11.8%. In the second period: penicillin 9.7%, amoxicillin/clavulanic acid 1.4%, tetracycline 8.3%, ciprofloxacin 23.6% and presence of betalactamase 10.5%. Resistance to ciprofloxacin in non-MSM (men having sex with men) was 20% and in MSM 56.2%. Resistance of Haemophilus spp in the first period was: 38.2% ampicillin, amoxicillin/clavulanic acid 8.8%, clarithromycin 35.3%, cotrimoxazole 64.7%, cefuroxime 5.9%, ciprofloxacin 8.8%, tetracycline 12.1% and presence of betalactamase 26.5%. In the second period:presence of betalactamase 41.9%, ampicillin 53.1%, amoxicillin/clavulanic acid 9.4%, cefuroxime 9.4%, clarithromycin 18.7%, tetracycline 34.4%, ciprofloxacin 15.6%, and cotrimoxazole 68.7%. Resistance of U. urealyticum was: ciprofloxacin 80.7%, ofloxacin 32.4%, erythromycin 17.5%, azithromycin 9.6%, tetracycline 3.5% and doxycycline 0.8%. CONCLUSIONS: N. gonorrhoeae showed a level of resistance to tetracycline and ciprofloxacin higher in the second period, being significant for ciprofloxacin. Quinolone resistance was higher in MSM. Haemophilus spp showed a level of resistance to ampicillin, ciprofloxacin and tetracycline higher in the second period, being significant for tetracycline. U.urealyticum showed high level of resistance to ciprofloxacin (80.7%)and ofloxacin (32.4%) and low level of resistance to doxycycline (0.8%) and tetracycline (3.5%).

Selection of Mycoplasma genitalium strains harbouring macrolide resistance-associated 23S rRNA mutations by treatment with a single 1 g dose of azithromycin.

OBJECTIVE: A single 1 g dose regimen of azithromycin has been recommended for the treatment of Mycoplasma genitalium infections. The authors evaluated whether this regimen could select M genitalium strains with macrolide resistance after treatment for M genitalium-positive non-gonococcal urethritis. METHODS: In seven men with non-gonococcal urethritis, who were infected with M genitalium without macrolide resistance-associated mutations but experienced microbiological azithromycin treatment failure, M genitalium DNAs in their post-treatment urine specimens were examined for mutations in the 23S rRNA gene and the ribosomal protein genes of L4 and L22. To assess the relatedness of M genitalium strains before and after treatment, their DNAs in pretreatment and post-treatment urine were genotyped by analysing short tandem repeats of an AGT/AAT unit in the MG309 gene and single nucleotide polymorphisms in the MG191 gene. RESULTS: In four of seven patients, M genitalium in post-treatment urine had an A-to-G transition at nucleotide position 2071 or 2072, corresponding to 2058 or 2059 in the 23S rRNA gene of Escherichia coli. In one of the four strains, Pro81Ser in the ribosomal protein L4 accompanied the mutation in the 23S rRNA gene. The genotyping of M genitalium DNAs suggested that these four post-treatment strains were selected from the respective closely related or identical pretreatment strains without macrolide resistance-associated mutations by the treatment. CONCLUSIONS: The single 1 g dose treatment of azithromycin could select M genitalium strains harbouring macrolide resistance-associated mutations. For M genitalium, this regimen might increase the risk of macrolide resistance selection after treatment.

In vitro activity of azithromycin against Mycoplasma genitalium and its efficacy in the treatment of male Mycoplasma genitalium-positive nongonococcal urethritis.

Many recent studies have shown that Mycoplasma genitalium is among the pathogens responsible for Chlamydia trachomatis-negative nongonococcal urethritis (NGU). A single 1-g dose of azithromycin (AZM) has been recommended for the treatment of NGU, including M. genitalium-positive NGU, irrespective of whether it is positive or negative for Chlamydia trachomatis. The purpose of this study was to determine the minimal inhibitory concentrations of AZM against Mycoplasma genitalium strains, and to assess its clinical efficacy against Mycoplasma genitalium-positive NGU. Seven Mycoplasma genitalium strains were obtained from the American Type Culture Collection, and susceptibility testing of seven antimicrobial agents was performed using a broth microdilution method. Thirty men with M. genitalium-positive NGU were enrolled in this study and treated with a single 1-g dose of AZM. AZM and clarithromycin (CAM) were highly active against M. genitalium strains. Fluoroquinolone activities were moderate, and of the three fluoroquinolones tested, gatifloxacin (GFLX) and sparfloxacin (SPFX) were more active than levofloxacin (LVFX). In 25 of 30 (83.3%) men treated with a single 1-g dose of AZM, M. genitalium was eradicated from first-void urine samples, as determined by polymerase chain reaction. AZM was highly active against M. genitalium, and a single 1-g dose of AZM for M. genitalium-positive NGU was tolerated in Japan. These findings may be helpful in establishing optimal treatment for M. genitalium-positive NGU.

[Clinico-epidemiological features and antimicrobial resistance pattern in gonococcal infection]. / Aspecte clinico-epidemiologice si particularitati ale sensibilitatii la antibiotice în infectia gonococica.

AIM: To analyze clinical and epidemiological features in patients with gonococcal infection attended Dermato-Venerology Clinic in Iasi and regional dermato-venerology offices and to evaluate gonococcal antimicrobial resistance pattern. METHODS: The study was carried out on 129 patients clinically diagnosed and bacteriologically confirmed with gonococcal infection who were subsequently submitted to a questionnaire. We studied their demographic characteristics (sex, age, nationality, marital status), clinical features (site of infection, symptoms, concurrent STI, previous history of gonorrhoea) and behavioral aspects (education, number and type of sexual partners, safe sexual practices). RESULTS: We found in our patients a strong association of gonorrhoea with young male individual, poor educational level and with clinical symptoms of urethritis. The level of antimicrobial resistance is higher than in other European countries. CONCLUSIONS: The poor health-seeking behavior, symptoms not specific enough, resistance pattern, lack of accessible and sensitive diagnostic methods lead to undiagnosed and probably mistreated gonorrhoea.

Antimicrobial susceptibility profile of Neisseria gonorrhoeae isolated from patients attending a STD facility in Maputo, Mozambique.

OBJECTIVE: To ascertain the effectiveness of kanamycin for the treatment of gonorrhoea in Maputo, Mozambique. METHODS & DESIGN: A cross-sectional study design was employed. Urethral and cervical specimens were collected for the isolation of Neisseria gonorrhoeae from patients attending Centro de Saúde do Porto. Antimicrobial susceptibilities were determined for kanamycin, spectinomycin, ciprofloxacin, ceftriaxone, cefixime, tetracycline and penicillin. RESULTS: Twenty-two (40%) Neisseria gonorrhoeae isolates were intermediate and 4(7%) were resistant to kanamycin; 42(77%) displayed high level resistance to tetracycline (MIC > or = 16 mg/L); 34 (65%) were penicillinase producers, and 52 (95%) had spectinomycin MICs of 64 mg/L. All isolates were susceptible to ciprofloxacin (MIC < or = 0.06 mg/L), ceftriaxone (MIC < or = 0.015 mg/L) and cefixime (MIC < or = 0.015 mg/L). CONCLUSION: The observations underscore the need for broader susceptibility surveillance studies to elucidate the pattern and extent of drug resistance in Mozambique. A review of the current treatment guidelines for genital discharge syndrome is warranted.

Azithromycin treatment failure in Mycoplasma genitalium-positive patients with nongonococcal urethritis is associated with induced macrolide resistance.

BACKGROUND: Mycoplasma genitalium is a common cause of nongonococcal urethritis. Treatment trials have shown that doxycycline is inefficient, whereas a 5-day course of azithromycin eradicates the bacterium from 95% of infected men. The aim of the study was to establish the reason for the occasional treatment failures. METHODS: Seven M. genitalium strains isolated from men who experienced azithromycin treatment failure were tested for in vitro susceptibility to macrolides with use of a cell culture-based method. The genetic basis for the drug resistance was established by sequencing parts of the 23S ribosomal RNA gene and the genes encoding the L4 and L22 proteins. Nine sets of specimens obtained before and after treatment from patients who experienced azithromycin treatment failure were examined with use of sequencing of polymerase chain reaction products. RESULTS: The 7 strains that were isolated from patients who experienced treatment failure with azithromycin had minimum inhibitory concentrations >8 microg/mL for azithromycin and erythromycin. Three different mutations at positions 2058 and 2059 (Escherichia coli numbering) in region V of the 23S rRNA gene were found. Of the 9 patients with specimens obtained before and after treatment, only 2 had an initial specimen in which the mutation was present, indicating that drug resistance was induced as the result of an inappropriate dosage of azithromycin. CONCLUSION: Development of macrolide resistance was shown to correlate with subsequent azithromycin treatment failure. The genetic basis for the drug resistance was shown to be mutations in region V of the 23S rRNA gene, which is well described in other Mollicutes. These findings raise concern about the use of single-dose azithromycin treatment of nongonococcal urethritis of unknown etiology.

Escalation in the relative prevalence of ciprofloxacin-resistant gonorrhoea among men with urethral discharge in two South African cities: association with HIV seropositivity.

OBJECTIVES: The objectives of this study were to assess the prevalence of ciprofloxacin-resistant gonorrhoea in two South African cities and to investigate the association between the isolation of ciprofloxacin-resistant Neisseria gonorrhoeae and the HIV serostatus of patients. METHODS: Gonococci were cultured from endourethral swabs taken from consecutive men with urethritis attending clinics in Johannesburg and Cape Town. Minimum inhibitory concentrations (MIC) for ciprofloxacin and ceftriaxone were determined with E-tests. Isolates with a ciprofloxacin MIC of 1 mg/l or greater were defined as resistant and isolates with a ceftriaxone MIC of 0.25 mg/l or less were defined as susceptible. Rapid tests were used to screen and confirm the presence of HIV antibodies. Survey data from 2004 were used as a baseline to assess trends in gonococcal resistance to ciprofloxacin. RESULTS: In 2004, the prevalence of ciprofloxacin resistance was 7% in Cape Town and 11% in Johannesburg. In 2007, 37/139 (27%) Cape Town isolates and 47/149 (32%) Johannesburg isolates were resistant to ciprofloxacin; in comparison with 2004 data, this represents 2.9-fold and 1.9-fold increases, respectively. All isolates were fully susceptible to ceftriaxone. There was a significant association between HIV seropositivity and the presence of ciprofloxacin-resistant gonorrhoea among patients (p = 0.034). CONCLUSIONS: Johannesburg and Cape Town have witnessed significant rises in the prevalence of ciprofloxacin-resistant gonorrhoea among men with urethritis. The resistant phenotype is linked to HIV seropositivity. There is now an urgent need to change national first-line therapy for presumptive gonococcal infections within South Africa.