Treatment efficacy, treatment failures and selection of macrolide resistance in patients with high load of Mycoplasma genitalium during treatment of male urethritis with josamycin

Chemical and biological characterization of Melaleuca subulata (Cheel) Craven leaves' volatile constituents supported by chemometric analysis and molecular docking

BACKGROUND

The genus Melaleuca (Myrtaceae) comprises dozens of essential oil (EO)-rich species that are appreciated worldwide for their various medicinal values. Additionally, they are renowned in traditional medicine for their antimicrobial, antifungal, and other skin-related activities. The current study investigated the chemical profile and skin-related activities of volatile constituents derived from M. subulata (Cheel) Craven (Synonym Callistemon subulatus) leaves cultivated in Egypt for the first time.

METHODS

The volatile components were extracted using hydrodistillation (HD), headspace (HS), and supercritical fluid (SF). GC/MS and Kovat's retention indices were implemented to identify the volatile compounds, while the variations among the components were assessed using Principal Component Analysis and Hierarchical Cluster Analysis. The radical scavenging activity was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC) and β-carotene assays. Moreover, the anti-aging effect was evaluated using anti-elastase, and anti-collagenase, while the antimicrobial potential was deduced from the agar diffusion and broth microdilution assays. Lastly, the molecular docking study was executed using C-docker protocol in Discovery Studio 4.5 to rationalize the binding affinity with targeted enzymes.

RESULTS

The SF extraction approach offered the highest EO yield, being 0.75%. According to the GC/MS analysis, monoterpene hydrocarbons were the most abundant volatile class in the HD oil sample (54.95%), with α-pinene being the most copious component (35.17%). On the contrary, the HS and SF volatile constituents were pioneered with oxygenated monoterpenes (72.01 and 36.41%) with eucalyptol and isopulegone being the most recognized components, representing 67.75 and 23.46%, respectively. The chemometric analysis showed segregate clustering of the three extraction methods with α-pinene, eucalyptol, and isopulegone serving as the main discriminating phytomarkers. Concerning the bioactivity context, both SF and HD-EOs exhibited antioxidant effects in terms of ORAC and β-carotene bleaching. The HD-EO displayed potent anti-tyrosinase activity, whereas the SF-EO exhibited significant anti-elastase properties. Moreover, SF-EO shows selective activity against gram-positive skin pathogens, especially S. aureus. Ultimately, molecular docking revealed binding scores for the volatile constituents; analogous to those of the docked reference drugs.

CONCLUSIONS

M. subulata leaves constitute bioactive volatile components that may be indorsed as bioactive hits for managing skin aging and infection, though further in vivo studies are recommended.

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.

Global analysis on the mutations associated with multidrug-resistant urogenital mycoplasmas and ureaplasmas infection: a systematic review and meta-analysis

BACKGROUND

The emergence of multidrug-resistant (MDR) strains of genital pathogens, notably Mycoplasma genitalium and Ureaplasma spp., constitutes a significant global threat today. The present study aimed to evaluate the prevalence and trend of changes in MDR mycoplasma and ureaplasma strains.

METHODS

An exhaustive search was performed across the ISI Web of Science, PubMed, Scopus, ScienceDirect, and Google Scholar databases to accumulate relevant studies without restrictions until April 2023. We used event rate and corresponding 95% confidence intervals to determine the frequency of resistance-related mutations and examine the trend of antibiotic resistance changes.

RESULTS

The data from 27 studies, including 24,662 patients across 14 countries, were evaluated. Out of the total studies, 20 focused on M. genitalium infections, and five on Ureaplasma spp. The frequency of resistance-associated mutations to macrolides, tetracyclines, and fluoroquinolones in clinical strains of M. genitalium was 43.5%, 13.1%, and 18.6%, respectively. The prevalence of M. genitalium strains with double resistance and MDR was 11.0% and 17.4%, respectively. The incidence of both double-drug-resistant and MDR strains was higher in the World Health Organization (WHO) Western Pacific Region than in European and American populations. For Ureaplasma strains, resistance-associated mutations to macrolides, tetracyclines, and fluoroquinolones were 40.8%, 25.7%, and 90.3%, respectively. The rate of antibiotic resistance was higher in the African population compared to the European and WHO Western Pacific Regions. The rate of MDR Ureaplasma infections was 13.2%, with a higher incidence in the African population compared to the WHO Western Pacific and European regions.

CONCLUSION

The proliferation and spread of MDR Mycoplasma and Ureaplasma strains present a significant public health challenge. The situation is indeed alarming, and the rising trend of MDR M. genitalium and MDR Ureaplasma infections suggests that therapies involving macrolides and fluoroquinolones may become less effective.

Novel mechanisms of macrolide resistance revealed by in vitro selection and genome analysis in Mycoplasma pneumoniae

Mycoplasma pneumoniae is an important pathogen causing upper and lower respiratory tract infections in children and other age groups. Macrolides are the recommended treatments of choice for M. pneumoniae infections. However, macrolide resistance in M. pneumoniae is increasing worldwide, which complicates the treatment strategies. The mechanisms of macrolide resistance have been extensively studied focusing on the mutations in 23S rRNA and ribosomal proteins. Since the secondary treatment choice for pediatric patients is very limited, we decided to look for potential new treatment strategies in macrolide drugs and investigate possible new mechanisms of resistance. We performed an in vitro selection of mutants resistant to five macrolides (erythromycin, roxithromycin, azithromycin, josamycin, and midecamycin) by inducing the parent M. pneumoniae strain M129 with increasing concentrations of the drugs. The evolving cultures in every passage were tested for their antimicrobial susceptibilities to eight drugs and mutations known to be associated with macrolide resistance by PCR and sequencing. The final selected mutants were also analyzed by whole-genome sequencing. Results showed that roxithromycin is the drug that most easily induces resistance (at 0.25 mg/L, with two passages, 23 days), while with midecamycin it is most difficult (at 5.12 mg/L, with seven passages, 87 days). Point mutations C2617A/T, A2063G, or A2064C in domain V of 23S rRNA were detected in mutants resistant to the 14- and 15-membered macrolides, while A2067G/C was selected for the 16-membered macrolides. Single amino acid changes (G72R, G72V) in ribosomal protein L4 emerged during the induction by midecamycin. Genome sequencing identified sequence variations in dnaK, rpoC, glpK, MPN449, and in one of the hsdS (MPN365) genes in the mutants. Mutants induced by the 14- or 15-membered macrolides were resistant to all macrolides, while those induced by the 16-membered macrolides (midecamycin and josamycin) remained susceptible to the 14- and 15-membered macrolides. In summary, these data demonstrated that midecamycin is less potent in inducing resistance than other macrolides, and the induced resistance is restrained to the 16-membered macrolides, suggesting a potential benefit of using midecamycin as a first treatment choice if the strain is susceptible.

Retrospective and Comparative Study of Three Molecular Assays for the Macrolide Resistance Detection in Mycoplasma genitalium Positive Urogenital Specimens

The capacity of Mycoplasma genitalium to develop resistance to macrolides makes detection of macrolide resistance genes by rapid real-time PCR assays increasingly necessary in clinical diagnostic laboratories so as to initiate appropriate treatment as rapidly as possible. The aim of this retrospective and comparative study was to conduct the clinical evaluation of three commercially available kits for macrolide resistance detection. A total of 111 M. genitalium positive samples analyzed in the Clinical Microbiology Laboratory of the Miguel Servet University Hospital, Zaragoza (Spain) were used. After M. genitalium molecular confirmation, the three assays under study were evaluated and discrepant results were resolved via sequencing. The clinical sensitivity for resistance detection was 83% (95% confidence interval, 69% to 93%) for the ResistancePlus^® MG panel kit (SpeeDx Pty Ltd., Sydney, Australia), 95% (84% to 99%) for Allplex^TM MG & AziR Assay (Seegene^®, Seoul, Korea), and 97% (88% to 99%) for the VIASURE macrolide resistance-associated mutations (23SrRNA) Real time PCR detection kit (Certest Biotec, Zaragoza, Spain). The clinical specificity was 100% (94% to 100%) for Allplex and VIASURE assays and 95% (86% to 99%) for SpeeDx assay. The results arising from this study are cause for strong consideration for the implementation of rapid real-time PCR assays in clinical diagnosis laboratories to eliminate treatment failure and transmission as soon as possible.

Genetic Determinants of Macrolide and Fluoroquinolone Resistance in Mycoplasma genitalium and Their Prevalence in Moscow, Russia

Macrolide (MLR) and fluoroquinolone (FQR) resistance in Mycoplasma genitalium (MG) has recently become a major problem worldwide. The available data on the prevalence of MLR and FQR in MG in Russia are limited. In this study, we aimed to evaluate the prevalence and pattern of mutations in 213 MG-positive urogenital swabs from patients in Moscow between March 2021 and March 2022. MLR- and FQR-associated mutations were searched in 23S rRNA as well as in the parC and gyrA genes using Sanger sequencing. The prevalence of MLR was 55/213 (26%), with A2059G and A2058G substitutions being the two most common variants (36/55, 65%, and 19/55, 35%, respectively). FQR detection showed 17% (37/213); two major variants were D84N (20/37, 54%) and S80I (12/37, 32.4%) and three minor variants were S80N (3/37, 8.1%), D84G (1/37, 2.7%), and D84Y (1/37, 2.7%). Fifteen of the fifty-five MLR cases (27%) simultaneously harbored FQR. This study revealed the high frequency of MLR and FQR. We conclude that the improvement of patient examination algorithms and therapeutic approaches should be combined with the routine monitoring of antibiotic resistance based on the sensitivity profiles presented. Such a complex approach will be essential for restraining the development of treatment resistance in MG.

Chlamydia trachomatis Coinfection Does Not Influence Mycoplasma genitalium Bacterial Load in Urogenital Samples

BACKGROUND

Mycoplasma genitalium (MG) is associated with urethritis in men and weakly associated with pelvic inflammatory disease in women. Mycoplasma genitalium coinfections with Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) are commonly reported; however, little is known about their interaction. One study suggested that MG/NG coinfections might increase the bacterial load of NG, which has been shown to have a higher transmission potential. As even less is known about the impact of a simultaneous MG/CT infection, we assessed whether patients with urogenital MG/CT coinfections have a higher bacterial load than patients with a single infection.

METHODS

There were 1673 urogenital samples from patients from a population-based chlamydia study, and our sexually transmitted infection clinic tested for both CT and MG. When positive, the load was quantified. Nonparametric tests compared the CT and MG load, and linear regression analyses tested the association of the CT and MG load within a patient.

RESULTS

In 60 MG-positive patients, MG load ranged from 1.7 to 6.0 log10 copies/ml, similar to the CT load distribution. Only 6 patients were MG-positive and CT-negative, but the MG load distribution was similar to that of CT-positive patients (n.s.). The MG and CT load was unrelated in coinfected persons (n.s.).

CONCLUSIONS

We found no correlation between the CT and MG load in urogenital samples, and the MG load distribution was similar in CT-positive and CT-negative patients. These results could have implications for the transmission risk of these infections.

Effects of Candida albicans on the metabolic activity and drug resistance of Streptococcus mutans based on D2O-labeled single-cell Raman microspectroscopy

OBJECTIVES

To evaluate the susceptibility of Streptococcus mutans (S. mutans) to NaF and the effects of Candida albicans (C. albicans) metabolites on the metabolic activity and drug resistance of S. mutans.

METHODS

The minimum inhibitory concentration (MIC) and MIC based on metabolic activity (MIC-MA) of NaF against S. mutans were measured through the broth dilution test and D2O-labeled single-cell Raman microspectroscopy, respectively, to explore the inhibitory effect of NaF on the growth and metabolism of S. mutans. The effects of different concentrations of C. albicans supernatant on the metabolic activity of S. mutans were evaluated by using D2O-labeled single-cell Raman microspectroscopy. The correlation between C. albicans and S. mutans was explored throughassessing the drug resistance of S. mutans against NaF in a mixed system containing C. albicans supernatant by using D2O-labeled single-cell Raman microspectroscopy.

RESULTS

The MIC and MIC-MA of NaF against S. mutans were 0.4 g·L-1 and 1.2 g·L-1, respectively. At the MIC level, S. mutans showed completely inhibited growth but retained high metabolic activity. Therefore, S. mutans may regain its virulence. At the MIC-MA level, the metabolic activity of S. mutans was inhibited only when the NaF concentration reached 3×MIC. At the concentration of OD600≥0.5, the C. albicans supernatant significantly promoted the metabolic activity of S. mutans at different time points (P<0.05). In the mixed system, the susceptibility of S. mutans to NaF decreased, and statistical differences at different time points were observed (P<0.05). The metabolic activity of S. mutans was inhibited completely only at the concentration of 4×MIC (1.6 g·L-1).

CONCLUSIONS

D2O-labeled single-cell Raman microspectroscopy is suitable for evaluating the effects of drugs on bacterial metabolic activity. In the mixed system, the metabolites in the C. albicans supernatant at the concentration of OD600≥0.5 significantly promoted the metabolic activity of S. mutans and reducedthe susceptibility of S. mutans to NaF.

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.

Assessment of the antimicrobial effects of sodium hypochlorite on Enterococcus faecalis by D2O-labeled single-cell Raman micro-spectroscopy

OBJECTIVES

To systematically evaluate the feasibility of D2O-labeled single-cell Raman micro-spectroscopy in drug resistance research and test the susceptibility of Enterococcus faecalis (E. faecalis)to sodium hypochlorite.

METHODS

1) The growth of E. faecalis in different doses of D2O and the regularity of D2O intake were evaluated through absorbance measurement and D2O-labeled single-cell Raman micro-spectroscopy to examine the universality of D2O-labeled single-cell Raman micro-spectroscopy in bacterial resistance research. 2) Broth dilution method and absorbance measurement were performed to determine the minimum inhibitory concentration (MIC) of NaClO against E. faecalis and the MIC based on metabolic activity (MIC-MA) in vitro via D2O-labeled single-cell raman micro-spectroscopy.

RESULTS

1) The growth of E. faecalis was not significantly inhibited by ≤40% D2O in the medium. E. faecalis could actively metabolize D2O and exhibit a C-D ratio in specific areas of Raman micro-spectroscopy results. The C-D ratio of E. faecalis at the stationary phase was positively correlated with D2O concentration. 2) The MIC and MIC-MA of NaClO against E. faecalis were 0.45 and 0.9 g·L-1, respectively. The concentration of MIC-MA was twice that of MIC.

CONCLUSIONS

D2O-labeled single-cell Raman micro-spectroscopy is important in screening antimicrobial agents and evaluating the efficacy of antimicrobial agents. It is suitable for evaluating the effect of drugs on bacterial metabolic activities. NaClO showed an effective antimicrobial activity against E. faecalis. E. faecalis ceased propagation yet remained highly metabolically active when it was exposed to NaClO at the MIC level. The metabolic activity of most cells was inhibited only when they were exposed to NaClO at the MIC-MA level.

Mycoplasma genitalium: A new superbug

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

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.

Integrating the Human and Animal Sides of Mycoplasmas Resistance to Antimicrobials

Mycoplasma infections are frequent in humans, as well as in a broad range of animals. However, antimicrobial treatment options are limited, partly due to the lack of a cell wall in these peculiar bacteria. Both veterinary and human medicines are facing increasing resistance prevalence for the most commonly used drugs, despite different usage practices. To date, very few reviews have integrated knowledge on resistance to antimicrobials in humans and animals, the latest dating back to 2014. To fill this gap, we examined, in parallel, antimicrobial usage, resistance mechanisms and either phenotype or genotype-based methods for antimicrobial susceptibility testing, as well as epidemiology of resistance of the most clinically relevant human and animal mycoplasma species. This review unveiled common features and differences that need to be taken into consideration in a "One Health" perspective. Lastly, two examples of critical cases of multiple drug resistance are highlighted, namely, the human M. genitalium and the animal M. bovis species, both of which can lead to the threat of untreatable infections.

Isolation, characterization, and molecular identification of soil bacteria showing antibacterial activity against human pathogenic bacteria

BACKGROUND

The present study dealt with the screening of soil bacteria with antibacterial activity from different locations in Bangalore, India. Antibiotics play the role of self-defense mechanism for the bacteria and are produced as secondary metabolites to protect themselves from other competitive microorganisms. The need for new antibiotics arose as the pathogenic bacteria acquire resistance to various antibiotics meant for treating human diseases. Given the importance of antibiotics of bacterial origin, standard techniques have been used to isolate and characterize the soil bacteria which showed antibacterial activity.

RESULTS

The isolated bacteria were tested against human pathogenic bacteria like Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae by primary and secondary screening methods. The isolates PR1, PR2, and PR3 were confirmed to have antibacterial activity against S. aureus, E. coli, P. aeruginosa, and K. pneumoniae by both methods. Studies on the effect of filter sterilization, autoclaving, and proteinase K treatment on culture filtrates showed filter sterilization as the best method. The effect of different carbon and nitrogen sources on the antibacterial activity showed that preference by each isolate differed for carbon and nitrogen requirements. The isolates PR1, PR2, and PR3 were identified as Bacillus aryabhattai strain PR-D07, Arthrobacter humicola strain PR-F07, and Neomicrococcus lactis strain PR-F11 through 16S rRNA sequencing.

CONCLUSION

Findings from this research work are encouraging and could proceed further to applied aspects. Only 3 bacterial isolates out of 263 isolates from soil samples displayed antibacterial activity against human pathogens S. aureus, E. coli, P. aeruginosa, and K. pneumoniae. They were identified as B. aryabhattai, A. humicola, and N. lactis by 16S rRNA studies and all of them are Gram-positive. Each isolate preferred different carbon and nitrogen sources for their enhanced antibacterial activity. Efficacy of the culture filtrates of these isolates was tested by filter sterilization, autoclaving, and proteinase K treatment. Filter-sterilized culture filtrates showed higher antibacterial activity than other treatments. A comparison of the antibacterial activity of culture filtrates and antibiotic streptomycin produced an inhibition zone of 18.5 mm and 15.5 mm respectively. This is the first report on the antibacterial activity of all the 3 bacterial strains (B. aryabhattai strain PR-D07, A. humicola strain PR-F07, and N. lactis strain PR-F11), against all the human pathogens, mentioned earlier. It is also found that the antibiotic factor is proteinaceous as proteinase K considerably reduced the antibacterial activity of the culture filtrates. With the above significant results, these 3 bacteria are considered to be promising candidates for the isolation of new antibacterial agents.

Photorhabdus sp. ETL Antimicrobial Properties and Characterization of Its Secondary Metabolites by Gas Chromatography-Mass Spectrometry

Entomopathogenic nematodes (EPNs) are known to be highly pathogenic to insect pests, due to their associated symbiotic bacteria, which produce virulence factors, exo-enzymes and other harmful secondary metabolites to conquer, kill, and degrade their insect hosts. However, these properties are not fully characterized. This study reports on the antimicrobial activities of Photorhabdus sp. strain ETL, symbiotically associated to an insect pathogenic nematode, Heterorhabditis zealandica, against human pathogenic bacteria and toxigenic fungi, as well as the non-targeted profiling of its secondary metabolites (SMs) using gas chromatography coupled to high-resolution time-of-flight mass spectrometry. Fatty acids including 3-eicosene, (E)-; 5-eicosene, (E)-; eicosene; 9-octadecenamide; undecanoic acid with shown antimicrobial activities were detected. This provided more insight on the composition and bioactivities of SMs produced by the Photorhabdus sp.

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

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

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.

Clinical evaluation of commercial PCR assays for antimicrobal resistance in Mycoplasma genitalium and estimation of resistance-mediated mutation prevalence in Moscow and Moscow region

Mycoplasma genitalium is a widespread sexually transmitted infection (STI) with growing rate of antimicrobials resistance. In our study, 137 vaginal and 131 urethral M. genitalium-positive swabs were sequentially collected through the work of Reference Center for STI during 2019. For prevalence evaluation of macrolide-resistance mutations three commercially available kits were used: AmpliSens® M. genitalium-ML/FQ-Resist-FL (Central Research Institute of Epidemiology, Russia), ResistancePlus® MG (SpeeDx, Australia), and S-DiaMGRes™ (Diagenode, Belgium). Macrolide resistance mutations were detected in 16% (43 of 268) of samples. Diagnostic characteristics were evaluated against Sanger sequencing. For AmpliSens® M. genitalium-ML/FQ-Resist-FL specificity was shown to be 100% (CI 95%, 98.4-100), and sensitivity was 90.7% (CI 95%, 77.9-97.4). ResistancePlus® MG specificity was 100% (CI 95%, 98.3-100), and sensitivity was 92.1% (CI 95%, 78.6-98.3). S-DiaMGRes™ specificity was shown to be 88.6% (CI 95%, 83.9-92.4), and sensitivity was 100% (CI 95%, 84.4-100). Mutations of parC gene region were detected in 14.5% (38 of 268) using AmpliSens® M. genitalium-ML/FQ-Resist-FL with further validation by Sanger sequencing. Of studied samples, 6.3% (17 of 268) contained both antimicrobials of class resistance mutations. Prevalence of macrolide-resistant M. genitalium in Moscow was 21.7% (23 of 106) and of fluoroquinolone-resistant M. genitaliuim was 20.8% (22 of 106). In Moscow region, macrolide-resistant M. genitalium were 12.3% (20 of 162) and 9.9% (16 of 162) of fluoroquinolone-resistant M. genitalium. All three kits can be used both for epidemiological monitoring of M. genitalium presence and mutation prevalence estimation. In Moscow, macrolide- and fluoroquinolone-resistant mutant prevalence increased in 3.9 and 2.7 times in 3 years.

Chemical composition and potentiating action of Norfloxacin mediated by the essential oil of Piper caldense C.D.C. against Staphylococcus aureus strains overexpressing efflux pump genes

Infectious diseases caused by multidrug-resistant microorganisms has increased in the last years. Piper species have been reported as a natural source of phytochemicals that can help in combating fungal and bacterial infections. This study had as objectives characterize the chemical composition of the essential oil from Piper caldense (EOPC), evaluate its potential antimicrobial activity, and investigate the synergistic effect with Norfloxacin against multidrug-resistant S. aureus overproducing efflux pumps, as well as, verify the EOPC ability to inhibit the Candida albicans filamentation. EOPC was extracted by hydrodistillation, and the chemical constituents were identified by gas chromatography, allowing the identification of 24 compounds (91.9%) classified as hydrocarbon sesquiterpenes (49.6%) and oxygenated sesquiterpenes (39.5%). Antimicrobial tests were performed using a 96-well plate microdilution method against C. albicans ATCC 10231, Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923 standard strains, as well as against multidrug-resistant strains S. aureus SA1199B (overexpressing norA gene), S. aureus K2068 (overexpressing mepA gene) and S. aureus K4100 (overexpressing qacC gene). The oil showed activity against C. albicans ATCC 10231 (≥ 512 µg/mL) and was able to inhibit hyphae formation, an important mechanism of virulence of C. albicans. On the other hand, EOPC was inactive against all bacterial strains tested (≤ 1,024 µg mL). However, when combined with Norfloxacin at subinhibitory concentration EOPC reduced the Norfloxacin and Ethidium bromide MIC values against S. aureus strains SA1199B, K2068 and K4100. These results indicate that EOPC is a source of phytochemicals acting as NorA, MepA and QacC inhibitors.

Macrolide and fluoroquinolone associated mutations in Mycoplasma genitalium in a retrospective study of male and female patients seeking care at a STI Clinic in Guangzhou, China, 2016-2018

Background

Antimicrobial resistance in M. genitalium is a growing clinical problem. We investigated the mutations associated with macrolide and fluoroquinolone resistance, two commonly used medical regimens for treatment in China. Our aim is to analyze the prevalence and diversity of mutations among M. genitalium-positive clinical specimens in Guangzhou, south China.

Methods

A total of 154 stored M. genitalium positive specimens from men and women attending a STI clinic were tested for macrolide and fluoroquinolone mutations. M. genitalium was detected via TaqMan MGB real-time PCR. Mutations associated with macrolide resistance were detected using primers targeting region V of the 23S rRNA gene. Fluoroquinolone resistant mutations were screened via primers targeting topoisomerase IV (parC) and DNA gyrase (gyrA).

Results

98.7% (152/154), 95.5% (147/154) and 90.3% (139/154) of M. genitalium positive samples produced sufficient amplicon for detecting resistance mutations in 23S rRNA, gyrA and parC genes, respectively. 66.4% (101/152), 0.7% (1/147) and 77.7% (108/139) samples manifested mutations in 23S rRNA, gyrA and parC genes, respectively. A2072G (59/101, 58.4%) and S83I (79/108, 73.1%) were highly predominating in 23S rRNA and parC genes, respectively. Two samples had amino acid substitutions in gyrA (M95I and A96T, respectively). Two samples had two amino acid substitutions in parC (S83I + D87Y). 48.6% (67/138) of samples harbored both macrolide and fluoroquinolone resistance-associated mutations. The most common combination of mutations was A2072G (23S rRNA) and S83I (parC) (40/67, 59.7%). One sample had three amino acid changes in 23S rRNA, gyrA and parC genes (A2072G + A96T + S83I).

Conclusions

The high antimicrobial resistance rate of M. genitalium in Guangzhou is a very worrying problem and suggests that antimicrobial resistance testing and the development of new antibiotic regimens are crucially needed.

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.

Mycoplasma genitalium and antimicrobial resistance in Europe: a comprehensive review

Antibiotic resistance in Mycoplasma genitalium has been emerging in Europe. Also, discrepancies on the management and treatment of sexually transmitted infections may have distinctly influenced the prevalence of antimicrobial resistance among European countries. This comprehensive review of the literature published between 2012 and 2018 updates antimicrobial resistance data in M. genitalium in Europe. Overall, macrolide resistance is rapidly increasing in this region, where many countries are exceeding 50%. The limited data regarding fluoroquinolone resistance estimate a prevalence of 5% (interquartile range, 5–6%). The study supports the need to conduct representative and well-defined surveillance on antimicrobial resistance in M. genitalium at both local and European levels. Also, further investigations on new promising antibiotics are required to fight against M. genitalium that may soon become untreatable.

Clinical Evaluation of Three Commercial PCR Assays for the Detection of Macrolide Resistance in Mycoplasma genitalium

As macrolide resistance in Mycoplasma genitalium is increasing worldwide, macrolide resistance-associated mutations should be assessed in M. genitalium-positive specimens. New commercial kits are available for detection of macrolide resistance concurrently with M. genitalium We prospectively evaluated the handling and clinical performances of three commercial kits for detection of macrolide resistance in M. genitalium Between August and December 2018, remnants of all urogenital specimens determined to be M. genitalium positive using an in-house real-time PCR assay were prospectively collected at the French National Reference Center for Bacterial Sexually Transmitted Infections, Bordeaux University Hospital, Bordeaux, France. The internal control of each kit was added to the primary specimen before DNA extraction, and the absence of amplification inhibition associated with the addition of the three internal controls was assessed. Specimens were evaluated with four assays: the ResistancePlus MG assay (SpeeDx), the S-DiaMGRes assay (Diagenode), the RealAccurate TVMGres assay (PathoFinder), and amplification and sequencing of the 23S rRNA gene (the reference assay). Overall, 195 M. genitalium-positive specimens were assessed. The positive agreement of M. genitalium detection for each kit ranged between 94.8% and 96.4%. Among 154 specimens with M. genitalium positivity as detected by the three commercial kits and 23S rRNA sequencing data, the clinical sensitivity and specificity ranges of the three commercial kits for detecting macrolide resistance-associated mutations were 95 to 100% and 94.6 to 97.3%, respectively. The sensitivity and specificity values were similar among the kits. The launch of three easy-to-use sensitive and specific commercial kits for simultaneous detection of M. genitalium and macrolide resistance will be useful for resistance-guided therapy.

Molecular basis of antimicrobial resistance in Mycoplasma genitalium

Mycoplasma genitalium is a sexually transmitted urogenital pathogen, and infection can result in serious symptoms. As M. genitalium is rather difficult to culture, infections are usually detected by molecular methods. Unfortunately, there has recently been a significant increase in resistance to azithromycin and moxifloxacin used for the treatment of M. genitalium infections. The increased resistance to (often empirically prescribed) M. genitalium treatments has resulted in frequent therapy failures and stresses the need for routine detection of antimicrobial resistance. In M. genitalium, antimicrobial resistance is almost always the result of DNA mutations and thus can easily be detected by molecular techniques. Regrettably, many microbiology laboratories do not use molecular techniques for the detection of bacterial antimicrobial resistance. As molecular tests are becoming available for M. genitalium, both for the establishment of infection and the detection of antimicrobial resistance, it is now more important to ensure that knowledge on the resistance mechanisms is transferred from the laboratory to the clinician. This review will provide a brief summary of the current status of antimicrobial resistance, its molecular mechanisms and the impact on the current status of M. genitalium treatment.

Phytochemical Analysis and Evaluation of Antimicrobial Activity of Peumus boldus, Psidium guajava, Vernonia polysphaera, Persea Americana, Eucalyptus citriodora Leaf Extracts and Jatropha multifida Raw Sap

BACKGROUND

Currently, the treatment of infectious diseases has not always been successful due to the emergence of microbial resistance worldwide.

OBJECTIVES

This study aimed to evaluate the antioxidant activity, content of total phenolic compounds and flavonoids, antifungal potential and antibacterial action of six medicinal plants found in the Cerrado, leaf extracts of Boldo (Peumus boldus), Goiaba (Psidium guajava), Assa-Peixe (Vernonia polysphaera), Abacate (Persea americana), Eucalipto (Eucalyptus citriodora) and raw sap of Bálsamo (Jatropha multifida).

METHODS

The antioxidant activity was also determined through the DPPH, ABTS and phosphomolybdenum assays. In addition, the total phenolic content and flavonoid dosage were analyzed using the Folin- Ciocalteu method and the aluminum chloride test, respectively.

RESULTS

All extracts, except from Assa-Peixe, showed promising values against Staphylococcus aureus, with halos varying from 13-20 mm. Analysis of the minimum inhibitory concentration (MIC) values of the six medicinal plants revealed inhibitory activity of S. aureus, with concentrations varying from 3.12-12.5 mg/mL, which is a significant result considering that S. aureus is one of the main causes of hospital infections.

CONCLUSION

In the analysis of the phytochemical profile, Goiaba contained the best yield of phenolic compounds and total flavonoids, as well as higher antioxidant activity by DPPH and phosphomolybdenum, demonstrating that this species contains antioxidant components that can sequester free radicals under in vitro conditions. Therefore, the crude extracts investigated are promising and their antibacterial and antioxidant actions should be thoroughly studied.

Analysis of Infection Loads in Mycoplasma genitalium Clinical Specimens by Use of a Commercial Diagnostic Test

Mycoplasma genitalium is a common sexually transmitted infection with a propensity to acquire resistance to commonly used antimicrobial therapies. Bacterial load has been linked to patient symptoms and the success of treatment. In this study, we demonstrate methodology to estimate load from routine diagnostic assays using the ResistancePlus MG test (SpeeDx Pty Ltd., Australia). The method gave comparable quantitation to an M. genitalium-specific 16S rRNA quantitative PCR (qPCR; Spearman r = 0.94) for the samples analyzed (n = 499, including urine and swab types as detailed below) and was, therefore, employed to analyze typical load levels for samples in a diagnostic laboratory (total of 1,012 tests). When stratified by sample type, female urine (median, 826 genomes/ml) had the lowest load. This was significantly lower than median loads for all other sample types (male urine [6.91 × 10³ genomes/ml], anal swabs [5.50 × 10³], cervical swabs [8.15 × 10³], endocervical swabs [3.97 × 10³], and vaginal swabs [6.95 × 10³]) (P < 0.0001). There were no significant differences in load estimates between the other sample types. Reproducibility of load estimates conducted on the same samples was high (r > 0.85). In conclusion, this methodology to provide load estimates for M. genitalium can be easily integrated into routine diagnostic laboratory workflow. Given the association between organism load, symptoms, and treatment success, load assessment has future diagnostic potential.

Current status of countermeasures for infectious diseases and resistant microbes in the field of urology

A worldwide increase in antimicrobial-resistant microbes due to the improper use of antimicrobial agents, along with a lack of progress in developing new antimicrobials, is becoming a societal problem. Although carbapenem-resistant Enterobacteriaceae, which are resistant to carbapenem antimicrobials, first appeared in 1993, treatment options remain limited. Mechanisms behind antimicrobial resistance involve changes to microbial outer membranes, drug efflux pump abnormalities, β-lactamase production and the creation of biofilms around cell bodies. Genetic information related to these forms of antimicrobial resistance exists on chromosomes and plasmids, and when located on the latter can easily be transmitted to other strains, no matter the species, which creates a risk of antimicrobial resistance spreading exceptionally rapidly. To prevent the spread of antimicrobial resistance, the World Health Organization in 2015 published an action plan on antimicrobial resistance, based on which World Health Organization member countries have laid out specific policies and targets. Urinary tract infections are a type of healthcare-associated infection, and the sexually transmitted disease pathogen, Neisseria gonorrhoeae, has been included in a list of microbes that pose a risk to human health published by the US Centers for Disease Control and Prevention. Urologists face numerous problems when attempting to use antimicrobials properly, which is one method of dealing with antimicrobial resistance. Therefore, this article describes the current state of resistant microbes associated with urinary tract infections and countermeasures for antimicrobial resistance, including new antimicrobials.

Wound healing potential of oil extracted from Parrotiopsis jacquemontiana (Decne) Rehder

ETHNOPHARMACOLOGICAL RELEVANCE

Oil extracted from Parrotiopsis jacquemontiana stem traditionally used for wound healing, body aches and dermatitis. In this study we have evaluated oil for its phytoconstituents, antioxidant, antimicrobial and wound healing activities.

METHODS

Phytochemical characterization of oil was determined by standard qualitative procedures, gas chromatography mass spectrometry technique (GC-MS) and Fourier transform infra-red spectroscopy (FT-IR). The in vitro antioxidant aptitude was determined by scavenging of DPPH radical, hydroxyl ion, nitric oxide, inhibition of β-carotene bleaching assay and iron chelation power assay. The antimicrobial potential of oil was investigated by disc diffusion method against multidrug resistant (MDR) bacterial isolates and fungal strains. Wound healing was performed in vivo with determination of wound contraction rates, histopathology, hemostatic potential and hydroxyproline estimation.

RESULTS

GC-MS analysis indicated that oil was constituted mainly of 2, 6-dimethyl-8-oxoocta-2, 6-dienoic acid, methyl ester (18.2%), syringol (17.8%), catechol (12.4%), guaiacol (5.2%), p-cresol (5.4%) and phenol, 2-propyl- (3.7%). FT-IR analysis revealed several important functional groups in its chemical composition especially phenolic O-H compound stretching. Scavenging of DPPH radical, hydroxyl ion, nitric oxide, inhibition of β-carotene oxidation and iron chelation power assays indicated strong antioxidant activities of oil. Further it efficiently inhibited growth of multidrug resistant isolates of Staphylococcus aureus, S. lugdenesis, Klebsiella pneumoniae, Escherichia coli, Coagulase -ve staphylococci and Pseudomonas aeruginosa. The minimum inhibitory concentrations ranged between (32-256) (μg/mL) of oil. The oil also strongly inhibited the growth of various fungal isolates with low level of minimum inhibitory concentrations (64-256) μg/mL. Remarkable rate for wound closure and epithelization, hemostatic potential and marked increase (p < 0.05) in hydroxyproline content was observed for oil during wound healing in rat.

CONCLUSION

The results suggested that oil can be used as a potential source of wound healing therapeutics.

Use of Pristinamycin for Macrolide-Resistant Mycoplasma genitalium Infection

High levels of macrolide resistance and increasing fluoroquinolone resistance are found in Mycoplasma genitalium in many countries. We evaluated pristinamycin for macrolide-resistant M. genitalium in a sexual health center in Australia. Microbiologic cure was determined by M. genitalium–specific 16S PCR 14–90 days after treatment began. Of 114 persons treated with pristinamycin, infection was cured in 85 (75%). This percentage did not change when pristinamycin was given at daily doses of 2 g or 4 g or at 3 g combined with 200 mg doxycycline. In infections with higher pretreatment bacterial load, treatment was twice as likely to fail for each 1 log₁₀ increase in bacterial load. Gastrointestinal side effects occurred in 7% of patients. Pristinamycin at maximum oral dose, or combined with doxycycline, cured 75% of macrolide-resistant M. genitalium infections. Pristinamycin is well-tolerated and remains an option where fluoroquinolones have failed or cannot be used.

Clinical case of failure of josamycin in a patient with urethritis caused by Mycoplasma genitalium

Mycoplasma genitalium is one of the obligate pathogens that cause sexually transmitted diseases. To detect this pathogen in routine practice, only molecular genetic methods are used that are also used to identify the resistance of MGE to antibiotics. The first-line drugs for the treatment of diseases caused by MGE, are tetracycline and macrolides. In recent years, many countries have increasingly recorded cases of unsuccessful therapy macrolides. Mutations that confer antibiotic resistance to macrolides for Mycoplasm genitalium are concentrated in nucleotide positions 2058 and 2059 in region V of the 23S rRNA gene. Unknown status of macrolide resistance M. genitalium can lead to the development of a persistent infection. We describe the first reported cases of clinical josamycin treatment failure from patient with ure - thritis. The reason for antibiotic resistance was a mutation in the 23S rRNA of MGE as a nucleotide substitution in position A2058G.

Mycoplasma genitalium infections in Cuba: surveillance of urogenital syndromes, 2014-2015

Mycoplasma genitalium is an emerging sexually transmitted pathogen implicated in urethritis in men and several inflammatory reproductive tract syndromes in women. The prevalence of M. genitalium infections in Cuban patients with urogenital syndromes is unknown. The aim of this study was to analyse the prevalence of M. genitalium infection in sexually-active Cuban men and women with urogenital syndromes as a part of aetiological surveillance of urogenital syndromes in Cuba. Samples from men and women with urogenital syndromes submitted to the Mycoplasma Reference Laboratory for mycoplasma diagnosis from 1 January 2014 to 1 June 2015 were analysed by polymerase chain reaction (PCR) for detection of M. genitalium. A total of 971 samples were received and processed. Of the patients tested, 5.7% (47/824) of women and 27.9% (41/147) of men were positive for M. genitalium. This paper presents the largest study of M. genitalium infections among Cuban patients with urogenital syndromes and is Cuba's first M. genitalium survey. We suggest that M. genitalium should be considered in the Cuban sexually transmitted infection management protocols as an important pathogen, particularly in men.

23S rRNA and L22 ribosomal protein are involved in the acquisition of macrolide and lincosamide resistance in Mycoplasma capricolum subsp. capricolum

Mycoplasma capricolum subsp. capricolum (Mcc) is one of the causative agents of contagious agalactia, and antimicrobial therapy is the most commonly applied measure to treat outbreaks of this disease. Macrolides and lincosamides bind specifically to nucleotides at domains II and V of the 23S rRNA. Furthermore, rplD and rplV genes encode ribosomal proteins L4 and L22, which are also implicated in the macrolide binding site. The aim of this work was to study the relationship between mutations in these genes and the acquisition of macrolide and lincosamide resistance in Mcc. For this purpose, in vitro selected resistant mutants and field isolates were studied. This study demonstrates the appearance of DNA point mutations at the 23S rRNA encoding genes (A2058G, A2059G and A2062C) and rplV gene (Ala89Asp) in association to high minimum inhibitory concentration values. Hence, it proves the importance of alterations in 23S rRNA domain V and ribosomal protein L22 as molecular mechanisms responsible for the acquisition of macrolide and lincosamide resistance in both field isolates and in vitro selected mutants. Moreover, these mutations enable us to provide an interpretative breakpoint of antimicrobial resistance for Mcc at MIC 0.8 μg/ml.

Macrolide and fluoroquinolone resistance in Mycoplasma genitalium in two Swedish counties, 2011-2015

Mycoplasma genitalium, causing non-gonococcal non-chlamydial urethritis and associated with cervicitis, has developed antimicrobial resistance (AMR) to both the macrolide azithromycin (first-line treatment) and the fluoroquinolone moxifloxacin (second-line treatment). Our aim was to estimate the prevalence of resistance, based on genetic AMR determinants, to these antimicrobials in the M. genitalium population in two Swedish counties, Örebro and Halland, 2011-2015. In total, 672 M. genitalium positive urogenital samples were sequenced for 23S rRNA and parC gene mutations associated with macrolide and fluoroquinolone resistance, respectively. Of the samples, 18.6% and 3.2% in Örebro and 15.2% and 2.7% in Halland contained mutations associated with macrolide and fluoroquinolone resistance, respectively. The predominating resistance-associated mutations in the 23S rRNA gene was A2059G (n = 39) in Örebro and A2058G (n = 13) and A2059G (n = 13) in Halland. The most prevalent possible resistance-associated ParC amino acid alterations were S83I (n = 4) in Örebro and S83N (n = 2) in Halland. Resistance-associated mutations to both macrolides and fluoroquinolones were found in 0.7% of samples. Our findings emphasize the need for routine AMR testing, at a minimum for macrolide resistance, of all M. genitalium-positive samples and regular national and international surveillance of AMR in M. genitalium, to ensure effective patient management and rational antimicrobial use.

Quantitative Real-Time Polymerase Chain Reaction for the Diagnosis of Mycoplasma genitalium Infection in South African Men With and Without Symptoms of Urethritis

BACKGROUND

This study was done to diagnose Mycoplasma genitalium infection based on bacterial load in urine specimens from symptomatic and asymptomatic men.

METHODS

Urine specimens from 94 men with visible urethral discharge, 206 with burning on micturition and 75 without symptoms presenting to a family practitioner were tested for M. genitalium as well as Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis by transcription-mediated amplification assays. A quantitative polymerase chain reaction assay was used to determine the bacterial load for all specimens in which M. genitalium was the only organism detected.

RESULTS

Among the 375 specimens collected, M. genitalium was detected in 59 (15.7%) men (both symptomatic and asymptomatic) using the transcription-mediated amplification assay, and in 45 (12.0%) of the total population, it was the only pathogen detected. One or more pathogens were detected in 129 (43%) of the symptomatic men, with N. gonorrhoeae in 50 (16.7%); C. trachomatis in 37 (12.3%) and T. vaginalis present in 24 (8.0%) patients. Among the 17 patients where mixed infections were detected, M. genitalium with N. gonorrhoeae was the most common (11/17; 64.7%). Patients with visible urethral discharge had significantly higher M. genitalium concentrations than those with burning on micturition. The median M. genitalium load in symptomatic men was significantly higher than that in asymptomatic men.

CONCLUSIONS

This study confirms the high prevalence of M. genitalium among men with urethritis in South Africa and demonstrates that there is a strong association with M. genitalium bacterial load and clinical urethritis. As the number of organisms increased, the severity of the symptoms increased, an indication of the role that the organism plays in disease progression.

Mycoplasma genitalium infections: current treatment options and resistance issues

Mycoplasma genitalium is one of the important causes of non-gonococcal urethritis. Rising incidence and emerging antimicrobial resistance are a major concern these days. The poor clinical outcomes with doxycycline therapy led to the use of azithromycin as the primary drug of choice. Single-dose azithromycin regimen over a period of time was changed to extended regimen following studies showing better clinical cures and less risk of resistance development. However, emerging macrolide resistance, either due to transmission of resistance or drug pressure has further worsened the management of this infection. The issues of drug resistance and treatment failures also exist in cases of M. genitalium infection. At present, the emergence of multidrug-resistant (MDR) M. genitalium strains is an alarming sign for its treatment and the associated public health impact due to its complications. However, newer drugs like pristinamycin, solithromycin, sitafloxacin, and others have shown a hope for the clinical cure, but need further clinical trials to optimize the therapeutic dosing schedules and formulate appropriate treatment regimens. Rampant and inappropriate use of these newer drugs will further sabotage future attempts to manage MDR strains. There is currently a need to formulate diagnostic algorithms and etiology-based treatment regimens rather than the syndromic approach, preferably using combination therapy instead of a monotherapy. Awareness about the current guidelines and recommended treatment regimens among clinicians and local practitioners is of utmost importance. Antimicrobial resistance testing and global surveillance are required to assess the efficacy of current treatment regimens and for guiding future research for the early detection and management of MDR M. genitalium infections.

Chemical constituents, antibacterial and antioxidant properties of the essential oil flower of Tagetes minuta grown in Cala community Eastern Cape, South Africa

Background

Tagetes minuta has a long record of human use for the treatment of stomach and intestinal diseases. Most drugs used for diseases treatment are less efficacious with side effects and this brought the search for new treatment regimens mainly from medicinal plants.

Method

The essential oil (EO) was extracted by Clevenger’s-type apparatus and its chemical composition, antioxidant and antibacterial properties were determined by GC-MS, spectrophotometric and broth dilution methods respectively. S. uberis, E. cloacae, S. aureus, M. smegmatis, L. ivanovii, Vibrio spp. and E. coli bacteria strains were used as test bacteria.

Results

GC-MS analysis revealed 98 compounds in the EO flower of T. minuta and β-Ocimene (14. 40%) was the major chemical constituents. The EO exhibited highest inhibitory effect against DPPH radical, followed by its effect on ABTS, while LP radical showed the least sensitivity with IC₅₀ values of 2.45 mg/mL, 2.76 mg/mL and 3.23 mg/mL respectively. The EO showed antibacterial activities against all test organisms with MIC value for S. aureus, M. smegatis and S. uberis at 0.125 mg/mL and for L. ivanovii, Vibrio spp., E. cloacae and E. coli at 0.06 mg/mL. The EO showed MBC against E. cloacae and E. coli at 0.06 mg/mL at 0.5 mg/mL for S. uberis and 0.125 mg/mL for Vibrio spp.

Conclusion

Findings from this study suggest that the EO of T. minuta flower may be a useful candidate in the search for lead constituents for the synthesis of new potent antibacterial and antioxidant agent.

Prevalence of macrolide and fluoroquinolone resistance-mediating mutations in Mycoplasma genitalium in five cities in Russia and Estonia

Background and objective

Resistance in the sexually transmitted bacterium Mycoplasma genitalium to all recommended therapeutic antimicrobials have rapidly emerged. However, to date, internationally reported resistance surveillance data for M. genitalium strains circulating in Eastern Europe are entirely lacking. The aim of this study was to estimate the prevalence of macrolide and fluoroquinolone resistance-associated mutations in M. genitalium in four cities in Russia and one in Estonia, 2013–2016.

Materials and methods

Consecutive urogenital samples found positive for M. genitalium during diagnostic testing were retrospectively analyzed for resistance-associated mutations in the 23S rRNA and parC genes using pyrosequencing and conventional Sanger sequencing, respectively.

Results

In total, 867 M. genitalium positive samples from 2013–2016 were analyzed. Macrolide resistance-associated mutations were detected in 4.6% of the samples from Russia (0.7–6.8% in different cities) and in 10% of the samples from Estonia. The mutations A2059G and A2058G were highly predominating in both Russia and Estonia, accounting together for 90.9% of the cases positive for nucleotide substitutions in the 23S rRNA gene. The rates of possible fluoroquinolone resistance-associated mutations were 6.2% in Russia (2.5–7.6% in different cities) and 5% in Estonia. The mutations S83I and S83N were the most frequent ones in Russia (24.4% each), whereas D87N highly predominated in Estonia (83.3% of all fluoroquinolone resistance-associated mutations). Approximately 1% of the samples in both countries harbored both macrolide and possible fluoroquinolone resistance-associated mutations, with A2058G and S83I being the most frequent combination (37.5%).

Conclusions

The prevalence of macrolide and fluoroquinolone resistance-associated mutations in M. genitalium was 4.6% and 6.2%, respectively, in Russia, and 10% and 5%, respectively, in Estonia. Despite the relatively low rates of macrolide and fluoroquinolone resistance in these countries, antimicrobial resistance surveillance and testing for resistance-associated mutations in M. genitalium positive cases would be valuable.

Meta-analysis of the efficacy of moxifloxacin in treating Mycoplasma genitalium infection

Mycoplasma genitalium is an important pathogen that is transmitted through sexual contact. For patients diagnosed with M. genitalium infection, the current guidelines recommend 1 g of azithromycin as the first-line treatment. Moxifloxacin is used as a second-line drug due to its remarkable efficacy; however, increased use of moxifloxacin to treat M. genitalium infections has caused the emergence of cases of moxifloxacin treatment failure. This meta-analysis aims to estimate the treatment efficacy of moxifloxacin for M. genitalium infection. Electronic databases were searched for articles published from 1983 to the end of May 2016 using the following search terms: ( Mycoplasma genitalium) AND (moxifloxacin OR 1-cyclopropyl–7-(2,8-diazabicyclo(4.3.0)non-8-yl)-6-fluoro-8-methoxy-1,4-dihydro-4-oxo-3-quinoline carboxylic acid OR Proflox OR moxifloxacin hydrochloride OR Octegra OR Avelox OR Avalox OR Izilox OR Actira OR [treatment efficacy]). All included studies were published in English; all participants were diagnosed with M. genitalium infection, and microbial cure times were measured within 12 months after treatment. Treatment efficacy was measured as microbial cure at the final follow-up after treatment. In total, 17 studies including 252 participants met the inclusion criteria. The majority of these studies were observational. The random-effects pooled microbial cure rate was 96% (95% confidence interval [CI], 90%–99%; I2 = 28.59%, P = 0.13). For studies with sample collection deadlines prior to 2010, the pooled microbial cure rate was 100% (95% CI, 99%–100%; I2 = 0.00%, P = 1.00). For studies with sample collection deadlines of 2010 and later, the pooled microbial cure rate was 89% (95% CI, 82%–94%; I2 = 0.00%, P = 0.59). The elimination rate of moxifloxacin for M. genitalium infection has decreased from 100% to 89% since 2010. This decline merits considerable attention. We suggest close follow-up to investigate the efficacy of moxifloxacin for treating M. genitalium infections. Additionally, sentinel points should be established to detect mutations in the gyrA/B and parC/E genes, which are associated with moxifloxacin resistance.

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.

Azithromycin 1.5g Over 5 Days Compared to 1g Single Dose in Urethral Mycoplasma genitalium: Impact on Treatment Outcome and Resistance

BACKGROUND

We evaluated the impact of extended azithromycin (1.5g over 5 days) on selection of macrolide resistance and microbiological cure in men with Mycoplasma genitalium urethritis during 2013-2015 and compared this to cases treated with azithromycin 1g in 2012-2013.

METHODS

Microbiological cure was determined for men with M. genitalium urethritis treated with azithromycin 1.5g using quantitative polymerase chain reaction specific for M. genitalium DNA on samples 14-100 days post-treatment. Pre- and post-treatment macrolide resistance mutations were detected by sequencing the 23 S gene.

RESULTS

There was no difference in proportions with microbiological cure between azithromycin 1.5g and 1g: 62/106 (58%; 95% confidence interval [CI], 49%, 68%) and 56/107 (52%; 95%CI 42-62%), P = .34, respectively. Also, there was no difference in the proportion of wild-type 23 S rRNA (presumed macrolide sensitive) infections cured after 1.5g and azithromycin 1g: 28/34 (82%; 95%CI 65-92%) and 49/60 (82%; 95%CI 70-90%), P=1.0, respectively. There was no difference between 1.5g and 1g in the proportions of wild-type infections with post-treatment resistance mutations: 4/34 (12%; 95%CI 3-27%) and 11/60 (18%; 95%CI 10-30%), respectively, P = .40. Pre-treatment resistance was present in 51/98 (52%; 95%CI 42-62%) cases in 2013-2015 compared to 47/107 (44%; 95%CI 34-54%) in 2012-2013, P = .25.

CONCLUSIONS

Extended azithromycin 1.5g was no more effective than a single 1g dose at achieving cure of M. genitalium urethritis and importantly did not reduce the selection of macrolide resistance. Nonmacrolide and new approaches for the treatment of M. genitalium urethritis are required.

Bacterial Load in Daily Urine Samples of Patients Infected with Mycoplasma genitalium, Mutation Analysis, and Response to Treatment

Objective. Increasing macrolide resistant strains of Mycoplasma genitalium is a challenge, and to differentiate between treatment failure and reinfection a timely test of cure (TOC) is warranted. The aim of this study was to evaluate the best time for TOC after five days' treatment of Mycoplasma genitalium infection with azithromycin. Methods. Nineteen patients with positive PCR for Mycoplasma genitalium in urine provided urine samples daily for 2 weeks and on days 21, 28, and 35. Samples were tested by a commercial qPCR and by sequencing of the 23S rRNA gene. Results. Eight patients with a wild type of Mycoplasma genitalium responded successfully within four days after treatment initiation. Eleven patients had a mutation in the 23S rRNA gene. These samples exhibited high variations in bacterial load, and some patients tested negative at several time points during the observation period. Conclusions. Day-to-day fluctuations in the mutation samples allow for false negative TOC during the first 5 weeks after start of treatment. Due to increasing macrolide resistance of Mycoplasma genitalium, pretreatment mutation analysis is recommended. When a wild type is verified, TOC performed one week after initiation of treatment is suggested.

Background review for the 2016 European guideline on Mycoplasma genitalium infections

Mycoplasma genitalium is a cause of 10-35% of non-chlamydial non-gonococcal urethritis in men and in women, and is associated with cervicitis and pelvic inflammatory disease (PID). Transmission of M. genitalium occurs through direct mucosal contact. In women, symptoms include vaginal discharge, dysuria or symptoms of PID - abdominal pain and dyspareunia. In men, urethritis, dysuria and discharge predominates. Asymptomatic infections are frequent. In this review, we present the evidence base for the recommendations in the 2016 European guideline on M. genitalium infections and describe indications for testing, recommended diagnostic methods, treatment and patient management. The guideline was prepared on behalf of the European branch of The International Union against Sexually Transmitted Infections; the European Academy of Dermatology and Venereology; the European Dermatology Forum; the European Society of Clinical Microbiology and Infectious Diseases; the Union of European Medical Specialists. The European Centre for Disease Prevention and Control and the European Office of the World Health Organisation also contributed to their development.

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.

High Resistance to Azithromycin in Clinical Samples from Patients with Sexually Transmitted Diseases in Guangxi Zhuang Autonomous Region, China

Azithromycin is used as an alternative medicine in patients with syphilis who are intolerant to penicillin. Nevertheless, the report of treatment failure of azithromycin for patients with syphilis has raised concerns in China in the past years. In this study, 178 patients with early syphilis, who were treated in sexually transmitted infections clinics in four cities in Guangxi Zhuang Autonomous Region were enrolled to investigate the regional prevalence of Treponema pallidum strain resistant to azithromycin. Nested PCR was performed to amplify the 23S ribosomal RNA (23SrRNA) gene. The point mutation of A2058G in 23SrRNA, which confers Treponema pallidum resistance to azithromycin, was measured by endonuclease digestion of PCR amplification products using MboII. A2058G point mutation was detected in 91.0% (162/178; 95% CI, 86.8%, 95.2%) of the specimens, but no difference in prevalence of azithromycin resistance was found between the patients who had taken antibiotics before enrollment and the patients who had not (91.8% vs. 89.4%), nor between the patients with and without past sexually transmitted infections (87.1% vs. 93.1%). We concluded that azithromycin may not be suitable for syphilis as a treatment option in Guangxi Zhuang Autonomous Region because of the extremely high prevalence of resistance in the general syphilis population.

Methods for in vitro evaluating antimicrobial activity: A review

In recent years, there has been a growing interest in researching and developing new antimicrobial agents from various sources to combat microbial resistance. Therefore, a greater attention has been paid to antimicrobial activity screening and evaluating methods. Several bioassays such as disk-diffusion, well diffusion and broth or agar dilution are well known and commonly used, but others such as flow cytofluorometric and bioluminescent methods are not widely used because they require specified equipment and further evaluation for reproducibility and standardization, even if they can provide rapid results of the antimicrobial agent's effects and a better understanding of their impact on the viability and cell damage inflicted to the tested microorganism. In this review article, an exhaustive list of in vitro antimicrobial susceptibility testing methods and detailed information on their advantages and limitations are reported.