Mycoplasma genitalium in the Far North Queensland backpacker population: An observational study of prevalence and azithromycin resistance

Mycoplasma genitalium infection and resistance-associated mutations to macrolides and fluoroquinolones among high-risk patients in Taiwan

BACKGROUND

Mycoplasma genitalium is an emerging etiology of sexually transmitted infections (STIs) with increasing resistance to antimicrobials. Surveillance on the epidemiology of M. genitalium infection and antimicrobial resistance is warranted.

METHODS

Between September 2021 and August 2023, people with HIV (PWH) and people without HIV (PWoH) at risk of STIs were screened for M. genitalium infection using a multiplex polymerase-chain-reaction assay of specimens collected from the rectum, urethra, oral cavity, and vagina. The prevalences of resistance-associated mutations (RAMs) of M. genitalium to fluoroquinolones, macrolides, and tetracycline were investigated.

RESULTS

During the 2-year study period, 1021 participants were enrolled, including 531 PWH and 490 PWoH. Overall, 83 (8.1%) and 34 (7.6%) participants had M. genitalium infection at baseline and during follow-up, respectively, with the rectum being the most common site of detection (61.5%). With the first course of antimicrobial treatment, 27 of 63 (42.9%) participants with M. genitalium infection were cured during follow-up, including 24 of 58 (41.4%) who received doxycycline monotherapy. The prevalence of RAMs to macrolides, fluoroquinolones, and tetracyclines at baseline were 24.3%, 22.4%, and 7.9%, respectively. Though PWH had more M. genitalium infection (10.2% vs 5.9%, p = 0.01), a higher rate of RAMs to macrolides (41.0% vs 14.7%, p < 0.01) was found in PWoH.

CONCLUSIONS

Among high-risk populations, the prevalence of M. genitalium infection was 8.1%. The overall genotypic resistance of M. genitalium to macrolides and fluoroquinolones was moderately high in Taiwan. Detection of M. genitalium infection and antimicrobial resistance is warranted to ensure resistance-guided antimicrobial treatments to be administered.

A systematic review and meta-analysis of sexually transmitted infections and blood-borne viruses in travellers

BACKGROUND

Sexually transmitted infections (STIs) and blood-borne viruses (BBVs) impose a global health and economic burden. International travellers facilitate the spread of infectious diseases, including STIs. Hence, this review assessed the prevalence/proportionate morbidity of travellers with STIs and sexually transmitted BBVs and factors associated with the infection in this population.

METHODS

PubMed, Scopus, Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase and Cochrane Library were searched from inception of the databases until November 2022. Published analytical observational studies reporting the prevalence/proportionate morbidity of travellers with STIs and factors associated with STIs by type of traveller [i.e. tourists, business travellers, students, visiting friends or relatives (VFRs), international truck drivers, backpackers, expatriates and men who have sex with men (MSM)] were included. The selection of articles, data extraction and risk of bias assessment were conducted by two independent reviewers. Meta-analyses were conducted for each STI by clinical presentation and type of traveller.

RESULTS

Thirty-two studies (n = 387 731 travellers) were included; 19 evaluated the proportionate morbidity of STIs among symptomatic travellers, while 13 examined the prevalence of STIs in asymptomatic travellers. The highest proportionate morbidity was found among VFRs (syphilis, 1.67%; 95% CI: 1.03-2.81%), backpackers (Chlamydia trachomatis, 6.58%; 95% CI: 5.96-7.25%) and MSM (HIV [2.50%;95% CI: 0.44-12.88%], gonorrhoea [4.17%; 95% CI: 1.1.5-13.98%], lymphogranuloma venereum [4.17%;95% CI: 1.1.5-13.98%] and HAV [20.0%; 95% CI: 14.99-26.17%]). The highest prevalence of STIs among asymptomatic were found in MSM (HIV [25.94%; 95% CI: 22.21-30.05%] and HBV [24.90%; 95% CI: 21.23-28.96%]) and backpackers (C. trachomatis, 3.92%; 95% CI: 2.72-5.32%). Short duration of the trip (<1 month), not having pre-travel consultation, travelling to Southeast Asia and being unvaccinated for HBV were identified as risk factors for STIs.

CONCLUSION

Strategies to prevent STIs and sexually transmitted BBVs should be discussed at pre-travel consultations, and recommendations should be prioritized in high-risk groups of travellers, such as backpackers, VFRs and MSMs. Additionally, healthcare providers should tailor recommendations for safe sex practices to individual travellers' unique needs.

Emergence and Mechanism of Resistance of Tulathromycin Against Mycoplasma hyopneumoniae in a PK/PD Model and the Fitness Costs of 23S rRNA Mutants

Macrolides are widely used in diseases caused by Mycoplasma spp. The new semi-synthetic macrolide antibiotic tulathromycin is currently in wide use for the treatment of respiratory diseases of livestock. The objective of this study was to evaluate the antibacterial effect of tulathromycin against Mycoplasma hyopneumoniae using an in vitro pharmacokinetic/pharmacodynamic (PK/PD) model to reveal mechanisms of antibiotic resistance and to evaluate the fitness of drug-resistant strains. In this study, high performance liquid chromatography-tandem mass spectrometry was used to determine drug concentrations for the in vitro model after dosing. The peak concentrations were in the range 0.3125–20 μg/mL (1 × MIC-64 × MIC). The ratio of the area under the concentration-time curve (AUC) over 72 h divided by the MIC (AUC_72h/MIC) had the highest correlation with the antibacterial effect of tulathromycin against M. hyopneumoniae. Tulathromycin also showed concentration-dependent antimicrobial effects and promoted the emergence of drug-resistant bacteria after being cultured for 168 h and most were mutations in 23S rRNA at site A2058G (E.coli numbering) and only a single isolate was an A2058T (E.coli numbering) mutant. In the presence of reserpine, we determined the MIC of tulathromycin, tilmicosin, tiamulin and tylosin against these drug-resistant bacteria and the strains with efflux pump mechanisms were found among the strains resistant to tilmicosin. Gene expression analysis indicated that the ABC and MATE transporter efflux pump genes RS01935, RS02670, RS01115, RS01970, RS02395 and RS03540 (MATE family efflux transporter) were up-regulated in the three strains (P < 0.05 or P < 0.01). These investigations provide guidance for clinical administration of tulathromycin and elucidate the mechanism and fitness cost of drug resistance in M. hyopneumoniae.

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.

Levels of Mycoplasma genitalium Antimicrobial Resistance Differ by Both Region and Gender in the State of Queensland, Australia: Implications for Treatment Guidelines

Mycoplasma genitalium is frequently associated with urogenital and rectal infections, with the number of cases of macrolide-resistant and quinolone-resistant M. genitalium infection continuing to increase. In this study, we examined the levels of resistance to these two common antibiotic treatments in geographically distinct locations in Queensland, Australia. Samples were screened for macrolide resistance-associated mutations using a commercially available kit (ResistancePlus MG; SpeeDx), and quinolone resistance-associated mutations were identified by PCR and DNA sequencing. Comparisons between antibiotic resistance mutations and location/gender were performed. The levels of M. genitalium macrolide resistance were high across both locations (62%). Quinolone resistance mutations were found in ∼10% of all samples, with a number of samples harboring mutations conferring resistance to both macrolides and quinolones. Quinolone resistance was higher in southeast Queensland than in north Queensland, and this was consistent in both males and females (P = 0.007). The M. genitalium isolates in rectal swab samples from males harbored high levels of macrolide (75.9%) and quinolone (19%) resistance, with 15.5% harboring resistance to both classes of antibiotics. Overall, the lowest observed level of resistance was to quinolones in females from north Queensland (1.6%). These data highlight the high levels of antibiotic resistance in M. genitalium isolates within Queensland and the challenges faced by sexually transmitted infection clinicians in managing these infections. The data do, however, show that the levels of antibiotic resistance may differ between populations within the same state, which has implications for clinical management and treatment guidelines. These findings also support the need for ongoing antibiotic resistance surveillance and tailored treatment.