Investigation of fluoroquinolone resistance mechanism in Mycoplasma hominis isolated from urogenital samples in a Chinese hospital

The complete genome sequence of unculturable Mycoplasma faucium obtained through clinical metagenomic next-generation sequencing

Introduction

Diagnosing Mycoplasma faucium poses challenges, and it's unclear if its rare isolation is due to infrequent occurrence or its fastidious nutritional requirements.

Methods

This study analyzes the complete genome sequence of M. faucium, obtained directly from the pus of a sternum infection in a lung transplant patient using metagenomic sequencing.

Results

Genome analysis revealed limited therapeutic options for the M. faucium infection, primarily susceptibility to tetracyclines. Three classes of mobile genetic elements were identified: two new insertion sequences, a new prophage (phiUMCG-1), and a species-specific variant of a mycoplasma integrative and conjugative element (MICE). Additionally, a Type I Restriction-Modification system was identified, featuring 5'-terminally truncated hsdS pseudogenes with overlapping repeats, indicating the potential for forming alternative hsdS variants through recombination.

Conclusion

This study represents the first-ever acquisition of a complete circularized bacterial genome directly from a patient sample obtained from invasive infection of a primary sterile site using culture-independent, PCR-free clinical metagenomics.

Trends of fluoroquinolones resistance in Mycoplasma and Ureaplasma urogenital isolates: Systematic review and meta-analysis

BACKGROUND

Mycoplasma and Ureaplasma spp. especially M. hominis, U. parvum, and U. urealyticum recognized as an important cause of urogenital infections. Sake of the presence of antibiotic resistance and a continuous rise in resistance, the treatment options are limited, and treatment has become more challenging and costlier.

OBJECTIVES

Therefore, this meta-analysis aimed to estimate worldwide resistance rates of genital Mycoplasmas and Ureaplasma to fluoroquinolones (ciprofloxacin, ofloxacin, moxifloxacin, and levofloxacin) agents.

METHODS

We searched the relevant published studies in PubMed, Scopus, and Embase from until 3, March 2022. All statistical analyses were carried out using the statistical package R.

RESULTS

The 30 studies included in the analysis were performed in 16 countries. In the metadata, the proportions of ciprofloxacin, ofloxacin, moxifloxacin, and levofloxacin resistance in Mycoplasma and Ureaplasma urogenital isolates were reported 59.8% (95% CI 49.6, 69.1), 31.2% (95% CI 23, 40), 7.3% (95% CI 1, 31), and 5.3% (95% CI 1, 2), respectively. According to the meta-regression, the ciprofloxacin, ofloxacin, moxifloxacin, and levofloxacin rate increased over time. There was a statistically significant difference in the fluoroquinolones resistance rates between different continents/countries (P < 0.05).

CONCLUSIONS

Based on the results obtained in this systematic review and meta-analysis we recommend the use of the newer group of fluoroquinolones especially levofloxacin as the first choice for the treatment of genital mycoplasmosis, as well as ofloxacin for the treatment of genital infections caused by U. parvum.

Mycoplasma hominis necrotising pneumonia in an immunocompetent adult male

Mycoplasma hominis, a common coloniser of the urogenital tract, is a rare cause of respiratory infections in an immunocompetent patient. M. hominis lacks a cell wall and can be difficult to identify with standard culture methods posing difficulties in diagnosis and treatment. We describe a case of M. hominis pneumonia in an immunocompetent man in his early 40s without any risk factors presenting with a cavitary lesion who developed empyema and necrotising pneumonia requiring surgical debridement. Identification of M. hominis and subsequent modification of antibiotic therapy led to favourable outcome. M. hominis should be considered in the differential diagnosis of patients with treatment resistant pneumonia especially in patients with trauma, intracranial injury, lung transplant or if immunocompromised. While M. Hominis is naturally resistant to all antibiotics that target cell wall synthesis, we recommend levofloxacin or other fluoroquinolone to most effectively treat with doxycycline as a potential alternative.

In Vitro Activity of Delafloxacin and Finafloxacin against Mycoplasma hominis and Ureaplasma Species

The in vitro activity of two new fluoroquinolones, delafloxacin and finafloxacin, were evaluated against M. hominis and Ureaplasma spp. The MICs of delafloxacin, finafloxacin, and two classical fluoroquinolones (moxifloxacin and levofloxacin) were tested against 29 M. hominis and 67 Ureaplasma spp. isolates using the broth microdilution method. The molecular mechanisms underlying fluoroquinolone resistance were also investigated. Delafloxacin exhibited low MICs against M. hominis and Ureaplasma spp., including the levofloxacin-resistant isolates. For M. hominis, delafloxacin showed low MIC₉₀ value of 1 μg/mL (MIC range, <0.031 -1 μg/mL) compared to 8 μg/mL for finafloxacin, 16 μg/mL for moxifloxacin, and 32 μg/mL for levofloxacin. For U. parvum and U. urealyticum, delafloxacin had low MIC₉₀ values (U. parvum, 2 μg/mL; U. urealyticum, 4 μg/mL) compared to 16 -32 μg/mL for finafloxacin, 16 μg/mL for moxifloxacin, and 32 - >32 μg/mL for levofloxacin. The two mutations GyrA S153L and ParC S91I were commonly identified in fluoroquinolone-resistant M. hominis, and ParC S83L was the most frequent mutation identified in fluoroquinolone-resistant Ureaplasma spp. Delafloxacin displayed lower MICs against fluoroquinolone-resistant isolates of both M. hominis and Ureaplasma spp. that have mutations in the quinolone resistance determining regions (QRDRs) than the two classical fluoroquinolones. Delafloxacin is a promising fluoroquinolone with low MICs against fluoroquinolone-resistant M. hominis and Ureaplasma spp. Our study confirms the potential clinical use of delafloxacin in treating antimicrobial-resistant M. hominis and Ureaplasma spp. infections.

IMPORTANCE Fluoroquinolone resistance in Mycoplasma hominis and Ureaplasma spp. is on the rise globally, which has compromised the efficacy of the currently available antimicrobial agents. This study evaluated the antimicrobial activity of two new fluoroquinolones, delafloxacin and finafloxacin, for the first time, against M. hominis and Ureaplasma spp. clinical isolates. Delafloxacin and finafloxacin displayed different antimicrobial susceptibility profiles against M. hominis and Ureaplasma spp. in vitro. Delafloxacin was found to be more effective against M. hominis and Ureaplasma spp. than three classical fluoroquinolones (finafloxacin, moxifloxacin, and levofloxacin). Finafloxacin displayed activity similar to moxifloxacin but superior to levofloxacin against M. hominis and Ureaplasma spp. Our findings demonstrate that delafloxacin is a promising fluoroquinolone with outstanding activity against fluoroquinolone-resistant M. hominis and Ureaplasma spp.

Clinical and Microbiological Characterization of Bloodstream Infections Caused by Mycoplasma hominis: An Overlooked Pathogen

Introduction

Methods

Results

Conclusions

Supplementary Information

Mycoplasma hominis bloodstream infection and persistent pneumonia in a neurosurgery patient: a case report

Background

Mycoplasma hominis is typically associated with a urogenital tract infection, while its association with bacteremia and pneumonia is rare and therefore easily overlooked. Here we report a M. hominis bloodstream infection and pneumonia in a surgical patient.

Case presentation

A 56-year-old male with symptoms of pneumonia underwent microsurgery and decompressive craniectomy after a left basal ganglia hemorrhage. The patient recovered well from surgery, but pulmonary symptoms progressively worsened, with antimicrobial therapies seemingly ineffective. Culturing of bilateral blood samples resulted in pin-point-sized colonies on blood agar plates, which were subsequently identified as M. hominis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Furthermore, sequencing of bronchoalveolar lavage samples also identified M. hominis as the main pathogen responsible for the pulmonary symptoms. The M. hominis strain was ciprofloxacin resistant, but susceptible to doxycycline and moxifloxacin. Doxycycline and moxifloxacin were subsequently used in a successful combination therapy that finally alleviated the patient’s fever and resulted in absorption of pleural effusion. At 1-month follow-up, following complaints of dysuria, a prostate abscess containing M. hominis was detected as the likely primary source of infection. The abscess was successfully drained and treated with doxycycline.

Conclusions

Mycoplasma hominis should be considered as a source of bloodstream infections and pneumonia, particularly when the response to standard antimicrobial therapy is limited. In this case, effective antimicrobial therapy was only commenced after identification of M. hominis and antimicrobial susceptibility testing.

Mycoplasma hominis meningitis after operative neurosurgery: A case report and review of literature

BACKGROUND

Mycoplasma hominis (M. hominis), which causes central nervous system infections in adults, is very rare. It is also relatively difficult to culture mycoplasma and culturing requires special media, resulting in a high rate of clinical underdiagnosis. Therefore, clinicians often treat patients based on their own experience before obtaining pathogenic results and may ignore infections with atypical pathogens, thus delaying the diagnosis and treatment of patients and increasing the length of hospital stay and costs.

CASE SUMMARY

A 44-year-old man presented to the hospital complaining of recurrent dizziness for 1 year, which had worsened in the last week. After admission, brain magnetic resonance imaging (MRI) revealed a 7.0 cm × 6.0 cm × 6.1 cm lesion at the skull base, which was irregular in shape and had a midline shift to the left. Based on imaging findings, meningioma was our primary consideration. After lesion resection, the patient had persistent fever and a diagnosis of suppurative meningitis based on cerebrospinal fluid (CSF) examination. The patient was treated with the highest level of antibiotics (meropenem and linezolid), but the response was ineffective. Finally, M. hominis was detected by next-generation metagenomic sequencing (mNGS) in the CSF. Therefore, we changed the antibiotics to moxifloxacin 0.4 g daily combined with doxycycline 0.1 g twice a day for 2 wk, and the patient had a normal temperature the next day.

CONCLUSION

Mycoplasma meningitis after neurosurgery is rare. We can use mNGS to detect M. hominis in the CSF and then provide targeted treatment.

Defining Fluoroquinolone Resistance-Mediating Mutations from Non-Resistance Polymorphisms in Mycoplasma hominis Topoisomerases

Often dismissed as a commensal, Mycoplasma hominis is an increasingly prominent target of research due to its role in septic arthritis and organ transplant failure in immunosuppressed patients, particularly lung transplantation. As a mollicute, its highly reductive genome and structure render it refractile to most forms of treatment and growing levels of resistance to the few sources of treatment left, such as fluoroquinolones. We examined antimicrobial susceptibility (AST) to fluoroquinolones on 72 isolates and observed resistance in three (4.1%), with corresponding mutations in the quinolone resistance-determining region (QRDR) of S83L or E87G in gyrA and S81I or E85V in parC. However, there were high levels of polymorphism identified between all isolates outside of the QRDR, indicating caution for a genomics-led approach for resistance screening, particularly as we observed a further two quinolone-susceptible isolates solely containing gyrA mutation S83L. However, both isolates spontaneously developed a second spontaneous E85K parC mutation and resistance following prolonged incubation in 4 mg/L levofloxacin for an extra 24–48 h. Continued AST surveillance and investigation is required to understand how gyrA QRDR mutations predispose M. hominis to rapid spontaneous mutation and fluoroquinolone resistance, absent from other susceptible isolates. The unusually high prevalence of polymorphisms in M. hominis also warrants increased genomics’ surveillance.

In vitro activities of acetylmidecamycin and other antimicrobials against human macrolide-resistant Mycoplasma pneumoniae isolates

OBJECTIVES

To assess the in vitro activities of acetylmidecamycin, a 16-membered macrolide, and 11 other antimicrobial agents against human mycoplasmas.

METHODS

A total of 187 clinical isolates, Mycoplasma pneumoniae (n = 110), Mycoplasma hominis (n = 26) and Ureaplasma species (n = 51), were included in this study. The MICs of 12 antimicrobial agents, including acetylmidecamycin, thiamphenicol, chloramphenicol and some other macrolides, fluoroquinolones and tetracyclines, for these clinical isolates were determined by the broth microdilution method.

RESULTS

For M. pneumoniae, the MIC90 values of the tested macrolides were: acetylmidecamycin (1 mg/L)<josamycin (4 mg/L)<midecamycin (8 mg/L)<azithromycin (16 mg/L)<erythromycin (>128 mg/L). Thiamphenicol and chloramphenicol had the same MIC90 (2 mg/L). For Ureaplasma species, the MIC90 values were: acetylmidecamycin (0.25 mg/L)<josamycin (0.5 mg/L)=midecamycin<azithromycin (1 mg/L)=erythromycin. Chloramphenicol had a lower MIC90 (2 mg/L) than that of thiamphenicol (4 mg/L). For M. hominis, the MIC90 values were: acetylmidecamycin (0.25 mg/L)<josamycin (0.5 mg/L)<midecamycin (2 mg/L)<azithromycin (>128 mg/L)=erythromycin. The MIC90 values of chloramphenicol and thiamphenicol were 2 and 4 mg/L, respectively.

CONCLUSIONS

The results indicated that acetylmidecamycin and thiamphenicol are active in vitro against the most common mycoplasma species infecting humans, including those resistant to macrolides and fluoroquinolones. Acetylmidecamycin and thiamphenicol might be a promising option for clinicians to treat infections caused by Mycoplasma and Ureaplasma spp., particularly macrolide-resistant M. pneumoniae in paediatrics and fluoroquinolone-resistant M. hominis in adults. Further investigation of their clinical roles in treating infections caused by these organisms is warranted.

Antimicrobial Resistance in Clinical Ureaplasma spp. and Mycoplasma hominis and Structural Mechanisms Underlying Quinolone Resistance

Antibiotic resistance is a global concern; however, data on antibiotic-resistant Ureaplasma spp. and Mycoplasma hominis are limited in comparison to similar data on other microbes. A total of 492 Ureaplasma spp. and 13 M. hominis strains obtained in Hangzhou, China, in 2018 were subjected to antimicrobial susceptibility testing for levofloxacin, moxifloxacin, erythromycin, clindamycin, and doxycycline using the broth microdilution method. The mechanisms underlying quinolone and macrolide resistance were determined. Meanwhile, a model of the topoisomerase IV complex bound to levofloxacin in wild-type Ureaplasma spp. was built to study the quinolone resistance mutations. For Ureaplasma spp., the levofloxacin, moxifloxacin, and erythromycin resistance rates were 84.69%, 51.44%, and 3.59% in U. parvum and 82.43%, 62.16%, and 5.40% in U. urealyticum, respectively. Of the 13 M. hominis strains, 11 were resistant to both levofloxacin and moxifloxacin, and five strains showed clindamycin resistance. ParC S83L was the most prevalent mutation in levofloxacin-resistant Ureaplasma strains, followed by ParE R448K. The two mutations GyrA S153L and ParC S91I were commonly identified in quinolone-resistant M. hominis A molecular dynamics-refined structure revealed that quinolone resistance-associated mutations inhibited the interaction and reduced affinity with gyrase or topoisomerase IV and quinolones. The novel mutations S21A in the L4 protein and G2654T and T2245C in 23S rRNA and the ermB gene were identified in erythromycin-resistant Ureaplasma spp. As fluoroquinolone resistance in Ureaplasma spp. and Mycoplasma hominis remains high in China, the rational use of antibiotics needs to be further enhanced.