Molecular mechanism of fluoroquinolones resistance in Mycoplasma hominis clinical isolates

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.

Deciphering the genetic basis of resistome and virulome diversity among multidrug-resistant Mycoplasma hominis

Mycoplasma hominis, a commensal bacterium that commonly inhabits the genital tract, leading to infections in both the genitourinary and extragenital regions. However, the antimicrobial resistance and pathogenic mechanisms of M. hominis isolated from extra-urogenital cystic abscess is largely unknown. This study reports the genomic epidemiological characteristics of a M. hominis isolate recovered from a pelvic abscess sample in China. Genomic DNA was extracted and sequenced using Illumina HiSeq X Ten platform. De novo assembly was performed and in silico analysis was accomplished by multiple bioinformatics tools. For phylogenomic analysis, publicly available M. hominis genomes were retrieved from NCBI GenBank database. Whole genome sequencing data showed that the genome size of M. hominis MH4246 was calculated as 679,746 bp, with 558 protein-coding sequences and a G + C content of 26.9%. M. hominis MH4246 is resistant to fluoroquinolones and macrolides, harboring mutations in the quinolone resistance-determining regions (QRDRs) (GyrA S153L, ParC S91I and ParE V417I) and 23S rRNA gene (G280A, C1500T, T1548C and T2218C). Multiple virulence determinants, such as tuf, hlyA, vaa, oppA, MHO_0730 and alr genes, were identified. Phylogenetic analysis showed that the closest relative of M. hominis MH4246 was the strain MH-1 recovered from China, which differed by 3490 SNPs. Overall, this study contributes to the comprehension of genomic characteristics, antimicrobial resistance patterns, and the mechanisms underlying the pathogenicity of this pathogen.

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

Introduction

Methods

Results

Conclusions

Supplementary Information

Mycoplasma hominis meningitis in an extremely preterm newborn: a case report

Background

Mycoplasma Hominis is a micro-organism which is a part of the human genitourinary tract flora. Neonates are susceptible to acquire this pathogen either in utero or through vertical transmission. In rare cases, it may cause central nervous system infections with severe morbidity and mortality in preterm and term neonates.

Case presentation

We present a case of Mycoplasma Hominis meningitis in an extremely preterm neonate who presented with lethargy, tachycardia and seizures on day 7 of life. There was no history of maternal systemic or genitourinary infection during pregnancy and at the time of delivery. Empirical antibiotic therapy for neonatal meningitis was commenced after sending blood and cerebrospinal fluid cultures. Cerebrospinal fluid analysis showed pleocytosis with neutrophilic predominance, but no bacteria was identified on gram staining. Blood culture yielded no growth of any bacterial pathogen. However, growth of Mycoplasma Hominis was suspected in cerebrospinal fluid culture which was confirmed by 16S ribosomal ribonucleic acid (RNA) polymerase chain reaction analysis. Subsequently, antibiotics were changed to Moxifloxacin and Doxycycline which were given for a total duration of 6 weeks. Multiple cerebrospinal fluid cultures were performed during this treatment. No growth of any pathogen was identified on any of these cerebrospinal fluid cultures.

Conclusions

We report a rare case of Mycoplasma Hominis meningitis in an extremely preterm neonate which was successfully treated with a combination therapy of Moxifloxacin and Doxycycline.

It is important to consider the possibility of Mycoplasma Hominis meningitis in neonates who present with clinical signs and pleocytosis in cerebrospinal fluid but negative gram staining and no growth on conventional culture media.

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.

Genomic characterisation of a multidrug-resistant Mycoplasma hominis isolate recovered from a synovial fluid sample in China

OBJECTIVES

Mycoplasma hominis is one of the smallest free-living opportunistic human pathogens responsible for a diverse range of infections. However, knowledge regarding the genetic and pathogenic mechanisms of M. hominis is still very limited. This study aimed to investigate the genomic features of a multidrug-resistant M. hominis isolate recovered from a synovial fluid sample in China.

METHODS

Antimicrobial susceptibility of M. hominis MH-1 was determined by broth microdilution. Genomic DNA was extracted and was sequenced using an Illumina HiSeq X Ten platform. De novo genome assembly was performed using SPAdes, and the draft genome was annotated using the NCBI Prokaryotic Genome Annotation Pipeline (PGAP). Core genome single nucleotide polymorphism (cgSNP) analysis between M. hominis MH-1 and all 25 M. hominis strains retrieved from the NCBI GenBank database was performed using BacWGSTdb server.

RESULTS

Antimicrobial susceptibility testing showed that M. hominis MH-1 was resistant to macrolides and fluoroquinolones. The genome size was calculated as 720 262 bp, with 608 protein-coding sequences and a G + C content of 26.8%. Several antimicrobial resistance genes, virulence genes, genomic islands and insertion sequences were identified in the genome. Phylogenetic analysis showed that the strains retrieved from NCBI as well as M. hominis MH-1 were not epidemiologically related. The closest relative of M. hominis MH-1 was recovered from the USA, which differed by 5898 SNPs.

CONCLUSION

This study reports the first genome sequence of a multidrug-resistant M. hominis isolate in China. These data may help to understand the genomic features and antimicrobial resistance mechanisms of this pathogen.

The Genome Structure of Ciprofloxacin-Resistant Mycoplasma Hominis Clinical Isolates

The genome structure of three ciprofloxacin-resistant Mycoplasma hominis clinical isolates was studied using next-generation sequencing on the Illumina platform. The protein sequences of the studied Mycoplasma strains were found to have a high degree of homology. Mycoplasma hominis (M45, M57, MH1866) was shown to have limited biosynthetic capabilities, associated with the predominance of the genes encoding the proteins involved in catabolic processes. Multiple single-nucleotide substitutions causing intraspecific polymorphism of Mycoplasma hominis were found. The genes encoding the efflux systems - ABC transporters (the ATP-binding cassette superfamily) and proteins of the MATE (multidrug and toxic compound extrusion) family - were identified. The molecular mechanism of ciprofloxacin resistance of the Mycoplasma hominis M45 and M57 isolates was found to be associated with the Ser83Leu substitution in DNA gyrase subunit A. In the Mycoplasma hominis MH1866 isolate it was related to the Lys144Arg substitution in topoisomerase IV subunit A.

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

PURPOSE

Mycoplasma hominis is considered among the causes of urogenital infections and shows increasing resistance to fluoroquinolones. However, data regarding the fluoroquinolone resistance mechanism of M. hominis in Southwest China are limited. This study aimed to investigate gene mutations of quinolone resistance-determining regions (QRDRs) of M. hominis isolated from clinical urogenital samples in a Chinese hospital.

METHODOLOGY

Strains of M. hominis were identified by 16S rRNA gene sequencing. The minimal inhibitory concentrations (MICs) of fluoroquinolones were determined by the broth microdilution method, following CLSI guidelines. PCR was used to amplify the QRDRs of the genes gyrA, gyrB, parC and parE. Positive products were sequenced, and gene mutations and amino acid substitutions were analysed by DNAMAN software and BLAST.

RESULTS

The resistance rates of M. hominis to ciprofloxacin (CIP), levofloxacin (LVX), moxifloxacin (MXF) and gatifloxacin (GAT) were 90.5, 85.7, 73.8 and 71.4 %, respectively. A total of 57 isolates of M. hominis were screened, among which 52 strains demonstrated different resistant phenotypes to fluoroquinolones, 41 harboured amino acid substitutions of GyrA S153L, 51 harboured ParC S91I and 22 harboured ParC K144R. ParE A463S and ParC A154T were recorded for the first time and no amino acid change was detected in GyrB.

CONCLUSION

The resistance of M. hominis to fluoroquinolones in Southwest China is mainly related to mutations in QRDRs of either gyrA or parC. High-level resistance is associated with mutations in both DNA gyrase and topoisomerase IV.

Mycoplasma hominis shows strain-dependent increase in resistance to selected antibiotics after symbiosis with Trichomonas vaginalis

OBJECTIVES

Mycoplasma hominis, a genetically heterogeneous, cell-wall-less bacterium, is able to live in symbiosis with the protozoan parasite Trichomonas vaginalis. Whilst the impact of this symbiosis on T. vaginalis has been investigated to a certain extent, less light has been shed on the influence on M. hominis.

METHODS

An in vitro minimum inhibitory concentration (MIC) study of the antimicrobial susceptibility of three clinical M. hominis isolates (V475, AKH136 and MhSS10) to clindamycin, moxifloxacin, ciprofloxacin and gentamicin was performed in dependence on symbiosis with T. vaginalis strain IR78.

RESULTS

Passaging of M. hominis through T. vaginalis led to an increase in MICs to all drugs investigated in M. hominis V475 and M. hominis MhSS10 (apart from gentamicin). Shifts from intermediate to resistant (MhSS10 for ciprofloxacin) and from susceptible to intermediate-resistant (V475 for gentamicin; P=0.015) were observed. Moreover, initial susceptibility of V475 to moxifloxacin (MIC=1.35μg/mL) was statistically significantly reduced (MIC=2.5μg/mL) following T. vaginalis passage concomitantly with mutations in the quinolone resistance-determining regions (QRDRs) of gyrA (S153L) and parC (E195G and K144R). In contrast, the susceptibility of M. hominis isolate AKH136 to all drugs investigated increased after passaging.

CONCLUSIONS

These findings suggest that symbiosis with T. vaginalis has an enhancing effect on selected antimicrobial resistances of distinct M. hominis isolates.

Mutations in the quinolone resistance determining region conferring resistance to fluoroquinolones in Mycoplasma agalactiae

M. agalactiae is the main causative agent of contagious agalactia, against which antimicrobial treatment is the main applied control measure. Quinolones are an effective group of antimicrobials inhibiting the growth of M. agalactiae, but in the last years, various reports have demonstrated an increase of resistance in field isolates due to its massive use. Nevertheless, the molecular mechanisms involved in the acquisition of fluoroquinolones resistance in M. agalactiae have not been elucidated yet. Therefore, the aim of this work was to analyze the presence of DNA variations that could be related to changes in fluoroquinolone susceptibility. For this purpose, three M. agalactiae strains were selected to obtain in vitro resistant mutants against enrofloxacin, marbofloxacin and moxifloxacin and afterwards, partial sequences of their gyrA, gyrB, parC and parE genes were analyzed. In addition, a set of field isolates with different MIC values were also studied. Changes related to variations in fluoroquinolones susceptibility were found in gyrB, parC and parE. Specifically, gyrB genes were affected at the predicted amino acid position 424, four amino acid changes were detected in parC (positions 78, 79, 80 and 84) and two substitutions were reported in parE (amino acid positions 429 and 459). Mutations at predicted positions 424 of gyrB and 429 of parE are novel DNA changes which had not been previously described and, on the whole, parC was the first gene showing alterations when changes in susceptibility to fluoroquinolones occurred. Thus, this gene is the most suitable target for a rapid study of fluoroquinolone resistance in field isolates of M. agalactiae.

Neonate with Mycoplasma hominis meningoencephalitis given moxifloxacin

Mycoplasma hominis is a commensal organism in the genitourinary tract that can cause life-threatening CNS infections in neonates after intrauterine infection or through vertical transmission during birth. We present a case of an 11-day-old neonate presenting with fever and supporting laboratory evidence of a CNS infection. No systemic maternal infection or maternal genitourinary tract infection occurred at the time of delivery. Empirical treatment was initiated, consisting of amoxicillin, cefotaxime, and aciclovir. After clinical deterioration, 16S ribosomal DNA PCR in cerebrospinal fluid detected M hominis, antibiotic treatment was switched to moxifloxacin, and pharmacokinetic data were obtained. This Grand Round illustrates the challenges that exist in the diagnosis and treatment of M hominis meningoencephalitis: bacterial cultures are often negative and recommended empirical antimicrobials do not provide adequate antimicrobial coverage. Optimal antimicrobial treatment regimens for M hominis meningoencephalitis are unknown. Although we describe successful treatment of a neonate with a complicated M hominis meningoencephalitis with moxifloxacin, caution with fluoroquinolone monotherapy (including moxifloxacin) has to be taken into account because resistance to fluoroquinolones has previously been described.

Mycoplasmas and Their Antibiotic Resistance: The Problems and Prospects in Controlling Infections

The present review discusses the problem of controlling mycoplasmas (class Mollicutes), the smallest of self-replicating prokaryotes, parasites of higher eukaryotes, and main contaminants of cell cultures and vaccines. Possible mechanisms for the rapid development of resistance to antimicrobial drugs in mycoplasmas have been analyzed. Omics technologies provide new opportunities for investigating the molecular basis of bacterial adaptation to stress factors and identifying resistomes, the total of all genes and their products contributing to antibiotic resistance in microbes. The data obtained using an integrated approach with post-genomics methods show that antibiotic resistance may be caused by more complex processes than has been believed heretofore. The development of antibiotic resistance in mycoplasmas is associated with essential changes in the genome, proteome, and secretome profiles, which involve many genes and proteins related to fundamental cellular processes and virulence.

Genetic Passive Immunization with Adenoviral Vector Expressing Chimeric Nanobody-Fc Molecules as Therapy for Genital Infection Caused by Mycoplasma hominis

Developing pathogen-specific recombinant antibody fragments (especially nanobodies) is a very promising strategy for the treatment of infectious disease. Nanobodies have great potential for gene therapy application due to their single-gene nature. Historically, Mycoplasma hominis has not been considered pathogenic bacteria due to the lack of acute infection and partially due to multiple studies demonstrating high frequency of isolation of M. hominis samples from asymptomatic patients. However, recent studies on the role of latent M. hominis infection in oncologic transformation, especially prostate cancer, and reports that M. hominis infects Trichomonas and confers antibiotic resistance to Trichomonas, have generated new interest in this field. In the present study we have generated specific nanobody against M. hominis (aMh), for which the identified target is the ABC-transporter substrate-binding protein. aMh exhibits specific antibacterial action against M. hominis. In an attempt to improve the therapeutic properties, we have developed the adenoviral vector-based gene therapy approach for passive immunization with nanobodies against M. hominis. For better penetration into the mucous layer of the genital tract, we fused aMh with the Fc-fragment of IgG. Application of this comprehensive approach with a single systemic administration of recombinant adenovirus expressing aMh-Fc demonstrated both prophylactic and therapeutic effects in a mouse model of genital M. hominis infection.