Prevalence and Antimicrobial Susceptibility of Ureaplasma spp. and Mycoplasma hominis in Asymptomatic Individuals in Korea

Ureaplasma infections: update on epidemiology, antimicrobial resistance, and pathogenesis

Human Ureaplasma species are being increasingly recognized as opportunistic pathogens in human genitourinary tract infections, infertility, adverse pregnancy, neonatal morbidities, and other adult invasive infections. Although some general reviews have focused on the detection and clinical manifestations of Ureaplasma spp., the molecular epidemiology, antimicrobial resistance, and pathogenesis of Ureaplasma spp. have not been adequately explained. The purpose of this review is to offer valuable insights into the current understanding and future research perspectives of the molecular epidemiology, antimicrobial resistance, and pathogenesis of human Ureaplasma infections. This review summarizes the conventional culture and detection methods and the latest molecular identification technologies for Ureaplasma spp. We also reviewed the global prevalence and mechanisms of antibiotic resistance for Ureaplasma spp. Aside from regular antibiotics, novel antibiotics with outstanding in vitro antimicrobial activity against Ureaplasma spp. are described. Furthermore, we discussed the pathogenic mechanisms of Ureaplasma spp., including adhesion, proinflammatory effects, cytotoxicity, and immune escape effects, from the perspectives of pathology, related molecules, and genetics.

Antimicrobial resistance rates of urogenital Mycoplasma hominis and Ureaplasma species before and during the COVID-19 pandemic: results from a Greek survey, 2014 to 2022

The prevalence of antibiotic-resistant urogenital mycoplasmas and ureaplasmas has been gradually increasing over the years, leading to greater concern for accurate diagnosis and treatment. In this study, the antimicrobial resistance trends in Greece were analyzed using 2992 Ureaplasma spp. and 371 M. hominis isolates collected between 2014 and 2022. Antibiotic sensitivity was determined using eight different antimicrobial agents (josamycin, pristinamycin, clindamycin, ofloxacin, azithromycin, tetracycline, erythromycin, and doxycycline), with the data analyzed using descriptive statistical methods. Resistance rates to clindamycin and erythromycin increased for both M. hominis and Ureaplasma spp., while remaining relatively low for Tetracycline, Doxycycline, and Ofloxacin. For Ureaplasma spp., high susceptibility was observed to pristinamycin, tetracycline, doxycycline, azithromycin, and josamycin, and intermediate susceptibility to erythromycin. However, the resistance rate for clindamycin dramatically increased from 60% in 2014 to a peak of 98.46% in 2021, and the erythromycin resistance rate increased from 9.54% in 2018 to 22.13% in 2021. M. hominis exhibited consistently high resistance rates to Erythromycin, while Azithromycin resistance significantly increased over time, from 52.78% in 2017 to 97.22% in 2022. The alarming escalation in antibiotic-resistant urogenital mycoplasmas and ureaplasmas in the Greek population is a significant concern. Antibiotic overconsumption may have played a crucial role in increasing resistance trends. The implementation of nationwide surveillance systems, proper antibiotic stewardship policies, and appropriate culture-based therapy policies are necessary to effectively control this emerging risk.

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.

Detection of Putative Virulence Genes alr, goiB, and goiC in Mycoplasma hominis Isolates from Austrian Patients

In Mycoplasma hominis, two genes (alr and goiB) have been found to be associated with the invasion of the amniotic cavity, and a single gene (goiC) to be associated with intra-amniotic infections and a high risk of preterm birth. The syntopic presence of Ureaplasma spp. in the same patient has been shown to correlate with the absence of goiC in M. hominis. The aim of our study was to investigate the presence of alr, goiB, and goiC genes in two groups of M. hominis isolates collected from symptomatic and asymptomatic male and non-pregnant female patients attending an Outpatients Centre. Group A consisted of 26 isolates from patients with only M. hominis confirmed; group B consisted of 24 isolates from patients with Ureaplasma spp. as the only co-infection. We extracted DNA from all M. hominis isolates and analysed the samples for the presence of alr, goiB, and goiC in a qPCR assay. Additionally, we determined their cytotoxicity against HeLa cells. We confirmed the presence of the alr gene in 85% of group A isolates and in 100% of group B isolates; goiB was detected in 46% of the samples in both groups, whereas goiC was found in 73% of group A and 79% of group B isolates, respectively. It was shown that co-colonisation with Ureaplasma spp. in the same patient had no effect on the presence of goiC in the respective M. hominis isolate. We did not observe any cytotoxic effect of the investigated isolates on human cells, regardless of the presence or absence of the investigated genes.

Mycoplasma hominis Meningitis Diagnosed by Metagenomic Next-Generation Sequencing in a Preterm Newborn: a Case Report and Literature Review

Mycoplasma hominis is mainly colonized in the genital tract and vertically transmitted to newborns; however, it rarely causes neonatal meningitis. We report a case of M. hominis meningitis in a premature infant. She was admitted to our hospital for treatment after 6 days of repeated fever. After admission, repeated cerebrospinal fluid (CSF) analysis showed that leukocytes and protein in CSF increased substantially and glucose decreased, but there was no growth in conventional CSF culture. The patient was diagnosed with M. hominis meningitis by metagenomic next-generation sequencing (mNGS). The antibiotic therapy used for the neonate was meropenem, vancomycin, and ampicillin against bacterial infection and azithromycin against mycoplasma infection. The child was subsequently considered cured and discharged from the hospital and followed up regularly in the neurology clinic. The mNGS may be a promising and effective diagnostic technique for identifying uncommon pathogens of meningitis in patients with meningitis symptoms and signs without microbial growth in routine CSF culture.

Prevalence of selected sexually transmitted infectious agents in a cohort of asymptomatic soldiers in Austria

BACKGROUND

According to the World Health Organization (WHO), more than one million sexually transmitted infections (STIs) are acquired every day worldwide. Although STIs may be asymptomatic in many cases, they can cause severe symptoms and can also lead to adverse pregnancy outcomes and both male and female infertility. Asymptomatic carriers seem to play an important role in terms of the distribution of STIs; however, studies revealing the prevalence of STIs in asymptomatic individuals are rare.

METHODS

In the current study, 654 leftovers of standard urine samples from healthy, asymptomatic Austrian soldiers were investigated for the prevalence of Trichomonas vaginalis, Chlamydia trachomatis, and genital mycoplasmas (Mycoplasma hominis, Mycoplasma genitalium, Ureaplasma urealyticum, Ureaplasma parvum, and Candidatus Mycoplasma girerdii) by specific PCRs.

RESULTS

We detected T. vaginalis, M. hominis, U. urealyticum, U. parvum, and C. trachomatis in the investigated samples with prevalence of 7.6%, 4%, 2.4%, 5.4%, and 3.2%, respectively; neither M. genitalium nor Ca. Mycoplasma girerdii was found in our sample collection.

CONCLUSIONS

Our study introduces data on STIs of a mainly male cohort, which are scarce because most of the available information on sexually transmitted infectious agents arises from fertility clinics (mainly women) or symptomatic patients.

Resistance to tetracyclines among clinical isolates of Mycoplasma hominis and Ureaplasma species: a systematic review and meta-analysis

BACKGROUND

Resistance to tetracyclines, the first-line treatment for urogenital infections caused by Mycoplasma hominis and Ureaplasma species, is increasing worldwide. The aim of the present study was to determine the global status of resistance to this class of antibiotics.

METHODS

Electronic databases were searched using keywords including 'Mycoplasma', 'Mycoplasma hominis', 'M. hominis', 'Ureaplasma', 'Ureaplasma urealyticum', 'Ureaplasma parvum', 'U. urealyticum', 'U. parvum', 'Ureaplasma species', 'resistance', 'antibiotic resistance', 'antibiotic susceptibility', 'antimicrobial resistance', 'antimicrobial susceptibility', 'tetracycline', 'doxycycline' and 'minocycline'. Finally, after some exclusions, 37 studies from different countries were included in the study and meta-analysis was performed on the data collected.

RESULTS

The midrange resistance rates for M. hominis and U. urealyticum/parvum to tetracycline, doxycycline and minocycline were 50.0%, 9.0% and 16.7% and 43.3%, 28.6% and 9.0%, respectively. A high level of heterogeneity was observed in all studies (I2 > 50%, P value < 0.05), except those representing doxycycline resistance in M. hominis isolates (I2 = 39.1%, P  = 0.02). No evidence of publication bias was observed in the studies and neither Egger's test nor Begg's test showed significant publication bias.

CONCLUSIONS

The results of the present study show that the overall resistance to tetracyclines is relatively high and prevalent among M. hominis and Ureaplasma species throughout the world. This highlights the importance of and necessity for regional and local antibiotic susceptibility testing before treatment choice as well as development of newer generations of tetracyclines to prevent antibiotic misuse, emergence and spread of resistant strains and, finally, the failure of treatment.

Infection Prevalence and Antibiotic Resistance Levels in Ureaplasma urealyticum and Mycoplasma hominis in Gynecological Outpatients of a Tertiary Hospital in China from 2015 to 2018

The aim of this study was to estimate the Ureaplasma urealyticum and Mycoplasma hominis infection prevalence and antibiotic resistance levels in gynecological outpatients. Clinical characteristics and laboratory data of gynecological outpatients of the Fourth People's Hospital of Chongqing from 2015 to 2018 were retrospectively analyzed. Antibiotic resistance levels in U. urealyticum and M. hominis were defined by a commercial Mycoplasma kit for antibiotic susceptibility testing. Univariate analysis and multivariate logistic regression analysis were performed to evaluate risk factors associated with Mycoplasma isolation. Comparisons of yearly distributions and resistance rates were assessed by chi-square tests. Fifty-six percent of gynecological outpatients were positive for U. urealyticum, and 11.02% were positive for M. hominis. In the univariate analysis, women aged 30–39 years or with a history of pregnancy or gynecological diseases had an increased risk for Mycoplasma isolation, while women who were postmenopausal or had an education level of undergraduate degree or above had a decreased risk of Mycoplasma isolation. In the multivariate logistic regression model, an independent risk factor for Mycoplasma isolation was a history of gynecological diseases, while a bachelor's degree, master's degree, or above were protective factors against Mycoplasma isolation. There were distinctly gradual increases in the positivity rates of U. urealyticum and M. hominis from 2015 to 2018 and an overall increasing trend of resistance to ten antibiotics among U. urealyticum and M. hominis. The top three antibiotics associated with resistance were ofloxacin, sparfloxacin, and levofloxacin. Doxycycline, josamycin, and minocycline were preferred because they had the lowest levels of resistance. Increases in the prevalence of infection and antibiotic resistance in U. urealyticum and M. hominis were observed from 2015 to 2018, clearly confirming the necessity to monitor the standardized administration of antibiotics.

Prevalence and Antimicrobial Susceptibility of Mycoplasma hominis and Ureaplasma Species in Nonpregnant Female Patients in South Korea Indicate an Increasing Trend of Pristinamycin-Resistant Isolates

Mycoplasma hominis and Ureaplasma species, commonly found in the lower urogenital tract, have been associated with various urogenital infections. This study aimed to estimate the prevalence and antimicrobial susceptibility trend of M. hominis and Ureaplasma sp. in female patients and to evaluate the risk factors for the acquisition of pristinamycin-resistant mycoplasma. Endocervical swab specimens obtained between March 2016 and December 2018 were analyzed using a Mycoplasma IST2 kit.

Mycoplasma hominis and Ureaplasma species, commonly found in the lower urogenital tract, have been associated with various urogenital infections. This study aimed to estimate the prevalence and antimicrobial susceptibility trend of M. hominis and Ureaplasma sp. in female patients and to evaluate the risk factors for the acquisition of pristinamycin-resistant mycoplasma. Endocervical swab specimens obtained between March 2016 and December 2018 were analyzed using a Mycoplasma IST2 kit. Because pristinamycin and josamycin are not available in South Korea, we conducted an age- and date-matched case-control study to evaluate the risk factors for the acquisition of pristinamycin-resistant isolates. Among 4,035 specimens, 1,589 (39.4%) cases were positive for genital mycoplasma, which included 49 (3.1%) cases of M. hominis, 1,243 (78.2%) cases of Ureaplasma sp., and 297 (18.7%) cases of both M. hominis and Ureaplasma species. Based on antimicrobial susceptibility tests, the antibiotic susceptible rate of both M. hominis and Ureaplasma species to pristinamycin decreased annually during the study period (100%, 97.1%, and 87.3% for 2016, 2017, and 2018, respectively, P < 0.001). According to a multivariate analysis, josamycin resistance (odds ratio, 7.18; 95% confidence interval, 1.20 to 43.00; P = 0.027) and coinfection (odds ratio, 145.38; 95% confidence interval, 21.80 to 3,017.23; P < 0.001) with Candida species were independent risk factors for the acquisition of pristinamycin-resistant isolates. Antibiotic-resistant genital mycoplasmas have been gradually increasing annually. Nationwide surveillance, proper antibiotic stewardship, and appropriate culture-based treatment strategies are required to control this upcoming threat.

Antimicrobial resistance, genetic characterization, and molecular epidemiology of Ureaplasma species in males with infertility

This study aimed to study the antimicrobial resistance, genetic characterization, and molecular epidemiology of Ureaplasma species in order to provide clinicians sufficient data to select optimal strategies of treatment for genitourinary tract infections of infertile male patients. Firstly, a total of 817 clinical semen specimens were detected for Ureaplasma species by molecular detection. Secondly, culture and identification of Ureaplasma species were achieved by using Mycoplasma ICS Test, and the antimicrobial susceptibility tests were determined by using broth microdilution assay. Then, the tetracycline resistance genetic determinants in Ureaplasma species were identified by PCR, and the fluoroquinolone and macrolide resistance genetic determinants were identified by DNA sequencing. Finally, the molecular epidemiology of Ureaplasma species was studied by both multilocus sequence typing (MLST) and expanded MLST (eMLST) schemes. Among the 817 semen specimens, 320 (39.17%) specimens were positive for Ureaplasma species. The percentages of resistance in 320 isolates against LEV, MXF, TET, and ERY were 47.5%, 39.38%, 19.69%, and 3.75%, respectively. The tet(M) and int-Tn genes were detected positive in all the tetracycline-resistant isolates. One macrolide-resistant UU isolate had a novel amino acid alteration (R66T) in L4 ribosomal protein and another UU isolate harbored a novel alteration (S109T) in L22. In fluoroquinolone-resistant isolates, S83L substitution in the ParC was predominant. In this area, ST22 and eST16 were the most prevalent ST and eST, respectively. One ST and 3 eSTs were newly identified in this study. This study has demonstrated that ERY can be first-line therapy for Ureaplasma species infections.

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.

In vitro Activities of Nemonoxacin and Other Antimicrobial Agents Against Human Mycoplasma and Ureaplasmas Isolates and Their Defined Resistance Mechanisms

Nemonoxacin, a newly developed non-fluorinated quinolone (NFQ), selectively inhibits bacterial DNA topoisomerase activity. However, its activities against Mycoplasmas have rarely been studied to date. Herein, the activities of nemonoxacin were evaluated against clinical isolates of 50 Mycoplasma pneumoniae, 20 Mycoplasma hominis, and 77 Ureaplasma spp., and they were compared to fluoroquinolones, tetracyclines, and macrolides. Nemonoxacin MICs (μg/ml) ranged from 0.03 to 0.25 for M. pneumoniae, 0.25 to 8 for M. hominis, and 0.06 to >16 for Ureaplasma spp., and all of the ranges are similar to those of fluoroquinolones. The activity of nemonoxacin against Mycoplasmas was not affected by resistance to macrolides in the strains tested, but it seems to have the same resistant mechanism as fluoroquinolones. In addition, minimum bactericidal concentrations (MBC) of nemonoxacin to M. pneumoniae were within two dilutions of the MIC values, indicating a bactericidal effect on M. pneumoniae. Nemonoxacin merits further study for treating infections caused by these organisms.

Comparison of two identification and susceptibility test kits for Ureaplasma spp and Mycoplasma hominis in amniotic fluid of patients at high risk for intra-amniotic infection

Objective: Ureaplasma urealyticum and Mycoplasma hominis are the most common microorganisms found in the amniotic fluid of patients at risk for preterm delivery. However, culture techniques for genital mycoplasms require special conditions, are barely considered as part of the evaluation of suspected intra-amniotic infection (IAI) and the results are available within 2 and 7 days. The objectives of this study are to validate the use of two commercially available kits (Mycoplasma IES y MYCOFAST^® RevolutioN) for the identification of Ureaplasma spp. and Mycoplasma hominis in amniotic fluid, to compare the results of these kits with those obtained by culture and real-time polymerase chain reaction (qPCR) and to report the antibiotic sensitivity profile of the genital mycoplasms identified.Methods: This is a prospective cohort study including women with singleton and twin gestations between 16 and 36 weeks. Patients were admitted to perform an amniocentesis due to pregnancy complications considered at high risk for IAI (e.g. preterm labor with intact membranes, preterm prelabour rupture of membranes, short cervix, etc.), treatment of polyhydramnios, and for the assessment of fetal death and fever without a focus.Results: Overall, 93 patients underwent amniocentesis and 63 had results available for all tests. The prevalence of a positive culture was 6% (4/63). There were four cases of Ureaplasma spp. and none of Mycoplasma hominis. The qPCR identified one case as Ureaplasma spp., one case as Ureaplasma parvum and two cases as Ureaplasma urealyticum. For all tests, the diagnostic performance was as follows: sensitivity 100% [95% CI (39.8-100%)], specificity 100% [95% CI (93.9-100%)], positive predictive value 100% [95% CI (39.8-100%)] and negative predictive value 100% [95% CI (93.9-100%)]. In this cohort, Ureaplasma spp. showed low resistance to erythromycin, but a high resistance to clindamycin and clarithromycin that may change according to the antibiotic concentration.Conclusions: To our knowledge, this is the first study that validates the use of the Mycoplasma IES and MYCOFAST^® RevolutioN kits for the identification of genital mycoplasmas in amniotic fluid. The results of these kits are mostly available within 24 hours, have an excellent correlation with those from broth cultures and qPCR and characterize the antibiotic sensitivity profile of the genital mycoplasms identified, providing an opportunity for specific treatment in cases of IAI. Further validation studies in other populations are needed.

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.