Trends in the rates of resistance of Ureaplasma urealyticum to antibiotics and identification of the mutation site in the quinolone resistance-determining region in Chinese patients

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.

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.

Tetracyclines resistance in Mycoplasma and Ureaplasma urogenital isolates derived from human: a systematic review and meta-analysis

BACKGROUND

Urogenital Mycoplasma infections are considered an important public health problem, owing to the presence of antibiotic resistance or decreased susceptibility, the treatment options are limited.

OBJECTIVE

Therefore, this meta-analysis aimed to estimate resistance rates of genital Mycoplasmas to tetracyclines (tetracycline, doxycycline, and minocycline).

METHODS

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

RESULTS

The 26 studies included in the analysis were performed in 15 countries. In the metadata, the proportions of tetracycline, doxycycline, and minocycline resistance in Mycoplasma and Ureaplasma urogenital isolates were reported 14.2% (95% CI 8.2-23.2%), 5% (95% CI 3-8.1%), and 11.9% (95% CI 6.3-21.5%), respectively. According to the meta-regression, the tetracycline and minocycline resistance rate decreased over time. Although, the doxycycline resistance rate increased over time. There was a statistically significant difference in the tetracyclines resistance rates between different continents/countries (P < 0.05).

CONCLUSION

The prevalence rate and antibiotic susceptibility profiles vary geographically. Therefore, rigorous or improved antimicrobial stewardship, contact tracing, and enhanced intensive surveillance systems are necessitated for preventing the emergence and further spreading of tetracyclines resistance in genital Mycoplasmas.

Prevalence and antibiotics resistance of Ureaplasma species and Mycoplasma hominis in Hangzhou, China, from 2013 to 2019

Ureaplasma spp. and Mycoplasma hominis, frequent colonizers in the lower urogenital tract, have been implicated in various infections, with antibiotic resistance growing and varying regionally. This study aims to investigate the prevalence and antibiotic resistance profiles of Ureaplasma spp. and M. hominis in outpatients in Hangzhou, China, from 2013 to 2019. A total of 135,263 outpatients were examined to determine the prevalence of Ureaplasma spp. and M. hominis, including 48,638 males and 86,625 females. Furthermore, trends in antibiotic susceptibility of Ureaplasma spp. and M. hominis during 1999–2019 were analyzed. The cultivation, identification, and antibiotic susceptibility of the bacteria (ofloxacin, ciprofloxacin, erythromycin, clarithromycin, azithromycin, josamycin, tetracycline, doxycycline, and pristinamycin) were determined using the Mycoplasma IST2 kit. Our study indicated that the overall prevalence of total Ureaplasma spp./M. hominis was 38.1% from 2013 to 2019. Ureaplasma spp. were the most frequently isolated species (overall prevalence, 31.3%), followed by Ureaplasma spp./M. hominis coinfection (6.0%) and single M. hominis infection (0.8%). The prevalence of Ureaplasma spp. and M. hominis was significantly higher in females than in males, and the highest positive rates of total Ureaplasma spp./M. hominis were observed in both female and male outpatients aged 14–20 years. During 2013–2019, josamycin, tetracycline, doxycycline, and pristinamycin maintained exceptionally high activity (overall resistance rates, <5%) against both Ureaplasma spp. and M. hominis, but ofloxacin and ciprofloxacin showed limited activity (overall resistance rates, >70%). During 1999–2019, the rates of resistance to ofloxacin and ciprofloxacin increased against both Ureaplasma spp. and M. hominis but decreased to erythromycin, clarithromycin, azithromycin, tetracycline, and doxycycline against Ureaplasma spp. In conclusion, our study demonstrates a high prevalence of Ureaplasma spp. compared to M. hominis and Ureaplasma spp./M. hominis, and their distribution was associated with sex and age. Josamycin, doxycycline, and tetracycline are promising antibiotics that have remarkable activity against Ureaplasma species and M. hominis.

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.

An Observational Study: Is N-Acetylcysteine Helpful in Performance Improvement of Mycoplasma IST2 Testing through Sample Homogenization?

Background

Culture is still the gold standard for the detection of genital mycoplasma which could cause urogenital infections in humans. Mycoplasma IST2 is a commercial kit widely used for the detection of M. hominis and Ureaplasma species. Its accuracy was partially impaired because clinical specimens are usually mixed with purulent or transparent mucus. We aimed to solve this problem through sample homogenization by N-acetylcysteine (NAC) treatment.

Methods

Twenty-two endocervical swab samples were collected from 22 female patients with suspected mycoplasma infection, while 11 of these specimens were with purulent or transparent mucus. Mycoplasma IST2 testing kit was used for mycoplasma culture and AST for the control group and NAC-treated group.

Results

Genital mycoplasma was detected in 15 of 22 samples for both groups. The colony number in 6 out of 11 purulent specimens (54.5%) was more than 10⁴ CFU/ml of genital mycoplasma for the NAC-treated group, while only one of 11 (9.1%) for the control group. For the nonpurulent specimens, no significant difference had been found in colony counting of genital mycoplasma between the control group and NAC-treated group (P > 0.05). The results of antimicrobial susceptibility testing for the NAC-treated group were highly similar to those for the control group.

Conclusions

Our results demonstrate that NAC is helpful in sample homogenization and NAC treatment can improve the detection efficiency of mycoplasma with Mycoplasma IST2 testing.

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.

Current understanding and treatment of intra-amniotic infection with Ureaplasma spp

Considerable evidence has shown that intra-amniotic infection with Ureaplasma spp. increases the risk of chorioamnionitis and preterm labor. Ureaplasma spp. are among the smallest organisms, and their isolation is uncommon in routine clinical practice because of their size and high auxotrophy. Although Ureaplasma spp. have been reported as causative agents of preterm birth, they also have a high incidence in vaginal swabs collected from healthy reproductive-age women; this has led to questions on the virulence of Ureaplasma spp. and to them being considered as harmless commensal bacteria. Therefore, many efforts have been made to clarify the pathogenicity of Ureaplasma spp. at the molecular level. Ureaplasma spp. are surrounded by lipoproteins, including multiple-banded antigen. Both multiple-banded antigen and its derivative, that is, the synthetic lipopeptide, UPM-1, induce an inflammatory response in a preterm mice model, which was adequate to cause preterm birth or stillbirth. In this review, we present an overview of the virulence mechanisms of Ureaplasma spp. and treatment of ureaplasma infection during pregnancy to prevent possible serious sequelae in infants. In addition, relevant mechanisms underlying antibiotic resistance in Ureaplasma spp. are discussed. Ureaplasma spp. are naturally resistant against β-lactam antibiotics because of the lack of a cell wall. Azithromycin is one of the effective agents that can control intrauterine ureaplasma infection. In fact, macrolide- and fluoroquinolone-resistant isolates of Ureaplasma spp. have already been observed in perinatal practice in Japan.

Co-infection Of Ureaplasma urealyticum And Human Papilloma Virus In Asymptomatic Sexually Active Individuals

This study aimed to determine the role of asymptomatic bacterial sexually transmitted infections (STIs), such as Chlamydia trachomatis (Ct), Mycoplasma genitalium (Mg), Mycoplasma hominis (Mh), and Ureaplasma urealyticum (Uu) in human papillomavirus (HPV) infection. In total, 264 asymptomatic outpatients aged between 21 and 80 years were prospectively enrolled in this study during routine gynecological screening tests. Specimens collected with a Cervex Brush were routinely analyzed with the Hybrid Capture 2 assay for HPV. Simultaneously, a specimen obtained with an endocervical swab was used to detect Ct and Mg with a monoplex real-time polymerase chain reaction (PCR) and to confirm Mh and Uu with a Mycoplasma IST 2 kit. The detection rates (%) of HPV, Ct, Mg, Mh, and Uu were 82/264 (31.1), 6/264 (2.3), 5/264 (1.9), 16/264 (6.1), and 95/264 (36.0), respectively. Of 95 Uu, 32 (33.7%) showed high density colonization (HDC, ≥10⁴ color-changing units/mL). HDC-Uu was significantly associated with HPV infection (p=0.014, chi-square test). Mg infection and Mh infection were not associated with HPV infection (p=0.981 and p=0.931, chi-square test). Age was not associated with HPV infection or bacterial infection. Our data suggested that asymptomatic HDC-Uu was closely associated with HPV infection. Therefore, simultaneous evaluation for Uu and HPV should be performed during gynecological screening, even in asymptomatic individuals.

Biochanin A partially restores the activity of ofloxacin and ciprofloxacin against topoisomerase IV mutation-associated fluoroquinolone-resistant Ureaplasma species

PURPOSE

This study aims to investigate the synergistic antimicrobial activity of four phytoalexins in combination with fluoroquinolones against Ureaplasma spp., a genus of cell wall-free bacteria that are intrinsically resistant to many available antibiotics, making treatment inherently difficult.

METHODOLOGY

A total of 22 958 urogenital tract specimens were assessed for Ureaplasma spp. identification and antimicrobial susceptibility. From these, 31 epidemiologically unrelated strains were randomly selected for antimicrobial susceptibility testing to determine the minimum inhibitory concentration (MIC) of four fluoroquinolones and the corresponding quinolone resistance-determining regions (QRDRs). Synergistic effects between fluoroquinolones and four phytoalexins (reserpine, piperine, carvacrol and biochanin A) were evaluated by fractional inhibitory concentration indices (FICIs).

RESULTS

Analysis of the QRDRs suggested a vital role for the mutation of Ser-83→Leu in ParC in fluoroquinolone-resistant strains, and the occurrence of mutations in QRDRs showed significant associations with the breakpoint of levofloxacin. Moreover, diverse synergistic effects of the four phytoalexins with ofloxacin or ciprofloxacin were observed and biochanin A was able to enhance the antimicrobial activity of fluoroquinolones significantly.

CONCLUSION

This is the first report of the antimicrobial activity of biochanin A in combination with fluoroquinolones against a pathogenic mycoplasma, and opens up the possibility of using components of biochanin A as a promising therapeutic option for treating antibiotic-resistant Ureaplasma spp. infections.

Clonality and distribution of clinical Ureaplasma isolates recovered from male patients and infertile couples in China

Ureaplasma spp. have gained increasing recognition as pathogens in both adult and neonatal patients with multiple clinical presentations. However, the clonality of this organism in the male population and infertile couples in China is largely unknown. In this study, 96 (53 U. parvum and 43 U. urealyticum) of 103 Ureaplasma spp. strains recovered from genital specimens from male patients and 15 pairs of infertile couples were analyzed using multilocus sequence typing (MLST)/expanded multilocus sequence typing (eMLST) schemes. A total of 39 sequence types (STs) and 53 expanded sequence types (eSTs) were identified, with three predominant STs (ST1, ST9 and ST22) and eSTs (eST16, eST41 and eST82). Moreover, phylogenetic analysis revealed two distinct clusters that were highly congruent with the taxonomic differences between the two Ureaplasma species. We found significant differences in the distributions of both clusters and sub-groups between the male and female patients (P < 0.001). Moreover, 66.7% and 40.0% of the male and female partners of the infertile couples tested positive for Ureaplasma spp. The present study also attained excellent agreement of the identification of both Ureaplasma species between paired urine and semen specimens from the male partners (k > 0.80). However, this concordance was observed only for the detection of U. urealyticum within the infertile couples. In conclusion, the distributions of the clusters and sub-groups significantly differed between the male and female patients. U. urealyticum is more likely to transmit between infertile couples and be associated with clinical manifestations by the specific epidemic clonal lineages.

The PK-PD Relationship and Resistance Development of Danofloxacin against Mycoplasma gallisepticum in An In Vivo Infection Model

Mycoplasma gallisepticum is the causative agent of chronic respiratory disease (CRD), a prevalent disease of poultry, which is responsible for significant economic losses in farms. Although several antimicrobial agents are currently recommended for the treatment and prevention of M. gallisepticum infections, investigations of M. gallisepticum have been hampered by their fastidious growth requirements and slow growth rate. As such, little work has been conducted concerning the PK/PD relationship and mechanisms of antibiotic resistance between antimicrobials against M. gallisepticum. In the present study, danofloxacin was orally administrated to the infected chickens once daily for 3 days by an established in vivo M. gallisepticum infection model. Not only the concentrations of danofloxacin in plasma and lung tissues were analyzed, but also the counting of viable cells and changes in antimicrobial susceptibility in air sac and lung were determined. The PK and PD data were fitted by WinNonlin to evaluate the PK/PD interactions of danofloxacin against M. gallisepticum. PCR amplification of quinolone resistance-determining regions (QRDRs) and DNA sequencing were performed to identify point mutations in gyrA, gyrB, parC, and parE of the selected resistant mutant strains. In addition, susceptibility of enrofloxacin, ofloxacin, levofloxacin, gatifloxacin, and norfloxacin against these mutant strains were also determined. The PK profiles indicated that danofloxacin concentration in the lung tissues was higher than plasma. Mycoplasmacidal activity was achieved when infected chickens were exposed to danofloxacin at the dose group above 2.5 mg/kg. The ratios of AUC₂₄/MIC (the area under the concentration-time curve over 24 h divided by the MIC) for 2 log₁₀ (CFU) and 3 log₁₀ (CFU) reduction were 31.97 and 97.98 L h/kg, respectively. Substitutions of Ser-83→Arg or Glu-87→Gly in gyrA; Glu-84→Lys in parC were observed in the resistant mutant strains that were selected from the dose group of 1 and 2.5 mg/kg. MICs of danofloxacin, enrofloxacin, ofloxacin, levofloxacin, gatifloxacin, and norfloxacin against the resistant mutant strains with a single mutation in position-83 were higher than that with a single mutation in position-87. These findings suggested that danofloxacin may be therapeutically effective to treat M. gallisepticum infection in chickens if administered at a dosage of 5.5 mg/kg once daily for 3 days.

Detection of emerging antibiotic resistance in bacteria isolated from subclinical mastitis in cattle in West Bengal

AIM

The aim of this work was to detect antibiotic resistance in Gram-negative bacteria isolated from subclinical mastitis in cattle in West Bengal.

MATERIALS AND METHODS

The milk samples were collected from the cattle suffering with subclinical mastitis in West Bengal. The milk samples were inoculated into the nutrient broth and incubated at 37°C. On the next day, the growth was transferred into nutrient agar and MacConkey agar. All the pure cultures obtained from nutrient agar slant were subjected to Gram-staining and standard biochemical tests. All the bacterial isolates were tested in vitro for their sensitivity to different antibiotics commonly used in veterinary practices. All Gram-negative isolates including positive control were subjected to polymerase chain reaction (PCR) for detection of bla_CTX-M, bla_TEM, bla_SHV, bla_VIM, tetA, tetB, tetC, and tetM genes considered for extended-spectrum β-lactamase (ESBL), metallo-β-lactamase, and tetracycline resistance.

RESULTS

In total, 50 Gram-negative organisms (Escherichia coli, Proteus, Pseudomonas, Klebsiella, and Enterobacter) were isolated from milk samples of subclinical mastitis infected cattle. Among these Gram-negative isolates, 48% (24/50) were found either ESBL producing or tetracycline resistant. Out of total 50 Gram-negative isolates, bla_CTX-M was detected in 18 (36%) isolates, and 6 (12%) harbored bla_TEM genes in PCR. None of the isolates carried bla_SHV genes. Further, in this study, 5 (10%) isolates harbored tet(A) gene, and 8 (16%) isolates carried tet(B) gene. No tet(C) gene was detected from the isolates.

CONCLUSION

This study showed emerging trend of antibiotic-resistant Gram-negative bacteria associated with subclinical mastitis in cattle in West Bengal, India.

Antibiotic resistance among Ureaplasma spp. isolates: cause for concern?

There is growing global concern regarding the rise of antibiotic-resistant organisms. Many of these reports have focused on various Gram-positive and Gram-negative pathogens, with little attention to the genus Ureaplasma. Ureaplasma spp. are associated with numerous infectious diseases affecting pregnant women, neonates and the immunocompromised. Treatment options are extremely limited due to high levels of intrinsic resistance resulting from the unique physiology of these organisms and further restricted in cases of the developing fetus or neonate, often limiting therapeutic options to predominantly macrolides or rarely fluoroquinolones. The increasing presence of macrolide- and fluoroquinolone-resistant strains among neonatal infections may result in pan-drug resistance and potentially untreatable conditions. Here, we review the requirements for accurate measurement of antimicrobial susceptibility, provide a comprehensive review of the antimicrobial resistance (AMR) for Ureaplasma species in the literature and contextualize these results relative to some investigators' reliance on commercial kits that are not CLSI compliant when determining AMR. The dramatic variation in the resistance patterns and impact of high levels of AMR amongst neonatal populations suggests the need for continued surveillance. Commercial kits represent an excellent tool for initial antibiotic susceptibility determination and screening. However, AMR reporting must utilize internationally standardized methods, as high-titre samples, or Mycoplasma hominis-contaminated samples routinely give false AMR results. Furthermore, there is a requirement for future reports to determine the underlying AMR mechanisms and determine whether expanding AMR is due to spontaneous mutation, transmission of resistance genes on mobile elements or selection and expansion of resistant clones.

Comparative analysis of male and female populations on prevalence and antibiotic resistance of Mycoplasma hominis in China, 2005-2014

The aim of this study was to estimate the prevalence and antimicrobial resistance rate of Mycoplasma hominis among male and female populations. A total of 67921 individuals were examined. All samples were isolated from patients at an outpatient clinic from January 2005 to December 2014. Species identification and antibiotic susceptibility testing were performed using Mycoplasma IST2. In this study, 523 (0.8%) and 4625 (6.8%) cultures, respectively, were positive for single M. hominis identification and simultaneous identification of both M. hominis and Ureaplasma spp. The results showed that both single and simultaneous identification were more frequent in the female than the male population. Moreover, the highest positive rates of single M. hominis identification were observed in 56-60-year-old males and 61-65-year-old females, and the rates of simultaneous identification were high in males aged >65 years and females aged 15-20 years. Among the seven antibiotics assessed, tetracycline, josamycin, doxycycline and pristinamycin were the most effective, whilst clarithromycin, ciprofloxacin and ofloxacin displayed extremely high resistance rates. Different antimicrobial susceptibility rates were observed between the two sexes, and the resistance rates to ofloxacin showed a significant difference (P<0.05). In conclusion, this study demonstrates that the prevalence of M. hominis varied significantly between the two sexes in the past 10 years and that the optimal antimicrobial therapy strategy should be directed by local susceptibility testing.

Antibiotic Resistance among Clinical Ureaplasma Isolates Recovered from Neonates in England and Wales between 2007 and 2013

Ureaplasma spp. are associated with numerous clinical sequelae with treatment options being limited due to patient and pathogen factors. This report examines the prevalence and mechanisms of antibiotic resistance among clinical strains isolated from 95 neonates, 32 women attending a sexual health clinic, and 3 patients under investigation for immunological disorders, between 2007 and 2013 in England and Wales. MICs were determined by using broth microdilution assays, and a subset of isolates were compared using the broth microdilution method and the Mycoplasma IST2 assay. The underlying molecular mechanisms for resistance were determined for all resistant isolates. Three isolates carried the tet(M) tetracycline resistance gene (2.3%; confidence interval [CI], 0.49 to 6.86%); two isolates were ciprofloxacin resistant (1.5%; CI, 0.07 to 5.79%) but sensitive to levofloxacin and moxifloxacin, while no resistance was seen to any macrolides tested. The MIC values for chloramphenicol were universally low (2 μg/ml), while inherently high-level MIC values for gentamicin were seen (44 to 66 μg/ml). The Mycoplasma IST2 assay identified a number of false positives for ciprofloxacin resistance, as the method does not conform to international testing guidelines. While antibiotic resistance among Ureaplasma isolates remains low, continued surveillance is essential to monitor trends and threats from importation of resistant clones.

Frequent topoisomerase IV mutations associated with fluoroquinolone resistance in Ureaplasma species

This study aimed to investigate the role of quinolone resistance-determining regions (QRDRs) of DNA gyrase (encoded by gyrA and gyrB) and topoisomerase IV (encoded by parC and parE) associated with fluoroquinolone resistance. A total of 114 Ureaplasma spp. strains, isolated from clinical female patients with symptomatic infection, were tested for species distribution and susceptibility to four fluoroquinolones. Moreover, we analysed the QRDRs and compared these with 14 ATCC reference strains of Ureaplasma spp. serovars to identify mutations that caused antimicrobial resistance. Our study indicated that moxifloxacin was the most effective fluoroquinolone against Ureaplasma spp. (MIC range: 0.125-32 μg ml⁻¹). However, extremely high MICs were estimated for ciprofloxacin (MIC range: 1-256 μg ml⁻¹) and ofloxacin (MIC range: 0.5-128 μg ml⁻¹), followed by levofloxacin (MIC range: 0.5-64 μg ml⁻¹). Seven amino acid substitutions were discovered in GyrB, ParC and ParE, but not in GyrA. Ser-83 → Leu/Trp (C248T/G) in ParC and Arg-448 → Lys (G1343A) in ParE, which were potentially responsible for fluoroquinolone resistance, were observed in 89 (77.2 %) and three (2.6 %) strains, respectively. Pro-462 → Ser (C1384T), Asn-481 → Ser (A1442G) and Ala-493 → Val (C1478T) in GyrB and Met-105 → Ile (G315T) in ParC seemed to be neutral polymorphisms, and were observed and occurred along with the amino acid change of Ser-83 → Leu (C248T) in ParC. Interestingly, two novel mutations of ParC and ParE were independently found in four strains. These observations suggest that amino acid mutation in topoisomerase IV appears to be the leading cause of fluoroquinolone resistance, especially the mutation of Ser-83 → Leu (C248T) in ParC. Moxifloxacin had the best activity against strains with Ser-83 → Leu mutation.

Antibiotic Susceptibility and Sequence Type Distribution of Ureaplasma Species Isolated from Genital Samples in Switzerland

Antibiotic resistance in Ureaplasma urealyticum/Ureaplasma parvum and Mycoplasma hominis is an issue of increasing importance. However, data regarding the susceptibility and, more importantly, the clonality of these organisms are limited. We analyzed 140 genital samples obtained in Bern, Switzerland, in 2014. Identification and antimicrobial susceptibility tests were performed by using the Mycoplasma IST 2 kit and sequencing of 16S rRNA genes. MICs for ciprofloxacin and azithromycin were obtained in broth microdilution assays. Clonality was analyzed with PCR-based subtyping and multilocus sequence typing (MLST), whereas quinolone resistance and macrolide resistance were studied by sequencing gyrA, gyrB, parC, and parE genes, as well as 23S rRNA genes and genes encoding L4/L22 ribosomal proteins. A total of 103 samples were confirmed as positive for U. urealyticum/U. parvum, whereas 21 were positive for both U. urealyticum/U. parvum and M. hominis. According to the IST 2 kit, the rates of nonsusceptibility were highest for ciprofloxacin (19.4%) and ofloxacin (9.7%), whereas low rates were observed for clarithromycin (4.9%), erythromycin (1.9%), and azithromycin (1%). However, inconsistent results between microdilution and IST 2 kit assays were recorded. Various sequence types (STs) observed previously in China (ST1, ST2, ST4, ST9, ST22, and ST47), as well as eight novel lineages, were detected. Only some quinolone-resistant isolates had amino acid substitutions in ParC (Ser83Leu in U. parvum of serovar 6) and ParE (Val417Thr in U. parvum of serovar 1 and the novel Thr417Val substitution in U. urealyticum). Isolates with mutations in 23S rRNA or substitutions in L4/L22 were not detected. This is the first study analyzing the susceptibility of U. urealyticum/U. parvum isolates in Switzerland and the clonality outside China. Resistance rates were low compared to those in other countries. We hypothesize that some hyperepidemic STs spread worldwide via sexual intercourse. Large combined microbiological and clinical studies should address this important issue.

In vitro activity of five quinolones and analysis of the quinolone resistance-determining regions of gyrA, gyrB, parC, and parE in Ureaplasma parvum and Ureaplasma urealyticum clinical isolates from perinatal patients in Japan

Ureaplasma spp. cause several disorders, such as nongonococcal urethritis, miscarriage, and preterm delivery with lung infections in neonates, characterized by pathological chorioamnionitis in the placenta. Although reports on antibiotic resistance in Ureaplasma are on the rise, reports on quinolone-resistant Ureaplasma infections in Japan are limited. The purpose of this study was to determine susceptibilities to five quinolones of Ureaplasma urealyticum and Ureaplasma parvum isolated from perinatal samples in Japan and to characterize the quinolone resistance-determining regions in the gyrA, gyrB, parC, and parE genes. Out of 28 clinical Ureaplasma strains, we isolated 9 with high MICs of quinolones and found a single parC gene mutation, resulting in the change S83L. Among 158 samples, the ParC S83L mutation was found in 37 samples (23.4%), including 1 sample harboring a ParC S83L-GyrB P462S double mutant. Novel mutations of ureaplasmal ParC (S83W and S84P) were independently found in one of the samples. Homology modeling of the ParC S83W mutant suggested steric hindrance of the quinolone-binding pocket (QBP), and de novo prediction of peptide structures revealed that the ParC S84P may break/kink the formation of the α4 helix in the QBP. Further investigations are required to unravel the extent and mechanism of antibiotic resistance of Ureaplasma spp. in Japan.

Epidemiological investigation and antimicrobial susceptibility analysis of ureaplasma species and Mycoplasma hominis in outpatients with genital manifestations

AIMS

The aim of this study was to assess the prevalence and drug resistance of Ureaplasma species and Mycoplasma hominis in outpatients with genital manifestation from 2005 to 2013 in Hangzhou, China.

METHODS

A total of 2689 female and 2336 male patients with various genital symptoms were included in this study. Species identification and antimicrobial susceptibility test were performed by using the mycoplasma IST-2 kit.

RESULTS

The prevalence rate of Ureaplasma species was 39.9%, M hominis was 1.2% in female patients, and the coinfection rate was 13.4%; while in males, the prevalence rate of Ureaplasma species was 18.8%, M hominis was 0.4%, and the coinfection rate was 2.9%. Moreover, significantly high positive rates for mycoplasmas (Ureaplasma species M hominis) and were found in 16–20-year-old females (65.2%) and males (27.3%). Ureaplasma species and M hominis displayed relatively lower resistance rates (<5.0%) to doxycycline, josamycin, tetracycline and pristinamycin, and the resistance rates did not change during the study period, while the resistance rates of Ureaplasma species to quinolones (ofloxacin and ciprofloxacin) were much higher (>50%) and increased significantly from 2005 to 2013.

CONCLUSIONS

Our study indicates that high positive rates of Ureaplasma species and M hominis were found in young outpatients with genital symptoms, and monitoring the local drug resistance is critical for prevention of the occurrence of resistant strains.

Transplacental transfer of Azithromycin and its use for eradicating intra-amniotic ureaplasma infection in a primate model

BACKGROUND

Our goals were to describe azithromycin (AZI) pharmacokinetics in maternal plasma (MP), fetal plasma (FP), and amniotic fluid (AF) following intra-amniotic infection (IAI) with Ureaplasma in pregnant rhesus monkeys and to explore concentration-response relationships.

METHODS

Following intra-amniotic inoculation of Ureaplasma parvum, rhesus monkeys received AZI (12.5 mg/kg every 12 hours intravenously for 10 days; n = 10). Intensive pharmacokinetic sampling of MP, FP, and AF was scheduled following the first (ie, single) dose and the last (ie, multiple) dose. Noncompartmental and pharmacokinetic modeling methods were used.

RESULTS

The AF area under the concentration-time curve at 12 hours was 0.22 µg×h/mL following a single dose and 6.3 µg×h/mL at day 10. MP and AF accumulation indices were 8.4 and 19, respectively. AZI AF half-life following the single dose and multiple dose were 156 and 129 hours, respectively. The median MP:FP ratio in concomitantly drawn samples was 3.2 (range, 1.3-9.6; n = 9). Eradication of U. parvum occurred at 6.6 days, with a 95% effective concentration (EC95) of 39 ng/mL for the maximum AZI AF concentration.

CONCLUSIONS

Our study demonstrates that a maternal multiple-dose AZI regimen is effective in eradicating U. parvum IAI by virtue of intra-amniotic accumulation and suggests that antenatal therapy has the potential to mitigate complications associated with U. parvum infection in pregnancy, such as preterm labor and fetal sequelae.

Development of a multilocus sequence typing scheme for Ureaplasma

Ureaplasma is a commensal of the human urogenital tract but is always associated with invasive diseases such as non-gonococcal urethritis and infertility adverse pregnancy outcomes. To better understand the molecular epidemiology and population structure of Ureaplasma, a multilocus sequence typing (MLST) scheme based on four housekeeping genes (ftsH, rpL22, valS, thrS) was developed and validated using 283 isolates, including 14 serovars of reference strains and 269 strains obtained from clinical patients. A total of 99 sequence types (STs) were revealed: the 14 type strains of the Ureaplasma serovars were assigned to 12 STs, and 87 novel and special STs appeared among the clinical isolates. ST1 and ST22 were the predominant STs, which contained 68 and 70 isolates, respectively. Two clonal lineages (CC1 and CC2) were shown by eBURST analysis, and linkage disequilibrium was revealed through a standardized index of association (I A (S)). The neighbor-joining tree results of 14 Ureaplasma serovars showed two genetically significantly distant clusters, which was highly congruent with the species taxonomy of ureaplasmas [Ureaplasma parvum (UPA) and Ureaplasma urealyticum (UUR)]. Analysis of the biotypes of 269 clinical isolates revealed that all the isolates of CC1 were UPA and those of CC2 were UUR. Additionally, CC2 was found more often in symptomatic patients with vaginitis, tubal obstruction, and cervicitis. In conclusion, this MLST scheme is adequate for investigations of molecular epidemiology and population structure with highly discriminating capacity.

Antibiotic susceptibility profiles of Mycoplasma hominis and ureaplasma urealyticum isolated during a population-based study concerning women infertility in northeast romania

The study was carried out on 1068 infertile women under initial evaluation. For Mycoplasma hominis, the highest resistance rates were registered for ciprofloxacin (72.22%), followed by macrolides and ofloxacin. For Ureaplasma urealyticum, the ciprofloxacin resistance was also high (51.72%), while the resistance rates to other tested antibiotics were significantly lower.

Ureaplasma urealyticum and Ureaplasma parvum in women of reproductive age

OBJECTIVES

To determine the incidence of Ureaplasma urealyticum and Ureaplasma parvum (UP) in symptomatic and asymptomatic women of reproductive age and to estimate antibiotic susceptibility of ureaplasma isolates.

MATERIALS AND METHODS

This study included 424 ureaplasma positive women of 1,370 tested women who visited gynecological practices during 2010. Cervicovaginal or urethral swab specimens from each patient were obtained for cultivation and molecular typing by RT-PCR.

RESULTS

Ureaplasma spp. was identified by cultivation in 424 (34.4 %) cases, of which 79.0 % were from women with symptoms and 21.0 % from women without symptoms. Among ureaplasma positive women, 121 (28.5 %) were pregnant. Genotyping was successful in 244 strains, and the majority of samples were identified as UP (92.6 %). Among genotyped isolates, there were 79.5 % from symptomatic and 20.5 % from asymptomatic women; 29.9 % from pregnant and 70.1 % from non-pregnant women. There was no difference in the incidence of ureaplasma type regarding symptoms. Antibiotic susceptibility of 424 ureaplasma isolates identified by cultivation showed that all strains were susceptible to doxycycline, josamycin, erythromycin, tetracycline, clarithromycin and pristinamycin, but there was lower susceptibility to quinolone antibiotics, i.e., 42.9 and 24.5 % isolates were susceptible to ofloxacin and ciprofloxacin, respectively.

CONCLUSION

This study shows that UP was the most frequent isolated ureaplasma species (92.6 %). Regarding antibiotic susceptibility, quinolones are not the best choice for the treatment of ureaplasma infections, while macrolides and tetracyclines are still effective.

Antibiotic susceptibilities and resistance genes of Ureaplasma parvum isolated in South Africa

OBJECTIVES

There is only limited information on the antimicrobial susceptibilities and resistance genes of Ureaplasma parvum in South Africa. This study was designed to detect and characterize resistance genes in U. parvum.

METHODS

Fifteen U. parvum isolates were investigated employing the broth microdilution method (tetracycline, doxycycline, ofloxacin, erythromycin, azithromycin and josamycin). Gene analyses were performed on target regions of: tet(M); gyrA, gyrB, parC and parE; erm(A), erm(B), erm(C) and erm(E); msr(A), msr(B), msr(C) and msr(D); 23S rRNA operons; and L4 and L22 ribosomal proteins.

RESULTS

Seven of the U. parvum isolates were fully susceptible to the antibiotics tested. Five strains exhibited resistance to tetracycline (MICs 16-256 mg/L), one strain was resistant to ofloxacin (MIC 128 mg/L) and four strains were resistant to macrolides (MICs 128 mg/L); two strains showed dual resistance to tetracycline and erythromycin. The five tetracycline-resistant strains were found to have mosaic tet(M) genes, with one strain containing different specific regions to those previously described. Mutations in the L22 ribosomal protein were seen in three strains that were resistant to erythromycin (two strains) and erythromycin + azithromycin (one strain). For a further strain that was resistant to erythromycin and azithromycin, possible mechanisms of resistance remained elusive.

CONCLUSIONS

This is the first report of quinolone, erythromycin and azithromycin resistance development in U. parvum from South Africa. A point mutation in parC (Pro-57 → Leu) and two novel mutations in parE (Ile-73 → Thr and a methionine insertion at codon 86) were found in an ofloxacin-resistant strain. The study reinforces the adaptability of U. parvum to develop resistance and acquire, modify and maintain transposon-located resistance genes.

Chromosomal mutations responsible for fluoroquinolone resistance in Ureaplasma species in the United States

We sequenced the full lengths of the gyrA, gyrB, parC, and parE genes in 13 fluoroquinolone-resistant Ureaplasma isolates (levofloxacin MICs, 4 to 32 μg/ml) and 10 susceptible isolates (MICs ≤ 2 μg/ml). Mutations were detected in all resistant isolates but in none of the susceptible isolates. The most prevalent mutation was the S83L substitution in the ParC protein. No plasmid-mediated fluoroquinolone resistance genes were detected.

Susceptibility of Ureaplasma urealyticum to tetracycline, doxycycline, erythromycin, roxithromycin, clarithromycin, azithromycin, levofloxacin and moxifloxacin

The in vitro activity of tetracycline, doxycycline, erythromycin, roxithromycin, clarithromycin, azithromycin, levofloxacin and moxifloxacin was tested against 63 clinical isolates of Ureaplasma urealyticum. The minimal inhibitory concentrations (MICs) and the minimal bactericidal concentrations (MBCs) were determined by the broth microdilution method in A7 medium. The MIC(50) and MIC(90) of the tested agents after 24 h of incubation were as follows: tetracycline, 0.5 and 2.0 μg/ml; doxycycline, 0.125 and 0.25 μg/ml; erythromycin, 2.0 and 8.0 μg/ml; roxithromycin, 2.0 and 4.0 μg/ml; clarithromycin, 0.25 and 1.0 μg/ml; azithromycin, 2.0 and 4.0 μg/ml; levofloxacin, 1.0 and 2.0 μg/ml; and moxifloxacin, 0.5 and 0.5 μg/ml, respectively. The MIC values after 24 h and 48 h incubation differed by no more than one dilution for all the agents with the exception of doxycycline (two dilution difference for MIC(90)). Overall, moxifloxacin was the most active agent in vitro against U. urealyticum, with the narrowest difference between MIC and MBC values, followed closely by levofloxacin. Clarithromycin was the most active macrolide.

[Frequency and antibiotic resistance of Ureaplasma urealyticum and Mycoplasma hominis in genital samples of sexually active individuals]

Ureaplasma urealyticum and Mycoplasma hominis have important role among the causative agents of sexually transmitted diseases.

AIM

The aim of the study was to determine the frequency and antibiotic resistance of Ureaplasma urealyticum and Mycoplasma hominis in genital samples obtained from patients examined in the Sexually Transmitted Diseases Centre of the Department of Dermatology, Venerology and Dermatooncology, Semmelweis University, Budapest between May 1, 2008 and July 31, 2010.

PATIENTS AND METHODS

Samples were taken from the urethra in men and from the cervix and urethra in women by universal swab (Biolab®) into Urea-Myco DUO kit (Bio-Rad®) and were incubated for 48 hours at 37 C°. Antibiotic sensitivity of positive samples was determined in U9 bouillon using SIR Mycoplasma kit (Bio-Rad®).

RESULTS

Samples for 4154 patients aged 16-60 years were examined. In 247/4154 samples (6%) U. urealyticum and in 26/4154 samples (0.63%) M. hominis was isolated from the genital tract. Most U. urealyticum and M. hominis strains (75% and 77%, respectively) were cultured from cervix, while the remaining 25%, and 23% from the male and female urethra, respectively. U. urealyticum and M. hominis were most commonly detected in patients aged between 21 and 40 years. The majority of U. urealyticum strains were sensitive to tetracycline (94%), doxycycline (95%), azithromycin (88%) and josamycin (90%), but were resistant to ofloxacin (21%), erythromycin (85%) and clindamycin (79%). Seventy-seven percent of the U. urealyticum strains were simultaneously resistant to erythromycin and clindamycin, suggesting that ex iuvantibus therapies may select cross-resistant strains to both antibiotics. The resistance of M. hominis to clindamycin, doxycycline, ofloxacin and tetracycline varied between 4% and 12 %.

CONCLUSIONS

Because none of the strains was sensitive to all examined antibiotics, the antibiotic sensitivity of U. urealyticum and M. hominis strains should be determined. The high rate of ofloxacin, erythromycin and clindamycin resistance should be considered in the therapy of U. urealyticum infections in Hungary. This is the first such a clinical microbiological study in this topic in Hungary.

A deep sternal wound infection caused by Ureaplasma urealyticum

Ureaplasma species are usually associated with infection of the urogenital tract. An unusual case of a sternal wound infection caused by Ureaplasma urealyticum in a 41-year-old male after aortic valve replacement is described.

Comparison of full gyrA, gyrB, parC and parE gene sequences between all Ureaplasma parvum and Ureaplasma urealyticum serovars to separate true fluoroquinolone antibiotic resistance mutations from non-resistance polymorphism

OBJECTIVES

To determine the role of amino acid substitutions in Ureaplasma GyrA, GyrB, ParC and ParE proteins in mediating fluoroquinolone resistance.

METHODS

Nucleic acid sequences from gyrA, gyrB, parC and parE genes from all 14 Ureaplasma serovars were aligned. Full genome sequences for serovars 1, 3-7, 9 and 11-14 were available from the National Center for Biotechnology Information database and we sequenced the full topoisomerase genes from ciprofloxacin-susceptible reference strains of serovars 2, 8 and 10. Phylogenetic trees were constructed to analyse nucleotide sequence similarity. Deduced amino acid sequences were compared with all 33 previously reported fluoroquinolone-resistant strains to clarify true fluoroquinolone-resistance-associated substitutions.

RESULTS

Non-resistance-associated polymorphisms were identified in GyrA (39), GyrB (26), ParC (107) and ParE (34) proteins. Phylogenetic analysis demonstrated species clustering for all genes, except parE in which serovars 4, 12, 10 and 13 formed a separate cluster more similar to Ureaplasma parvum than the remaining Ureaplasma urealyticum serovars. Examination of all previously reported fluoroquinolone-resistant strains found that one-third of identified residue substitutions could be attributed to normal species polymorphism; therefore, the mechanism of resistance for these strains is still undetermined. In particular, Glu or Asp at position 112 in GyrA and Ala or Thr at 125/136 in ParC were substitutions identified when U. urealyticum strain sequences were previously aligned with the published serovar 3 genome sequence.

CONCLUSION

Combining analysis of the recently available Ureaplasma genomes with sequences from the additional serovars has enabled us to clarify which substitutions found by previous investigators could potentially be responsible for fluoroquinolone resistance.

Concurrent titration and determination of antibiotic resistance in ureaplasma species with identification of novel point mutations in genes associated with resistance

Antibiotic resistance determination of Ureaplasma spp. (Ureaplasma parvum and Ureaplasma urealyticum) usually requires predetermination of bacterial titer, followed by antibiotic interrogation using a set bacterial input. This 96-well method allows simultaneous quantification of bacteria in the presence and absence of antibiotics. A method for determining precise MICs and a method for screening against multiple antibiotics using breakpoint thresholds are detailed. Of the 61 Ureaplasma-positive clinical isolates screened, one (1.6%) was resistant to erythromycin (MIC, >64 mg/liter) and clarithromycin (MIC, 4 mg/liter), one to ciprofloxacin (1.6%), and one to tetracycline/doxycycline (1.6%). Five isolates were also consistently found to have an elevated MIC of 8 mg/liter for erythromycin, but this may not represent true antibiotic resistance, as no mutations were found in the 23S rRNA operons or ribosome-associated L4 and L22 proteins for these strains. However, two amino acids (R66Q67) were deleted from the L4 protein of the erythromycin-/clarithromycin-resistant strain. The tetM genetic element was detected in the tetracycline-resistant clinical isolate as well as in the positive control Vancouver strain serotype 9. The tetM gene was also found in a fully tetracycline-susceptible Ureaplasma clinical isolate, and no mutations were found in the coding region that would explain its failure to mediate tetracycline resistance. An amino acid substitution (D82N) was found in the ParC subunit of the ciprofloxacin-resistant isolate, adjacent to the S83L mutation reported by other investigators in many ciprofloxacin-resistant Ureaplasma isolates. It is now possible to detect antibiotic resistance in Ureaplasma within 48 h of positive culture without prior knowledge of bacterial load, identifying them for further molecular analysis.

Ureaplasma urealyticum meningitis in an adult patient

A 38-year-old patient developed meningitis after a complicated kidney transplantation and organ rejection. Ureaplasma urealyticum was identified as the etiological agent by molecular and microbiological analyses of the cerebrospinal fluid. The patient was successfully treated with doxycycline and chloramphenicol. This is the first report of Ureaplasma urealyticum meningitis in an adult.