Dataset Information

Direct detection of macrolide resistance in Mycoplasma genitalium isolates from clinical specimens from France by use of real-time PCR and melting curve analysis.

ABSTRACT: Mycoplasma genitalium is a sexually transmitted organism commonly treated with azithromycin. However, macrolide resistance has been reported and is associated with point mutations in the 23S rRNA gene. To evaluate the prevalence of macrolide resistance in M. genitalium isolates from clinical specimens from France, we first used a previously reported high-resolution melting assay. Because susceptible and resistant M. genitalium isolates were hardly discriminated in M. genitalium-positive clinical specimens, we developed a new molecular assay for the rapid detection of macrolide resistance. An assay using real-time PCR based on fluorescence resonance energy transfer (FRET) coupled with melting curve analysis was designed. The assay was first validated on characterized macrolide-resistant M. genitalium isolates and then applied to 202 urogenital M. genitalium-positive specimens collected from 178 patients from France in 2011 and 2012. Resistant genotypes were confirmed by 23S rRNA gene sequencing. Among the 202 M. genitalium-positive specimens, 155 were amplified, demonstrating a sensitivity of 76.7%. A substitution in the 23S rRNA gene was found in 14.2% of the patient samples. Nine and six patients had M. genitalium isolates with a substitution at positions 2059 and 2058, respectively. In four cases, a mixed population of wild-type and mutated M. genitalium isolates was observed. The prevalence of M. genitalium macrolide resistance has been stable in France since its detection in 2006. Our FRET PCR assay is able to discriminate between wild-type and resistant genotypes directly from clinical specimens. This assay will allow clinicians to shorten the time to the initiation of effective disease treatment.

SUBMITTER: Touati A

PROVIDER: S-EPMC3993663 | biostudies-literature | 2014 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Direct detection of macrolide resistance in Mycoplasma genitalium isolates from clinical specimens from France by use of real-time PCR and melting curve analysis.

Touati Arabella A Peuchant Olivia O Jensen Jorgen S JS Bébéar Cécile C Pereyre Sabine S

Journal of clinical microbiology 20140226 5

Mycoplasma genitalium is a sexually transmitted organism commonly treated with azithromycin. However, macrolide resistance has been reported and is associated with point mutations in the 23S rRNA gene. To evaluate the prevalence of macrolide resistance in M. genitalium isolates from clinical specimens from France, we first used a previously reported high-resolution melting assay. Because susceptible and resistant M. genitalium isolates were hardly discriminated in M. genitalium-positive clinical ...[more]

PMID: 24574291

Similar Datasets

Project description:BackgroundThis study evaluated the distribution of macrolide-resistant Mycoplasma genitalium in multiple urogenital specimens collected from women enrolled in a prospective multicenter US clinical study.MethodsFour female urogenital specimens (vaginal swab, urine, endocervical swab, ectocervical brush/spatula) collected from each subject were tested using a transcription-mediated amplification (TMA) assay for M. genitalium. TMA-positive specimens were evaluated by reverse transcription-polymerase chain reaction and bidirectional Sanger sequencing of M. genitalium 23S rRNA to identify the presence of macrolide-resistance-mediating mutations (MRMs) at base positions 2058/2059.ResultsOf 140 women with ≥1 TMA-positive specimens, 128 (91.4%) yielded M. genitalium 23S rRNA sequence. MRMs were found in 52% of vaginal specimens, 46.3% of urine specimens, 37.8% of endocervical specimens, and 46% of ectocervical specimens. There were 44 unique specimen type/sequence phenotype combinations of M. genitalium infection. Most (81; 63.3%) women had single specimen-sequence phenotype (macrolide-susceptible, MRM, or both) infections, while 24 (18.8%) women had multiple specimen-sequence phenotype concordant infections, and 23 (17.9%) women had multiple specimen-sequence phenotype discordant infections. The sensitivity for any single specimen type to detect overall urogenital tract macrolide-resistant M. genitalium infection status was 96.3% for vaginal swab samples, 82.6% for urine samples, 70.8% for endocervical swab samples, and 82.1% for ectocervical brush/spatula liquid Pap samples.ConclusionsThe distribution of M. genitalium infections in female urogenital tract specimens is highly complex, with multiple phenotypic combinations of the organism infecting a significant proportion of women at different anatomic specimen collection sites. Vaginal swab sampling yielded the highest sensitivity for identifying women with macrolide-resistant M. genitalium urogenital tract infections.

Project description:BackgroundTraditional drug susceptibility testing cannot be performed in clinical laboratories due to the slow-growing characteristics of Mycoplasma genitalium when cultured in vitro. Sanger sequencing is the standard method for detecting drug resistance-associated mutations. It has been used in some laboratories to guide the choice of macrolide antibiotics for Mycoplasma genitalium infected patients. Furthermore, resistance to fluoroquinolone has become another emerging clinical challenge.ObjectiveSequencing analysis can detect unknown mutations, but it is time-consuming, requires professional analytical skills and the appropriate testing equipment. The main objective of this study was to establish a nested real-time PCR method for the simultaneous detection of 23S rRNA and parC genotypes in relation to the macrolide and fluoroquinolone resistance.Results105 MG-positive samples and 27 samples containing other pathogens were used for validation. The limit of the nested real-time PCR detection was 500 copies/reaction and there was no cross-reaction with Ureaplasma urealyticum, Mycoplasma hominis, Chlamydia trachomatis, Neisseria gonorrhoeae, Human papillomavirus, Herpes simplex virus, Candida albicans and Ureaplasma parvum, but the 23S rRNA assay cross-reacted with Mycoplasma pneumoniae. Compared with sequencing results, the sensitivity of 23S rRNA was 100% (95% CI; 93.3 -100), the specificity was 94.3% (95% CI; 79.4 - 99.0), the overall consistency was 98% (95% CI; 92.5 - 99.7) and kappa value was 0.96 (P < 0.001); the sensitivity of parC was 100% (95% CI; 93.4 - 100), the specificity was 89.7% (95% CI; 71.5 - 97.3) and the overall consistency was 96.9% (95% CI; 90.7 - 99.2) with a kappa value of 0.92 (P < 0.001).ConclusionsThe results of this sensitive and rapid alternative for identifying resistant genotypes of Mycoplasma genitalium are intuitive and easy to interpret, especially for mixed MG populations. Although the relevant 23S rRNA primers need further adjustment, this reliable method would provide an effective diagnostic tool for the selection of antibiotics in clinical practice.

Project description:BackgroundMycoplasma genitalium (MG) causes urethritis, cervicitis and pelvic inflammatory disease. The MG treatment failure rate using 1 g azithromycin at an Australian Sexual Health clinic in 2007-9 was 31% (95%CI 23-40%). We developed a rapid high resolution melt analysis (HRMA) assay targeting resistance mutations in the MG 23S rRNA gene, and validated it against DNA sequencing by examining pre- and post-treatment archived samples from MG-infected patients.Methodology/principal findingsAvailable MG-positive pre-treatment (n = 82) and post-treatment samples from individuals with clinical treatment failure (n = 20) were screened for 23S rRNA gene mutations. Sixteen (20%) pre-treatment samples possessed resistance mutations (A2058G, A2059G, A2059C), which were significantly more common in patients with symptomatic azithromycin-treatment failure (12/26; 44%) than in those clinically cured (4/56; 7%), p<0.001. All 20 patients experiencing azithromycin-failure had detectable mutations in their post-treatment samples. In 9 of these cases, the same mutational types were present in both pre- and post-treatment samples indicating transmitted resistance, whilst in 11 of these cases (55%), mutations were absent in pre-treatment samples indicating likely selection of resistant isolates have occurred. HRMA was able to detect all mutational changes determined in this study by DNA sequencing. An additional HRMA assay incorporating an unlabelled probe was also developed to detect type 4 single-nucleotide polymorphisms found in other populations, with a slightly lower sensitivity of 90%.Conclusions/significanceTreatment failure is associated with the detection of macrolide resistance mutations, which appear to be almost equally due to selection of resistant isolates following exposure to 1 g azithromycin and pre-existing transmitted resistance. The application of a rapid molecular assay to detect resistance at the time of initial detection of infection allows clinicians to shorten the time to initiate effective second line treatment. This has the potential to reduce transmission of resistant strains and to avoid sequelae associated with persistent untreated infection.

Dataset Information

Direct detection of macrolide resistance in Mycoplasma genitalium isolates from clinical specimens from France by use of real-time PCR and melting curve analysis.

Publications

Direct detection of macrolide resistance in Mycoplasma genitalium isolates from clinical specimens from France by use of real-time PCR and melting curve analysis.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets