Mycoplasma genitalium infections in asymptomatic men and men with urethritis attending a sexually transmitted diseases clinic in New Orleans

Mycoplasma genitalium: an efficient strategy to generate genetic variation from a minimal genome

Mycoplasma genitalium, a human pathogen associated with sexually transmitted diseases, is unique in that it has smallest genome of any known free-living organism. The goal of this study was to investigate if and how M. genitalium uses a minimal genome to generate genetic variations. We analysed the sequence variability of the third gene (MG192 or mgpC) of the M. genitalium MgPa adhesion operon, demonstrated that the MG192 gene is highly variable among and within M. genitalium strains in vitro and in vivo, and identified MG192 sequence shifts in the course of in vitro passage of the G37 type strain and in sequential specimens from an M. genitalium-infected patient. In order to establish the origin of the MG192 variants, we examined nine genomic loci containing partial copies of the MgPa operon, known as MgPar sequences. Our analysis suggests that the MG192 sequence variation is achieved by recombination between the MG192 expression site and MgPar sequences via gene cross-over and, possibly, also by gene conversion. It appears plausible that M. genitalium has the ability to generate unlimited variants from its minimized genome, which presumably allows the organism to adapt to diverse environments and/or to evade host defences by antigenic variation.

Mycoplasma genitalium among women with nongonococcal, nonchlamydial pelvic inflammatory disease

Pelvic inflammatory disease (PID) is a frequent condition of young women, often resulting in reproductive morbidity. Although Neisseria gonorrhoeae and/or Chlamydia trachomatis are/is recovered from approximately a third to a half of women with PID, the etiologic agent is often unidentified. We need PCR to test for M genitalium among a pilot sample of 50 women with nongonococcal, nonchlamydial endometritis enrolled in the PID evaluation and clinical health (PEACH) study. All participants had pelvic pain, pelvic organ tenderness, and leukorrhea, mucopurulent cervicitis, or untreated cervicitis. Endometritis was defined as ≥5 surface epithelium neutrophils per ×400 field absent of menstrual endometrium and/or ≥2 stromal plasma cells per ×120 field. We detected M genitalium in 7 (14%) of the women tested: 6 (12%) in cervical specimens and 4 (8%) in endometrial specimens. We conclude that M genitalium is prevalent in the endometrium of women with nongonococcal, nonchlamydial PID.

Management of women with cervicitis

In the past several years, the collective understanding of cervicitis has extended beyond the recognition of Chlamydia trachomatis and Neisseria gonorrhoeae as the prime etiologic suspects. Trichomonas vaginalis and herpes simplex virus cause cervicitis, and both Mycoplasma genitalium and bacterial vaginosis have emerged as new candidate etiologic agents or conditions. However, major gaps in our knowledge of this common condition remain. Putative etiologic agents have not been identified in many women with cervicitis. Moreover, cervicitis occurs in a relatively small proportion of women with chlamydia or gonorrhea. Finally, scant research has addressed the clinical response of nonchlamydial and nongonococcal cervicitis to antibiotic therapy, and there are no data on the benefit of sex partner treatment for such women. New research into the etiology, immunology, and natural history of this common condition is needed, especially in view of the well-established links between cervicitis and an increased risk of upper genital tract infection and human immunodeficiency virus type 1 acquisition.

Mycoplasma genitalium among adolescent women and their partners

PURPOSE

Mycoplasma genitalium is a possible sexually transmitted pathogen and its study among the adolescent age group has been limited. In this longitudinal study, the epidemiology, natural history, and associated clinical findings of M. genitalium among adolescents in a primary care setting were explored.

METHODS

A sample of 383 young women (14-17 years of age) and 117 male partners provided sexual behavior data and urogenital samples for polymerase chain reaction testing to detect M. genitalium, Chlamydia trachomatis, and other sexually transmitted infections. Women were tested quarterly for up to 27 months and, during every other quarter, tested weekly. The presence of any signs or symptoms of infection among the female subjects was also documented.

RESULTS

Cumulatively, 13.6% (52/383) of women tested positive for M. genitalium. All women with M. genitalium, except one, were sexually experienced. M. genitalium was associated with number of sexual partners (p < .001) and C. trachomatis infection (p < .03). M. genitalium was more likely among male partners of M. genitalium-positive women (p < .02); 31.3% of untreated M. genitalium cases had infection lasting over 8 weeks. M. genitalium was not associated with the presence of clinical signs or symptoms of infection.

CONCLUSIONS

Findings support sexual transmissibility of M. genitalium and add to understanding of M. genitalium natural history and clinical findings.

Mycoplasma genitalium among young adults in the United States: an emerging sexually transmitted infection

OBJECTIVES

We sought to determine the prevalence of and risk factors associated with Mycoplasma genitalium infection in a nationally representative sample of young adults in the United States.

METHODS

Urine specimens from 1714 women and 1218 men who participated in Wave III of the National Longitudinal Study of Adolescent Health (N=14322) were tested for M genitalium. Poststratification sampling weights were used to generate nationally representative estimates.

RESULTS

The prevalence of M genitalium was 1.0% compared with 0.4%, 4.2%, and 2.3% for gonococcal, chlamydial, and trichomonal infections, respectively. No M genitalium-positive individuals reported symptoms of discharge. M genitalium prevalence among those who reported vaginal intercourse was 1.1% compared with 0.05% among those who did not. In multivariate analyses, M genitalium prevalence was 11 times higher among respondents who reported living with a sexual partner, 7 times higher among Blacks, and 4 times higher among those who used condoms during their last vaginal intercourse. Prevalence of M genitalium increased by 10% for each additional sexual partner.

CONCLUSIONS

M genitalium was more prevalent than Neisseria gonorrhoeae but less prevalent than Chlamydia trachomatis, and it was strongly associated with sexual activity.

Is the urethral smear necessary in asymptomatic men attending a genitourinary medicine clinic?

Available evidence does not support the performance of urethral smears in asymptomatic men

Performance of the gen-probe transcription-mediated [corrected] amplification research assay compared to that of a multitarget real-time PCR for Mycoplasma genitalium detection

Mycoplasma genitalium (MG) can cause nongonococcal urethritis and is potentially associated with urethritis, endometritis, and cervicitis. Several assays have been developed to detect MG. Molecular amplification assays for organism detection can be problematic due to the potential for false-positive and false-negative results. Confirmatory testing is often required in these situations, requiring additional time and resources. Use of multigene targets could integrate both detection and verification at lower cost. Utilizing two targets, the MgPa adhesion gene and the 16S rRNA gene, a multitarget real-time (MTRT) PCR for the detection of MG was developed. Samples from patients attending sexually transmitted disease clinics were collected in duplicate. Urine samples from males (n = 286) and self-collected vaginal swabs from females (n = 321) were analyzed by MTRT PCR for MG and the Gen-Probe transcription-mediated [corrected] amplification (TMA) assay, which targets MG rRNA for detection (TMA-MG research use only). Utilizing the criteria of any two targets being positively amplified, the MTRT PCR had a sensitivity and specificity of 91.8% (101 positive samples/110 samples tested) and 99.5% (495/497), respectively, with a positive predictive value (PPV) of 98.1% (101/103) and a negative predictive value (NPV) of 98.2% (495/504). The Gen-Probe TMA-MG assay had a sensitivity, specificity, PPV, and NPV of 98.1% (108/110), 98.1% (488/497), 92.3% (108/117), and 99.5% (488/490), respectively. Comparison between the MTRT PCR and TMA-MG assay by kappa statistic analysis indicated that an overall kappa value was 0.941 (95% confidence interval, 0.907 and 0.976). Both assays demonstrated accuracy in the detection of MG from urine samples from male patients and self-collected vaginal swabs from female patients.

Comparison of transcription-mediated amplification and PCR assay results for various genital specimen types for detection of Mycoplasma genitalium

Mycoplasma genitalium is now recognized as a possible cause of several idiopathic sexually transmitted disease (STD) syndromes. However, due to the difficulty of culture of this fastidious bacterium, nucleic acid amplification tests (NAATs) are necessary for its detection in patient specimens. In the current study we compared a newly developed research-only transcription-mediated amplification (TMA) assay (Gen-Probe Incorporated) to our in-house DNA-based PCR assay for detection of M. genitalium. The relative performance characteristics of these two NAATs were assessed with genital specimens from 284 women and 352 men reporting to an STD clinic in Seattle, WA. Among the women, M. genitalium was detected by the TMA and PCR assays in 36 (13%) and 39 (14%) vaginal swab specimens, respectively (kappa = 0.923); 26 (9%) and 23 (8%) cervical swab specimens, respectively (kappa = 0.843); and 25 (9%) and 28 (10%) urine specimens, respectively (kappa = 0.687). Among the M. genitalium-positive women, the relative sensitivities of detection for the TMA and PCR assays were 84% and 91%, respectively, for vaginal swab specimens; 60% and 53%, respectively, for cervical swab specimens; and 58% and 65%, respectively, for urine specimens. By using an infected patient (a woman positive at any site by TMA assay and at any site by PCR) as a proxy for a "gold standard," the specificities of detection were >99.5% for both the TMA and the PCR assays. Among the men, M. genitalium was detected in 24 urine specimens (6.8%) by the TMA assay, 26 (7.4%) urine specimens by PCR assay, and 32 urine specimens (9%) by either test (kappa = 0.791). We conclude that the M. genitalium TMA and PCR assays are highly specific and that vaginal swab specimens are the most sensitive specimen type for the detection of M. genitalium in women.

Epidemiology, pathogenesis and treatment of pelvic inflammatory disease

Pelvic inflammatory disease, the infection and inflammation of the female upper genital tract, is a common cause of infertility, chronic pain and ectopic pregnancy. Diagnosis and management are challenging, due largely to a polymicrobial etiology which is not fully delineated. Signs and symptoms of this syndrome vary widely, further complicating diagnosis and treatment. Due to the potential for serious sequelae, a low threshold for diagnosis and treatment is recommended. Since pelvic inflammatory disease has a multimicrobial etiology including Neisseria gonorrhoeae, Chlamydia trachomatis and anaerobic and mycoplasmal bacteria, treatment of pelvic inflammatory disease should be broad spectrum. Recent treatment trials have focused on shorter duration regimens such as azithromycin and monotherapies including ofloxacin, although data are sparse. Research comparing sequelae development by differing antimicrobial regimens is extremely limited, but will ultimately shape future treatment guidelines. Several promising short-duration and monotherapy antibiotic regimens should be evaluated in pelvic inflammatory disease treatment trials for compliance, microbiological and clinical cure, and reduction of subsequent adverse reproductive and gynecological morbidity.

Sexually transmitted infections: screening, syndromes, and symptoms

STI are among the most common pathological conditions affecting sexually active adolescents. Both screening of asymptomatic adolescents and a thoughtful, thorough approach to the evaluation of symptoms are critical measures in STI identification and control.

Cervicitis and Genitourinary Symptoms in Women Culture Positive for Mycoplasma genitalium

PROBLEM

Mycoplasma genitalium has been associated with male urethritis. We sought to relate M. genitalium to genitourinary signs and symptoms in women.

METHOD OF STUDY

We compared 26 culture-positive women (group 1), 257 additional polymerase chain reaction-positive women (group 2), and 107 negative control women. We used logistic regression to evaluate signs and symptoms, controlling for co-infections, pregnancy, age, and intervention group assignment.

RESULTS

Comparing group 1 with controls, we found significantly elevated odds ratios (ORs) for intermediate vaginal discharge (OR = 5.4; 95% confidence interval 1.01, 29.2) and action in response to discharge [3.9 (1.1, 13.5)]. Non-significant increases were observed for pathologic vaginal discharge [3.8 (0.78, 18.2)], pathologic dyspareunia [1.5 (0.25, 9.0)], vaginal odor [2.1 (0.75, 5.7)], and cervical mucopus [4.1 (0.74, 22.4)]. Group 2 results were similar, but showed no increase in cervical mucopus relative to controls.

CONCLUSION

Infection with M. genitalium in women is independently related to increased genitourinary symptomatology.

Detection of Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma urealyticum, and Ureaplasma parvum DNAs in urine from asymptomatic healthy young Japanese men

The aim of this study was to estimate the detection rates of Mycoplasma and Ureaplasma, which are presumptive causes of sexually transmitted diseases (STDs), in young men in Sapporo, Japan. In addition, we examined the associations among Chlamydia trachomatis, Mycoplasma, and Ureaplasma. A survey of 100 asymptomatic healthy male volunteers was carried out. C. trachomatis, Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma urealyticum, and Ureaplasma parvum in first-voided urine specimens were detected by polymerase chain reaction assay. Detection rates were 1% for M. genitalium, 4% for M. hominis, 12% for U. urealyticum, and 23% for U. parvum. C. trachomatis was detected in 6% of samples. No M. hominis, U. urealyticum, or U. parvum was detected simultaneously in any sample positive for C. trachomatis. The detection rate of urinary M. genitalium was extremely low, which is similar to previous reports from Japan. The detection rates of urethral U. urealyticum and U. parvum were significantly related to sexual activity. We need to determine whether these pathogens have a role in the sexual transmission of disease or just in colonization.

Mycoplasma genitalium

Mycoplasma genitalium was initially isolated from men with nongonococcal urethritis in 1980. Subsequent studies to assess the association of M. genitalium with human disease were inhibited however because on repeated attempts the organism proved extremely difficult to culture. Fortunately, the development and use of specific polymerase chain reaction assays allowed progress in this arena and provided evidence of the association between M. genitalium and urethritis, cervicitis, and endometritis. A serologic association has also been noted between M. genitalium antibody and salpingitis and tubal factor infertility. In addition, sexual transmission of M. genitalium in heterosexual partners has also been demonstrated. Currently, studies are underway to further assess these associations and provide additional information about the significance of this organism with regards to sexual transmission, infertility in women, and its association with other genital tract disease processes. Recent studies have suggested that M. genitalium-associated infections are best treated with azithromycin.

Mycoplasma genitalium urethritis in men

Mycoplasma genitalium was first isolated from two men with non-gonococcal urethritis (NGU) and thereafter shown to produce urethritis in subhuman primates, inoculated intraurethrally. This mycoplasma has been detected significantly more often in patients with acute NGU, particularly in patients with non-chlamydial NGU, than in subjects without urethritis. The prevalence of M. genitalium-positive non-chlamydial NGU ranges from 18 to 46% of all non-chlamydial NGU cases. In addition, the persistence of M. genitalium in the urethra after antimicrobial chemotherapy is associated with persistence or recurrence of NGU. The various results reported to date tend to support the proposition that M. genitalium is a pathogen of NGU. M. genitalium is highly susceptible to tetracyclines, macrolides, and some new fluoroquinolones, but the clinical data on the chemotherapy in M. genitalium-positive NGU is extremely limited. Because of the possible association between the post-treatment presence of M. genitalium in the urethra and persistent or recurrent NGU, the eradication of this mycoplasma from the urethra is essential in the management of patients with M. genitalium-positive NGU. Further studies are required to establish the optimal chemotherapy for M. genitalium-positive NGU.

High prevalence of genital mycoplasmas among sexually active young adults with urethritis or cervicitis symptoms in La Crosse, Wisconsin

Sexually active young adults in the small college town of La Crosse, Wisconsin, were evaluated for conventional sexually transmitted pathogens and tested for infections with mycoplasmas. The prevalence in 65 symptomatic men or women and 137 healthy volunteers (67 men and 70 women) was compared. Urine specimens from both cohorts were tested by ligase chain reaction for Chlamydia trachomatis or Neisseria gonorrhoeae. In addition, the urethral or cervical swabs from the symptomatic subjects were tested by PCR for Mycoplasma genitalium and cultured for Mycoplasma hominis and the ureaplasmas. The results confirmed a relatively low prevalence of gonorrhea among symptomatic men (12%) and chlamydia among symptomatic men (15%) and normal women (3%). In contrast, infections with mycoplasmas, especially the ureaplasmas (57%), were common and the organisms were the only potential sexually transmitted pathogen detected in 40 (62%) symptomatic subjects. Because of the high prevalence, we also evaluated urethral swabs from an additional 25 normal female volunteers and recovered ureaplasmas from 4 (16%) subjects. Additionally, the participants rarely used protection during sexual intercourse and some symptomatic subjects apparently acquired their infections despite using condoms regularly. The findings demonstrate a strong association between abnormal urogenital findings and detection of myoplasmas, particularly ureaplasmas, and suggest the infections will remain common.

Single-nucleotide polymorphisms in the rRNA operon and variable numbers of tandem repeats in the lipoprotein gene among Mycoplasma genitalium strains from clinical specimens

We characterized the single-nucleotide polymorphisms in the rRNA operon and variable numbers of tandem repeats in the lipoprotein gene MG309 among Mycoplasma genitalium strains from clinical specimens by PCR and sequencing. Analysis of 31 M. genitalium-infected patient specimens and 7 American Type Culture Collection strains identified six types of rRNA sequences and 11 different numbers of MG309 repeats. Examination of sequential specimens from 10 patients showed that these genotypes were stable for at least 5 weeks. These data suggest the potential usefulness of the rRNA genotypes and the MG309 repeats for genotyping of M. genitalium.

Comparison of first void urine and urogenital swab specimens for detection of Mycoplasma genitalium and Chlamydia trachomatis by polymerase chain reaction in patients attending a sexually transmitted disease clinic

OBJECTIVE

The objective of this study was to compare urogenital swab specimens and first void urine (FVU) specimens from male and female patients at a sexually transmitted disease clinic for the detection of Mycoplasma genitalium and Chlamydia trachomatis infections using in-house, inhibitor-controlled polymerase chain reaction (PCR).

STUDY DESIGN

Urethral swabs and FVU were collected from 1856 men and 753 women who also had a cervical swab collected. A positive diagnosis of infection was made if any 1 of the specimens tested positive and were confirmed in a second PCR assay targeting independent genes.

RESULTS

M. genitalium DNA and C. trachomatis DNA were detected in 126 (6.8%) and 246 (13.3%) of the male sample sets and in 51 (6.8%) and 73 (9.7%) of the female specimen sets, respectively. Using our in-house PCR and sample preparation methods, FVU was found to be the most sensitive diagnostic specimen for both pathogens, but for optimal sensitivity, it should be supplemented with a cervical specimen in women. In a small subset of female FVUs, storage at -20 degrees C led to false-negative M. genitalium PCR results in 27% of specimens found positive when a sample preparation was performed before freezing. The age-specific prevalence of M. genitalium in men was almost constant between 18 and 45 years of age in contrast to C. trachomatis infections, which were more common in younger men.

CONCLUSION

Urine appeared to be a better diagnostic specimen than the urethral swab for M. genitalium and C. trachomatis detection by PCR in this cohort of sexually transmitted disease clinic attendees but should be supplemented with a cervical specimen in women.

Mycoplasma genitalium: the aetiological agent of urethritis and other sexually transmitted diseases

Mycoplasma genitalium was first isolated in 1980 from two of 13 men with non-gonococcal urethritis (NGU). It shares several features with M. pneumoniae, a recognized respiratory tract pathogen. It is extremely difficult to isolate by culture. The development of sensitive and specific polymerase chain reaction (PCR) assays in the early 1990s made clinical studies possible and a significant number of publications have shown a strong association between M. genitalium and NGU, independent of Chlamydia trachomatis. The purpose of this review is to evaluate the currently available information on the associations between M. genitalium and urogenital tract infections in men and women and assess their fulfilment of the Henle-Koch postulates. It is concluded that there is very strong evidence that M. genitalium is a cause of NGU in men and cervicitis in women. Evidence for upper genital tract infections in women has begun to accrue, but further studies are needed. The optimal treatment of M. genitalium infections remains to be determined, but antibiotics of the macrolide group appear to be more active than tetracyclines.

Development and performance of a microwell-plate-based polymerase chain reaction assay for Mycoplasma genitalium

BACKGROUND

Mycoplasma genitalium is associated with, and could be the cause of, idiopathic cases of urethritis, endometritis, and cervicitis. Further epidemiologic studies on this organism are needed, but currently used polymerase chain reaction (PCR) assays are labor-intensive and culture is insensitive.

GOAL

The goal was to develop and evaluate a microwell-plate-based PCR assay for M. genitalium.

STUDY DESIGN

We adapted an M. genitalium PCR assay targeting the MgPa gene to a 96-microwell plate format with colorimetric detection of PCR products and incorporation of an internal inhibition control to determine the limit of detection of this assay (termed MgPa-IMW) for M. genitalium DNA and evaluate its performance on cervical and male urine specimens.

RESULTS

The MgPa-IMW PCR assay detected 1 and 17 genome copies of M. genitalium (with 27% and 95% confidence) and was able to detect specimens inhibited for amplification. This assay was 100% concordant (50 positive and 50 negative) with the Southern-blot-based PCR assay with cervical specimens. Similarly, this test was 89% concordant with the Southern-blot-based assay for 64 male urine specimens (25 positive, 32 negative, 7 discordant), 97% concordant after correcting for specimens no longer positive by the Southern blot-based assay after freezer storage.

CONCLUSION

The MgPa-IMW assay is sensitive and specific for the detection of M. genitalium in patient specimens and should facilitate large-scale screening for this organism.

Rapid detection of Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma parvum, and Ureaplasma urealyticum organisms in genitourinary samples by PCR-microtiter plate hybridization assay

We present a method for detecting the presence of Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma parvum, and Ureaplasma urealyticum organisms, which are thought to be associated with nongonococcal urethritis (NGU) and other genitourinary infections, in clinical samples. This method consists of PCR amplification of a part of the 16S rRNA gene followed by 96-well microtiter plate hybridization assay using four species-specific capture probes to detect the targets. To test the efficacy of this method, we applied it to the detection of the four species in the urine of patients with NGU. There were no cross-reactions with other human mycoplasmas or ureaplasmas, and the PCR-microtiter plate hybridization assay detected as few as 10 copies of the 16S rRNA gene of each of the four species. Based on these results, this PCR-microtiter plate hybridization assay can be considered an effective tool for the diagnosis of genitourinary infections with mycoplasmas or ureaplasmas.