Jørgen Skov Jensen

Mycoplasma genitalium: from Chrysalis to Multicolored Butterfly

SUMMARY The history, replication, genetics, characteristics (both biological and physical), and factors involved in the pathogenesis of Mycoplasma genitalium are presented. The latter factors include adhesion, the influence of hormones, motility, possible toxin production, and immunological responses. The preferred site of colonization, together with current detection procedures, mainly by PCR technology, is discussed. The relationships between M. genitalium and various diseases are highlighted. These diseases include acute and chronic nongonococcal urethritis, balanoposthitis, chronic prostatitis, and acute epididymitis in men and urethritis, bacterial vaginosis, vaginitis, cervicitis, pelvic inflammatory disease, and reproductive disease in women. A causative relationship, or otherwise strong association, between several of these diseases and M. genitalium is apparent, and the extent of this, on a subjective basis, is presented; also provided is a comparison between M. genitalium and two other genital tract-orientated mollicutes, namely, Mycoplasma hominis, the first mycoplasma of human origin to be discovered, and Ureaplasma species. Also discussed is the relationship between M. genitalium and infertility and also arthritis in both men and women, as is infection in homosexual and immunodeficient patients. Decreased immunity, as in HIV infections, may enhance mycoplasmal detection and increase disease severity. Finally, aspects of the antimicrobial susceptibility and resistance of M. genitalium, together with the treatment and possible prevention of mycoplasmal disease, are discussed.

Use of TaqMan 5′ Nuclease Real-Time PCR for Quantitative Detection of Mycoplasma genitalium DNA in Males with and without Urethritis Who Were Attendees at a Sexually Transmitted Disease Clinic

ABSTRACT Mycoplasma genitalium is a cause of nongonococcal urethritis, particularly in patients not infected with Chlamydia trachomatis. A quantitative 5′ nuclease assay (TaqMan PCR) was developed and validated. The assay detected a fragment of the MgPa adhesin gene by use of a TaqMan MGB (minor groove binder) probe and included an internal processing control to detect PCR inhibition. Urethral swab specimens and first-void urine samples from M. genitalium-positive men were examined, and the M. genitalium DNA load was correlated to symptoms and signs. The assay consistently detected <5 genome copies without cross-reactions with other mycoplasmas. Urine and urethral swab specimens from men with urethritis had higher M. genitalium DNA loads than specimens from men without urethritis. However, a very broad overlap of DNA loads between patients with and without urethritis was observed. Urethral swab specimens from patients with urethral discharge had a significantly higher DNA load than specimens from patients without discharge. This correlation was not found in first-void urine specimens.

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.

Mycoplasma genitalium: prevalence, clinical significance, and transmission

Objectives: To study the prevalence, symptoms and signs of Mycoplasma genitalium and Chlamydia trachomatis infections in STD clinic attendees and in partners of M genitalium infected patients. Methods:M genitalium and C trachomatis were detected by polymerase chain reaction from urethral and endocervical swab specimens in a cross sectional study among 445 female and 501 male STD clinic attendees. Partners of 26 female and 26 male M genitalium positive index patients were examined. Results: The prevalence of C trachomatis and M genitalium was 4% and 6.3%, respectively, among the women and 5.4% and 6%, respectively, among the men. Dual infections were uncommon. M genitalium was strongly associated with urethritis in both men and women and with cervicitis in women. Among M genitalium infected men, symptomatic urethritis was more common than asymptomatic urethritis. M genitalium and C trachomatis were not associated with symptoms of urethritis or cervicitis in women. Of 26 male partners of M genitalium positive female index patients, 38% were positive, and 77% of the negative partners had symptoms of urethritis. The concordance rate for 22 female partners of male index patients was 45%. For both men and women the M genitalium prevalence was significantly higher in partners of M genitalium positive index patients than in M genitalium negative index patients with urethritis and/or cervicitis. Conclusions:M genitalium is associated with urethritis in both men and women and with cervicitis in women. A high concordance rate was found among sexual partners of M genitalium infected patients, indicating that the infection is sexually transmitted.

Signs and symptoms of urethritis and cervicitis among women with or without Mycoplasma genitalium or Chlamydia trachomatis infection.

Objectives: To study the prevalence, symptoms, and signs of Mycoplasma genitalium and Chlamydia trachomatis infections in women attending a Swedish STD clinic, accessible for both sexes, and in a group of young women called in the cervical cancer screening programme. Methods: A cross sectional study among female STD clinic attendees in Örebro and a study among women called for Papanicolaou smear screening. Attendees were examined for urethritis and cervicitis. First void urine and endocervical samples were tested for M genitalium and C trachomatis. Results: The prevalence of C trachomatis and M genitalium in the STD clinic population was 10% (45/465) and 6% (26/461), respectively. Dual infection was diagnosed in four women. In the cancer screening group of women the corresponding prevalence was 2% (1/59) and 0%, respectively. Among the STD clinic attendees there were no significant differences in symptoms (32% v 23%, RR 1.4, 95% CI 0.6 to 3.4) or signs (71% v 50%, RR 1.4, 95% CI 0.9 to 2.3) between C trachomatis and M genitalium infections. Microscopic signs of cervicitis were significantly more common among M genitalium and C trachomatis infected women than in the cancer screening group of women. 56% (15/27) of male partners of M genitalium infected women were infected with M genitalium compared to 59% of male partners of C trachomatis infected women who were infected with C trachomatis (p = 0.80). Conclusions:M genitalium is a common infection associated with cervicitis and with a high prevalence of infected sexual partners supporting its role as a cause of sexually transmitted infection.

Azithromycin Treatment Failure in Mycoplasma genitalium–Positive Patients with Nongonococcal Urethritis Is Associated with Induced Macrolide Resistance

BACKGROUND Mycoplasma genitalium is a common cause of nongonococcal urethritis. Treatment trials have shown that doxycycline is inefficient, whereas a 5-day course of azithromycin eradicates the bacterium from 95% of infected men. The aim of the study was to establish the reason for the occasional treatment failures. METHODS Seven M. genitalium strains isolated from men who experienced azithromycin treatment failure were tested for in vitro susceptibility to macrolides with use of a cell culture-based method. The genetic basis for the drug resistance was established by sequencing parts of the 23S ribosomal RNA gene and the genes encoding the L4 and L22 proteins. Nine sets of specimens obtained before and after treatment from patients who experienced azithromycin treatment failure were examined with use of sequencing of polymerase chain reaction products. RESULTS The 7 strains that were isolated from patients who experienced treatment failure with azithromycin had minimum inhibitory concentrations >8 microg/mL for azithromycin and erythromycin. Three different mutations at positions 2058 and 2059 (Escherichia coli numbering) in region V of the 23S rRNA gene were found. Of the 9 patients with specimens obtained before and after treatment, only 2 had an initial specimen in which the mutation was present, indicating that drug resistance was induced as the result of an inappropriate dosage of azithromycin. CONCLUSION Development of macrolide resistance was shown to correlate with subsequent azithromycin treatment failure. The genetic basis for the drug resistance was shown to be mutations in region V of the 23S rRNA gene, which is well described in other Mollicutes. These findings raise concern about the use of single-dose azithromycin treatment of nongonococcal urethritis of unknown etiology.

Azithromycin failure in Mycoplasma genitalium urethritis.

We report significant failure rates (28%, 95% confidence interval 15%–45%) after administering 1 g azithromycin to men with Mycoplasma genitalium–positive nongonococcal urethritis. In vitro evidence supported reduced susceptibility of M. genitalium to macrolides. Moxifloxacin administration resulted in rapid symptom resolution and eradication of infection in all cases. These findings have implications for management of urethritis.

Mycoplasma genitalium: a cause of male urethritis?

BACKGROUND--Male urethritis may be caused by mycoplasmas. Since Mycoplasma genitalium has previously been isolated from the urethra of two men with non-gonococcal urethritis (NGU), it was the aim of the study further to elucidate its role by measuring the prevalence of this organism in men with NGU. MATERIAL AND METHODS--The polymerase chain reaction was used. Two different sequences of the gene coding for the main adhesin MgPa were amplified. Urethral, rectal, and throat samples from 99 male sexually transmitted disease (STD) patients with and without urethritis were studied. RESULTS--M genitalium DNA was demonstrated in 17/99 (17%) of the urethral swabs, but in none of the rectal and throat swabs. Significantly more patients with urethritis (13/52) were positive for M genitalium DNA than were patients without urethritis (4/47) (p < 0.03). In those with urethritis M genitalium DNA was found more often in Chlamydia trachomatis negative NGU (12/34) than in those with chlamydial NGU (1/14) (p = 0.05). Attempts to culture M genitalium from the PCR positive specimens were unsuccessful. CONCLUSION--M genitalium DNA was found significantly more often in male STD patients with non-chlamydial NGU than in men with chlamydial urethritis (p = 0.05) and in men without urethritis (p = 0.003), suggesting that M genitalium may be a cause of NGU. M genitalium DNA was not demonstrated in any of the throat or rectal swabsindicating that the urogenital tract is probably the primary site of infection or colonisation of this species.

Symptomatic urethritis is more prevalent in men infected with Mycoplasma genitalium than with Chlamydia trachomatis

Objectives: To study the prevalence, symptoms, and signs of Mycoplasma genitalium and Chlamydia trachomatis infections in men attending a Swedish STD clinic and to study the criteria for urethritis. Methods: A cross sectional study among STD clinic attendees in Örebro, Sweden. Attendees were examined for microscopic urethritis and first void urine (FVU) was tested for M genitalium and C trachomatis. Results: The prevalence of M genitalium and C trachomatis was 7% (34/512) and 12% (61/512), respectively. Dual infection was diagnosed in four men. In both infections 90% of the patients had signs of microscopic urethritis. M genitalium positive men had symptomatic urethritis significantly more often than those infected with C trachomatis (73% v 40%, RR 1.8; 95% CI 1.2 to 2.7). 63% of female partners of men infected with M genitalium were infected with M genitalium compared with chlamydial infection in 67% of female partners of men infected with C trachomatis. Non-chlamydial non-gonococcal urethritis without evidence of M genitalium infection was diagnosed in 180 men (35%). Symptoms and/or visible discharge were reported in 49% in this group. Conclusions:M genitalium is a common infection associated with symptomatic urethritis and with a high prevalence of infected sexual partners supporting its role as a sexually transmitted infection.

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°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.