Mycoplasma genitalium: prevalence in men presenting with urethritis to a South Australian public sexual health clinic.

BACKGROUND/AIM: This study aimed to determine the prevalence of Mycoplasma genitalium infection among male patients with dysuria and/or urethral discharge. An analysis of the clinical, demographic and microbiological factors associated with M. genitalium infection was also conducted. METHOD: From May 2007 to June 2011, men presenting to the clinic with self-reported symptoms of dysuria and/or urethral discharge were identified and underwent urethral swab, which was microscopically assessed for objective non-gonococcal urethritis. A first-void urine sample was tested for Chlamydia trachomatis and Neisseria gonorrhoeae using the Aptima Combo-2 assay. A portion of the urine sample was sent for polymerase chain reaction analysis for M. genitalium. RESULTS: One thousand, one hundred and eighty-two men with dysuria and/or urethral discharge were tested for M. genitalium. Of those, 96 men (8.1%) were positive for M. genitalium. Men identifying as solely MSM (men who have sex with men) constituted 16.3% (n = 193) of the sample. Their infection rate was 3.1% (n = 6). The infection rate for heterosexual and bisexual men was 9.1%. For all men, the M. genitalium co-infection rate was 14.6% (n = 14) with C. trachomatis and 3.1% (n = 3) with N. gonorrhoeae. Factors associated with M. genitalium infection were analysed by univariate analysis. We determined that five investigated predictors were significantly associated with M. genitalium infection, urethral discharge, non-gonococcal urethritis on Gram stain of urethral smears, identification as heterosexual or bisexual, and absence of co-infection with C. trachomatis or N. gonorrhoeae. CONCLUSION: In Adelaide, M. genitalium is an important sexually transmitted infection among men with dysuria and/or urethral discharge, and is primarily an infection of heterosexual and bisexual men.

Comparison of antigen detection, polymerase chain reaction and culture for detection of Chlamydia trachomatis in genital infection.

An in-house polymerase chain reaction (PCR) test using ribosomal RNA gene primers was compared with chlamydia antigen detection (DIF) and culture for the detection of Chlamydia trachomatis. Five hundred and forty-eight fresh (unstored) genital swabs and 174 urines (collected at the same time) from patients attending a sexually-transmitted diseases clinic were examined. PCR, DIF and culture detected chlamydia in 43, 35 and 42 swabs respectively from the 43 resolved positive cases. The specificity on the resolved negative specimens was 100% for each of the tests. From the urines, PCR and DIF detected the organism in 16 and 15 cases respectively of the 23 resolved positive males tested but in only 2 and 3 cases respectively of the 9 resolved positive females tested. Specificities were 100% in all cases. Both of the non-culture tests manifested problems with urine due to inhibitory activity (in PCR test) or excessive debris (in DIF test) in about 5% of the specimens. Culture of the urines yielded sensitivities of 40% in the males and 22% in the females. Overall PCR was more sensitive than either culture or DIF on both urethral and cervical swabs and urines. The urines yielded less than three-quarters the number of positives that was obtained from the swabs and were considered to be an unsatisfactory specimen for chlamydial diagnosis. It is concluded that PCR is a satisfactory alternative to culture on genital swabs and may be preferable in situations where the viability of the organisms is in question. DIF remains useful because of its speed and simplicity but is insufficiently sensitive to be relied upon by itself.

Urine and the laboratory diagnosis of Chlamydia trachomatis in males.

OBJECTIVE: To determine whether the use of urine samples from male patients can replace urethral swabs for the rapid detection of Chlamydia trachomatis by the Pharmacia EIA. SETTING: The STD clinic, Adelaide, South Australia. PATIENTS: There were two separate groups of male patients. Group A (398) patients provided urethral specimens for the EIA and culture tests. The patients in Group B (356) provided an urethral swab and a urine sample for the EIA test. METHODS: The urine samples and urethral swabs were tested for the presence of C trachomatis by the Pharmacia Chlamydia EIA. In addition, the urethral swabs from Group A patients were cultured for the organism by standard cell cultures. The infected cell cultures were identified by an immunofluorescence test using a FITC-monoclonal antibody to C trachomatis (Kallestad). RESULTS: When the EIA was validated against culture, it showed a sensitivity of 100% and a specificity of 95% with the urethral swabs from Group A patients. The urine specimens were positive in 24% of those patients who yielded a positive EIA result in the urethral swabs. CONCLUSIONS: Although the EIA test on urethral swabs showed high sensitivity and specificity when validated against culture, our results showed that the use of urine samples cannot replace urethral swabs for the laboratory diagnosis of this sexually transmitted disease.