Endocervical swabs transported in first void urine as combined specimens in the detection of Mycoplasma genitalium by real-time PCR.

The aim of this study was to determine whether a patient's endocervical swab specimen can be transported in first void urine (FVU) as combined specimens for the detection of Mycoplasma genitalium by real-time PCR. The study also compared two different DNA extraction methods for observation of possible PCR inhibition. Three specimens, one endocervical swab specimen transported in 2-SP medium, one endocervical swab specimen transported in FVU and a FVU specimen, were collected from 329 women. All sample types underwent manual DNA extraction whereas in the DNA extraction study, 329 endocervical swab specimens transported in FVU were subjected to both manual Chelex and automated BioRobot M48 DNA extraction. A total of 100 endocervical swab specimens transported in FVU from patients PCR-negative for M. genitalium in the study were used in the PCR inhibition analysis. M. genitalium was detected in 25/329 (7.6 %) women. The endocervical swab specimens transported in 2-SP medium and transported in FVU were positive for M. genitalium in 17/25 (68 %) and 24/25 (96 %) women, respectively. The FVU specimens alone were positive for M. genitalium in 22/25 (88 %) women. In the DNA extraction study, M. genitalium DNA was detected in 24/329 (7.3 %) and 28/329 (8.5 %) of endocervical swab specimens transported in FVU subjected to manual Chelex extraction and automated BioRobot M48 extraction, respectively. Partial PCR inhibition was detected in 6 % of samples subjected to manual Chelex extraction whereas no inhibition was detected with the automated BioRobot M48 extraction. Thus endocervical swab specimens transported in FVU demonstrate higher sensitivity than FVU specimens only and have considerably increased sensitivity compared with endocervical swab specimens transported in 2-SP medium for detection of M. genitalium DNA. Moreover, automated BioRobot M48 extraction was shown to be superior to a crude manual Chelex extraction, leaving no PCR inhibition and giving a slightly higher DNA yield and/or better sensitivity.

A comparative study of three different PCR assays for detection of Mycoplasma genitalium in urogenital specimens from men and women.

The aim of this study was to compare conventional 16S rRNA gene PCR, real-time 16S rRNA gene PCR and real-time Mycoplasma genitalium adhesin protein (MgPa) gene PCR as detection methods for M. genitalium infection. The study also determined the prevalence of M. genitalium in male and female patients attending a sexually transmitted infections clinic in a rural area in the west of Sweden. First void urine (FVU) and/or urethral swabs were collected from 381 men, and FVU and/or cervical swabs and/or urethral swabs were collected from 298 women. A total of 213 specimens were used in the PCR comparative study: 98 consecutively sampled specimens from patients enrolled in the prevalence study, 36 consecutively sampled specimens from patients with symptoms of urethritis and 79 specimens from patients positive for M. genitalium by real-time MgPa gene PCR in the prevalence study. A true-positive M. genitalium DNA specimen was defined as either a specimen positive in any two PCR assays or a specimen whose PCR product was verified by DNA sequencing. The prevalence of M. genitalium infection in men and women was 27/381 (7.1 %) and 23/298 (7.7 %), respectively. In the PCR comparative study, M. genitalium DNA was detected in 61/76 (80.3 %) of true-positive specimens by conventional 16S rRNA gene PCR, in 52/76 (68.4 %) by real-time 16S rRNA gene PCR and in 74/76 (97.4 %) by real-time MgPa gene PCR. Real-time MgPa gene PCR thus had higher sensitivity compared with conventional 16S rRNA gene PCR and had considerably increased sensitivity compared with real-time 16S rRNA gene PCR for detection of M. genitalium DNA. Real-time MgPa gene PCR is well suited for the clinical diagnosis of M. genitalium.