Detection of Mycoplasma genitalium in urogenital specimens by real-time PCR and by conventional PCR assay

• A real-time LightCycler PCR (LC-PCR) with hybridization probesfor detection of Mycoplasma genitalium in endocervical and firstvoid urine specimens was developed and compared to a conventionalPCR. The primers for both assays were identical and designedto amplify a 427 bp fragment of the 16S rRNA gene of M. genitalium.The LC-PCR assay had a detection limit of < 5 bacterial genomesper reaction when dilutions of genomic DNA from a type strainof M. genitalium were tested. First void urine from 398 menand first void urine and endocervical specimens from 301 womenattending an STD clinic were analysed by LC-PCR and by the conventionalPCR. Using the conventional PCR as reference, the LC-PCR hada specificity of 99.7 % and a sensitivity of 72.2 % for thedetection of M. genitalium in first void urine samples frommen. There was no significant difference in the performanceof the LC-PCR assay compared to the conventional PCR when endocervicalswabs were considered (58 and 65 %, respectively) or with aset of endocervical swab/urine specimens for which the LC-PCRassay detected 73 % of the infections (specificity = 98.6 %and sensitivity = 68.2 %) while the conventional PCR detected85 % of the infections. With female urine specimens there wasa significant difference between the two assays (38 and 73 %,respectively; P = 0.01 McNemar's test). This illustrates theneed to analyse both endocervical and urine specimens, becauseM. genitalium DNA was detected in only one of the two specimensin a great number of the M. genitalium-infected women. The lowersensitivity of the LC-PCR assay was probably caused by a combinationof inhibition and limitations regarding the amount of templateDNA. The LC-PCR assay was easy to perform and the simultaneousamplification and detection eliminated the need for furtherhandling of PCR products. With improvement in sample preparationmethods and increased volumes of the template DNA, the LC-PCRassay could be a useful routine diagnostic method.

Keyword

MEDICINE

MEDICIN

Medicine

Medicin

Publication and Content Type

ref (subject category)

art (subject category)