Clinical validation of a real-time polymerase chain reaction detection of Neisseria gonorrheae porA pseudogene versus culture techniques.
BACKGROUND
Diagnosing Neisseria gonorrheae using nucleic acid amplification tests (NAATs) might increase the sensitivity, compared to cultivation. However, using NAATs has also been problematic mainly due to the close genetic relationships between different Neisseria species, resulting in false positive diagnoses. This study was conducted to clinically validate a previously published real-time polymerase chain reaction (PCR) method targeting the porA pseudogene in N. gonorrheae in comparison to culture techniques.


METHODS
In total, 360 samples, urethra (n = 109), rectum (n = 84), pharynx (n = 119), and cervix (n = 48) from 185 males and 57 females, were analyzed using porA pseudogene PCR and cultivation. Sequencing of the entire porA pseudogene and the 16S rRNA gene were used to resolve discrepant results.


RESULTS
Of the 360 samples, 37 were positive by both culture and PCR, however, the PCR identified 15 additional confirmed positive samples. The PCR method showed a sensitivity, specificity, positive predictive value, and negative predictive value of 100% in a preselected population. The preselected population had a true gonorrhea prevalence of 17.4%.


CONCLUSIONS
The present porA pseudogene real-time PCR comprises a valuable supplement to the traditional culture techniques for diagnosis of N. gonorrheae, especially for samples from extragenital sites such as pharynx and rectum.
Hjelmevoll
Stig Ove
SO
Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway. stig.ove.hjelmevoll@unn.no
Olsen
Merethe Elise
ME
Sollid
Johanna U Ericson
JU
Haaheim
Håkon
H
Melby
Kjetil K
KK
Moi
Harald
H
Unemo
Magnus
M
Skogen
Vegard
V
D046508:Culture Techniques / Q000379:methods*; D004269:DNA, Bacterial / Q000032:analysis; D005260:Female; D006069:Gonorrhea / Q000175:diagnosis* / Q000382:microbiology; D006801:Humans; D008297:Male; D009344:Neisseria gonorrhoeae / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods*; D018272:Porins / Q000235:genetics*; D011237:Predictive Value of Tests; D011544:Pseudogenes / Q000235:genetics
D004269:DNA, Bacterial; D018272:Porins; C057699:porin protein, Neisseria