Verification of clinical samples, positive in AMPLICOR Neisseria gonorrhoeae polymerase chain reaction, by 16S rRNA and gyrA compared with culture

We compared 956 samples for AMPLICOR Neisseria gonorrhoeae polymerase chain reaction (PCR) (Roche) with species verification using the 16S rRNA gene to verification using gyrA gene. Control was the culture method. The gyrA verification uses pyrosequencing of the quinolone resistance-determining region of gyrA. Of 52 samples with optical density >= 0.2 in PCR, 27 were negative in culture, two samples from pharynx were false negative in culture and four samples from pharynx were false positives in verification with 16S rRNA. Twenty-five samples showed growth of gonococci, 18 of the corresponding PCR samples were verified by both methods; three urine samples were positive only in gyrA; and one pharynx specimen was positive only in 16S rRNA. Three samples were lost. We conclude that AMPLICOR N. gonorrhoeae PCR with verification in gyrA gene can be considered as a diagnostic tool in populations with low prevalence of gonorrhoea and that pharynx specimens should not be analysed by PCR.