Neisseria gonorrhoeae (gonococcus) is a labile organism, and often does not survive the time from specimen collection to “plating-out” in the laboratory. This is the reason that Genito-Urinary Medicine clinics use on-site facilities where direct “plating out”, and microscopy are done. In fact, of 18 000 genital swab specimens received from non-GUM sources in a recent 6 month period, gonococcus was only isolated on 3 occasions. Similarly the labile protozoan Trichomonas vaginalis was identified in 2 of these specimens. By comparison in the same period, gonococcus and trichomonas were identified on 88 and 41 occasions in 6000 specimens received from GUM clinics served by the laboratory.

To improve the service for all users outside the GUM departments, the Microbiology laboratory will be including the molecular test for gonococcus along with that for chlamydia. When the blue-shaft Gen-Probe APTIMA swab is collected, this will also be processed for gonococcus by a similar nucleic acid amplification test (NAAT).

There may be concerns that NAATs do not provide antibiotic profiles of the organism. However the improved diagnostic sensitivity of the molecular test far outweighs the absence of these profiles, and gonococcal isolates from GUM clinics do provide useful antibiotic susceptibility information, which largely reflect those in the community. All specimens positive by the gonococcal NAAT will be confirmed by a second molecular test. It would always be appropriate to consider prompt referral of the patient with a positive gonococcal (and chlamydia) test to the GUM physician, where further sampling, and culture for gonococcus, can be done.

In relation to vaginal discharges in adults, the most recent HPA guidelines recommend that a high vaginal swab specimen is collected when the symptoms and signs are not characteristic of bacterial vaginosis, candidiasis or trichomoniasis, or when the discharge is recurrent (> 3 episodes/year).¹ As always, it is very important to include the clinical details on the request form. If for example, trichomonas is the likely cause of a vaginal discharge, please state this on the request form. Clearly a swab for MC&S should always be collected in the appropriate obstetric or gynaecology setting.

For further information and discussion, please contact both Dr Keith Struthers and Dr Savita Gossain: ( This email address is being protected from spambots. You need JavaScript enabled to view it. ; This email address is being protected from spambots. You need JavaScript enabled to view it. ).