Infection: Neisseria gonorrhoeae infection; gonorrhoea; gonococcal infection; GC
- A bacteria that causes sexually transmitted infections.
- Up to 80% of women with genital infection may be asymptomatic, in men the number is lower, around 10-15%. Rectal and pharyngeal infection is usually asymptomatic.
- Can cause vaginal/urethral discharge, dysuria, lower abdominal pain, abnormal vaginal bleeding, testicular pain/swelling, or anal pain/discharge. Also conjunctivitis.
Did you know?
If symptomatic, tends to cause more aggressive infection than chlamydia. Rarely can cause disseminated disease with rash and septic arthritis.
Who should I test?
Test sexually active people with signs or symptoms, and known contacts.
Test females and men who have sex with men (MSM) as part of routine sexual health check.
- It can take up to 2 weeks to test positive if infection occurs relating to specific sexual event.
Although testing is very specific, positive results in people with a very low pre-test probability have a higher chance of being false positives. Caution is advised when testing in very low pre-test probability groups, especially if a false positive result could have significant negative consequences e.g. children, older people in stable relationships. Many labs will not accept tests in children without prior discussion with an expert.
Test of choice:
Request Gonorrhoea NAAT
NAAT/PCR on vaginal swab (self- or clinician-collected) for women, first void urine (>1 hour after last void) for men. Anorectal swabs and pharyngeal swabs can also be taken in women based on sexual history, and are indicated in MSM.
- A specific kit is usually required for NAAT testing e.g. the Aptima swabs/urine kit.
- Chlamydia is tested in parallel from the same sample, and other STI testing, e.g. Trichomonas, can be shared also.
- Excellent sensitivity – a negative test on a well-collected sample makes the diagnosis very unlikely
- Excellent specificity – a positive test in an at risk person makes the diagnosis highly likely
- First void urine can also be used in women, but is 2nd line due to lower sensitivity.
Culture on an endocervical swab or a urethral swab can be taken in symptomatic women and men, respectively. Culture requires a (usually purple) bacterial swab, rather than the NAAT swab. If culture is performed, it should be in parallel to NAAT, not instead of.
- The sensitivity is lower than NAAT, however the specificity is very high.
- Also permits susceptibility testing. Important if intolerance of standard treatment, possible treatment failure, or other risk factors for antibiotic resistance.
- ll sexual contacts from the prior 3 months should be notified.
- Reinfection is common. Offer repeat sexual health check at 3 months.
- Test of cure is not required if symptoms resolve, unless pregnant or rectal infection.
- Don’t retest with NAAT within 3 weeks of treatment (including for test of cure), as the test may remain positive due to residual dead organisms.