Screening for Neisseria Gonorrhoea within a Chlamydia
Screening Programme in England – results from the first 18 months
SJ Lavelle, KE Jones, H Mallinson, AMC Webb
Liverpool and South Sefton Chlamydia Screening Programme,
Liverpool, United Kingdom; Royal Liverpool Hospital Department of GU Medicine,
Liverpool, United Kingdom; University Hospital Aintree Clinical Microbiology
& Health Protection Agency Collaborating Laboratory, Liverpool, United
Kingdom and Abacus Centres for Contraception and Reproductive Health, Liverpool,
Objectives To identify the prevalence of Neisseria
gonorrhoea (NG) within a population screened for Chlamydia trachomatis (CT). To
monitor confirmatory microscopy, culture and partner findings following reactive
AC2 gonorrhoea screening tests.
Methods Between June 2004 and December 2005, all
gonorrhoea screening tests performed using Genprobe Aptima 2 Combo Assay (AC2)
for clients taking part in a Chlamydia Screening Programme were monitored.
Clients with AC2 NG reactive results were referred to a local Genito Urinary
Medicine (GUM) Department for confirmatory microscopy, culture, treatment and
partner follow up.
Results 158 (1%) of 15470 women and 26 (1.4%) of 1908 men
had AC2 reactive gonorrhoea screening tests. Of those clients who agreed to
follow up and were tested before any treatment, supportive evidence for a
gonorrhoea diagnosis was found in 116 (88%) of 131 women and 14 (93%) of 15 men.
In the population opportunistically screened for chlamydia, CT prevalence rates
were 12.5% for women and 13.5% for men. Although both women and men showed a
higher relative risk for NG if chlamydia positive, of the 158 women who were
reactive for NG by AC2, 84 (53%) were negative for chlamydia.
Conclusions STIs are rising in England and reduction of
gonorrhoea rates is an objective of the Department of Health Sexual Health and
HIV Strategy. AC2 tests provide an acceptable and accurate means of testing for
gonorrhoea in an asymptomatic population in the community. AC2 had a higher
positive predictive value than might be suggested by previous clinical trials in
this low prevalence population. It must also be noted that a number of clients
with asymptomatic gonorrhoea would not have been diagnosed if concomitant
chlamydia and gonorrhoea screening was not undertaken. Although antibiotic
sensitivity must be monitored, AC2 testing may offer a more acceptable
alternative to microscopy and culture for NG in some populations.