Screening for Neisseria gonorrhoea within a Chlamydia Screening
Programme in England – results from the first 18 months
S.J. Lavelle, K.E. Jones, H.
Mallinson, A.M.C. Webb
Liverpool and South Sefton Chlamydia Screening Programme,
Liverpool, UK, Royal Liverpool Hospital Department of GU Medicine, Liverpool,
UK, University Hospital Aintree Clinical Microbiology
& Health Protection Agency Collaborating Laboratory, Liverpool, UK and
Abacus Centres for Contraception and Reproductive Health, Liverpool, UK
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 One hundred and fifty-eight (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.