Screening for Neisseria Gonorrhoea within a Chlamydia Screening Programme in England – results from the first 18 months

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,

United Kingdom

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.

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