Soaring UK rates of Chlamydia infection partly caused by more sensitive tests

February 01, 2006

More sensitive testing methods might account for some of the sharp increase in reported Chlamydia trachomatis infections, suggests research in the journal Sexually Transmitted Infections.

Chlamydia is the most common sexually transmitted infection in the developed world, and is thought to cost the UK alone around £50 million a year.

The findings are based on 11 years of monitoring test results for the detection of Chlamydia at one Scottish health board.

More than 81,000 test results were obtained between 1992 and 2003. But after 1998, tests were switched from cultures to the more sensitive nucleic acid amplification testing, or NAAT as it is known.

Using the culture tests, just over 6 per cent of women and just over 7 per cent of men tested positive. But almost 10 per cent of women and just over 11 per cent of men tested positive, using NAAT.

The increase equates to a 62 per cent jump in positive results for women and a 56 per cent jump in positive results for men, say the authors.

Further analysis of the results showed that the increases were strongly linked to the type of test used, irrespective of the year of test, sex of the patient, or young age, a known risk factor for the infection.

The authors explain that the way national Chlamydia infection rates are calculated means that switching to a more sensitive test would give the impression of an increase in prevalence even if there were none.

"Part of the recently seen increase in Chlamydia trachomatis prevalence in the United Kingdom is likely to be directly and/or indirectly caused by the gradual shift of laboratories to the more sensitive NAAT diagnostics," they add.

And they suggest that as more laboratories switch to NAAT, their rates of positive test results will also rise. Nationally collected data should therefore record type of test used to avoid any "artificial" increases, they say.

BMJ Specialty Journals

Related Chlamydia Articles from Brightsurf:

Chlamydia: Greedy for glutamine
If chlamydiae want to multiply in a human cell, the first thing they need is a lot of glutamine.

Chlamydia build their own entrance into human cells
Chlamydia, a type of pathogenic bacteria, need to penetrate human cells in order to multiply.

Targeted gene modification in animal pathogenic chlamydia
Researchers at Umeå University (Sweden), in collaboration with researchers at the University of Maryland and Duke University (USA), now for the first time successfully performed targeted gene mutation in the zoonotic pathogen Chlamydia caviae.

How Chlamydia gain access to human cells
Infection biologists at Heinrich Heine University Düsseldorf (HHU) and the University of Freiburg have found out how the LIPP protein discovered in Düsseldorf helps Chlamydia to infect human cells.

Researchers discover how chlamydia takes up new DNA from host
A recent paper by a team of molecular biologists headquartered at the University of Kansas pinpointed a gene that allows chlamydia to take up DNA from its host environment.

Chlamydia in testicular tissue linked to male infertility
The potential impact of undiagnosed sexually transmitted chlamydia infection on men's fertility has been highlighted in a study led by scientists at Queensland University of Technology (QUT), which for the first time found chlamydia in the testicular tissue biopsies of infertile men whose infertility had no identified cause.

New rapid DNA test to diagnose chlamydia infection in koalas
A new DNA test to detect chlamydia infection in koalas which gives on-the-spot results within 30 minutes has been developed in a collaboration between researchers in Brisbane, Australia.

Researchers identify how vaginal microbiome can elicit resistance to chlamydia
The vaginal microbiome is believed to protect women against Chlamydia trachomatis, the etiological agent of the most prevalent sexually transmitted infections (STIs) in developed countries.

The Lancet Infectious Diseases: First ever phase 1 trial of genital chlamydia vaccine finds it is safe and provokes immune response
The first ever chlamydia vaccine to reach phase 1 clinical trial has been found to be safe and able to provoke an immune response, according to a study published in The Lancet Infectious Diseases journal.

Last chlamydia-free koala population may safeguard future of species
The last, large, isolated, healthy chlamydia-free population of koalas in Australia may have been identified on Kangaroo Island, said Morris Animal Foundation-funded researchers at the University of Adelaide.

Read More: Chlamydia News and Chlamydia Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to