Special Tampon Helps Diagnose STD

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Sept. 18, 2000 (Toronto) -- Specimens collected from special tampons worked as well as a vaginal exam to diagnose vaginal trichomoniasis, a common sexually transmitted disease (STD). If the method holds up, it could lead to easier diagnosis as women test themselves and bring samples to the clinic instead of undergoing an invasive gynecological exam.

Trichomoniasis is caused by a protozoan called Trichomonas vaginalis, and can be present without symptoms. Infection causes a yellowish, foul-smelling vaginal discharge in most women that is sometimes accompanied by itching and burning. Some studies have shown an association with preterm delivery in pregnant women. It is often seen alongside other infections, such as HIV.

Although the infection is easily treated with antibiotics given to both partners, diagnosis in women requires a trip to a clinic and a vaginal swab taken during a speculum exam. That may discourage some infected women from being tested, says lead researcher Patrick Sturm, MD, PhD, presenting here today at the 40th Interscience Conference on Antimicrobial Agents and Chemotherapy.

To develop an easier test, Sturm, a medical researcher at the University of Natal in Durban, South Africa, and his colleagues used a specially designed tampon, about the size of a normal menstrual tampon, which women could insert for 15 to 30 minutes, place in a tube, and take to the clinic for testing. The researchers used a sensitive technique called the polymerase chain reaction (PCR) to make the diagnosis.

The tampon worked as well as the standard method of culturing for the organisms, Sturm says. The researchers tested 1,030 pregnant women by both methods and compared the results.

When they used the culturing method requiring physical exam they diagnosed Trichomonas infections in 19% of the women. But when they used PCR to spot the presence of the parasite in samples from the tampon, they diagnosed the disease in 24% of them, a significant difference. The tampon PCR method failed to detect the parasite in only eight of the 1,030 women, Sturm says.

"It's more sensitive than the standard culturing method," Sturm says.

Samples from a single tampon could be used to test for multiple STDs, Sturm says. Early results from the lab show that sampling by this method works as well as standard tests to detect the Chlamydia trachomatis and Neisseria gonorrhoeae, he says.

Enthusiastic about the findings, Denise Roditi, MMed, a clinical microbiologist at Groote Schuur Hospital in Cape Town, South Africa, says the method also could help stem the spread of STDs, including HIV, in Africa.

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