Abbott RealTime PCR Test for Detection of New Variant Strain of Chlamydia Receives CE Mark Certification

Working in collaboration with international researchers in the area of sexually transmitted disease, Abbott has developed a newly formulated molecular test capable of detecting a new variant strain of Chlamydia trachomatis found in one in five chlamydia cases in Sweden.

The assay, which is intended to be performed on the automated Abbott m2000 real-time PCR clinical diagnostic system, has received CE Mark certification in the European Union.

According to the WHO, more than 85 million cases of chlamydia occur worldwide every year, and last month the U.S. Centers for Disease Control reported that more than one million chlamydia cases were transmitted in the United States in 2006, a new record for any sexually transmitted disease.

Despite the significant global prevalence of chlamydia, however, reports from the Swedish Institute for Infectious Disease Control last year showed an unusual trend - a marked decrease in transmission of the infection in that country.

"We observed a 25 percent decrease in chlamydia genital infections in 2006, but were unaware of new preventive programs or other initiatives that could have caused such a drop," said Torvald Ripa, M.D., Ph.D., assistant professor, Department of Clinical Microbiology and Infection Control, Hospital of Halmstad, Sweden. "So there was great suspicion that a variant strain of the bacterium was at play, hampering our ability to detect all the infections and causing a lot of false-negative results," he said.

Subsequent investigation by Ripa and colleagues confirmed the existence and transmission of a variant chlamydia strain that was eluding detection by leading molecular diagnostic systems used to test some 500,000 Swedes annually. He published his findings in May 2007 in Sexually Transmitted Diseases. The variant type of chlamydia was believed to escape detection because it contains a deletion in the target region of some diagnostic assays.

Through a special regulatory exemption by the Swedish Medical Products Agency, certain sites in Sweden have been using the Abbott RealTime CT investigational assay for chlamydia screening.

Now, with CE Mark certification, laboratories in all European Union nations will have access to the test. Even though wide incidence of the mutant strain has been limited to Sweden, Ripa said isolated cases have been reported in Norway, Denmark, Ireland and France. International travel is expected to carry the variant strain to other countries eventually.

"New tests were needed to target additional parts of the chlamydia bacteria, and Abbott responded fast to our request for research test kits that would pick up the variant strain," Ripa said. "By March 2007, we were double testing some 1,200 samples with the new research kit and current assays and concluded that the new research test had the ability to detect the mutant." Abbott then moved quickly to complete development of the assay and submit it for CE mark certification.

According to Ripa, surveillance showed that the mutant strain was responsible for 22 percent of Swedish chlamydia infections and posed a serious public health problem. Undetected, untreated chlamydia can lead to pain and pelvic inflammatory disease and subsequent infertility in women.

A significant percent of women and men who are infected with chlamydia don't have symptoms. An infected person can transmit the disease anytime, including to a newborn, whether or not symptoms are present. Fortunately, chlamydia infections may be treated with antibiotics.