Developer of anthrax quick test finds similar test for strep throat

The culprit in bacterial streptococcus pharyngitis, or strep throat, can be vicious. Ask a parent who suspects their child has caught the virus, or the family of 29 Texans, including nine children, who died in 1997 after the bacteria manifested itself into a flesh eating disease. This virulent disorder used to cause physicians to order patients to immediately start taking antibiotics – even when a bacterial origin had not been established.

But taking antibiotics when not needed reduces the curative effects of antibiotics. That is why physicians applauded the introduction of the Rapid Streptococcal Antigen Test or the “rapid strep” test. Research indicates that this test, which takes about 20 minutes, is just as accurate as the much slower culture analysis. (If the rapid test is not clearly negative and symptoms exist, a doctor may also perform a regular culture.)

Advocates claim the rapid test is 80 to 90 percent sensitive in detecting group A beta-hemolytic streptococcus in throat swabs and 90 to 95 percent specific in eliminating streptococcal infection as a consideration in rapid test-negative patients. Detection of streptococci by rapid antigen tests or throat culture has consistently been shown to be a cost-effective strategy in the management of sore throat, independent of the issues surrounding antibiotic overuse.

But the leader of a team that developed a rapid test for anthrax exposure has completed an assessment of various testing procedures used in the rapid test and found the results wanting. He suggests that rapid antigen testing lacks sensitivity, negative results require a back-up culture and that its sensitivity may be declining. One alternative is rRNA (ribosomal ribonucleic acid) testing which has enhanced sensitivity but is still not as effective as a culture. His conclusion is that assessing PCR (polymerase chain reaction) using the same principle and diagnostic equipment in a proposed test for anthrax may offer the best test for bacterial strep throat.

The Study

Presenting “Rapid Testing for Streptococcal Infection: How Effective Is It?” is physician Franklin R. Cockerill III, Professor and Chair, Microbiology, Mayo Clinic and Mayo Medical School, Rochester, MN. His comments will be offered at the 54th Annual Meeting of the American Association for Clinical Chemistry (AACC). AACC (http://www.aacc.org/) is the scientific organization for clinical laboratory professionals, physicians, and research scientists. Their primary commitment is the understanding of laboratory testing to identify, monitor and treat human disease. More than 11,000 attendees are expected for the meeting, which is being held at the Orange County Convention Center, Orlando, FL, July 28-August 1, 2002.

Background

The most common manifestation of Group A streptococcus is “strep throat,” due to bacterial pathogens. Group A is responsible for 15-30 percent of cases reported. Characteristic symptoms are sudden onset of sore throat, pain on swallowing, fever, headache, abdominal pain, nausea and vomiting; uncharacteristic symptoms include hoarseness, cough and diarrhea. The signs of the disease are redness and signs of pus in the throat.

The Preferred Test

Dr. Cockerill proposes “Rapid-cycle real time PCR” as the preferred test for bacterial streptococcus pharyngitis. PCR, or polymerase chain reaction, is an enzymatic method for the repeated copying and amplification of the two strands of DNA of a particular gene sequence. It is widely used in the detection of HIV.

He believes the LightCycler® instrument for polymerase chain reaction (PCR)-based assays is the optimum diagnostic equipment to detect streptococcus group A bacterium, and is also suggested for anthrax detection. In comparing the Group A Streptococcus LightCycler® assay against the antigen/culture method, he found:

Processing and analytical time for 32 samples (specimens and controls) were 1.5 hours for PCR and up to 2 days for the antigen/culture method.
Personal time for administering the LightCycler® test was three minutes and seven minutes for the antigen/culture procedure.
Sensitivity was higher in all categories when compared against cultures (except an equal measure for legionella).

Conclusion

Dr. Cockerill finds that, when compared to cultures, time to process LightCycler® assays were significantly shorter than culture based tests.

Editor’s Note: To interview Dr. Cockerill, please contact Donna Krupa at 703.527.7357 (direct dial), 703.967.2751 (cell) or djkrupa1@aol.com.
Or contact the AACC Newsroom at: 407.685.4215.

Media Contact

Donna Krupa EurekAlert!

Alle Nachrichten aus der Kategorie: Health and Medicine

This subject area encompasses research and studies in the field of human medicine.

Among the wide-ranging list of topics covered here are anesthesiology, anatomy, surgery, human genetics, hygiene and environmental medicine, internal medicine, neurology, pharmacology, physiology, urology and dental medicine.

Zurück zur Startseite

Kommentare (0)

Schreib Kommentar

Neueste Beiträge

How Stable is the Antarctic Ice Sheet?

Scientists from Heidelberg University investigate which factors determine the stability of ice masses in East Antarctica. As temperatures rise due to climate change, the melting of polar ice sheets is…

Smart sensors for future fast charging batteries

European project “Spartacus” launched Faster charging, longer stability of performance not only for electric vehicles but also for smartphones and other battery powered products. What still sounds like science fiction…

Small molecules control bacterial resistance to antibiotics

Antibiotics have revolutionized medicine by providing effective treatments for infectious diseases such as cholera. But the pathogens that cause disease are increasingly developing resistance to the antibiotics that are most…

Partners

By continuing to use the site, you agree to the use of cookies. more information

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.

Close