Researchers crack genetic code for strep throat bacteria

Tuesday, April 10th 2001, 12:00 am
By: News On 6

OKLAHOMA CITY (AP) _ University of Oklahoma scientists have cracked the genetic code for the bacteria that causes strep throat, rheumatic fever and a flesh-eating disease, leading to hopes that better treatments can be found for these illnesses.

``We've got the complete dictionary on this bug,'' Oklahoma microbiologist Joseph Ferretti said. ``That's really exciting. Now that we know some of its secrets, we can find a way to combat it.''

Ferretti said penicillin is a strong treatment for illnesses caused by Streptococcus pyogenes, but he hopes researchers may be able to develop new antibiotics and vaccinations to better fight Streptococcus now that its complete DNA sequence has been determined. There are no proven vaccines to prevent Streptococcus infections, Ferretti said.

Ferretti headed a five-year project, funded by the National Institute of Allergy and Infectious Disease, at the university's Health Sciences Center.

The genetic sequence will be published Tuesday in the Proceedings of the National Academy of Sciences and is online for scientists around the world. The information is public and free to other medical researchers because it was developed at a public university.

While Ferretti declined to put a timeline on when the research might lead to better drugs, he said the research ``will greatly accelerate all previous efforts to fight'' Streptococcus.

Illnesses like strep throat and rheumatic fever can be contracted through the air and contact with other people.

Ferretti said researchers obtained a strain of the microorganism through a wound on a patient who had a serious infection. They grew the strain, isolated its DNA, then used computers to sequence the genetic code.

Scientists throughout the world had input on the project. Ferretti has researched Streptococcus for 30 years.

The bacteria causes thousands of human illnesses each year, including strep throat, impetigo, pneumonia, toxic shock syndrome, blood poisoning, scarlet fever, rheumatic fever, rheumatic heart disease and a flesh-eating disease called necrotizing fasciitis.

Millions of cases of strep throat and impetigo occur each year in the United States, Ferretti said. Toxic shock syndrome and the flesh-eating disease can occur when bacteria invades blood and muscle tissue, he said. Of the 10,000 cases of flesh-eating disease in the United States last year, 13 percent resulted in death, Ferretti said.

Rheumatic fever is the major cause of acquired heart disease in children living in developing nations.

During the five-year study, researchers discovered six toxins caused by Streptococcus that were previously unknown. They also learned of 20 new factors related to the microorganism that can make people sick, including how toxins travel through the body.

``This organism has known us for the past couple of million years,'' Ferretti said. ``Now that we know the genetic blueprint, we can devise new ways to treat it.''

Dr. Michael Gilmore, vice president for research at the OU Health Sciences Center, was not involved in the study but called it a ``bonanza'' for researchers working to discover a cure for disease caused by the microorganism.

``It tells us all the different tools the Streptococcus has to cause disease,'' he said.

Gilmore said about 100 such genome projects are under way at universities and companies, targeting organisms that could either cause disease or could be useful in industry.

The OU Health Sciences Center ranks second in the world for the number of microbial genomes that have been or are being sequenced. In the last two years, scientists there have helped map an entire human chromosome and the genome of a plant.

The human genome project was part of a nationwide study attempting to detail the tens of thousands of genes that carry instructions for everything in a human _ from brain function to hair color to foot size.

Deciphering the genetic makeup of a plant is expected to help the world grow better food and identify future medicines.