GAITHERSBURG, Md., July 6, 2001 — Scientists at the U.S. Department of Agriculture have developed a new test based on IGEN International Inc.'s proprietary ORIGEN(r) technology and used the test to detect potentially pathogenic E. coli O157 bacteria in creek water.
In a report of their study, the investigators concluded the test appears suitable for routine screening of water samples, tracking the spread of bacteria in contaminated water supplies, and pinpointing sources of waterborne infections.
As reported in the July issue of the peer-reviewed journal Applied and Environmental Microbiology (Vol. 67, No. 7, pp. 2908-2915), the USDA scientists used the test to analyze creek water samples spiked with known concentrations of E. coli O157. They tested raw water samples, samples in which bacteria had been concentrated, and enriched samples, in which bacteria had been allowed to grow before testing. The results suggest the test detects as few as 25,000 E. coli O157 cells per liter (roughly one quart) of raw water, 250 cells per liter in concentrated samples, and one or two viable cells per liter in samples that are both concentrated and enriched.
Other testing methods are suitable for detection of E. coli O157 in fecal, food, or water samples that have been enriched or subjected to chemical treatment to extract the bacteria. But none of these other methods has been shown to detect E. coli O157 in raw or concentrated surface water samples, which contain sediments, organic particles, and unidentified microorganisms that can distort test results. The USDA study describes for the first time development and optimization of an ORIGEN-based test for quantitative detection of E. coli O157 in raw and concentrated surface water samples.
A test that can help identify the source of a waterborne outbreak would enable treatment at the source, thereby decreasing the number of illnesses, and perhaps deaths, caused by the outbreak. The ability to detect a small number of cells is essential because even low levels of the O157:H7 type of E. coli can cause serious gastrointestinal illness that, especially in young children and the elderly, may lead to a potentially fatal kidney disorder.
"This study suggests that new guidelines for testing water could be implemented based on ORIGEN technology, significantly expanding the market for IGEN's products," said Richard J. Massey, Ph.D., IGEN's President and Chief Operating Officer. "The study also provides further confirmation that ORIGEN technology can provide high performance across a wide variety of applications. We plan to aggressively market our PATHIGEN™ test kits in the food safety testing sector as well as additional markets, including human point-of-care testing, veterinary diagnostics, and environmental applications, such as water safety testing."
The USDA investigators also noted in their report that ORIGEN technology is potentially applicable to a wide range of waterborne microorganisms. Pathogens that may be waterborne include bacteria, such as Legionella, the cause of Legionnaires' disease; protozoa, such as Cryptosporidium, which caused diarrheal illness in 403,000 people in Milwaukee in 1993; and viruses, such as Norwalk virus, an emerging pathogen that causes acute gastrointestinal illness and is associated with shellfish harvested from contaminated waters.
E. coli O157:H7 lives in the intestines of some cattle without causing disease in these animals. Human infection usually results from consumption of undercooked ground beef, but it has also been associated with other foods and inadequately treated drinking and swimming pool water. In the United States each year, E. coli O157:H7 infections cause illness in an estimated 73,000 people, 11,000 of whom suffer from waterborne infections.
IGEN already markets PATHIGEN tests for a variety of foodborne bacteria. In May, the company presented the results of a study demonstrating the feasibility of using PATHIGEN tests for human point-of-care testing. And last month, the British government started an evaluation of PATHIGEN tests for veterinary use. Combined with the environmental testing sector, these applications represent at worldwide annual market for microbiology testing products of approximately $2 billion.
IGEN develops and markets biological detection systems based on its proprietary ORIGEN technology, which provides a unique combination of sensitivity, reliability, speed, and flexibility. ORIGEN-based systems are used in a wide variety of applications, including clinical diagnostics, pharmaceutical research and development, life science research, and food safety and veterinary testing. These systems are marketed by IGEN and its licensees and/or distributors — Roche Diagnostics, Organon Teknika, Eisai Co. Ltd., Sumitomo Corp., and Sanko Junyaku Co. Ltd. IGEN and ORIGEN are registered trademarks, and PATHIGEN is a trademark, of IGEN International Inc. More information about the company can be found at http://www.igen.com . An abstract of the USDA study is available at http://aem.asm.org/cgi/content/abstract/67/7/2908 .
