One leader of the new research group, University of Illinois at Urbana-Champaign microbiologist Abigail Salyers, said resistance can lurk undetected in harmless organisms. It's widespread . In Atlanta, a 1994 study of infections caused by Streptococcus pneumonia found that 25 percent of 431 patients had a bug that resisted penicillin, and that 25 percent of all cases were resistant to several antibiotics. Resistant tuberculosis has spread from New York City to Denver, Florida, Nevada and Paris. You can skip ahead to our coverage of the mechanisms of resistance .
Hospitals serve as centers for the formation and transmission of drug-resistant organisms.
About 2 million Americans are infected in hospitals each year and more than half of these infections resist at least one antibiotic, according to Dennis Maki, a University of Wisconsin-Madison expert in hospital infections. Resistance is an especially vexing problem for people with impaired immune systems , such as AIDS, and cancer patients, and recipients of organ transplants. About 90 percent of AIDS patients who get multiple-drug resistant TB die. Even the last-ditch antibiotics are being overwhelmed. Of particular concern is Vancomycin resistance, which is becoming fairly common in certain strains of enterococcus, a common gut bacteria.