A sometimes-lethal type of bacteria that causes many cases of pneumonia, bloodstream infections and other illnesses is rapidly becoming resistant to antibiotics, a government study found.
Experts have warned for a decade that overuse of antibiotics is helping germs become resistant to drugs, first to penicillin, then to newer antibiotics, raising the specter of more deaths and amputations.
"It's become even more worrisome in the last two years," said Dr. Cynthia G. Whitney of the Centers for Disease Control and Prevention. "There are definitely some strains that are fast learners."
The CDC study looked at Streptococcus pneumonia, the nation's most common bacterial cause of meningitis, children's ear infections and pneumonia. Also called pneumococcus, it is a frequent cause of bacteremia, a bloodstream infection that kills many elderly people.
Between 1995 and 1998, Whitney and colleagues collected 12,045 blood or other fluid samples from U.S. patients infected with Streptococcus pneumonia. Each sample was tested against antibiotics from nine of the 10 or so classes that fight bacteria, with increasingly strong doses of the antibiotic applied until the bacteria were killed.
Over the three-year span, the percentage of pneumococcus samples resistant to three or more antibiotic classes grew from 9 percent to 14 percent. The percentage resistant to penicillin went from 21 percent to 25 percent.
Resistance was particularly high in children under 5 and in whites, two groups generally receiving more antibiotics than others, as well as in parts of the South.
However, the researchers noted that new vaccines, including one approved recently for use in babies, can protect against most drug-resistant strains of the bacteria. Also, a few new antibiotics have been coming onto the market in recent years, and 19 more are in development and could go on sale over the next eight years.
In fact, the researchers found that as newer antibiotics came into greater use, the prevalence of pneumococcus resistant to the older antibiotics decreased.
"It gives us hope maybe we can reverse this trend," Whitney said.
The research was reported in Thursday's New England Journal of Medicine.
In an editorial, Drs. Richard P. Wenzel and Michael B. Edmond of Virginia Commonwealth University said that the rise of drug resistance "should cause great concern and incite a commitment to act responsibly."
"The antibiotic era is barely 60 years old, yet the inappropriate use of these drugs threatens our ability to cope with infections," they said.
On the Net:
New England Journal of Medicine: http://www.nejm.com
Centers for Disease Control and Prevention site: http://www.cdc.gov/drugresistance