April 30, 2003 (New York) -- New viruses like the one that causes SARS (severe acute respiratory syndrome) may grab headlines as they emerge, but it's the growing number of good old-fashioned bacteria that are now resistant to even the most powerful antibiotics that pose the larger threat to the general public, according to infectious disease experts.
Common illnesses, such as pneumonia, meningitis, and sexually transmitted diseases, that are caused by bacteria were once easily treatable with antibiotics but have now become increasingly deadly due to antibiotic resistance.
"We're even running out of drugs to treat our most common infections. Not just less common hospital-based infections," says Neil Fishman, MD, director of the department of healthcare epidemiology and infection control at the University of Pennsylvania Medical Center.
Fishman says antibiotic-resistant "super bugs" cause an estimated 19,000 deaths in the U.S. each year, compared with only 372 deaths worldwide that have been attributed to SARS since the outbreak began six months ago.
Fishman spoke today at a roundtable about antibiotic resistance in New York organized by the Infectious Diseases of Society of America, the Society for Healthcare Epidemiology of America, and the Society of Infectious Disease Pharmacists.
Experts at the meeting say too little action is being taken to curb the mushrooming problem of antibiotic resistance, which makes currently available antibiotics powerless against previously treatable infections. Antibiotic-resistant super bugs are created when bacteria develop genetic traits that make them withstand treatment with antibiotic drugs.
Although antibiotic resistance has been around since the discovery of antibiotics more than 60 years ago, the problem has grown exponentially in recent years due to a combination of factors that Fishman calls a "perfect storm."
For example, E. coli is the most common cause of urinary tract infections (UTIs) and antibiotics known as fluoroquinolones (including Cipro and others) are the primary drugs used to treat UTIs. But Fishman says the number of fluoroquinolone-resistant UTIs seen by his hospital alone grew from 6% in 2000 to 16% in 2002.
Factors contributing to this rapid growth of antibiotic resistance include the overuse of powerful, broad-spectrum antibiotics to treat common infections, such as ear infections, and the misuse of antibiotics in situations where they are not appropriate, such as treating viral infections like the common cold.
The more a bacteria is exposed to antibiotics, the more likely it is to begin to develop a resistance to it, says Martin Blaser, MD, chairman of the department of medicine and professor of microbiology at New York University. He says this issue is especially concerning in light of the use of antibiotics in children.
"Anyone who has children knows that your children have received antibiotics more often than you did and certainly much more than your parents did," says Blaser. He says that by the age of 15 the average child in the U.S. has already received an average of four courses of antibiotics just to treat ear infections.
Blaser says an antibiotic prescribed for an ear infection doesn't just affect the ear, but it affects all the bacteria in the body, which gives them an opportunity to grow resistant to future doses of antibiotics.
In addition, the food industry has been feeding animals low doses of antibiotics to help them gain weight, not to treat infection, since the 1950s.
"About half of all antibiotic use in the United States is in the food industry for growth promotion," says Blaser. "Countries in Europe have banned this phenomenon, but we have not."
Blaser says animals that are fed antibiotics eventually become resistant to the drugs and can potentially pass this antibiotic resistance on to people who eat their meat.
He says research shows that resistance to common antibiotics, such as fluoroquinolones, has emerged in regions at the same time that livestock animals are given the antibiotics for growth promotion. And recent studies from Europe suggest that when use of antibiotics for growth promotion is eliminated, antibiotic resistance in humans is reduced.
Experts at the briefing say the threat of super bugs is further compounded by the fact that the development of new antibiotics is not keeping pace with the rate at which the antibiotic-resistant bacteria is emerging. Of the 89 new drugs approved in 2002 by the FDA, none were antibiotics and only five of the more than 400 new drugs currently in the pipeline are antibiotics.
Michael Ryback, PharmD, professor of pharmacology and medicine at Wayne State University in Michigan, says the problem has gotten to the point that some have even suggested developing new classes of antibiotics and putting them on the shelf so there might be something to turn to in the future.
In the meantime, Ryback says the best defense against any infectious disease --whether it's caused by a virus like SARS or bacteria - is to avoid getting sick in the first place by practicing good hygiene and a healthy lifestyle.
"Staying healthy and keeping your immune system viable is your greatest defense against all illnesses," Ryback tells WebMD. "Antibiotics and vaccines are only adjuncts."