Antibiotics, like penicillin, are drugs designed to kill bacteria. But sometimes a few bacteria resist the drug and survive. The survivors divide and are resistant to the antibiotic. Another antibiotic may work, but when bacteria survive many drugs they become harder and harder to kill.
When will antibiotics become ineffective against infections?
Penicillin and sulfa drugs were once hailed as humanitys victory over infection. Nature is catching up to these antibiotics. Bacteria such as E. Coli and Staphylococcus aureus, or staph, have already developed resistance to many drugs.
Marissa Miller, an official with the National Institute of Allergy and Infectious Disease (NIAID), warns: "We are on the precipice of the pre-antibiotic age," when death from pneumonia and staph infections were the norm.
Now, bacteria are often resistant to one or two antibiotics. Even more frightening, The University of Pennsylvania Medical Center reports that at least one person has died of an infection caused by a newstrainof bacteria resistant to all antibiotics including vancomycin, the "antibiotic of last resort."
Vancomycin, drug of last resort
Since its introduction by Lilly in the 1960s, vancomycin has been touted as one of the most potent antibiotics ever discovered. It works by blocking the synthesis of bacterial cell walls. If the bacteria lacks this protective wall, it will burst, and die.
Vancomycin is used in hospitals to treat the most critically ill, such as "people in intensive care units or undergoing chemotherapy," as Marissa Miller explains. These patients immune response to bacterial attack are already weakened by their illness or injury, which provides a fertile ground for microorganisms like Enterococci and staph. According to The Davis Drug Guide vancomycin can cause serious side effects like kidney failure and hearing loss.
New weapons to combat bacterial disease may soon be on the scene. Paul Axelsen, MD, a researcher at University of Pennsylvania, reports that he and his team are working to develop a new form of vancomycin, to which bacteria will not be resistant.
Axelsens lab performs "purely computational studies, to try and make vancomycin more effective against resistant bacteria. In the other half [of the lab], we do experiments to find out more accurately exactly how vancomycin works."
He and his team, armed with a grant from the National Institutes of Health, worked out the chemical structure and specific mode of action of vancomycin. Other researchers at Princeton and Merck are doing similar research.
While promising, some experts are concerned that varying vancomycin is only a quick fix to a bigger problem. "Developing better and better vancomycin is not going to keep us from infection in the future," says Miller. "What it essentially does is buy us time. . .for the long term its not a solution."
The front line of the war against bacterial drug resistance
Until the early 1990s infectious diseases were considered curable with existing antibiotics; why spend millions of dollars to develop more? Now, with resistant bacteria emerging all over the world, researchers are developing new antibiotics.
The Center for Disease Control developed guidelines to regulate the use of antibiotics. Vancomycin is particularly restricted to keep it effective as long as possible.
Marissa Miller thinks that the best long-term solution may be vaccines against infectious disease: "We at the NIH are working very hard on developing new vaccines that prevent the infections from occurring in the first place, and alleviating the need for drug treatment."
How Can You Combat Bacterial Resistance?
The CDC recommends the following measures that the public can take to ward off bacterial resistance:
- Dont insist on antibiotics. Many infections are caused by viruses, against which antibiotics are useless.
- When antibiotics are prescribed, finish all the medication. Bacteria that survive the first few days of an antibiotic can pass on their genes to their daughters, resulting in resistant strains.
- Practice good hygiene. This includes hand washing, keeping your immune system healthy by maintaining a healthy lifestyle, and avoidance of exposure to infections.
Elsewhere on the Web
"Deconstructing Vancomycin." Christopher Walsh, Science Magazine, 16 April 1999.
"Vancomycin Resistant Staph Aureus." Northwest Center News Archive.
"Perspectives - Use of Antimicrobial Growth Promoters in Food Animals and Enterococcus faecium Resistance to Therapeutic Antimicrobial Drugs in Europe." Emerging Infectious Diseases, May-June 1999.
"Vancomycin Derivatives That Inhibit Peptidoglycan Biosynthesis Without Binding D-Ala-D-Ala." Science Magazine, 16 April 1999.
The National Institute of Allerg and Infectious Diseases