Antibiotics are losing their magic touch - Page 4© Yasser Anathallee
Page 4
Dec 25, 1999
The report also states that peak resistance occurrence is related to foreign travel. In fact, on a larger scale, antibiotic resistance that emerges in one place can often spread far and wide. The ever-increasing volume and frequency of international travel has facilitated the transfer of resistant bacteria from country to country. Investigators have documented the migration of multidrug-resistant Streptococcus pneumoniae from Spain to the U.K., the U.S., South Africa and elsewhere (Levy, 1999).
The facts are frightening. Antibiotic resistance is increasing worldwide-more kinds of bacteria are becoming resistant, even to multiple drugs. For example, pneumococci, the deadliest bacteria in the U.S., kills 40 000 yearly, causes 7 to 10 million middle ear infections, 50 000 cases of pneumonia and thousands of cases of meningitis and bloodstream infections. At one time, it was easy and cheap to treat pneumococci with penicillin, its semi-synthetic derivatives like ampicillin and other antibiotics has made pneumococci multidrug resistant. Tuberculosis as well is becoming an ever-increasing problem, killing 3 million people each year (WHO Report,(Lancet), 1998).
Why has the situation been left to deteriorate so much? With more than 25 000 antibiotic products available in the mid-60's, the medical community became complacent, and the pharmaceutical industry shifted priorities to focus on molecular biology and genetic research (Spake. 1999). The situation is even described as 'an example of the failure to use medical advances for the wider benefit of humankind' (Grange, 1999). The pharmaceutical industry is now scrambling to find new better antibiotics.
New strategies are being used for designing the latest antibiotics. One of these, Zyvox, or linezolid, now being tested, represents a new class of antibiotics that may be available next year. More recently, the Food and Drug Administration (FDA) has approved a new antibiotic: Synercid, the first alternative in 30 years to the antibiotic of last resort, vancomycin. Indeed, the need was so great that the FDA has allowed hundreds of patients at risk of death from drug-resistant germs to be treated with Synercid under a special emergency program while the agency decided whether the drug was safe and effective enough for broad sale (infobeat/cnn). Genetic mapping of microbes, and of humans, may make it easier to devise new drugs tailored to bacterial survival mechanisms. Researchers have proposed that carbohydrate modified vancomycin compounds are effective against resistant bacteria because they interact directly with bacterial proteins involved in the transglycosylation step of cell wall biosynthesis. These compounds are effective against resistant bacteria as they operate by a different mechanism than vancomycin , moreover, peptide binding is not required for activity (Ge et al., 1999). Others suggest the use of an enzyme for specificity. Staphylococcus aureus Sortase, an enzyme that anchors to surface proteins of the cell wall may be a useful target for the development of new antimicrobial drugs, especially for use against gram positive bacteria (Mazmanian et al., 1999).
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