Some doctors prescribe antibiotics against nonbacterial organisms, notably viruses that cause the common cold, for which the drugs are not effective. In the Third World, antibiotics are a cure-all, and are mostly available without prescription. Repeated exposure of bacteria to drugs can result in the development of resistant strains. These resistant bacteria can then spread throughout the population. Thus, treatment for some diseases is now more difficult and expensive.
For example, one type of penicillin, 100% effective in the 1940s against the common [Staphylococcus aureus] bacterium (MRSA), is now only 10% effective. When an antibiotic is no longer effective, others must be developed to deal with the new resistant forms of the disease. This increases costs and the new drugs may have side effects. The new drug needed to successfully treat [Staphylococcus aureus] bacterium is 10 times as expensive as the original penicillin. Reduced effectiveness of these drugs costs lives, especially in developing countries.
In 1993, about 8% of the enterococci encountered in American hospitals were resistant to vancomycin, 20 times the rate of 4 years previously. This makes enterococcus very dangerous, as it is usually resistant to virtually all antibiotics if it resists vancomycin. Consequently, 19,000 patients a year have untreatable infections.
Up to 75% of antibiotic prescriptions each year in the USA are for acute respiratory infections, mostly caused by viruses. Streptococcus bacteria cause about 10% of sore throat cases in adults; sinusitis is sometimes caused by bacteria. Antibiotic treatment of colds, bronchitis and other upper-respiratory infections is almost always inappropriate.
2. Up to 50% of the antibiotics prescribed could be eliminated through more appropriate prescribing practices. Curbing antibiotic prescriptions for respiratory infections such as sinusitis, bronchitis and other, non-specific infections can reduce the prevalence of antibiotic-resistant bacteria.