But in the last few decades, mutant strains of several types of bacteria with the ability to resist antibiotics have emerged, including those that cause TB, pneumonia, cholera, typhoid, salmonella, and staphylococcal dysentery. These diseases are coming back resistant to the antibiotics that have been used to treat them, and people infected with these resistant strains have to be treated with alternative antibiotics. For years scientists have been combating drug resistance by coming up with new types of antibiotics, and for years bacteria have been evolving ways around these antibiotics.
Antibiotic resistance is a major health problem in the United States. According to the U.S. Food and Drug Administration (FDA), about 70 percent of bacteria that cause infections in hospitals are resistant to at least one antibiotic, and some are so resistant that no antibiotics are effective, and they must be treated with experimental and potentially toxic drugs.
Now some super bugs -- multiple drug-resistant bacteria -- are emerging as an even greater threat. Multiple drug-resistant TB is no longer susceptible to broad categories of antibiotics, such as rifampicin, isoniazid, and streptomycin. Some strains of the common hospital infection-causing bacteria Staphylococcus aureus are resistant to all antibiotics except vancomycin, which is a drug of last resort, and some strains of Streptococcus pneumoniae are even resistant to vancomycin. Certain strains of Shigella dysenteriae, the cause of epidemic dysentery, have even become resistant to all but a single drug -- the quinolone ciprofloxacin -- and may soon become completely untreatable. This is a major concern for public health because, according to the Worl
Source:Scripps Research Institute